Adaptive Radiotherapy Guided by PET/CT in Patients with Locally Advanced Non-Small Cell Lung Cancer: A Phase II Randomized Study

PURPOSE/OBJECTIVE(S)

The aim of this study was to determine whether adaptive radiotherapy guided by functional imaging with flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can improve local tumor control in patients with locally advanced non-small cell lung cancer (LA-NSCLC).

MATERIALS/METHODS

This was a phase II randomized study comparing the efficacy and safety between PET-guided adaptive radiotherapy and conventional radiotherapy. The primary end point was 2-year local-regional tumor control (LRTC) rate. Secondary end points included local-regional progression-free survival (LR-PFS), progression-free survival (PFS), overall survival (OS), and radiation-related toxicities.

RESULTS

Between November 2012 and June 2017, 72 patients were 1:1 randomized to adaptive and conventional arms. The 2- and 5-year LRTC rates were 63.2% and 58.0% versus 43.0% and 37.6% (P = 0.035) in the adaptive and conventional arms, respectively. The median LR-PFS (14.3 versus 12.0 months; P = 0.010) and PFS (12.8 versus 8.9 months; P = 0.034) were significantly longer in the adaptive arm than in the conventional arm. The median OS was 36.3 months in the adaptive arm and 28.8 months in the conventional arm (P = 0.266). The esophageal volume of receiving ≥60 Gy (V60) in the adaptive arm was lower than that in the conventional arm (P = 0.011), while the V30 for the heart in the adaptive arm was lower than that in the conventional arm (P = 0.077). Other radiological metrological parameters of tumor, organs at risk, and the incidence of ≥grade 2 radiation-related toxicities were not significantly different between the 2 arms.

CONCLUSION

Compared with conventional radiotherapy, PET-guided adaptive radiotherapy significantly improved the 2-year LRTC rate, LR-PFS, and PFS without increased risks of radiation-related toxicities in patients with LA-NSCLC.

Clinicians for CARE: A Systematic Review and Meta-Analysis of Interventions to Support Caregivers of Patients With Heart Disease

Background

Caregivers provide critical support for patients with chronic diseases, including heart disease, but often experience caregiver stress that negatively impacts their health, quality of life, and patient outcomes. We aimed to inform health care teams on an evidence‐based approach to supporting the caregivers of patients with heart disease.

Methods and Results

We conducted a systematic review and meta‐analysis of randomized controlled trials written in English that evaluated interventions to support caregivers of patients with heart disease. We identified 15,561 articles as of April 2, 2020 from 6 databases; of which 20 unique randomized controlled trials were evaluated, representing a total of 1570 patients and 1776 caregivers. Most interventions focused on improving quality of life, and reducing burden, depression, and anxiety; 85% (17 of 20) of the randomized controlled trials provided psychoeducation for caregivers. Interventions had mixed results, with moderate non‐significant effects observed for depression (Hedges’ g=−0.64; 95% CI, −1.34 to 0.06) and burden (Hedges’ g=−0.51; 95% CI, −2.71 to 1.70) at 2 to 4 months postintervention and small non‐significant effects observed for quality of life and anxiety. These results were limited by the heterogeneity of outcome measures and intervention delivery methods. A qualitative synthesis of major themes of the interventions resulted in clinical recommendations represented with the acronym “CARE” (Caregiver‐Centered, Active engagement, Reinforcement, Education).

Conclusions

This systematic review highlights the need for greater understanding of the challenges faced by caregivers and the development of guidelines to help clinicians address those challenges. More research is necessary to develop clinical interventions that consistently improve caregiver outcomes.

Cost-effectiveness of a Digital Health Intervention for Acute Myocardial Infarction Recovery

BACKGROUND

Acute myocardial infarction (AMI) is a common cause of hospital admissions, readmissions, and mortality worldwide. Digital health interventions (DHIs) that promote self-management, adherence to guideline-directed therapy, and cardiovascular risk reduction may improve health outcomes in this population. The "Corrie" DHI consists of a smartphone application, smartwatch, and wireless blood pressure monitor to support medication tracking, education, vital signs monitoring, and care coordination. We aimed to assess the cost-effectiveness of this DHI plus standard of care in reducing 30-day readmissions among AMI patients in comparison to standard of care alone.

METHODS

A Markov model was used to explore cost-effectiveness from the hospital perspective. The time horizon of the analysis was 1 year, with 30-day cycles, using inflation-adjusted cost data with no discount rate. Currencies were quantified in US dollars, and effectiveness was measured in quality-adjusted life-years (QALYs). The results were interpreted as an incremental cost-effectiveness ratio at a threshold of $100,000 per QALY. Univariate sensitivity and multivariate probabilistic sensitivity analyses tested model uncertainty.

RESULTS

The DHI reduced costs and increased QALYs on average, dominating standard of care in 99.7% of simulations in the probabilistic analysis. Based on the assumption that the DHI costs $2750 per patient, use of the DHI leads to a cost-savings of $7274 per patient compared with standard of care alone.

CONCLUSIONS

Our results demonstrate that this DHI is cost-saving through the reduction of risk for all-cause readmission following AMI. DHIs that promote improved adherence with guideline-based health care can reduce hospital readmissions and associated costs.

Heart rate trajectories in patients recovering from acute myocardial infarction: A longitudinal analysis of Apple Watch heart rate recordings

Background

Using mobile health, vital signs such as heart rate (HR) can be used to assess a patient’s recovery process from acute events including acute myocardial infarction (AMI).

Objective

We aimed to characterize clinical correlates associated with HR change in the subacute period among patients recovering from AMI.

Methods

HR measurements were collected from 91 patients (4447 HR recordings) enrolled in the MiCORE study using the Apple Watch and Corrie smartphone application. Mixed regression models were used to estimate the associations of patient-level characteristics during hospital admission with HR changes over 30 days postdischarge.

Results

The mean daily HR at admission was 78.0 beats per minute (bpm) (95% confidence interval 76.1 to 79.8), declining 0.2 bpm/day (-0.3 to -0.1) under a linear model of HR change. History of coronary artery bypass graft, history of depression, or being discharged on anticoagulants was associated with a higher admission HR. Having a history of hypertension, type 2 diabetes mellitus (T2DM), or hyperlipidemia was associated with a slower decrease in HR over time, but not with HR during admission.

Conclusion

While a declining HR was observed in AMI patients over 30 days postdischarge, patients with hypertension, T2DM, or hyperlipidemia showed a slower decrease in HR relative to their counterparts. This study demonstrates the feasibility of using wearables to model the recovery process of patients with AMI and represents a first step in helping pinpoint patients vulnerable to decompensation.

Digital Health Intervention in Acute Myocardial Infarction

BACKGROUND

Thirty-day readmissions among patients with acute myocardial infarction (AMI) contribute to the US health care burden of preventable complications and costs. Digital health interventions (DHIs) may improve patient health care self-management and outcomes. We aimed to determine if patients with AMI using a DHI have lower 30-day unplanned all-cause readmissions than a historical control.

METHODS

This nonrandomized controlled trial with a historical control, conducted at 4 US hospitals from 2015 to 2019, included 1064 patients with AMI (DHI n=200, control n=864). The DHI integrated a smartphone application, smartwatch, and blood pressure monitor to support guideline-directed care during hospitalization and through 30-days post-discharge via (1) medication reminders, (2) vital sign and activity tracking, (3) education, and (4) outpatient care coordination. The Patient Activation Measure assessed patient knowledge, skills, and confidence for health care self-management. All-cause 30-day readmissions were measured through administrative databases. Propensity score-adjusted Cox proportional hazard models estimated hazard ratios of readmission for the DHI group relative to the control group.

RESULTS

Following propensity score adjustment, baseline characteristics were well-balanced between the DHI versus control patients (standardized differences <0.07), including a mean age of 59.3 versus 60.1 years, 30% versus 29% Women, 70% versus 70% White, 54% versus 54% with private insurance, 61% versus 60% patients with a non ST-elevation myocardial infarction, and 15% versus 15% with high comorbidity burden. DHI patients were predominantly in the highest levels of patient activation for health care self-management (mean score 71.7±16.6 at 30 days). The DHI group had fewer all-cause 30-day readmissions than the control group (6.5% versus 16.8%, respectively). Adjusting for hospital site and a propensity score inclusive of age, sex, race, AMI type, comorbidities, and 6 additional confounding factors, the DHI group had a 52% lower risk for all-cause 30-day readmissions (hazard ratio, 0.48 [95% CI, 0.26-0.88]). Similar results were obtained in a sensitivity analysis employing propensity matching.

CONCLUSIONS

Our results suggest that in patients with AMI, the DHI may be associated with high patient activation for health care self-management and lower risk of all-cause unplanned 30-day readmissions. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03760796.

The role of a clinician amid the rise of mobile health technology

Mobile health (mHealth) interventions have demonstrated promise in improving outcomes by motivating patients to adopt and maintain healthy lifestyle changes as well as improve adherence to guideline-directed medical therapy. Early results combining behavioral economic strategies with mHealth delivery have demonstrated mixed results. In reviewing these studies, we propose that the success of a mHealth intervention links more strongly with how well it connects patients back to routine clinical care, rather than its behavior modification technique in isolation. This underscores the critical role of clinician-patient partnerships in the design and delivery of such interventions, while also raising important questions regarding long-term sustainability and scalability. Further exploration of our hypothesis may increase opportunities for multidisciplinary clinical teams to connect with and engage patients using mHealth technologies in unprecedented ways.

Early blood pressure assessment after acute myocardial infarction: Insights using digital health technology

Objective

There is rising interest in digital health in preventive cardiology, particularly for blood pressure (BP) management. In a digital health study of early BP assessment following acute myocardial infarction (AMI), we sought to examine feasibility and the (1) proportion of post-AMI patients with controlled BP and hypotension, and (2) association between prior cardiovascular disease (CVD) and BP post-AMI.

Methods

In this substudy of the parent Myocardial infarction, COmbined-device, Recovery Enhancement (MiCORE) study, type 1 AMI patients were enrolled between October 2017 and April 2019. Participants self-monitored their BP through 30 days after hospital discharge using an FDA-approved wireless BP monitor connected with a smartphone application. Linear mixed-effects models assessed the association between prior CVD and BP trajectory post-discharge, adjusting for antihypertensive medications and a propensity score inclusive of CVD risk factors.

Results

Sixty-eight AMI patients (mean age 58 ​± ​10 years, 75% male, 68% white race, 68% history of hypertension, 24% prior CVD) provided 2638 measurements over 30 days. The percentage of BP control <130/80 ​mmHg was 59.6% (95% CI: 54.3–64.9%) and <140/90 ​mmHg was 83.7% (95% CI: 80.3–87.2%). The percentage of systolic BP ​<90 ​mmHg was 1.1% (95% CI: 0.17–2.0%) and the percentage of diastolic BP ​<60 ​mmHg was 3.9% (95% CI: 2.6–5.2%). Prior CVD was associated with 12.2 ​mmHg higher mean daily systolic BP during admission (95% CI: 3.5–20.9 ​mmHg), which persisted over follow-up. There was no association between prior CVD and diastolic BP.

Conclusion

The digital health program was feasible and ~40% of post-AMI patients who engaged in it had uncontrolled BP according to recent guideline cutpoints, while hypotension occurred rarely. The gap in BP control was especially large in patients in whom AMI represented recurrent CVD. These data suggest an opportunity for more aggressive secondary prevention early after MI as care models integrate digital health.

•

Digital health reveals home blood pressure trends during early recovery after an event.

•

~40% of early MI patients had mean daily blood pressure exceeding the guideline goal of <130/80 ​mmHg.

•

Hypotension occurred rarely over 30 days post-MI.

•

The gap in BP control was especially large in patients in whom MI represented recurrent CVD.

•

There is opportunity for more aggressive secondary prevention early after MI as care models integrate digital health.

Corrie Health Digital Platform for Self-Management in Secondary Prevention After Acute Myocardial Infarction

BACKGROUND

Unplanned readmissions after hospitalization for acute myocardial infarction are among the leading causes of preventable morbidity, mortality, and healthcare costs. Digital health interventions could be an effective tool in promoting self-management, adherence to guideline-directed therapy, and cardiovascular risk reduction. A digital health intervention developed at Johns Hopkins-the Corrie Health Digital Platform (Corrie)-includes the first cardiology Apple CareKit smartphone application, which is paired with an Apple Watch and iHealth Bluetooth-enabled blood pressure cuff. Corrie targets: (1) self-management of cardiac medications, (2) self-tracking of vital signs, (3) education about cardiovascular disease through articles and animated videos, and (4) care coordination that includes outpatient follow-up appointments.

METHODS AND RESULTS

The 3 phases of the MiCORE study (Myocardial infarction, Combined-device, Recovery Enhancement) include (1) the development of Corrie, (2) a pilot study to assess the usability and feasibility of Corrie, and (3) a prospective research study to primarily compare time to first readmission within 30 days postdischarge among patients with Corrie to patients in the historical standard of care comparison group. In Phase 2, the feasibility of deploying Corrie in an acute care setting was established among a sample of 60 patients with acute myocardial infarction. Phase 3 is ongoing and patients from 4 hospitals are being enrolled as early as possible during their hospital stay if they are 18 years or older, admitted with acute myocardial infarction (ST-segment-elevation myocardial infarction or type I non-ST-segment-elevation myocardial infarction), and own a smartphone. Patients are either being enrolled with their own personal devices or they are provided an iPhone and/or Apple Watch for the duration of the study. Phase 3 started in October 2017 and we aim to recruit 140 participants.

CONCLUSIONS

This article will provide an in-depth understanding of the feasibility associated with implementing a digital health intervention in an acute care setting and the potential of Corrie as a self-management tool for acute myocardial infarction recovery.

Abrupt involution induces inflammation, estrogenic signaling, and hyperplasia linking lack of breastfeeding with increased risk of breast cancer

Background

A large collaborative analysis of data from 47 epidemiological studies concluded that longer duration of breastfeeding reduces the risk of developing breast cancer. Despite the strong epidemiological evidence, the molecular mechanisms linking prolonged breastfeeding to decreased risk of breast cancer remain poorly understood.

Methods

We modeled two types of breastfeeding behaviors in wild type FVB/N mice: (1) normal or gradual involution of breast tissue following prolonged breastfeeding and (2) forced or abrupt involution following short-term breastfeeding. To accomplish this, pups were gradually weaned between 28 and 31 days (gradual involution) or abruptly at 7 days postpartum (abrupt involution). Mammary glands were examined for histological changes, proliferation, and inflammatory markers by immunohistochemistry. Fluorescence-activated cell sorting was used to quantify mammary epithelial subpopulations. Gene set enrichment analysis was used to analyze gene expression data from mouse mammary luminal progenitor cells. Similar analysis was done using gene expression data generated from human breast samples obtained from parous women enrolled on a tissue collection study, OSU-2011C0094, and were undergoing reduction mammoplasty without history of breast cancer.

Results

Mammary glands from mice that underwent abrupt involution exhibited denser stroma, altered collagen composition, higher inflammation and proliferation, increased estrogen receptor α and progesterone receptor expression compared to those that underwent gradual involution. Importantly, when aged to 4 months postpartum, mice that were in the abrupt involution cohort developed ductal hyperplasia and squamous metaplasia. Abrupt involution also resulted in a significant expansion of the luminal progenitor cell compartment associated with enrichment of Notch and estrogen signaling pathway genes. Breast tissues obtained from healthy women who breastfed for < 6 months vs ≥ 6 months showed significant enrichment of Notch signaling pathway genes, along with a trend for enrichment for luminal progenitor gene signature similar to what is observed in BRCA1 mutation carriers and basal-like breast tumors.

Conclusions

We report here for the first time that forced or abrupt involution of the mammary glands following pregnancy and lack of breastfeeding results in expansion of luminal progenitor cells, higher inflammation, proliferation, and ductal hyperplasia, a known risk factor for developing breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1163-7) contains supplementary material, which is available to authorized users.

Technical Guidance for Clinicians Interested in Partnering With Engineers in Mobile Health Development and Evaluation

The explosion of mobile health (mHealth) interventions has prompted significant investment and exploration that has extended past industry into academia. Although research in this space is emerging, it focuses on the clinical and population level impact across different populations. To realize the full potential of mHealth, an intimate understanding of how mHealth is being used by patients and potential differences in usage between various demographic groups must also be prioritized. In this viewpoint, we use our experiences in building an mHealth intervention that incorporates an iOS app, Bluetooth-enabled blood pressure cuff, and Apple Watch to share knowledge on (1) how user interaction data can be tracked in the context of health care privacy laws, (2) what is required for effective, nuanced communication between clinicians and engineers to design mHealth interventions that are patient-centered and have high clinical impact, and (3) how to handle and set up a process to handle user interaction data efficiently.

Abstract P1-09-06: Gene-set enrichment analysis (GSEA) of breast tissue from healthy women with less than six months history of breastfeeding shows enrichment in Hedgehog signaling, notch signaling and luminal progenitor gene signatures

Introduction: Multiple epidemiological studies have shown that prolonged breastfeeding is associated with a reduced risk of developing triple negative/basal-like breast cancer (TN/BLBC). We have modeled abrupt involution (AI) due to lack of breastfeeding and gradual involution (GI) of the mammary gland that occurs over time upon prolonged breastfeeding in wild-type FVB/N mice and discovered prominent histological and molecular changes in the AI glands over time. Our studies revealed for the first time a clear and persistent expansion of mammary luminal progenitor (LP) epithelial cells in AI glands (AACR abstract#2242, 2018). Here, we corroborate animal studies using normal human breast tissue obtained from a reduction mammoplasty tissue collection study (OSU-2011C0094).

Methods: Breast tissue obtained from parous premenopausal women with no history of breast cancer who breastfed for ≥6 months (GI, n=16) versus those who breastfed for &lt;6 months (AI, n=16) (OSU-2011C0094) was used for gene expression analysis. RNA isolated from these normal mammary tissues was analyzed using Affymatrix Gene ChIP Human Transcriptome array 2.0; Gene Set Enrichment Analysis (GSEA) was used to analyze the microarray data. Molecular Signatures Database was used in GSEA querying C2 curated gene sets, Hallmark gene sets, and Lim-Mammary-Luminal-Progenitor gene sets. H&E sections of the breast tissue were used to assess lobular type by counting number of ductules per terminal ductal lobular unit (TDLU). False discovery rate (FDR) q-values and p-values were used for multiple comparison adjustment.

Results: GSEA revealed that breast tissue obtained from women in the AI cohort exhibited strong positive enrichment for Notch and Hedgehog Signaling (Hhg) pathways (FDR q-value= 0.20 and 0.12, respectively). In GI women, GSEA showed an overall trend towards enrichment in metabolic pathways and immune system functions. Moreover, there was non-significant trend towards positive enrichment of mouse LP gene signature in AI women only (FDR q-value= 0.30). Age and BMI were not statistically different between AI and GI cohorts. Analysis of TDLU, the primary anatomical source of most breast cancers, revealed that breast tissue from AI women had proportionally higher lobular type 1 only epithelium than GI women who exhibited more differentiated lobular epithelium (p-value= 0.049).

Conclusion: We report here for the first time that mammary glands from women who breastfed &lt;6 months were enriched for stem-cell signaling pathways and LP gene signature. This reflects some similarity to BRCA1 mutation carriers, who demonstrate expanded luminal progenitor population. In addition, higher Type 1 TDLU's are seen in breast tissue from parous women who breastfed &lt;6 months. Together, these data demonstrate features for TN/BLBC precursors enriched in patients who breastfed for &lt;6 months. Understanding this mechanistic link will help in developing prevention strategies, particularly for African-American women who have lower prevalence of breastfeeding and higher incidence of TN/BLBC.

Citation Format: Basree MM, Shinde N, Palettas M, Weng D, Stover DG, Sizemore GM, Shields P, Majumder S, Ramaswamy B. Gene-set enrichment analysis (GSEA) of breast tissue from healthy women with less than six months history of breastfeeding shows enrichment in Hedgehog signaling, notch signaling and luminal progenitor gene signatures [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-09-06.

Wavelength agile multi-photon microscopy with a fiber amplified diode laser

Multi-photon microscopy is a powerful tool in biomolecular research. Less complex and more cost effective excitation light sources will make this technique accessible to a broader community. Semiconductor diode seeded fiber lasers have proven to be especially robust, low cost and easy to use. However, their wavelength tuning range is often limited, so only a limited number of fluorophores can be accessed. Therefore, different approaches have been proposed to extend the spectral coverage of these lasers. Recently, we showed that four-wave mixing (FWM) assisted stimulated Raman scattering (SRS) can be harnessed to red-shift high power pulses from 1064 nm to a narrowband output at 1122 nm and 1186 nm and therefore extend the number of accessible fluorophores. In this contribution, we show the applicability of all three wavelengths for multi-photon microscopy and analyze the performance.

Platelet Deposition Induced by Severely Damaged Vessel Wall Is Inhibited by a Boroarginine Synthetic Peptide with Antithrombin Activity

Thrombin plays a key role in platelet activation and thrombosis. Specific inhibition of thrombin appears to be one of the best approaches to prevent thrombus formation. We have studied the effects of a synthetic a-aminoboronic acid derivative - [Ac, (D) Phe-Pro-Boro-Arg-Hydrocloric acid] - on platelet deposition on severely damaged arterial wall. Platelet deposition was evaluated under well characterized rheological conditions in an original perfusion chamber and detected by autologous mIn-labeled platelets. The study was performed “in vivo” in a porcine model of arterial thrombosis triggered by severely damaged vessel wall at blood flow conditions mimicking mild stenosis (1690 s−1) and patent (212 s−1) vessels. In addition, ex-vivo platelet aggregation activity was evaluated by whole blood impedance aggregometry using collagen, ADP and thrombin as agonists. The synthetic a-aminoboronic peptide was intravenously administered as a bolus followed by continuous infusion. Ex vivo thrombin-induced whole blood platelet aggregation was totally abolished, while ADP- and Collagen-induced whole blood platelet aggregation was not modified. The effects of the synthetic antithrombin on platelet deposition were evaluated in native blood (non-anticoagulated) conditions and in combination with heparin. Under both experimental conditions, the synthetic peptide significantly inhibited platelet deposition at local flow conditions of both high (1690 s−1) and low (212s−1) shear rates. Our results suggest that specific inhibition of locally generated thrombin might be a good strategy to prevent platelet dependent arterial thrombus formation independently of the local flow shear rate of the area at risk.

A Social Media Peer Group for Mothers To Prevent Obesity from Infancy: The Grow2Gether Randomized Trial

BACKGROUND

Few studies have addressed obesity prevention among low-income families whose infants are at increased obesity risk. We tested a Facebook peer-group intervention for low-income mothers to foster behaviors promoting healthy infant growth.

METHODS

In this randomized controlled trial, 87 pregnant women (Medicaid insured, BMI ≥25 kg/m2) were randomized to the Grow2Gether intervention or text message appointment reminders. Grow2Gether participants joined a private Facebook group of 9-13 women from 2 months before delivery until infant age 9 months. A psychologist facilitated groups featuring a curriculum of weekly videos addressing feeding, sleep, parenting, and maternal well-being. Feasibility was assessed using the frequency and content of participation, and acceptability using surveys. Maternal beliefs and behaviors and infant growth were assessed at birth, 2, 4, 6, and 9 months. Differences in infant growth between study arms were explored. We conducted intention-to-treat analyses using quasi-least-squares regression.

RESULTS

Eighty-eight percent (75/85) of intervention participants (42% (36/85) food insecure, 88% (75/85) black) reported the group was helpful. Participants posted 30 times/group/week on average. At 9 months, the intervention group had significant improvement in feeding behaviors (Infant Feeding Style Questionnaire) compared to the control group (p = 0.01, effect size = 0.45). Intervention group mothers were significantly less likely to pressure infants to finish food and, at age 6 months, give cereal in the bottle. Differences were not observed for other outcomes, including maternal feeding beliefs or infant weight-for-length.

CONCLUSIONS

A social media peer-group intervention was engaging and significantly impacted certain feeding behaviors in families with infants at high risk of obesity.

Single pulse two photon fluorescence lifetime imaging (SP-FLIM) with MHz pixel rate

Two-photon-excited fluorescence lifetime imaging microscopy (FLIM) is a chemically specific 3-D sensing modality providing valuable information about the microstructure, composition and function of a sample. However, a more widespread application of this technique is hindered by the need for a sophisticated ultra-short pulse laser source and by speed limitations of current FLIM detection systems. To overcome these limitations, we combined a robust sub-nanosecond fiber laser as the excitation source with high analog bandwidth detection. Due to the long pulse length in our configuration, more fluorescence photons are generated per pulse, which allows us to derive the lifetime with a single excitation pulse only. In this paper, we show high quality FLIM images acquired at a pixel rate of 1 MHz. This approach is a promising candidate for an easy-to-use and benchtop FLIM system to make this technique available to a wider research community.

Comprehensive population-wide analysis of Lynch syndrome in Iceland reveals founder mutations in MSH6 and PMS2

Lynch syndrome, caused by germline mutations in the mismatch repair genes, is associated with increased cancer risk. Here using a large whole-genome sequencing data bank, cancer registry and colorectal tumour bank we determine the prevalence of Lynch syndrome, associated cancer risks and pathogenicity of several variants in the Icelandic population. We use colorectal cancer samples from 1,182 patients diagnosed between 2000-2009. One-hundred and thirty-two (11.2%) tumours are mismatch repair deficient per immunohistochemistry. Twenty-one (1.8%) have Lynch syndrome while 106 (9.0%) have somatic hypermethylation or mutations in the mismatch repair genes. The population prevalence of Lynch syndrome is 0.442%. We discover a translocation disrupting MLH1 and three mutations in MSH6 and PMS2 that increase endometrial, colorectal, brain and ovarian cancer risk. We find thirteen mismatch repair variants of uncertain significance that are not associated with cancer risk. We find that founder mutations in MSH6 and PMS2 prevail in Iceland unlike most other populations.

Asthma Control Test

We compared results of a modified version of the Asthma Control Test using parent proxy report (PP-ACT) with results reported by children and parents using the validated Childhood-Asthma Control Test (C-ACT). 104 parent-child dyads with a child aged 6 to 12 years with asthma were randomized to complete PP-ACT followed by C-ACT or C-ACT followed by PP-ACT. Scores ≤19 indicated uncontrolled asthma. We calculated sensitivity, specificity, positive predictive value, and negative predictive value for the PP-ACT in comparison with the C-ACT, and calculated concordance between the 2 scales. The PP-ACT had sensitivity of 86% and negative predictive value of 88% for detecting uncontrolled asthma. More than 75% of surveys were concordant (κ = 0.54, moderate agreement). Our results suggest that while the PP-ACT missed few children with uncontrolled asthma and may simplify reporting of asthma control in circumstances when child report is not feasible or creates barriers to survey receipt, limitations of proxy reporting should be considered.

Abstract 1066: Racial disparities of genome-wide DNA methylation profiles and association with breast tissues biomarkers in healthy women

Breast cancer is the most common cancer in women, with more aggressive disease observed among African Americans (AA) compared to European Americans (EA). It is a complex and heterogeneous disease, characterized by genetic and epigenetic alterations. Racial differences in DNA methylation have been shown in breast cancers, but it is not clear if these differences exist in healthy women who have not had breast cancer. We identified genome-wide differentially methylated (DM) CpGs by race, in order to: 1) understand methylation patterns of promoter and non-promoter related DM CpGs; 2) study their association with tissue biomarkers of proliferation and differentiation; and 3) examine if these correlations were similar for AA and EA. Normal breast tissues were collected from healthy women undergoing reduction mammoplasty (N = 83). Tissue DNA was analyzed using the Infinium HumanMethylation450 BeadChip for differential genome-wide methylation between AA (N = 22) and EA (N = 61). Analysis methods included age and BMI-adjusted Generalized Linear Regression models, hierarchical clustering and Principal Component Analysis (PCA). Correction for multiple comparisons was performed. We further evaluated the performance of the threshold for classification between EA and AA using the area under the curve (AUC) and by 10-fold cross validation. Biological functions of the DM genes were assigned using the Ingenuity Pathway Analysis (IPA). Partial correlation analysis was performed between the DM CpGs and proliferation (Ki-67, Leptin, IGF1, and IGFBP3) or differentiation (Adiponectin)-related tissue biomarkers. 485 or 23 DM CpGs were identified after FDR or Bonferroni correction at p&lt;0.05, respectively. The AUC was 0.8 and 1 and% correct rates were 78% and 100%, respectively. A heat map and PCA showed distinct methylation patterns between EA and AA. A larger variation was observed in promoters while relatively consistent methylation levels were found in intergenic regions. IPA among 177 DM CpGs in promoter regions showed 136 genes associated with cancers that play roles in cell death and survival, cellular development, and cell-to-cell signaling. Of the 23 DM CpGs, 9 CpGs are known oncogenes or tumor suppressors in breast or other cancers. 8 CpGs were significantly correlated with at least one biomarker in EA (p&lt;0.05), but not in AA. One CpG site was significantly correlated in AA only (p&lt;0.05). 4 DM CpGs were differentially correlated between EA and AA at P-interaction&lt;0.05. This is the first genome-wide study to show differences in methylation between AA and EA in normal breast tissues. A subset of the CpGs was correlated with breast tissue biomarkers of proliferation and differentiation and these correlation patterns were different by race. These findings may provide further insights on the contribution of DNA methylation differences as determinants of racial disparities in breast cancer.

Citation Format: Min-Ae Song, Catalin Marian, Theodore M. Brasky, Daniel Weng, Cenny Taslim, Jo L. Freudenheim, Peter G. Shields. Racial disparities of genome-wide DNA methylation profiles and association with breast tissues biomarkers in healthy women. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1066. doi:10.1158/1538-7445.AM2015-1066

Stratification of Fullerenes

Dodecylated C60 {(Do)nC60(H)n} and butylated C60 {(Bu)nC60(H)n} were synthesized. Spectroscopic and thermal methods, mass spectrometry, XPD, have been employed to characterize the products. X-ray Powder Diffraction (XPD) results reveal that the facecentered- cubic (fcc) structure of C60 expands to a primitive hexagonal structure upon butylation and to a layered structure upon dodecylation. Butylated C60 diffraction pattern has been indexed as a primitive hexagonal structure with ao = 11.5 angstroms and axial ratio = 1.169. The dodecylated C60 also shows sidechain melting behavior with a transition temperature of around 25°C. The paraffinic crystals are produced by the interdigitation of the sidechains. Butylated C60 does not show any sidechain melting.

BRCA mutation status and risk of secondary malignancy following chemotherapy for breast cancer

11017

Background: Since the BRCA gene is responsible for excisional DNA repair, we hypothesized that breast cancer patients with BRCA mutation would be more susceptible to the induction of second malignancies following chemotherapy treatment than breast cancer patients who tested negative for BRCA mutations. Methods: Breast cancer patients tested for BRCA1 and BRCA2 mutations at the Cleveland Clinic were identified and evaluated for history of neoadjuvant or adjuvant chemotherapy and for the occurrence of subsequent non-breast primary invasive cancer. Patients with inadequate follow-up and those with inoperable disease at diagnosis were excluded from the analysis. Fisher’s exact test was used to compare different cohorts. The IRB at Cleveland Clinic approved the study. Results: Of 115 identified breast cancer patients tested for BRCA mutations, 77 met the inclusion criteria. Twenty-seven of these patients carried BRCA1 or BRCA2 mutations and 50 tested negative for these mutations. Twelve patients (44%) in the BRCA positive group and 8 patients (16%) in the BRCA negative group underwent prophylactic oophorectomy. Median follow-up for the two groups was 53.5 months (75 months in the BRCA positive group and 48.5 months in the BRCA negative group). Median age at diagnosis was 42 years (40.5 years in the BRCA positive group and 44.5 in the BRCA negative group). In the BRCA positive group 3 of 25 patients (12%) treated with chemotherapy developed second malignancies (ovarian cancer, transitional cell cancer in urinary tract and renal cell carcinoma) compared with none of the 2 patients who did not get chemotherapy (p= 1.0). In the BRCA negative group, 2/34 patients (6%), treated with chemotherapy developed second cancers compared with 2/16 patients (12%), who were not treated with chemotherapy (p=0.58). Cancers in the BRCA negative group included two bladder carcinomas in the chemotherapy treated patients and in the non-chemotherapy group, non-small cell lung cancer, uterine, ovarian, endometrial and peritoneal cancers. Conclusions: At more than 4-years of follow up, chemotherapy in operable breast cancer patients was not associated with an increase in the risk of secondary malignancy or with a differential effect on this endpoint by BRCA mutation status in this retrospective study.

No significant financial relationships to disclose.

Therapeutic radiation for breast cancer in BRCA mutation carriers and contralateral breast cancer (CBC) risk

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Background: BRCA mutation carriers diagnosed with breast cancer are at high risk for contralateral second primary breast cancers. Mutations in BRCA1 and BRCA2 lead to defects in DNA repair. Radiation treatment for breast cancer is felt to increase risk of CBC, but the interaction between BRCA status and local radiation therapy with respect to their effects on CBC is unclear. Methods: Through an IRB approved database registry at the Cleveland Clinic, breast cancer patients tested for BRCA1 and BRCA2 mutations were identified and evaluated for CBC events and radiation treatment history. Patients with inadequate clinical follow-up, those with bilateral synchronous breast cancer and those undergoing bilateral mastectomy within one year of the original breast cancer diagnosis were excluded from the analysis. Chi-square test was used to compare CBC rates with or without prior radiation separately in patients testing positive and those testing negative for BRCA mutations. Results: Of 115 identified breast cancer patients tested for BRCA mutations, 57 met the inclusion criteria. Twenty-one carried BRCA1 or BRCA2 mutations and 36 tested negative for these mutations. Median follow-up for the two groups was 69.5 months (92 months in BRCA positive group and 51.5 months in BRCA negative group). Median age at diagnosis was 45 years (41 years in BRCA positive group and 48.5 in BRCA negative group). Among the 21 carriers, 9 patients (43%) developed CBC while only 3 of 36 patients (8%) testing negative for BRCA mutations developed CBC. Thirteen of 21 mutation carriers (62%) had received radiation treatment for the original cancer: CBC occurred in 3 of 13 (23%) radiated patients and 6 of 8 (75%) patients who had not received radiation (p= 0.02). Among 36 patients with negative BRCA testing, 30 (83%) had received radiation: CBC occurred in 3 of 30 (10%) mutation negative patients who had received prior radiation and in 0 of the 6 patients who had not received radiation (p = 0.42). Conclusions: CBC incidence was higher among BRCA mutation carriers than a control group suspected of having hereditary breast cancer but testing negative for these mutations. The use of radiation in the presence of a BRCA mutation, however, does not appear to further increase the risk for CBC.

No significant financial relationships to disclose.

Role of p38 MAP Kinase in Regulation of Cell Migration and Proliferation in Healing Corneal Epithelium

PURPOSE

The purpose of the present study was to examine the roles of signaling pathways potentially activated by TGFbeta (i.e., Smad and p38 mitogen-activated kinase [MAPK]) in regulation of cell migration and proliferation of healing mouse corneal epithelium.

METHODS

Activation of Smads or p38MAPK was evaluated by immunohistochemistry in healing mouse corneal epithelium after debridement. The role of endogenous TGFbeta or p38MAPK in epithelial healing was determined in organ-cultured mouse corneas with an epithelial defect, in the presence or absence of a TGFbeta-neutralizing antibody or p38MAPK inhibitors, respectively. Cell proliferation was evaluated by incorporation of bromodeoxyuridine.

RESULTS

Migrating mouse corneal epithelium had minimal cell proliferation. Smad3 and -4 were found in nuclei of normal corneal epithelium, whereas they were absent in nuclei of migrating cells in association with Smad7 upregulation on epithelial debridement. Administration of TGFbeta-neutralizing antibody reduced the protein expression of Smad7 in vivo after a corneal injury. In contrast, phosphorylation and nuclear translocation of p38MAPK were markedly evident in migrating epithelium during healing, but not in uninjured epithelium. In organ culture, addition of p38MAPK inhibitors blocked cell migration more markedly than neutralizing TGFbeta-antibody and enhanced cell proliferation in the injured corneal epithelium, in association with phosphorylation of Erk.

CONCLUSIONS

Endogenous TGFbeta enhances migration of corneal epithelium during wound healing in mice. The p38MAPK, but not the Smad, cascade plays a major role in promoting cell migration and in suppressing cell proliferation in migrating epithelium.

Contribution of the periosteum to bone formation in guided bone regeneration. A study in monkeys

The periosteum has been referred to as a protective barrier in the regeneration of bone defects. The objective of this study was to determine the contribution of periosteum as a natural barrier to bone formation in guided bone regeneration. Mucoperiosteal flaps were elevated bilaterally on the buccal aspect of the mandibular angle in 5 cynomolgus monkeys. Bleeding was induced by perforating the cortical bone. A hemispherical titanium mesh was fixed over the areas thus creating a void 5 mm in height between the mesh and the bone surface. One one side the mesh was covered with an ePTFE membrane (test side). The contralateral side did not receive further treatment (control side). After 4 month healing, histomorphometric analyses were used to determine the percentage of new bone in the void underneath the mesh, and the ratio between mineralized tissue and marrow spaces in new and old bone. The mean percentage of new bone tissue was 77.2 +/- 7.5% for the test sides and 68.6 +/- 8.4% for the control sides (P = 0.018, t-test). This new bone contained 80.0 +/- 3.6% mineralized tissue in the test group and 82.5 +/- 5.0% in the control group (P > 0.05, t-test). In both groups the newly formed bone exhibited significantly less mineralized tissue than the old bone (P < 0.05, t-test). It is concluded from this study that new bone formation was enhanced by the additional use of an ePTFE membrane under a periosteum-lined mucoperiosteal flap when space maintenance was excluded as a critical factor.

Comparison of bioabsorbable and non-resorbable membranes in the treatment of dehiscence-type defects. A histomorphometric study in dogs

BACKGROUND

The goal of this investigation was to compare, histologically and histometrically, the healing process of dehiscence-type defects treated by guided tissue regeneration (GTR) with bioabsorbable polylactic acid (PLA) membranes and non-resorbable expanded polytetrafluoroethylene (ePTF) membranes.

METHODS

Six mongrel dogs were used. Buccal osseous dehiscences were surgically created on the distal roots of the mandibular third and fourth premolars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: GTR with bioabsorbable membrane (PLA), GTR with non-resorbable membrane (ePTFE), open flap debridement (OFD), and non-treated control (NTC). After 3 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included: gingival recession, epithelial length, connective tissue adaptation, new cementum, and new bone area.

RESULTS

A superior length of new cementum was observed in the sites treated by GTR, regardless of the type of barrier used, in comparison with OFD (P <0.05). No statistically significant differences were found between PLA and ePTFE in any of the parameters with the exception of bone area. PLA presented a greater bone area when compared to ePTFE, OFD, and NTC (P <0.05).

CONCLUSIONS

Within the limits of this study, it can be concluded that both barriers are equally effective for new cementum formation. The bioabsorbable membrane may provide a greater bone area than the non-resorbable membrane.

A single-incision technique to harvest subepithelial connective tissue grafts from the palate

This article describes a new and simplified surgical approach to harvest subepithelial connective tissue grafts from the palate. For this procedure, only a single incision parallel to the gingival margin is used to access the donor site for graft preparation and harvesting. Grafts of variable size and thickness can be obtained. Since no band of epithelium is removed with the connective tissue graft the palatal donor site can heal with primary intention. No stents or hemostatic agents are necessary to cover the donor area postoperatively, and suturing can be reduced to a minimum. The harvesting technique is illustrated step by step, and the clinical application of connective tissue grafts harvested with the proposed method is demonstrated with the coverage of a gingival recession.

Functional and esthetic outcome enhancement of periodontal surgery by application of plastic surgery principles

The closure of surgical wounds in a layer-by-layer fashion, a common principle of plastic surgery, is applied in this article to the field of periodontal surgery with the introduction of a new flap design. The suggested technique is indicated with all periodontal procedures that aim for hard and soft tissue augmentation (guided bone regeneration, mucogingival surgery, or plastic periodontal surgery) where passive, tension-free wound closure is fundamental for wound healing and a successful functional and esthetic outcome. By means of a series of incisions, buccal and lingual flaps are split several times; this results in a double-partial thickness flap and a coronally positioned palatal sliding flap, respectively. Thus, several tissue layers are obtained and the passive advancement of flaps becomes possible for the coverage of augmented areas. Wound closure with microsurgical suture material is accomplished in a multilayer approach, which ensures adaptation and closure of the outer tissue layers without any tension. Two case reports demonstrate the new plastic periodontal approach.

Identification of elf1, a beta-spectrin, in early mouse liver development

Beta-spectrins play essential roles in cell-cell interactions and in the maintenance of cell polarity. Our aim was to identify beta-spectrin genes important for the establishment of hepatocyte polarity and differentiation. Using subtractive screening of cDNA libraries from early embryonic mouse livers (post-coital days 10, 11, and 12), we have isolated elf1 (embryonic liver fodrin 1), a differentially expressed beta-spectrin or fodrin (betaSpIIsigmaI). Elf1 encodes a 220-amino acid protein with an NH2 terminal actin-binding domain. In situ hybridization studies demonstrate elf1 expression initially in day 10 embryonic heart tissue, then in day 11-11.5 hepatic tissue. These studies suggest that elf1 may play a role in the emergence of hepatocyte polarity during liver development.

Healing patterns in recession defects treated with ePTFE membranes and with free connective tissue grafts. A histologic and histometric study in the beagle dog

This study focussed on the biologic success of 2 different procedures for root coverage. In the maxillary canines of 7 beagle dogs, buccal recessions were created and treated on one side with an ePTFE membrane (GTR-group) and on the contralateral side with a free connective tissue graft from the palate (CT-group). 2 areas served as negative controls. After 4 months of healing, histologic sections were processed and histologically analyzed. The evaluated parameters were coverage height, bone, cementum and connective tissue attachment regeneration, length of the epithelium, resorption, and ankylosis. Histologically, both GTR-group and CT-group produced more new bone, new cementum and new connective tissue attachment than the two control teeth. When histologically evaluated, the amount of new bone was more pronounced in the GTR-group than in the CT-group, however, no statistical differences in any of the evaluated parameters could be detected between the 2 procedures tested. Frequency and distribution of resorption and ankylosis were similar in the GTR-group and in the CT-group. Within the limits of this study, no differences in terms of the biologic rehabilitation between those recessions treated with ePTFE membranes and those treated with a free connective tissue graft could be found.

Periimplant tissue management: optimal timing for an aesthetic result

When implants are utilized to restore the dentition in an aesthetically prominent region, there are four different time points when the periimplant tissue can be influenced-prior to implant placement, simultaneously with implant placement or during the healing phase of the implant, at second-stage surgery, and during the maintenance phase. There is no single optimal point in time for managing the periimplant tissues; the patients present for treatment at various stages, and each case has to be individually evaluated and an appropriate treatment plan designed. The earlier periimplant tissue management is initiated, the greater are the opportunities for a successful result. The learning objective of this article is to review these options by means of case presentations. The different surgical procedures are explained and their advantages or disadvantages discussed. Four case reports are used to demonstrate the rationale and the clinical procedures. An improvement in the aesthetic harmony was attained in all four cases.

A new technique to combine barrier removal at dehisced implant sites with a plastic periodontal procedure

Three case reports are used to describe a new surgical technique that permits the combination of barrier removal and an apically repositioning flap procedure at implant exposure surgery of previously dehisced or fenestrated implant sites. The flap procedure allows the creation of an adequate zone of keratinized mucosa. In contrast to existing techniques, this method eliminates bone denudation on the interproximal and oral aspect by means of a split-thickness flap surgery. Advantages of this procedure are optimal protection of the bone and reduction of postsurgical discomfort by minimizing the possibility of infection and resorption processes on the bone surface. Furthermore, flap management and fixation are facilitated. Although the necessity of keratinized mucosa around implants is controversial, its presence is favorable in cases where esthetics is important.

Catalase inhibition with 3-amino-1,2,4-triazole does not abolish infarct size reduction in heat-shocked rats

BACKGROUND

Recent studies have shown that improved myocardial salvage after heat-shock pretreatment correlates with the amount of induced cardiac heat-shock protein (HSP)72. However, heat shock also induces myocardial catalase activity, potentially reducing free radical-mediated ischemic injury. The aim of the present study was to determine whether catalase inhibition with 3-amino-1,2,4-triazole (3-AT) abolishes the reduction of infarct size conferred by heat-shock treatment in rats.

METHODS AND RESULTS

Myocardial catalase activity was measured in both heat-shocked and control rats 60 minutes after either 3-AT (1000 mg/kg IV) or saline infusion. In separate experiments, heat-shocked and control rats were treated with 3-AT or saline 60 minutes before being subjected to 35 minutes of left coronary artery occlusion and 120 minutes of reperfusion. Infarct size was determined by dual perfusion with triphenyltetrazolium chloride and phthalocyanine blue dye. Heat-shock treatment significantly increased myocardial catalase compared with control animals (180.5 +/- 4.8, n = 6, versus 86.2 +/- 14.7, n = 5, units/g wet wt; P < .05). Treatment with 3-AT significantly reduced myocardial catalase activity in both heat-shocked and control animals (29.6 +/- 5.7, n = 5, and 36.4 +/- 15.3, n = 6, respectively). Heat-shock treatment significantly reduced infarct size in rats that were both treated and untreated with 3-AT compared with respective control groups (22.5 +/- 3.7%, n = 26, 28.2 +/- 4.0%, n = 22, 52.0 +/- 3.0%, n = 23, and 48.6 +/- 3.2%, n = 26, respectively; P < .0001 for both heat-shocked groups versus both control groups; infarct mass/risk area mass x 100).

CONCLUSIONS

Catalase inhibition with 3-AT does not abolish the reduction of infarct size in heat-shocked rats.

Characterization of the relative thrombogenicity of atherosclerotic plaque components: implications for consequences of plaque rupture

OBJECTIVES

The purpose of this study was to determine whether different components of human atherosclerotic plaques exposed to flowing blood resulted in different degrees of thrombus formation.

BACKGROUND

It is likely that the nature of the substrate exposed after spontaneous or angioplasty-induced plaque rupture is one factor determining whether an unstable plaque proceeds rapidly to an occlusive thrombus or persists as a nonocclusive mural thrombus. Although observational data show that plaque rupture is a potent stimulus for thrombosis, and exposed collagen is suggested to have a predominant role in thrombosis, the relative thrombogenicity of different components of human atherosclerotic plaques is not well established.

METHODS

We investigated thrombus formation on foam cell-rich matrix (obtained from fatty streaks), collagen-rich matrix (from sclerotic plaques), collagen-poor matrix without cholesterol crystals (from fibrolipid plaques), atheromatous core with abundant cholesterol crystals (from atheromatous plaques) and segments of normal intima derived from human aortas at necropsy. Specimens were mounted in a tubular chamber placed within an ex vivo extracorporeal perfusion system and exposed to heparinized porcine blood (mean [+/- SEM] activated partial thromboplastin time ratio 1.5 +/- 0.04) for 5 min under high shear rate conditions (1,690 s-1). Thrombus was quantitated by measurement of indium-labeled platelets and morphometric analysis. Under similar conditions, substrates were perfused with heparinized human blood (2 IU/ml) in an in vitro system, and thrombus formation was similarly evaluated.

RESULTS

Thrombus formation on atheromatous core was up to sixfold greater than that on other substrates, including collagen-rich matrix (p = 0.0001) in both heterologous and homologous systems. Although the atheromatous core had a more irregular exposed surface and thrombus formation tended to increase with increasing roughness, the atheromatous core remained the most thrombogenic substrate when the substrates were normalized by the degree of irregularity as defined by the roughness index (p = 0.002).

CONCLUSIONS

The atheromatous core is the most thrombogenic component of human atherosclerotic plaques. Therefore, plaques with a large atheromatous core content are at high risk of leading to acute coronary syndromes after spontaneous or mechanically induced rupture because of the increased thrombogenicity of their content.

Platelet deposition induced by severely damaged vessel wall is inhibited by a boroarginine synthetic peptide with antithrombin activity

Thrombin plays a key role in platelet activation and thrombosis. Specific inhibition of thrombin appears to be one of the best approaches to prevent thrombus formation. We have studied the effects of a synthetic alpha-aminoboronic acid derivative- [Ac, (D) Phe-Pro-Boro-Arg-Hydrochloric acid] - on platelet deposition on severely damaged arterial wall. Platelet deposition was evaluated under well characterized rheological conditions in an original perfusion chamber and detected by autologous 111In-labeled platelets. The study was performed "in vivo" in a porcine model of arterial thrombosis triggered by severely damaged vessel wall at blood flow conditions mimicking mild stenosis (1690 s-1) and patent (212 s-1) vessels. In addition, ex-vivo platelet aggregation activity was evaluated by whole blood impedance aggregometry using collagen, ADP and thrombin as agonists. The synthetic alpha-aminoboronic peptide was intravenously administered as a bolus followed by continuous infusion. Ex vivo thrombin-induced whole blood platelet aggregation was totally abolished, while ADP- and Collagen-induced whole blood platelet aggregation was not modified. The effects of the synthetic antithrombin on platelet deposition were evaluated in native blood (non-anticoagulated) conditions and in combination with heparin. Under both experimental conditions, the synthetic peptide significantly inhibited platelet deposition at local flow conditions of both high (1690 s-1) and low (212s-1) shear rates. Our results suggest that specific inhibition of locally generated thrombin might be a good strategy to prevent platelet dependent arterial thrombus formation independently of the local flow shear rate of the area at risk.

Blood interactions with novel polyurethaneurea hydrogels

The influence on blood of polyurethaneurea hydrogels in vitro was investigated based on poly(ethylene oxide). A hydrogel was compared with the regenerated cellulose membrane Cuprophan in terms of complement activation, as determined by measurement of C3a concentration. The hydrogel induced less complement activation and the presence of poly(ethylene oxide) is likely to be beneficial to platelet reactivity. The ability to vary the polymer composition and the solubility of the polymers in organic solvents makes the polyurethaneurea hydrogels strong candidates for composite biomaterials.