Cell cycle status of male and female gametes during Arabidopsis reproduction

Fertilization in Arabidopsis (Arabidopsis thaliana) is a highly coordinated process that begins with a pollen tube delivering the 2 sperm cells into the embryo sac. Each sperm cell can then fertilize either the egg or the central cell to initiate embryo or endosperm development, respectively. The success of this double fertilization process requires a tight cell cycle synchrony between the male and female gametes to allow karyogamy (nuclei fusion). However, the cell cycle status of the male and female gametes during fertilization remains elusive as DNA quantification and DNA replication assays have given conflicting results. Here, to reconcile these results, we quantified the DNA replication state by DNA sequencing and performed microscopic analyses of fluorescent markers covering all phases of the cell cycle. We show that male and female Arabidopsis gametes are both arrested prior to DNA replication at maturity and initiate their DNA replication only during fertilization.

Nuclear GSH import precedes coordinated cell cycle changes during regeneration

Arabidopsis root tip regeneration requires cell division and cellular reprogramming. Here, we present new datasets that describe the cell cycle in Arabidopsis roots that maintain developmental context and cell-type resolution and provide an expanded set of cell cycle phase transcriptional markers. Using these data, we provide in vivo confirmation of a longstanding model in plants that glutathione (GSH) and reactive oxygen species (ROS) vary in a cell cycle dependent manner. We then demonstrate using long term time lapse imaging that cells in G1 phase undergo a transient peak of GSH prior to a tissue-wide coordinated entry into S phase. This coordinated S phase entry precedes a period of fast divisions, which we show appears to potentiate cellular reprogramming during regeneration. Taken together, this work demonstrates a role for GSH in coordinating cell cycle regulation and cellular reprogramming during regeneration.

The Arabidopsis SHORTROOT network coordinates shoot apical meristem development with auxin-dependent lateral organ initiation

Plants produce new organs post-embryonically throughout their entire life cycle. This is due to stem cells present in the shoot and root apical meristems, the SAM and RAM, respectively. In the SAM, stem cells are located in the central zone where they divide slowly. Stem cell daughters are displaced laterally and enter the peripheral zone, where their mitotic activity increases and lateral organ primordia are formed. How the spatial arrangement of these different domains is initiated and controlled during SAM growth and development, and how sites of lateral organ primordia are determined in the peripheral zone is not yet completely understood. We found that the SHORTROOT (SHR) transcription factor together with its target transcription factors SCARECROW (SCR), SCARECROW-LIKE23 (SCL23) and JACKDAW (JKD), promotes formation of lateral organs and controls shoot meristem size. SHR, SCR, SCL23, and JKD are expressed in distinct, but partially overlapping patterns in the SAM. They can physically interact and activate expression of key cell cycle regulators such as CYCLIND6;1 (CYCD6;1) to promote the formation of new cell layers. In the peripheral zone, auxin accumulates at sites of lateral organ primordia initiation and activates SHR expression via the auxin response factor MONOPTEROS (MP) and auxin response elements in the SHR promoter. In the central zone, the SHR-target SCL23 physically interacts with the key stem cell regulator WUSCHEL (WUS) to promote stem cell fate. Both SCL23 and WUS expression are subject to negative feedback regulation from stem cells through the CLAVATA signaling pathway. Together, our findings illustrate how SHR-dependent transcription factor complexes act in different domains of the shoot meristem to mediate cell division and auxin dependent organ initiation in the peripheral zone, and coordinate this activity with stem cell maintenance in the central zone of the SAM.

Very APBI in 1 or 2 Days: Late Toxicity and Early Oncological Outcomes of the GEC-ESTRO Cohort

PURPOSE/OBJECTIVE(S)

To analyze late toxicity after very accelerated partial breast irradiation (VAPBI) for low-risk breast cancer.

MATERIALS/METHODS

In this retrospective observational international multicenter study (HDH F20220713143949) from 7 European centers, patients with low-risk breast cancer underwent lumpectomy + adjuvant VAPBI based on high-dose rate (HDR) multicatheter interstitial brachytherapy (MIB). VAPBI was performed with 4 (4 × 6.2 Gy/2 d), 3 (3 × 7.45 Gy/2 d) or 1 fraction (1 × 16 Gy or 1 × 18 Gy/1 d). Primary endpoint was late toxicity. Secondary endpoints were oncological outcome based on cumulative incidence of breast cancer local relapse (LR) and distant metastasis disease (DMD) and cause-specific (CSS) and overall (OS) survival. Prognostic factors for late toxicity were analyzed.

RESULTS

From 01/2012 to 06/2022, the GEC-ESTRO VAPBI cohort included 516 pts with an early breast cancer. Median follow-up was 42 months [95% CI = 39 - 44]. Median age was 71 years [40 - 100]. Median tumor size was 12 mm [1 - 46]. Tumor was mainly invasive ductal carcinoma (78%), pN0 (88.5%), with positive hormonal receptors (98.5%) and negative HER2 overexpression (96%). Patients underwent hormonal and chemo-therapy in 93.8% and 2.3% respectively. Catheter placement was performed peri or post-operatively in 50.2% and 49.8% respectively. Median time interval between surgery and VABPI was 10 days [6 - 65]. VAPBI delivered 1, 3 and 4 fractions for 205 pts (39.7%), 167 pts (32.4%) and 144 pts (28%) respectively. Median CTV was 40.7 cc [95% CI = 26.6 - 72], median V100%, V150%, D90% and Dose non-uniformity ratio (DNR) were 90.2% [95% CI = 84.1 - 97.2], 24.2% [95% CI = 18.9 - 31.6], 103.8% [95% CI = 100.1 - 107.4] and 0.28 [95% CI = 0.23 - 0.33] respectively, 211 late toxicity events were observed in 168 pts (32.6%). Fibrosis, dyschromia, pain and telangiectasia were observed in 26.7%, 7.9%, 7.2% and 0.4 respectively. Grade 2 and 3 late toxicities were observed in 7.2 and 0.6% respectively (no G4). Grade ≥2 late toxicity was observed in 8.1%, 16.7% and 3.7% after 1, 3 and 4 fractions, respectively (p = 0.004). CTV > 50 cc (p = 0.007) and V150 > 40% (p = 0.027) were prognostic factors for G≥2 late toxicity. Regarding oncological outcome, 4-year cumulative incidence of LR, RR and DMD were 2% [95% CI = 0 - 3], 1% [95% CI = 0 - 2] and 1% [95% CI = 0 - 2] respectively. CSS and OS were 98% [95% CI = 96 - 100] and 93% [95% CI = 90 - 96] respectively. No significant difference was observed in terms of oncological outcome between the 3-fractionation groups.

CONCLUSION

VAPBI based on 1 or 2 days of HDR MIB represents an attractive de-escalation irradiation approach for low-risk breast cancer. Late toxicity profile appears acceptable while early oncological outcome shows excellent local control. Brachytherapy technique remains a key component of clinical outcome. Longer follow-up is warranted in order to confirm these encouraging preliminary results.

PlantACT! - how to tackle the climate crisis

Greenhouse gas (GHG) emissions have created a global climate crisis which requires immediate interventions to mitigate the negative effects on all aspects of life on this planet. As current agriculture and land use contributes up to 25% of total GHG emissions, plant scientists take center stage in finding possible solutions for a transition to sustainable agriculture and land use. In this article, the PlantACT! (Plants for climate ACTion!) initiative of plant scientists lays out a road map of how and in which areas plant scientists can contribute to finding immediate, mid-term, and long-term solutions, and what changes are necessary to implement these solutions at the personal, institutional, and funding levels.

Histone variants and modifications during abiotic stress response

Plants have developed multiple mechanisms as an adaptive response to abiotic stresses, such as salinity, drought, heat, cold, and oxidative stress. Understanding these regulatory networks is critical for coping with the negative impact of abiotic stress on crop productivity worldwide and, eventually, for the rational design of strategies to improve plant performance. Plant alterations upon stress are driven by changes in transcriptional regulation, which rely on locus-specific changes in chromatin accessibility. This process encompasses post-translational modifications of histone proteins that alter the DNA-histones binding, the exchange of canonical histones by variants that modify chromatin conformation, and DNA methylation, which has an implication in the silencing and activation of hypervariable genes. Here, we review the current understanding of the role of the major epigenetic modifications during the abiotic stress response and discuss the intricate relationship among them.

A Journey to the Core of the Plant Cell Cycle

Production of new cells as a result of progression through the cell division cycle is a fundamental biological process for the perpetuation of both unicellular and multicellular organisms. In the case of plants, their developmental strategies and their largely sessile nature has imposed a series of evolutionary trends. Studies of the plant cell division cycle began with cytological and physiological approaches in the 1950s and 1960s. The decade of 1990 marked a turn point with the increasing development of novel cellular and molecular protocols combined with advances in genetics and, later, genomics, leading to an exponential growth of the field. In this article, I review the current status of plant cell cycle studies but also discuss early studies and the relevance of a multidisciplinary background as a source of innovative questions and answers. In addition to advances in a deeper understanding of the plant cell cycle machinery, current studies focus on the intimate interaction of cell cycle components with almost every aspect of plant biology.

Deceleration of the cell cycle underpins a switch from proliferative to terminal divisions in plant stomatal lineage

Differentiation of specialized cell types requires precise cell-cycle control. Plant stomata are generated through asymmetric divisions of a stem-cell-like precursor followed by a single symmetric division that creates paired guard cells surrounding a pore. The stomatal-lineage-specific transcription factor MUTE terminates the asymmetric divisions and commits to differentiation. However, the role of cell-cycle machineries in this transition remains unknown. We discover that the symmetric division is slower than the asymmetric division in Arabidopsis. We identify a plant-specific cyclin-dependent kinase inhibitor, SIAMESE-RELATED4 (SMR4), as a MUTE-induced molecular brake that decelerates the cell cycle. SMR4 physically and functionally associates with CYCD3;1 and extends the G1 phase of asymmetric divisions. By contrast, SMR4 fails to interact with CYCD5;1, a MUTE-induced G1 cyclin, and permits the symmetric division. Our work unravels a molecular framework of the proliferation-to-differentiation switch within the stomatal lineage and suggests that a timely proliferative cell cycle is critical for stomatal-lineage identity.

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During stomatal differentiation, asymmetric divisions are faster than terminal divisions

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Upon commitment to differentiation, MUTE induces the cell-cycle inhibitor SMR4

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SMR4 decelerates the asymmetric cell division cycle via selective binding to cyclin D

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Regulating duration of the G1 phase is critical for epidermal cell fate specification

Cycling in a crowd: Coordination of plant cell division, growth, and cell fate

The reiterative organogenesis that drives plant growth relies on the constant production of new cells, which remain encased by interconnected cell walls. For these reasons, plant morphogenesis strictly depends on the rate and orientation of both cell division and cell growth. Important progress has been made in recent years in understanding how cell cycle progression and the orientation of cell divisions are coordinated with cell and organ growth and with the acquisition of specialized cell fates. We review basic concepts and players in plant cell cycle and division, and then focus on their links to growth-related cues, such as metabolic state, cell size, cell geometry, and cell mechanics, and on how cell cycle progression and cell division are linked to specific cell fates. The retinoblastoma pathway has emerged as a major player in the coordination of the cell cycle with both growth and cell identity, while microtubule dynamics are central in the coordination of oriented cell divisions. Future challenges include clarifying feedbacks between growth and cell cycle progression, revealing the molecular basis of cell division orientation in response to mechanical and chemical signals, and probing the links between cell fate changes and chromatin dynamics during the cell cycle.

Tools for Assessing Cell-Cycle Progression in Plants

Estimation of cell-cycle parameters is crucial for understanding the developmental programs established during the formation of an organism. A number of complementary approaches have been developed and adapted to plants to assess the cell-cycle status in different proliferative tissues. The most classical methods relying on metabolic labeling are still very much employed and give valuable information on cell-cycle progression in fixed tissues. However, the growing knowledge of plant cell-cycle regulators with defined expression pattern together with the development of fluorescent proteins technology enabled the generation of fusion proteins that function individually or in conjunction as cell-cycle reporters. Together with the improvement of imaging techniques, in vivo live imaging to monitor plant cell-cycle progression in normal growth conditions or in response to different stimuli has been possible. Here, we review these tools and their specific outputs for plant cell-cycle analysis.

A perspective on cell proliferation kinetics in the root apical meristem

Organogenesis in plants is primarily postembryonic and relies on a strict balance between cell division and cell expansion. The root is a particularly well-suited model to study cell proliferation in detail since the two processes are spatially and temporally separated for all the different tissues. In addition, the root is amenable to detailed microscopic analysis to identify cells progressing through the cell cycle. While it is clear that cell proliferation activity is restricted to the root apical meristem (RAM), understanding cell proliferation kinetics and identifying its parameters have required much effort over many years. Here, we review the main concepts, experimental settings, and findings aimed at obtaining a detailed knowledge of how cells proliferate within the RAM. The combination of novel tools, experimental strategies, and mathematical models has contributed to our current view of cell proliferation in the RAM. We also discuss several lines of research that need to be explored in the future.

Feasible and effective use of a simulation-based curriculum for post-graduate emergency medicine trainees in India to improve learner self-efficacy, knowledge, and skills

BACKGROUND

Pediatric emergency medicine training is in its infancy in India. Simulation provides an educational avenue to equip trainees with the skills to improve pediatric care. We hypothesized that a simulation-based curriculum can improve Indian post-graduate emergency medicine (EM) trainees' self-efficacy, knowledge, and skills in pediatric care.

METHODS

We designed a simulation-based curriculum for management of common pediatric emergencies including sepsis, trauma, and respiratory illness and pediatric-specific procedures including vascular access and airway skills. Training included didactics, procedural skill stations, and simulation. Measures included a self-efficacy survey, knowledge test, skills checklist, and follow-up survey. Results were analyzed using the Wilcoxon signed-rank test and paired-samples t test. A 6-month follow-up survey was done to evaluate lasting effects of the intervention.

RESULTS

Seventy residents from four academic hospitals in India participated. Trainees reported feeling significantly more confident, after training, in performing procedures, and managing pediatric emergencies (p < 0.001). After the simulation-based curriculum, trainees demonstrated an increase in medical knowledge of 19% (p < 0.01) and improvement in procedural skills from baseline to mastery of 18%, 20%, 16%, and 19% for intubation, bag-valve mask ventilation, intravenous access, and intraosseous access respectively (p < 0.01). At 6-month follow-up, self-efficacy in procedural skills and management of pediatric emergencies improved from baseline.

CONCLUSIONS

A simulation-based curriculum is an effective and sustainable way to improve Indian post-graduate EM trainees' self-efficacy, knowledge, and skills in pediatric emergency care.

The Polycomb group protein MEDEA controls cell proliferation and embryonic patterning in Arabidopsis

Establishing the embryonic body plan of multicellular organisms relies on precisely orchestrated cell divisions coupled with pattern formation, which, in animals, are regulated by Polycomb group (PcG) proteins. The conserved Polycomb Repressive Complex 2 (PRC2) mediates H3K27 trimethylation and comes in different flavors in Arabidopsis. The PRC2 catalytic subunit MEDEA is required for seed development; however, a role for PRC2 in embryonic patterning has been dismissed. Here, we demonstrate that embryos derived from medea eggs abort because MEDEA is required for patterning and cell lineage determination in the early embryo. Similar to PcG proteins in mammals, MEDEA regulates embryonic patterning and growth by controlling cell-cycle progression through repression of CYCD1;1, which encodes a core cell-cycle component. Thus, Arabidopsis embryogenesis is epigenetically regulated by PcG proteins, revealing that the PRC2-dependent modulation of cell-cycle progression was independently recruited to control embryonic cell proliferation and patterning in animals and plants.

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MEDEA, a Polycomb Repressive Complex 2 (PRC2) subunit, is required in embryo and endosperm

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MEDEA links cell proliferation and differentiation during embryonic pattern formation

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The PRC2 protein MEDEA directly regulates core cell-cycle components, i.e., cyclin CYCD1;1

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Body plan and cell proliferation are epigenetically regulated in both animals and plants

Cell size controlled in plants using DNA content as an internal scale

How eukaryotic cells assess and maintain sizes specific for their species and cell type remains unclear. We show that in the Arabidopsis shoot stem cell niche, cell size variability caused by asymmetric divisions is corrected by adjusting the growth period before DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to DNA synthesis and associates with mitotic chromosomes. The F BOX-LIKE 17 (FBL17) protein removes excess KRP4. Consequently, daughter cells are born with comparable amounts of KRP4. Inhibitor dilution models predicted that KRP4 inherited through chromatin would robustly regulate size, whereas inheritance of excess free KRP4 would disrupt size homeostasis, as confirmed by mutant analyses. We propose that a cell cycle regulator, stabilized by association with mitotic chromosomes, reads DNA content as a cell size-independent scale.

POS0304 EPIDEMIOLOGY AND ECONOMIC BURDEN ASSOCIATED WITH MENTAL HEALTH COMORBIDITIES IN SYSTEMIC LUPUS ERYTHEMATOSUS AND LUPUS NEPHRITIS PATIENTS

Background:

Systemic lupus erythematosus (SLE), a multisystem autoimmune disease, is associated with mental health (MH) disorders. There is scarce information on the epidemiology and economic burden associated with MH comorbidities and the impact on SLE as well as the subpopulation with lupus nephritis (LN).

Objectives:

Examined the incidence and prevalence rate of MH, healthcare resource utilization (HCRU), and costs associated with MH comorbidities in SLE/LN patients.

Methods:

Adult SLE and LN patients with ≥1 inpatient or ≥2 outpatient diagnosis claims for SLE/LN (ICD-9 code: 710.0; and ICD-10 codes M32.10-19, M32.8, M32.9) were identified between 01JAN2013-30JUN2019 from two large US commercial databases. Inclusion required continuous enrollment benefits 12 months pre-/post-index date. Patients were divided into two groups: those with (WMH) vs. those without (NMH). WMH was defined as a MH diagnosis of depression, anxiety, bipolar disorder, or psychosis. Index date for the WMH group was first MH diagnosis claim. For the NMH group, a random index date was assigned between 01JAN2014-30JUN2018. The groups were then matched with a 1:1 ratio based on age, sex, and region within their respective databases. Incidence and prevalence rate of MH in the SLE/LN population were determined. All-cause healthcare costs and HCRU per patients per year (PPPY) were examined with generalized linear models.

Results:

A total of 7,760 SLE and 336 LN patients were identified. The majority of patients were female (SLE=93.5%; LN=95.2%) with a mean age of 55.1 years (SLE) and 44.5 years (LN). The prevalence rate of MH was 35.7% for SLE and 28.8% for LN patients and the incidence rate was 18.5% and 15.3%, respectively. Anxiety and depression were the most common MH comorbidities (Figure 1). WMH inpatient stays averaged an additional 2.6 and 7.2 days longer than NMH for SLE and LN, respectively. In addition, WMH patients averaged 10.4 (SLE) and 18.4 (LN) significantly more outpatient visits PPPY than NMH. Overall healthcare cost PPPY was significantly higher for WMH patient in both SLE ($49,553 vs $26,064), and LN ($112,169 vs $39,529). Inpatient costs were approximately 3 – 5 times greater in the WMH group (Table 1).

Table 1.

Follow-up Healthcare Cost and Utilization for SLE/LN Case and Control Population

SLE with MH Comorbidities N=3,880 (WMH)SLE without MH comorbidities N=3,880 (NMH)P-valueLN with MH Comorbidities N=168 (WMH)LN without MH comorbidities N=168 (NMH)P-valueAll-cause health care utilization PPPYMeanMeanMeanMeanMean # inpatient visits1.360.50<0.00011.860.86<0.0001Mean # outpatient visits32.1121.67<0.000147.8529.45<0.0001Mean # office visits13.499.74<0.000114.9410.29<0.0001Mean # ER visits1.270.66<0.00011.400.630.0005Mean # other outpatient visits25.5517.08<0.000141.4824.19<0.0001Mean # pharmacy Rx33.3320.82<0.000136.9623.81<0.0001Length of inpatient stay (mean, days)3.691.09<0.00019.532.37<0.0001All-cause health care costs PPPYOutpatient costs (ER+ office +other)$19,271$12,847<0.0001$34,956$19,530<0.0001Pharmacy costs$7,222$4,707<0.0001$7,874$4,254<0.0001Inpatient costs$22,605$8,191<0.0001$68,216$14,680<0.0001Total costs$49,553$26,064<0.0001$112,169$39,529<0.0001

PPPY: Per patient per year; ER: Emergency room; LN: Lupus nephritis; SLE: Systemic lupus erythematosus

Conclusion:

This real-world study shows that MH comorbidities have a high incidence and prevalence rate in SLE and LN patients. Health care costs and utilization for SLE and LN patients with MH comorbidities were significantly higher than patients without MH comorbidities. This study highlights not just the high prevalence of MH comorbidity but its large contribution to SLE healthcare costs.

Figure 1.

Incidence and Prevalence Rate of Mental Health Comorbidities in the SLE and LN Populations LN: Lupus nephritis; SLE: Systemic lupus erythematosus

Disclosure of Interests:

Michelle A Petri Consultant of: Yes, Grant/research support from: Yes, Dominik Naessens Shareholder of: Yes (Johnson and Johnson), Employee of: Employee of Janssen Pharmaceuticals., Adesuwa Ogbomo: None declared, Anna Ratiu: None declared, Cynthia Gutierrez: None declared, Chetan Karyekar Shareholder of: Own Stock Options as part of being a company employee., Employee of: Current employee of Janssen Pharmaceuticals

Chromatin, DNA Replication, and Transcription: Closing the Triangle

Chromatin features are correctly transferred to the daughter strands during genome replication. Recent discoveries demonstrate that replicative DNA polymerases interact physically with histone dimers and tetramers, facilitating histone transfer at the DNA replication fork. This role may explain the transcriptional phenotypic defects of Arabidopsis mutants in genes encoding DNA polymerase subunits.

Origin Recognition Complex (ORC) Evolution Is Influenced by Global Gene Duplication/Loss Patterns in Eukaryotic Genomes

The conservation of orthologs of most subunits of the origin recognition complex (ORC) has served to propose that the whole complex is common to all eukaryotes. However, various uncertainties have arisen concerning ORC subunit composition in a variety of lineages. Also, it is unclear whether the ancestral diversification of ORC in eukaryotes was accompanied by the neofunctionalization of some subunits, for example, role of ORC1 in centriole homeostasis. We have addressed these questions by reconstructing the distribution and evolutionary history of ORC1-5/CDC6 in a taxon-rich eukaryotic data set. First, we identified ORC subunits previously undetected in divergent lineages, which allowed us to propose a series of parsimonious scenarios for the origin of this multiprotein complex. Contrary to previous expectations, we found a global tendency in eukaryotes to increase or decrease the number of subunits as a consequence of genome duplications or streamlining, respectively. Interestingly, parasites show significantly lower number of subunits than free-living eukaryotes, especially those with the lowest genome size and gene content metrics. We also investigated the evolutionary origin of the ORC1 role in centriole homeostasis mediated by the PACT region in human cells. In particular, we tested the consequences of reducing ORC1 levels in the centriole-containing green alga Chlamydomonas reinhardtii. We found that the proportion of centrioles to flagella and nuclei was not dramatically affected. This, together with the PACT region not being significantly more conserved in centriole-bearing eukaryotes, supports the notion that this neofunctionalization of ORC1 would be a recent acquisition rather than an ancestral eukaryotic feature.

High parathormone levels are associated with adverse cardiovascular events in coronary patients with high fibroblast growth factor-23

Background

Disturbances of the components of the mineral metabolism (MM) (vitamin D, phosphate, parathormone [PTH], fibroblast growth factor-23 [FGF23] and klotho) have been linked to cardiovascular disease. However, the available data are controversial, probably because most studies deal with individual rather than with the whole MM components.

Purpose

To the study the relationship between MM components and cardiovascular events, after controlling for other well-known markers (N-Terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity troponin I [hs-TnI], and high-sensitivity c-reactive protein [hs-CRP]), and relevant clinical variables in stable coronary artery disease (CAD) patients.

Methods

We analyzed the aforementioned markers in 964 CAD patients and followed them subsequently. The primary outcome (PO) was the composite of ischemic events (acute coronary syndrome, stroke or transient ischemic attack), heart failure and death. Secondary outcomes were any ischemic event and the composite of heart failure and death.

Results

Median follow-up was 5.39 years (2.81 - 6.92). Age was 60 (52–72) years and 76.2% patients were male. Median glomerular filtration rate was 80.4 (65.3–93.1) ml/min/1.73 m2. 185 patients developed the PO.

At the univariate analysis PTH, FGF23, NT-proBNP and hs-TnI were directly associated with the PO, while calcidiol and Klotho were inversely related, and phosphate did not reach statistical significance. However, only PTH (HR 1.058 [CI 1.021–1.097]; p=0.002) and NT-proBNP (HR 1.020 [CI 1.012–1.028]; p&lt;0.001) were independent predictors of the PO at multivariate Cox regression analysis. Both PTH and NT-proBNP were also independent predictors of HF or death (HR 1.066 [1.016 - 1.119]; p=0.009 and HR 1.024 [1.014 - 1.034]; p&lt;0.001 respectively), while only PTH predicted ischemic events (HR 1.052 [1.010–1.096]; p=0.016).

After dividing patients in two subgroups according to whether they had FGF23 plasma levels above the median (85.5 RU/ml) or not, PTH remained as a predictor of the PO only in the subgroup with FGF23 &gt;85.5 RU/ml (p&lt;0.001), but not in patients with FGF23 ≤85.5 RU/ml (p=0.551). There was a significant interaction between FGF23 and PTH plasma levels (p=0.002).

Conclusion

PTH predicts cardiovascular events in CAD patients with elevated FGF23 levels even after taking into account all the other components of MM and controlling for NT-ProBNP, hs-CPR and TnI. There is an interaction between PTH and FGF23 levels, and they should be assessed together when exploring their potential predictive power.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Fondo de Investigaciones Sanitarias

A comprehensive fluorescent sensor for spatiotemporal cell cycle analysis in Arabidopsis

Assessing cell proliferation dynamics is crucial to understand the spatiotemporal control of organogenesis. Here we have generated a versatile fluorescent sensor, PlaCCI (plant cell cycle indicator) on the basis of the expression of CDT1a-CFP, H3.1-mCherry and CYCB1;1-YFP, that identifies cell cycle phases in Arabidopsis thaliana. This tool works in a variety of organs, and all markers and the antibiotic resistance are expressed from a single cassette, facilitating the selection in mutant backgrounds. We also show the robustness of PlaCCI line in live-imaging experiments to follow and quantify cell cycle phase progression.

Roles of plant retinoblastoma protein: cell cycle and beyond

The human retinoblastoma (RB1) protein is a tumor suppressor that negatively regulates cell cycle progression through its interaction with members of the E2F/DP family of transcription factors. However, RB-related (RBR) proteins are an early acquisition during eukaryote evolution present in plant lineages, including unicellular algae, ancient plants (ferns, lycophytes, liverworts, mosses), gymnosperms, and angiosperms. The main RBR protein domains and interactions with E2Fs are conserved in all eukaryotes and not only regulate the G1/S transition but also the G2/M transition, as part of DREAM complexes. RBR proteins are also important for asymmetric cell division, stem cell maintenance, and the DNA damage response (DDR). RBR proteins play crucial roles at every developmental phase transition, in association with chromatin factors, as well as during the reproductive phase during female and male gametes production and embryo development. Here, we review the processes where plant RBR proteins play a role and discuss possible avenues of research to obtain a full picture of the multifunctional roles of RBR for plant life.

Similar yet critically different: the distribution, dynamics and function of histone variants

Organization of the genetic information into chromatin plays an important role in the regulation of all DNA template-based reactions. The incorporation of different variant versions of the core histones H3, H2A, and H2B, or the linker histone H1 results in nucleosomes with unique properties. Histone variants can differ by only a few amino acids or larger protein domains and their incorporation may directly affect nucleosome stability and higher order chromatin organization or indirectly influence chromatin function through histone variant-specific binding partners. Histone variants employ dedicated histone deposition machinery for their timely and locus-specific incorporation into chromatin. Plants have evolved specific histone variants with unique expression patterns and features. In this review, we discuss our current knowledge on histone variants in Arabidopsis, their mode of deposition, variant-specific post-translational modifications, and genome-wide distribution, as well as their role in defining different chromatin states.

OP0035 EXAMINATION OF INTERSTITIAL LUNG DISEASE IN PATIENTS WITH RHEUMATOID ARTHRITIS – PREVALENCE, TIME TO ONSET, AND CLINICAL CHARACTERISTICS

Background:

Interstitial lung disease (ILD) is a known extraarticular manifestation of rheumatoid arthritis (RA). Previous studies have shown variability in the prevalence of RA-ILD, as well as clinical characteristics and risk factors of RA-ILD.

Objectives:

To evaluate the prevalence and time to onset of ILD and compare the clinical characteristics between RA patients (pts) with or without ILD using a large US electronic medical record (EMR)-based dataset.

Methods:

Pts with an initial RA diagnosis (ICD-9-CM code: 714.0; ICD-10-CM codes: M05 & M06) during the study period (01JAN2009-20SEP2019) were included from the Discus Analytics JointMan database. The initial RA diagnosis date was defined as the index date. Pts with ILD were identified by ICD diagnosis codes or by provider indication in the JointMan record. Pts who developed ILD before RA were excluded from this analysis. The prevalence and time to onset of ILD were reported. Pt demographics, comorbidities, RA characteristics and disease activity scores were compared for 6 months prior to or on the index date (baseline period) for selected adult RA pts with available information.

Results:

Among 8,963 identified RA pts, 337 (3.8%) were diagnosed with ILD on or after RA diagnosis. The median time to ILD onset post-RA was 2.3 years, and 47% had ILD within 2 years after RA diagnosis. RA-ILD pts were significantly older than those without ILD (65.8 years vs. 59.1 years; p<0.001; Table 1). At baseline, a higher percentage of RA-ILD pts had history of chronic obstructive pulmonary disease, positive rheumatoid factor, rheumatoid nodules, erosive joint disease, positive anti-cyclic citrullinated peptide antibody, and joint swelling compared to RA-only pts (Table 2). The mean ESR and RA disease activity scores were also significantly higher for RA-ILD pts.

Table 1.

Patient Demographics

Patient demographicsRA-ONLY COhort(N = 5,612)RA-ild coHORT(N = 205)P-valueAge, Mean ± SD, years59.1 ± 14.265.8 ± 11.8<.001Male, N (%)1,375 (24.5%)72 (35.1%)0.001Race, N (%) White4,014 (71.5%)165 (80.5%)0.005 African American365 (6.5%)9 (4.4%)0.226 Other/Missing1,233 (22.0%)31 (15.1%)0.020Table 2.

Baseline Clinical Characteristics

Clinical CharacteristicsRA-ONLY COhort(N = 3,846)RA-ild coHORT(N = 115)P-valueHistory of Chronic Obstructive Pulmonary Disease, N (%)102 (2.7%)8 (7.0%)0.006Hypertension, N (%)900 (23.4%)23 (20.0%)0.395Serious Infection, N (%)38 (1.0%)3 (2.6%)0.091Rheumatoid Factor Positive, N (%)1,388 (36.1%)69 (60.0%)<.001Joint Stiffness, N (%)1,092 (28.4%)39 (33.9%)0.197Rheumatoid Nodules, N (%)153 (4.0%)17 (14.8%)<.001Erosive Joint Disease, N (%)459 (11.9%)23 (20.0%)0.009Anti-CCP Antibody Positive, N (%)858 (22.3%)45 (39.1%)<.001Joint Swelling*, N (%)2,861 (58.0%)123 (68.0%)0.008Joint Tenderness*, N (%)3,728 (75.6%)138 (76.2%)0.851ESR**, Mean ± SD, mm/hr22.0 ± 22.630.1 ± 25.5<.001CRP**, Mean ± SD, mg/L22.5 ± 13.060.6 ± 25.00.086CDAI, Mean ± SD16.4 ± 12.318.9 ± 15.70.044DAS28-CRP, Mean ± SD2.6 ± 1.23.1 ± 1.4<.001DAS28-ESR, Mean ± SD3.3 ± 1.43.9 ± 1.5<.001SDAI, Mean ± SD20.2 ± 29.328.6 ± 40.20.048

* A total of 4,929 non-ILD and 181 ILD patients had joint swelling and tenderness data.

** Variables were calculated among patients who had available information.

Conclusion:

This large real-world RA population provides insight into the burden of ILD in RA pts. Pts with ILD had a higher proportion of comorbidities and RA-related conditions and higher RA activity. Further analysis is warranted to assess the risk factors of ILD and its prognosis.

Disclosure of Interests:

Joe Zhuo Shareholder of: Bristol-Myers Squibb, Employee of: Bristol-Myers Squibb, Qisu Zhang Consultant of: I am a paid employee of STATinMED Research which is a paid consultant to Bristol-Myers Squibb Company., Keith Knapp Consultant of: In the last year, I was a paid consultant to Bristol Myers-Squibb Company., Employee of: I am a paid employee of Discus Analytics., Yuexi Wang Consultant of: I am a paid employee of STATinMED Research which is a paid consultant to Bristol-Myers Squibb Company., Cynthia Gutierrez Consultant of: I am a paid employee of STATinMED Research which is a paid consultant to Bristol-Myers Squibb Company., Ding He Consultant of: I am a paid employee of STATinMED Research which is a paid consultant to Bristol-Myers Squibb Company., Lin Xie Consultant of: I am a paid employee of STATinMED Research which is a paid consultant to Bristol-Myers Squibb Company., Sonie Lama Shareholder of: I own shares of Bristol-Myers Squibb Company., Employee of: I am a paid employee of Bristol-Myers Squibb Company., Gary Craig Consultant of: I have served as a consultant to Bristol-Myers Squibb Company., Employee of: I am a paid employee of Arthritis Northwest and VP of Discus Analytics., Speakers bureau: I am a member of the speakers bureau for Bristol-Myers Squibb Company.

SAT0616-HPR IMPLICATED FACTORS IN THERAPEUTIC ADHERENCE OF PATIENTS WITH RHEUMATOID ARTHRITIS: THE PATIENT´S PERSPECTIVE

Background:

Therapeutic adherence has become a topic of growing interest for medical research. Studies have reported non-adherence rates of 20-50% in rheumatoid arthritis (RA) patients (1). Poor adherence has a negative impact on disease outcomes and implies an economic burden for the health system (2). Identifying the potential risk factors for non-adherence is essential to develop intervention strategies to solve this problem

Objectives:

To establish the contribution of illness and medication beliefs to therapeutic adherence in RA. To explore the association of treatment adherence with other patient and disease factors.

Methods:

RA patients ≥ 18 years old from a military hospital diagnosed with RA based on ACR /EULAR 2010 criteria were included in a cross-sectional study. Compliance Questionnaire Rheumatology (CQR) was used to assess treatment adherence. Unsatisfactory compliance was defined as taking correct dosing < 80%. Illness and medication beliefs were evaluated using the “Brief Illness Perception Questionnaire “(IPQ-b) and the “Beliefs about medicine questionnaire” (BMQ). Demographic data and clinical characteristics were collected by standardized clinical interview and revision of medical records.

Results:

144 patients were included the study, 106 (73.6%) women, with a mean age of 62 years (SD 12) and median disease duration of 5 years (interquartile range 25-75: 2-11). 113 (78.4%) patients showed good treatment adherence. No differences were observed regarding demographics and clinical characteristics. Strong beliefs about drugs potential damage was associated with poor compliance (13±5 vs. 11±3, p= 0.013), meanwhile increased belief in medication necessity was associated with good compliance (21±3 vs. 20±3, p= 0.015). From the illness perception measures, adherent patients had increased feeling of treatment control (8.8± 1.5 vs 7.7± 2.1,p= 0.008) and greater emotional response (6.2±3.1 vs 4.8±3.4,p= 0.042). In a multivariate analysis was found that for each unit of increase in the score of BMQ´s damage domain, adherence was reduced by 20% (CI 95% 0.7-0.9, p= 0.001); for each unit of increase in the treatment control item of the IPQ-b, adherence increased 1.42 times (CI 95% 1.1-1.8,p= 0.006); and for each unit of increase in the emotional response item of the IPQ-b, adherence increased 1.2 times (CI 95% 1.08-1.46,p= 0.002).

Conclusion:

Illness and medication beliefs could influence compliance to treatment in patients with RA.

References:

[1]van den Bemt BJ, van den Hoogen FH, Benraad B, et al. Adherence rates and association with nonadherence in patients with rheumatoid arthritis using disease modifyin antirheumatic drugs. J Rheumatol. 2009;36(10):2164–70.

[2]Martikainen JA, Kautiainen H, Rantalaiho V, et al.. Longterm Work Productivity Costs Due to Absenteeism and Permanent Work Disability in Patients with Early Rheumatoid Arthritis : A Nationwide Register Study of 7831 Patients. J Rheumatol. 2016;43(12):2101–5.

Disclosure of Interests:

María Ahijón: None declared, Patricia Carreira Grant/research support from: Actelion, Roche, MSD, Consultant of: GlaxoSmithKline, VivaCell Biotechnology, Emerald Health Pharmaceuticals, Boehringer Ingelheim, Roche, Speakers bureau: Actelion, GlaxoSmithKline, Roche, Carmen De La Cruz: None declared, Raúl Veiga: None declared, Carlos Gutierrez: None declared

A combinatorial biomarker predicts pathologic complete response to neoadjuvant lapatinib and trastuzumab without chemotherapy in patients with HER2+ breast cancer

BACKGROUND

HER2-positive (+) breast cancers, defined by HER2 overexpression and/or amplification, are often addicted to HER2 to maintain their malignant phenotype. Yet, some HER2+ tumors do not benefit from anti-HER2 therapy. We hypothesize that HER2 amplification levels and PI3K pathway activation are key determinants of response to HER2-targeted treatments without chemotherapy.

PATIENTS AND METHODS

Baseline HER2+ tumors from patients treated with neoadjuvant lapatinib plus trastuzumab [with endocrine therapy for estrogen receptor (ER)+ tumors] in TBCRC006 (NCT00548184) were evaluated in a central laboratory for HER2 amplification by fluorescence in situ hybridization (FISH) (n = 56). HER2 copy number (CN) and FISH ratios, and PI3K pathway status, defined by PIK3CA mutations or PTEN levels by immunohistochemistry were available for 41 tumors. Results were correlated with pathologic complete response (pCR; no residual invasive tumor in breast).

RESULTS

Thirteen of the 56 patients (23%) achieved pCR. None of the 11 patients with HER2 ratio <4 and/or CN <10 achieved pCR, whereas 13/45 patients (29%) with HER2 ratio ≥4 and/or CN ≥10 attained pCR (P = 0.0513). Of the 18 patients with tumors expressing high PTEN or wild-type (WT) PIK3CA (intact PI3K pathway), 7 (39%) achieved pCR, compared with 1/23 (4%) with PI3K pathway alterations (P = 0.0133). Seven of the 16 patients (44%) with HER2 ratio ≥4 and intact PI3K pathway achieved pCR, whereas only 1/25 (4%) patients not meeting these criteria achieved pCR (P = 0.0031).

CONCLUSIONS

Our findings suggest that there is a clinical subtype in breast cancer with high HER2 amplification and intact PI3K pathway that is especially sensitive to HER2-targeted therapies without chemotherapy. A combination of HER2 FISH ratio and PI3K pathway status warrants validation to identify patients who may be treated with HER2-targeted therapy without chemotherapy.

Differences in firing efficiency, chromatin, and transcription underlie the developmental plasticity of the Arabidopsis DNA replication origins

Eukaryotic genome replication depends on thousands of DNA replication origins (ORIs). A major challenge is to learn ORI biology in multicellular organisms in the context of growing organs to understand their developmental plasticity. We have identified a set of ORIs of Arabidopsis thaliana and their chromatin landscape at two stages of post-embryonic development. ORIs associate with multiple chromatin signatures including transcription start sites (TSS) but also proximal and distal regulatory regions and heterochromatin, where ORIs colocalize with retrotransposons. In addition, quantitative analysis of ORI activity led us to conclude that strong ORIs have high GC content and clusters of GGN trinucleotides. Development primarily influences ORI firing strength rather than ORI location. ORIs that preferentially fire at early developmental stages colocalize with GC-rich heterochromatin, but at later stages with transcribed genes, perhaps as a consequence of changes in chromatin features associated with developmental processes. Our study provides the set of ORIs active in an organism at the post-embryo stage that should allow us to study ORI biology in response to development, environment, and mutations with a quantitative approach. In a wider scope, the computational strategies developed here can be transferred to other eukaryotic systems.

Abstract P2-07-06: Cumulative copy number imbalances after neoadjuvant chemotherapy residual breast tumor is an independent predictor of relapse

Background: Identifying breast cancer patients after neoadjuvant chemotherapy (NAC) at greatest risk of recurrence would enhance selection of patients who may benefit from novel adjuvant treatments.

Patients. 243 stage I-III breast cancer patients who underwent NAC with ≥10% residual tumor cellularity were identified from the MD Anderson Cancer Center and Ben Taub General Hospital, Harris County hospital. Tumor DNA was isolated for DNA copy number using OncoScan CNV FFPE, Affymetrix. Median follow-up was 67.8 months. Continuous residual cancer burden (RCB) scores with CNI data were available for 152 cases. To test if CNIs covering large regions were associated with recurrence after adjusting for prognostic variables and study site, data were summed to a chromosome-arm level. Eleven chromosome arms with false discovery rate &lt;0.05 for breast cancer recurrence were identified. A stepwise multivariable model including age at diagnosis, tumor subtype, histologic grade, pre- and post-treatment stage, study site, and the 11 chromosomal arms were used to fit a parsimonious multivariate model for recurrence. Minimizing the Akaike Information Criterion yielded a final model with post-stage and a 5-arm CNI (5A-CNI) indicator including 2q, 3q, 4q, 10p, and 18p. Tumors were classified on 5A-CNI as 0 [no CNI], 1 [1- 2] and 2 [&gt; 2].

Results. The study population included 76 non-Hispanic White, 89 Hispanic, and 68 African American patients with a mean age of 49.1 years. 105 patients were classified as 5A-CNI-0, 97 as 5A-CNI-1 and 41 as 5A-CNI-2. A higher 5A-CNI score was associated with tumor grade, ER-negative tumors (p&lt;0.002) and tumor subtype (p=0.014). For 5A-CNI scores of 0, 1 and 2, recurrence rates of 14%, 34% and 58.5% were observed, respectively. In the final multivariable model adjusted for post-stage, RCB and study site, when compared to 5A-CNI-0, the hazard of recurrence was elevated for 5A-CNI-1 (HR= 2.27 [95% CI, 1.01-5.1]) and 5A-CNI-2 tumors (HR=7.43 [95% CI, 2.85-19.39]). Further, while the sample size is limiting, of 10 patients who were RCB3 and 5A-CNI-2, 9 relapsed (90%) during follow-up compared to only 6 of 43 (14%) of RCB3 patients with 5A-CNI-0 (p&lt;10-6). For patients with RCB1 or 2, relapse did not differ by 5A-CNI score. Neither race nor ethnicity were found to be independently associated with recurrence or tumor subtype. However, African American, followed by Hispanic patients, were more likely than non-Hispanic White patients to be classified as 5A-CNI-2 (p=0.013).

Table 1.Significant difference in distribution of 5 arm CNI classifier by Race/Ethnicity in Study Sample (p =0.013).5A-CNI012Non-Hispanic Whiten=44; 57.9%n=25; 32.9%n=7; 9.2%Hispanicn=32; 36%n=42; 47.2%n=15; 16.9%African Americann=28; 41.2%n=23; 33.8%n=17; 25%

Conclusion. The 5A-CNI score in post NAC tumor identifies a patient population with very poor prognosis independent of current clinical prognostic factors including RCB. Validation of these findings may lead to a post NAC genomic test that identifies patients who would benefit from additional treatment Further investigation of the nature of the association between the 5A-CNI score and race/ethnicity, which appears independent of tumor subtype, is warranted.

Citation Format: Thompson PA, Brewster A, Tsavachidis S, Armstrong G, Do K-A, Ha M-J, Gutierrez C, Symmans F, Bondy M. Cumulative copy number imbalances after neoadjuvant chemotherapy residual breast tumor is an independent predictor of relapse [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 P2-07-06.

Abstract P4-15-05: Biomarkers of response to neoadjuvant endocrine therapy with anastrozole (Ana) alone or in combination with fulvestrant (Ful) in ER-positive (ER+) HER2-negative (HER2-) breast cancer (PACT01 trial)

Background: In recent years, several clinical trials showed that fulvestrant (Ful), alone or in combination with an aromatase inhibitor (AI), is more effective than an AI alone. PACT01 is a randomized neoadjuvant trial of Anastrazole (Ana) alone or in combination with Ful in ER+/HER2- breast cancer.

Methods: Patients with newly diagnosed ER+/HER2- breast cancers, 2 cm or larger in size, were randomized to 16 weeks of Ana (1 mg orally every day) alone or in combination with Ful (500mg IM days 1, 15, 29, and every 28 days thereafter) for 16 weeks. Patients then proceeded to surgery. Tumor tissue was collected at baseline, day 28 (D28), and at the time of surgery. Primary endpoint was the reduction of Ki67 in tumor tissue between baseline and D28. Baseline and D28 samples were stained for ER, PR, HER2, and Ki67. ER and PR were scored for intensity and percentage (H-score), HER2 was scored for intensity of membrane staining; and Ki67 was scored as percentage. Data were summarized descriptively. Changes in biomarkers from baseline to D28 were calculated and compared by Wilcoxon signed rank test.

Results: PACT01 trial enrolled 72 patients. Three of them did not start treatment. Baseline samples were collected from the remaining 69 patients, and D28 samples from 60 patients (5 refused, 2 withdrew, 1 lost to follow up, 1 unknown). Samples from 18 patients had no tumor (5 at baseline, 9 at D28, 4 at both). Of the 42 patients with paired samples, 20 received Ana and 22 received Ana+Ful. All cases except one were centrally confirmed to be ER+, and all were HER2-. Table 1 summarizes median expression of Ki67, ER, and PR. Both treatment regimens led to a significant reduction in Ki67 between baseline and D28. However, Ana+Ful did not reduce Ki67 more effectively than Ana alone. Ki67 was reduced to &lt;10% in 60% of the Ana arm and 68% of the Ana+Ful, which was not statistically significant.PR was similarly reduced in both treatment arms. ER was significantly reduced at D28 in the Ana+Ful arm (p=0.0004) but not in the Ana alone arm. Safety profile of both treatment arms was consistent with package insert and published studies.

Median expression of Ki67, ER and PR in Anastrazole and Anastrazole + Fulvestrant Arms at Baseline and Day 28ARMTimepointNKi67 (%)ER H-scorePR H-scoreAnaBaseline2024.8182.5100.3 Day 28205.6*170.025.0Ana + FluBaseline2225.6198.120.5 Day 28225.1*117.50.0* p=0.0004. Other comparisons were not stastistically significant

Conclusions:In this small neoadjuvant trial, the addition of Ful to Ana did not increase Ki67 suppression at D28. This may be due to untreated primary tumors being exquisitely sensitive to Ana and that fulvestrant may not add to it. It is also possible that the effect of Ful may be noted later in the course of treatment. Further biomarker data on tissue collected at the end of treatment will be presented at the meeting.

Citation Format: Dhamne S, Nagi C, Wang T, Pavlick AC, Reusser B, Schiff R, Julie N, Niravath P, Silberfein EJ, Sedgwick EL, Sepulveda KA, Gutierrez C, Hilsenbeck SG, Chang JC, Osborne CK, Rimawi MF. Biomarkers of response to neoadjuvant endocrine therapy with anastrozole (Ana) alone or in combination with fulvestrant (Ful) in ER-positive (ER+) HER2-negative (HER2-) breast cancer (PACT01 trial) [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 P4-15-05.

Development and content validation of measures assessing adherence barriers and behaviors for use in clinical care

BACKGROUND

Providers are often unaware of poor adherence to prescribed medications for their patients with chronic diseases.

OBJECTIVE

To develop brief, computer-administered patient-reported measures in English and Spanish assessing adherence behaviors and barriers. Design, Participants, and Main Measures: Item pools were constructed from existing measures of medication adherence behaviors and barriers, which informed development of a patient concept elicitation interview guide to identify medication adherence behavior and barrier-related concepts. Two hundred six patients either living with HIV (PLWH) or without were interviewed. Interviews were coded, concepts matched to item pool content, and new items were developed for novel concepts. A provider/investigator team highlighted clinically relevant items. Cognitive interviews were conducted with patients on final candidate items (n = 37). The instruments were administered to 2081 PLWH.

KEY RESULTS

Behavioral themes from concept elicitation interviews included routines incorporating time of day, placement, visual cues, and intentionality to miss or skip doses. Barrier themes included health-related (e.g. depressed mood, feeling ill), attitudes/beliefs (e.g., need for medication), access (e.g., cost/insurance problems), and circumstantial barriers (e.g., lack of privacy, disruption of daily routine). The final instruments included 6 behavior items, and 1 barrier item with up to 23 response options. PLWH endorsed a mean (SD) of 3.5 (1.1) behaviors. The 201 PLWH who missed ≥2 doses in the previous week endorsed a mean (SD) of 3.1 (2.5) barriers. The intraclass correlation coefficient (ICC) for the numbers of behaviors endorsed in 61 PLWH after 4-16 days was 0.54 and for the number of barriers for the 20 PLWH with ≥2 missed doses the ICC was 0.89, representing fair and excellent test-retest reliability.

CONCLUSION

Measures of medication adherence behaviors and barriers were developed for use with patients living with chronic diseases focusing on clinical relevance, brevity, and content validity for use in clinical care.

[Epidemiology of Q fever in Spain (2018)]

Q fever is an anthropozoonosis whose causative agent is Coxiella burnetii, which has an important impact from the human and animal health point of view. In this review, a brief historical reference of the infection by C. burnetii and Q fever has been made initially. In a second section the basic epidemiological aspects of this infection are described (reservoirs/ sources of infection, form of transmission and epidemiological forms). Subsequently, the data of the infection by C. burnetii in Spain will be are indicated, particularly the clinical series, the seroepidemiological studies in humans, the affectation of different types of mammals and the participation of the ticks in the biological cycle. In addition, basic data on C. burnetii infection/ disease in other regions of the world will be are also included. Finally, and taking into account the previous data will indicate the main epidemiological characteristics of Q fever at present.

Abstract P2-03-01: Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration

Aims: (i) Determine whether between-observer reproducibility for Ki67 when assessed on whole sections according to a standardized scoring protocol is adequate for clinical application. (ii) Compare between-observer reproducibility of Ki67 scores assessed on hot-spots to scores using a global method that averages across a tissue section.

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including aiding decisions based on prognosis, but unacceptable levels of between-laboratory variability have been observed. The International Ki67 in Breast Cancer Working Group has undertaken a systematic program to determine whether Ki67 measurement can be analytically validated and standardized across labs. In phase 1, variability in visual interpretation was identified as an important source of variability. Phases 2 and 3a showed that adherence to defined scoring methods substantially improved reproducibility in scoring tissue microarrays and core-cut biopsies. We now assess whether acceptable reproducibility can be achieved on whole sections.

Methods: Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 to assemble 4 sets of 30 stained tumor sections, circulated around 23 labs in 12 countries. Ki67 was scored by 2 methods by all labs: (a) global: 4 fields of 100 tumor cells each were selected to reflect observed heterogeneity in nuclear staining (b) hot-spot: the field with highest Ki67 percentage of tumor cells with nuclear staining was selected and up to 500 cells scored. Ki67 scores were log2-transformed for statistical analyses and back-transformed for presentation. The primary objective was to assess whether either method could achieve an intraclass correlation coefficient (ICC) significantly greater than 0.8, considered substantial to almost-perfect reproducibility. Secondary objectives were to assess which method had highest observed ICC and to assess whether observers identified the same “hot-spots”.

Results: ICC for the global method was 0.87 (95%CI: 0.799-0.93), marginally meeting the prespecified success criterion. The ICC for the hot-spot method was 0.83 (95%CI: 0.74-0.90) and had a CI extending below the success criterion. Across the 23 labs, geometric mean value of the 30 scores ranged from 8.5 to 19.6 for the global method and from 12.8 to 30.3 for the hot-spot method. The overall mean (95% CI) of these values was 12.9 (11.9-14.0) and 20.9 (19.1-22.8), respectively. Visually, between-laboratory agreement in location of selected hot-spot varies between cases. The median times for scoring were 9 and 6 minutes for global and hot-spot methods respectively.

Conclusions: The global method marginally met the prespecified criterion of success; it should now be evaluated for clinical validity in appropriate cohorts of cases. The hot-spot method was observed to have slightly less reproducibility between labs. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between labs further.

(Supported by a grant from the Breast Cancer Research Foundation)

Citation Format: Nielsen TO, Leung SCY, Zabaglo LA, Arun I, Badve SS, Bane AL, Bartlet JMS, Borgquist S, Chang MC, Dodson A, Ehinger A, Fineberg S, Focke CM, Gao D, Gown AM, Gutierrez C, Hugh JC, Kos Z, Lænkholm A-V, Mastropasqua MG, Moriya T, Nofech-Mozes S, Osborne CK, Penault-Llorca FM, Piper T, Sakatani T, Salgado R, Starczynski J, Sugie T, van der Vegt B, Viale G, Hayes DF, McShane LM, Dowsett M. Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-01.

Replication of ribosomal DNA in Arabidopsis occurs both inside and outside the nucleolus during S phase progression

Ribosomal RNA genes (rDNA) have been used as valuable experimental systems in numerous studies. Here, we focus on elucidating the spatiotemporal organisation of rDNA replication in Arabidopsis thaliana To determine the subnuclear distribution of rDNA and the progression of its replication during the S phase, we apply 5-ethynyl-2'-deoxyuridine (EdU) labelling, fluorescence-activated cell sorting, fluorescence in situ hybridization and structured illumination microscopy. We show that rDNA is replicated inside and outside the nucleolus, where active transcription occurs at the same time. Nascent rDNA shows a maximum of nucleolar associations during early S phase. In addition to EdU patterns typical for early or late S phase, we describe two intermediate EdU profiles characteristic for mid S phase. Moreover, the use of lines containing mutations in the chromatin assembly factor-1 gene fas1 and wild-type progeny of fas1xfas2 crosses depleted of inactive copies allows for selective observation of the replication pattern of active rDNA. High-resolution data are presented, revealing the culmination of replication in the mid S phase in the nucleolus and its vicinity. Taken together, our results provide a detailed snapshot of replication of active and inactive rDNA during S phase progression.

A Rapid and Efficient ChIP Protocol to Profile Chromatin Binding Proteins and Epigenetic Modifications in Arabidopsis

Chromatin immunoprecipitation (ChIP) is a widely used and very powerful procedure to identify the proteins that are associated with the DNA to regulate developmental processes. These proteins can be transcription factors, or specific histone variants and modified histones, which are all crucial for gene regulation. In order to obtain reliable results, ChIP must be carried out under highly reproducible conditions. Here, we describe a simple and fast ChIP protocol adapted for Arabidopsis seedlings, which can serve as a basis for other species, organs or more sophisticated procedures, such as the sequential ChIP. We also provide user-oriented troubleshooting to increase the chances of successful applications.

Retrotransposons are specified as DNA replication origins in the gene-poor regions of Arabidopsis heterochromatin

Genomic stability depends on faithful genome replication. This is achieved by the concerted activity of thousands of DNA replication origins (ORIs) scattered throughout the genome. The DNA and chromatin features determining ORI specification are not presently known. We have generated a high-resolution genome-wide map of 3230 ORIs in cultured Arabidopsis thaliana cells. Here, we focused on defining the features associated with ORIs in heterochromatin. In pericentromeric gene-poor domains ORIs associate almost exclusively with the retrotransposon class of transposable elements (TEs), in particular of the Gypsy family. ORI activity in retrotransposons occurs independently of TE expression and while maintaining high levels of H3K9me2 and H3K27me1, typical marks of repressed heterochromatin. ORI-TEs largely colocalize with chromatin signatures defining GC-rich heterochromatin. Importantly, TEs with active ORIs contain a local GC content higher than the TEs lacking them. Our results lead us to conclude that ORI colocalization with retrotransposons is determined by their transposition mechanism based on transcription, and a specific chromatin landscape. Our detailed analysis of ORIs responsible for heterochromatin replication has implications on the mechanisms of ORI specification in other multicellular organisms in which retrotransposons are major components of heterochromatin and of the entire genome.

Identification of a divergent genotype of equine arteritis virus from South American donkeys

A novel equine arteritis virus (EAV) was isolated and sequenced from feral donkeys in Chile. Phylogenetic analysis indicates that the new virus and South African asinine strains diverged at least 100 years from equine EAV strains. The results indicate that asinine strains belonged to a different EAV genotype.

Recommendations of the Spanish brachytherapy group (GEB) of Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for high-dose rate (HDR) non melanoma skin cancer brachytherapy

Clinical indications of brachytherapy in non-melanoma skin cancers, description of applicators and dosimetry recommendations are described based on the literature review, clinical practice and experience of Spanish Group of Brachytherapy and Spanish Society of Medical Physics reported in the XIV Annual Consensus Meeting on Non Melanoma Skin Cancer Brachytherapy held in Benidorm, Alicante (Spain) on October 21st, 2016. All the recommendations for which consensus was achieved are highlighted in blue. Regular and small surfaces may be treated with Leipzig, Valencia, flap applicators or electronic brachytherapy (EBT). For irregular surfaces, customized molds or interstitial implants should be employed. The dose is prescribed at a maximum depth of 3-4 mm of the clinical target volume/planning target volume (CTV/PTV) in all cases except in flaps or molds in which 5 mm is appropriate. Interstitial brachytherapy should be used for CTV/PTV >5 mm. Different total doses and fraction sizes are used with very similar clinical and toxicity results. Hypofractionation is very useful twice or 3 times a week, being comfortable for patients and practical for Radiotherapy Departments. In interstitial brachytherapy 2 fractions twice a day are applied.