Dissociable Contributions of Basolateral Amygdala and Ventrolateral Orbitofrontal Cortex to Flexible Learning Under Uncertainty

Reversal learning measures the ability to form flexible associations between choice outcomes with stimuli and actions that precede them. This type of learning is thought to rely on several cortical and subcortical areas, including the highly interconnected orbitofrontal cortex (OFC) and basolateral amygdala (BLA), and is often impaired in various neuropsychiatric and substance use disorders. However, the unique contributions of these regions to stimulus- and action-based reversal learning have not been systematically compared using a chemogenetic approach particularly before and after the first reversal that introduces new uncertainty. Here, we examined the roles of ventrolateral OFC (vlOFC) and BLA during reversal learning. Male and female rats were prepared with inhibitory designer receptors exclusively activated by designer drugs targeting projection neurons in these regions and tested on a series of deterministic and probabilistic reversals during which they learned about stimulus identity or side (left or right) associated with different reward probabilities. Using a counterbalanced within-subject design, we inhibited these regions prior to reversal sessions. We assessed initial and pre-/post-reversal changes in performance to measure learning and adjustments to reversals, respectively. We found that inhibition of the ventrolateral orbitofrontal cortex (vlOFC), but not BLA, eliminated adjustments to stimulus-based reversals. Inhibition of BLA, but not vlOFC, selectively impaired action-based probabilistic reversal learning, leaving deterministic reversal learning intact. vlOFC exhibited a sex-dependent role in early adjustment to action-based reversals, but not in overall learning. These results reveal dissociable roles for BLA and vlOFC in flexible learning and highlight a more crucial role for BLA in learning meaningful changes in the reward environment.

Spinal gunshot wounds: A retrospective, multicenter, cohort study

INTRODUCTION AND OBJECTIVE

To describe the demographic and clinical characteristics and treatment of patients with spinal gunshot wounds across Latin America.

MATERIAL AND METHODS

Retrospective, multicenter cohort study of patients treated for gunshot wounds to the spine spanning 12 institutions across Latin America between January 2015 and January 2022. Demographic and clinical data were recorded, including the time of injury, initial assessment, characteristics of the vertebral gunshot injury, and treatment.

RESULTS

Data on 423 patients with spinal gunshot injuries were extracted from institutions in Mexico (82%), Argentina, Brazil, Colombia, and Venezuela. Patients were predominantly male civilians in low-risk-of-violence professions, and of lower/middle social status, and a sizeable majority of gunshots were from low-energy firearms. Vertebral injuries mainly affected the thoracic and lumbar spine. Neurological injury was documented in n=320 (76%) patients, with spinal cord injuries in 269 (63%). Treatment was largely conservative, with just 90 (21%) patients treated surgically, principally using posterior open midline approach to the spine (n=79; 87%). Injury features distinguishing surgical from non-surgical cases were neurological compromise (p=0.004), canal compromise (p<0.001), dirty wounds (p<0.001), bullet or bone fragment remains in the spinal canal (p<0.001) and injury pattern (p<0.001). After a multivariate analysis through a binary logistic regression model, the aforementioned variables remained statistically significant except neurological compromise.

CONCLUSIONS

In this multicenter study of spinal gunshot victims, most were treated non-surgically, despite neurological injury in 76% and spinal injury in 63% of patients.

Stratification of adolescents across mental phenomena emphasizes the importance of transdiagnostic distress: a replication in two general population cohorts

Characterizing patterns of mental phenomena in epidemiological studies of adolescents can provide insight into the latent organization of psychiatric disorders. This avoids the biases of chronicity and selection inherent in clinical samples, guides models of shared aetiology within psychiatric disorders and informs the development and implementation of interventions. We applied Gaussian mixture modelling to measures of mental phenomena from two general population cohorts: the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 3018) and the Neuroscience in Psychiatry Network (NSPN, n = 2023). We defined classes according to their patterns of both positive (e.g. wellbeing and self-esteem) and negative (e.g. depression, anxiety, and psychotic experiences) phenomena. Subsequently, we characterized classes by considering the distribution of diagnoses and sex split across classes. Four well-separated classes were identified within each cohort. Classes primarily differed by overall severity of transdiagnostic distress rather than particular patterns of phenomena akin to diagnoses. Further, as overall severity of distress increased, so did within-class variability, the proportion of individuals with operational psychiatric diagnoses. These results suggest that classes of mental phenomena in the general population of adolescents may not be the same as those found in clinical samples. Classes differentiated only by overall severity support the existence of a general, transdiagnostic mental distress factor and have important implications for intervention.

Our voices, our lives: Unforeseen stories after the violence and opening the door to becoming whole again

We are a group of 11 women in Albuquerque, New Mexico. Nine of us are immigrants from Mexico. One of us is from an immigrant household. One of us is neither. We have been working collaboratively on a research study called Tertulias (Spanish for "a social gathering"), which is an innovative women's peer support group approach we created to reduce social isolation, depression, and stress among women immigrants from Mexico, and to increase their resilience and sense of empowerment. In the process of implementing the Tertulias study, we are revealing the profound power of peer support, friendship, and small, quotidian kindnesses. But we are also exposing the immensity and scope of trauma, fear, loneliness, depression, and self-blame that exist in the Mexican immigrant community because of domestic violence. Our experience with domestic violence and with the consciousness-raising and support we found in Tertulias has made us want to be involved in a positive manner to do something about this issue in our community. We want our experience to mean something-to be used to make a difference. We are opening our hearts and sharing our stories and ideas. We wanted to be included as co-authors of this article because we want our stories to be received and heard by other women. We want to plant seeds to help other women find their inner strength to be able to escape from their chains. We have to return for others. It is a commitment-to understand how we were able to do it and share that with others. Through our experience participating in Tertulias, we learned that we could overcome what felt overwhelming and impenetrable. We could leave the violence and rediscover and recreate ourselves and our lives.

Sex-differences in oral anticoagulation therapy in patients hospitalised with atrial fibrillation: a nationwide cohort study

Background

Important disparities in the treatment and outcomes of women and men with atrial fibrillation are well recognized. Whether introduction of direct oral anticoagulants has reduced disparities in treatment is uncertain.

Methods

All patients who had an incident hospitalization from 2010 to 2019 with non-valvular atrial fibrillation in Scotland were included in this cohort study. Community drug dispensing data were used to determine prescribed oral anticoagulation therapy and comorbidity status. Logistic regression modelling was used to evaluate patient factors associated with treatment with vitamin K antagonists and direct oral anticoagulants.

Results

A total of 172,989 patients (48% women [82,833/172,989]) had an incident hospitalization with non-valvular atrial fibrillation in Scotland between 2010 and 2019. The proportion of patients with thromboembolic risk factors (CHA2DS2VASc score &gt;0 in men and &gt;1 in women) treated with oral anticoagulation therapy increased from 36.8% to 66.3% over this 10-year period. By 2019, factor Xa inhibitors accounted for 83.6% of all oral anticoagulants prescribed, while treatment with vitamin K antagonists and direct thrombin inhibitors declined to 15.9% and 0.6%, respectively. Women were less likely to be prescribed any oral anticoagulation therapy compared to men (adjusted odds ratio, aOR 0.68 [95% CI, CI 0.67–0.70]). This disparity was mainly attributed to vitamin K antagonists (aOR 0.68 [95% CI 0.66–0.70]), whilst there was less disparity in use of factor Xa inhibitors between women and men (aOR 0.92 [95% CI 0.90–0.95]). At 1 year following hospitalization with atrial fibrillation, patients not prescribed oral anticoagulation therapy were more likely to have subsequent major adverse cardiovascular events compared to those prescribed with oral anticoagulation therapy (38.8% [15,380/39,608] versus 17.0% [6,761/39,671] in women and 35.2% [12,977/36,868] versus 16.4% [7,395/45,093] in men).

Conclusions

Women with non-valvular atrial fibrillation were significantly less likely to be prescribed vitamin K antagonists compared to men. Most patients admitted to hospital in Scotland with incident non-valvular atrial fibrillation are now treated with factor Xa inhibitors and this is associated with less treatment disparities between women and men.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by the British Heart Foundation through a Clinical Research Training Fellowship (FS/18/25/33454), Intermediate Clinical Research Fellowship (FS/19/17/34172), Senior Clinical Research Fellowship (FS/16/14/32023) and a Research Excellence Award (RE/18/5/34216), and a research grant to NHS Lothian from Bristol Myers Squibb Pharmaceuticals Ltd and Pfizer UK Ltd.

A global ensemble of ocean wave climate statistics from contemporary wave reanalysis and hindcasts

There are numerous global ocean wave reanalysis and hindcast products currently being distributed and used across different scientific fields. However, there is not a consistent dataset that can sample across all existing products based on a standardized framework. Here, we present and describe the first coordinated multi-product ensemble of present-day global wave fields available to date. This dataset, produced through the Coordinated Ocean Wave Climate Project (COWCLIP) phase 2, includes general and extreme statistics of significant wave height (H_s), mean wave period (T_m) and mean wave direction (θ_m) computed across 1980–2014, at different frequency resolutions (monthly, seasonally, and annually). This coordinated global ensemble has been derived from fourteen state-of-the-science global wave products obtained from different atmospheric reanalysis forcing and downscaling methods. This data set has been processed, under a specific framework for consistency and quality, following standard Data Reference Syntax, Directory Structures and Metadata specifications. This new comprehensive dataset provides support to future broad-scale analysis of historical wave climatology and variability as well as coastal risk and vulnerability assessments across offshore and coastal engineering applications.

Measurement(s)	Significant wave height • Mean wave period • Mean wave direction
Technology Type(s)	Global wave reanalysis and hindcasts
Sample Characteristic - Environment	Wind-waves
Sample Characteristic - Location	Global

Factors affecting In vitro methane production from cecum contents of White Roman geese

The goal of this research was to gain understanding of in vitro methane (CH4) production from the cecal contents of White Roman geese under various incubation conditions. Five experiments were conducted to ascertain the effects of i) incubation time, ii) pH, iii) the addition of formic acid to the culture media, iv) temperature, and v) the addition of salt to the nutritive liquid. Methane production increased significantly with the supplementation of formic acid in the culture fluid (Experiment III). Additionally, CH4 production Experiment V was higher than that without saline. In contrast, low CH4 production occurred under acidic conditions (pH ≦5.4) and at temperatures higher or lower than typical bird body temperature (43 °C) without formic acid and saline solution in the culture media. Since bird body temperature cannot be controlled easily, approaches such as maintaining cecum fluid at low pH and preventing the formation of formic acid by adjusting the recipes of feeds could be considered for controlling in vivo CH4 production from the intestinal tract digesta of geese.

A randomized control trial to test a peer support group approach for reducing social isolation and depression among female Mexican immigrants

BACKGROUND

Female Mexican Immigrants (FMIs) experience high rates of depression compared with other populations. For this population, depression is often exacerbated by social isolation associated with the experience of immigration. Aim 1. To measure whether a culturally situated peer group intervention will reduce depression and stress associated with the experience of immigration. Aim 2. To test whether an intervention using a "women's funds of knowledge" approach results in improved resilience, knowledge and empowerment. Aim 3. To investigate whether a culturally situated peer group intervention using a women's funds of knowledge approach can give participants a sense and experience of social and physical connection ("emplacement") that is lost in the process of immigration.

METHODS

This mixed-methods study will implement "Tertulias" ("conversational gatherings" in Spanish), a peer support group intervention designed to improve health outcomes for FMI participants in Albuquerque, New Mexico. We will document results of the intervention on our primary hypotheses of a decrease in depression, and increases in resilience and social support, as well as on our secondary hypotheses of decreased stress (including testing of hair cortisol as a biomarker for chronic stress), and an increase in social connectedness and positive assessment of knowledge and empowerment.

DISCUSSION

This project will address mental health disparities in an underserved population that experiences high rates of social isolation. Successful completion of this project will demonstrate that health challenges that may appear too complex and too hard to address can be using a multi-level, holistic approach. Our use of hair samples to test for the 3-month average levels of systemic cortisol will contribute to the literature on an emerging biomarker for analyzing chronic stress.

TRIAL REGISTRATION

This study was registered with ClinicalTrials.gov on 2/3/20, Identifier # NCT04254198 .

Relationship between episodes of unsustained VTs detected early after an ICD implant and subsequent monomorphic VTs causing appropriate therapy

Introduction

Non-sustained ventricular tachycardias (NSVT) are observed frequently among ICD patients with left ventricular dysfunction (LVD).

Purpose

To analyze the relationship between episodes of NSVTs and monomorphic VTs (MVTs) that subsequently cause appropriate therapies.

Methods

416 ICD patients with LVD (LVEF &lt;45%) followed for 41±27 months. ICD programming (detection and therapies) was standardized. NSVT was defined as any VT of ≥5 beats which did not met the detection criteria occurring within the first 6 months after ICD implant. We analyzed 2201 NSVTs (10+7 beats), which occurred in 250 of the 416 patients (Median=2; IQR=0–7). The mean cycle length (CL) of NSVT was 323±32 ms (adjusted per multiple episodes/patient, generalized estimating equation method (GEEM)).

Results

During the follow-up, 1441 MVT occurred in 183 patients. After showing a significant correlation between burden of NSVT and the occurrence of appropriate therapies due to MVT (C coefficient=0.68; p&lt;0.001), we observed that subjects with &gt;5 NSVT presented an excess of adjusted risk: HR=1.97 (95% CI=1.45–2.72); p&lt;0.001. However, the adjusted mean CL of NSVTs was similar in patients with (322±34) vs. without MVT (324±26 ms); p=0.3.

Among patients who presented NSVTs and MVTs (n=145 subjects), we analyzed the relationship between the adjusted mean CL of the NSVTs (n=1288 episodes) and the CL of the first appropriate therapy due to MVT occurring subsequently. We found a significant and positive correlation between the two (r=0.88; p&lt;0.001); the strongest correlation was observed in subjects with &gt;5 NSVTs (r=0.97, n=52)). The robustness of such correlation was similar in individuals with ischemic (r=0.86; n=91) versus non-ischemic cardiomyopathy (r=0.90; n=54), and in primary (r=0.86; n=75) versus secondary prevention (r=0.90; n=70). The agreement between the CL of first MVT and the adjusted mean CL of NSVT episodes (GEEM) was determined according to the Bland-Altman Method. The difference between the two values was 2±8.3 ms, with only 7.6% (11/145) of patients in whom the difference between the two CL was outside the concordance limits. The agreement was greater, again, in individuals with &gt;5 NSVTs. As shown in the Figure, in more than 95% of patients both values were within the interval of agreement (0.32±4 ms).

Conclusions

1-The burden of NSVTs occurring early after an ICD implant, but not their CL, is associated with a higher incidence of appropriate therapies due to MVT at follow-up.

2-The CL of the NSVTs and that of the first and subsequent MVTs is virtually the same in patients with higher NSVT burden. Therefore, it could be the same tachycardia, but with different duration.

Figure 1

Funding Acknowledgement

Type of funding source: None

An incoherent HIFU transducer for treatment of the medial branch nerve: Numerical study and in vivo validation

BACKGROUND

Chronic back pain due to facet related degenerative changes affects 4-6 million patients a year in the United States. Patients refractory to conservative therapy may warrant targeted injections of steroids into the joint or percutaneous medial branch nerve denervation with radiofrequency ablation. We numerically tested a novel noninvasive high intensity focused ultrasound transducer to optimize nerve ablation near a bone-soft tissue interface.

METHODS

A transducer with 4 elements operating in an incoherent mode was modeled numerically and tested pre-clinically under fluoroscopic guidance. After 6 lumbar medial branch nerve ablations were performed in 2 pigs, they were followed clinically for 1 week and then sacrificed for pathological evaluation.

RESULTS

Simulations show that the acoustic spot size in water at 6 dB was 14mm axial x 1.6mm lateral and 52mm axial x 1.6mm lateral for coherent and incoherent modes, respectively. We measured the size of N = 6 lesions induced in vivo in a pig model and compared them to the size of the simulated thermal dose. The best match between the simulated and measured lesion size was found with a maximum absorption coefficient in the cortical bone adjusted to 30 dB/cm/MHz. This absorption was used to simulate clinical scenarios in humans to generate lesions with no potential side effects at 1000 and 1500 J.

CONCLUSION

The elongated spot obtained with the incoherent mode facilitates the targeting during fluoroscopic-guided medial branch nerve ablation.

Depreciación del caballo Pura Raza Española con la deformación del borde dorsal del cuello

Se plantea como objetivo estimar la depreciación de un caballo Pura Raza Española con la deformación del borde dorsal del cuello. Se estudió a una población de 500 caballos de Pura Raza Española clasificados en 4 edades: Potros (6 meses-4 años), en doma 4-8 años, adultos 8-12 años y maduros (12-20 años), pertenecientes a 65 propietarios, 10 centros de cría Pura Raza Española y un matadero en Andalucía y Extremadura, España. Se realizó la estimación de la depreciación para un año una vez detectada la deformación del borde dorsal de cuello, de manera separada por 3 grupos etarios: caballos en doma 4-8 años, caballos adultos 8-12 años y caballos maduros (12-20 años), mediante tres métodos, el método de línea recta, el método de la reducción de saldo (5%) y el método de la suma de los dígitos de los años. En relación a la depreciación del caballo de Pura Raza Española con deformación del borde dorsal del cuello, estimada para un año, es bastante alta y proporcional al costo del caballo. En conclusión, la depreciación del caballo de Pura Raza Española con la deformación del borde dorsal del cuello, se puede presentar en promedio a partir de los 6 años de edad (aproximadamente entre 4-8 años), la depreciación calculada por los tres métodos línea recta, reducción del saldo al 5% y suma de los dígitos fue similar, solo presento variación por el grupo etario 4-8 años 95%, 8-12 años 99% y 12-20 años 98% de depreciación respetivamente.

P2879Effectiveness of first versus subsequentes ATP attemps: predictors and clinical consequences

Introduction

Antitachycardia pacing (ATP) terminates the majority (but not all) of slow VTs (S-VT) with a cycle length (CL) >320 ms.

Purpose

To analyze the efficacy, safety and predictors of ATP, comparing the first (ATP-1) to the second (ATP-2) and third (ATP-3) attempts.

Methods

We studied 556 S-VT (CL=354±18 ms; range: 321–415 ms; 1.6% syncopes) occurring in 67 patients. ATP programming was standardized, including three consecutive bursts of 15 pulses at 91% of VT CL.

Results

ATP effectiveness declined significantly from ATP-1 (436/556: 78%) compared to ATP-2 (24/103: 23%) and ATP-3 (10/79: 13%), p<0.01 for all comparisons. The percentage of variation of RR intervals (P-RR, %) was significantly higher prior to effective ATP-1 (2.73±1.45 vs 1.23±0.9; p<0.001). After an ineffective ATP-1, the P-RR decreased dramatically, with no differences between episodes terminated or not at ATP-2 (0.6±0.14 vs 0.44±0.16; p=0.6) or ATP-3 (0.54±0.15 vs. 0.52±0.14; p=0.7). The postpacing interval – CL difference (PPI-CLd) after an unsuccessful ATP-1 was shorter in episodes terminating at ATP-2 or ATP-3 (180±24 vs 211±15 ms; p<0.001) being 200 ms the cut-off point with the best sensitivity and specificity for non-effective ATP-2 and ATP-3 (93% and 74%, respectively). By multivariate analysis, the duration of native QRS complex (dQRS) (ms) was found the only independent predictor of a PPI-CLd ≥200 ms (OR=1.04; p=0.003). The best cutoff point of dQRS for PP-CLd ≥200 ms was 120 ms (sensitivity and specificity of 66% and 79%, respectively).

Several predictors of ATP efficacy were found by logistic regression: a) ATP-1: P-RR (OR=7.3; p<0.001), beta-blockers (OR=4.1; p<0.001) and dQRS (OR=0.95; p<0.001); b) ATP-2: PPI-CLd (OR=0.94; p=0.001) and dQRS (OR=0.96; p=0.04); c) ATP-3: PPI-CLd (OR=0.93; p=0.009).

Patients with a dQRS≥120 ms had a lower adjusted effectiveness of ATP and a higher proportion of S-VT causing syncope. Table.

Table 1 Patients with QRS <120 ms Patients with QRS ≥120 ms p value Adjusted effectiveness of ATP-1 89% (82–96) 70% (59–80) 0.008 Adjusted effectiveness of ATP-2 47% (32–63) 23% (11–35) 0.036 Adjusted effectiveness of ATP-3 18% (3–33) 3% (0–6) 0.003 Adjusted incidence of syncope due to S-VT 0.18% (0–0.6) 4.1% (2.1–6.1) 0.025 Values are expressed as mean (95% CI). Generalized Estimating Equations Method.

Conclusions

The efficacy of ATP in terminating S-VT is mainly due to the ATP-1. The regularization of RR intervals after ineffective ATP-1 underlies the lower efficacy of ATP-2 and ATP-3. Since the dQRS correlated significantly with the PPI-CLd, patients with a dQRS≥120 ms had a lower ATP-1, ATP-2 and ATP-3 effectiveness, leading to a higher incidence of syncope.

3325Incidence, outcomes and microbiology in patients with infective endocarditis

Introduction

Despite recent improvements in management, infective endocarditis remains associated with high morbidity and mortality. Over the last few decades, several factors have impacted on both the incidence and outcomes following infective endocarditis.

Purpose

Using a national linkage approach, we describe the changing age- and sex-stratified incidence and outcomes of infective endocarditis in Scotland over the last 25 years.

Methods

We conducted a consecutive retrospective individual patient linkage study across multiple national databases. Using data extracted from the Scottish hospital discharge dataset held by the Information Services Division of NHS National Services Scotland, we extracted episodes for all patients aged 20 years or older who were admitted with infective endocarditis between January 1, 1990, and December 31, 2014 in Scotland, UK. Patient episodes with infective endocarditis were linked to national prescribing and microbiology databases. The primary outcome was 1-year mortality following the index presentation. Generalised additive models were constructed to estimate the crude and age- and sex-stratified incidence rates (using a poison distribution) as well as trends in mortality (using a binomial distribution) adjusted for age, sex and comorbidity.

Results

Across 12,446 individual patients, there were a total of 12,667 hospitalisations (mean age 68±17 years, 55% females) with infective endocarditis using a 5-year look back period. The estimated crude rate of hospitalisation increased from 7.38 per 100,000 (95% CI 6.58 to 8.28) in 1990 to 15.09 per 100,000 (95% CI 13.90 to 16.39) in 2014 (p<0.001). Over the period of the study, 31% (3,877/12,667) of people admitted to hospital with infective endocarditis died within one year of admission. Case fatality fell markedly in both men and women from 1990 to 2014 (Figure). Microbiology was status was available for 34% of all hospitalisations with staphylococcus cultures associated with worse outcomes.

Conclusions

Despite the crude incidence of infective endocarditis doubling over the last 25 years and case fatality remaining high, the risk of death has markedly fallen over the last two decades. Staphylococcus cultures remain an independent marker of poor prognosis in this cohort.

Acknowledgement/Funding

British Heart Foundation

Scale Thickness Predicts Skin Puncture-Force Resistance in Three Pleuronectiform Fishes

In fishes, the skin and scales provide a physical barrier to the external environment and must withstand direct physical insult from biotic and abiotic features of the habitat. Flatfishes likely rely heavily on their scales for physical defense because they rest directly on the substrate. Using a flatfish model, we asked: what are the effects of scale type and scale morphology on puncture force resistance? We also asked: are there morphological and functional differences between the eyed and blind sides in flatfishes and do the morphological and functional properties of scales vary with organism size? Using a large size range of three species of Pleuronectid flatfish (Isopsetta isolepis, n = 10; Parophrys vetulus, n = 10; and Platichthys stellatus, n = 12), we measured the force required to puncture the integument using a sample of skin+scales taken from the eyed and blind side of each individual. We also measured the diameter, area, and thickness of the scales of each individual. Scaling relationships (body length vs. variable of interest) were derived for each species and compared with a priori expectations of geometric similarity. We found no relationship between scale type and puncture resistance and no differences in morphological parameters or puncture resistance between the eyed and blind side within a given species. These flatfish species do vary in their ability to withstand puncture forces; however, once scale thickness is taken into account, species differences disappear. Thus, the ability of a flatfish to withstand mechanical insult from puncture-forces varies depending on the thickness of the scale.

Tree root dynamics in montane and sub-alpine mixed forest patches

BACKGROUND AND AIMS

The structure of heterogeneous forests has consequences for their biophysical environment. Variations in the local climate significantly affect tree physiological processes. We hypothesize that forest structure also alters tree root elongation and longevity through temporal and spatial variations in soil temperature and water potential.

METHODS

We installed rhizotrons in paired vegetation communities of closed forest (tree islands) and open patches (canopy gaps), along a soil temperature gradient (elevations of 1400, 1700 and 2000 m) in a heterogeneous mixed forest. We measured the number of growing tree roots, elongation and mortality every month over 4 years.

KEY RESULTS

The results showed that the mean daily root elongation rate (RER) was not correlated with soil water potential but was significantly and positively correlated with soil temperature between 0 and 8 °C only. The RER peaked in spring, and a smaller peak was usually observed in the autumn. Root longevity was dependent on altitude and the season in which roots were initiated, and root diameter was a significant factor explaining much of the variability observed. The finest roots usually grew faster and had a higher risk of mortality in gaps than in closed forest. At 2000 m, the finest roots had a higher risk of mortality compared with the lower altitudes.

CONCLUSIONS

The RER was largely driven by soil temperature and was lower in cold soils. At the treeline, ephemeral fine roots were more numerous, probably in order to compensate for the shorter growing season. Differences in soil climate and root dynamics between gaps and closed forest were marked at 1400 and 1700 m, but not at 2000 m, where canopy cover was more sparse. Therefore, heterogeneous forest structure and situation play a significant role in determining root demography in temperate, montane forests, mostly through impacts on soil temperature.

Fasciola and fasciolosis in ruminants in Europe: Identifying research needs

Fasciola hepatica is a trematode parasite with a global distribution, which is responsible for considerable disease and production losses in a range of food producing species. It is also identified by WHO as a re-emerging neglected tropical disease associated with endemic and epidemic outbreaks of disease in human populations. In Europe, F. hepatica is mostly associated with disease in sheep, cattle and goats. This study reviews the most recent advances in our understanding of the transmission, diagnosis, epidemiology and the economic impact of fasciolosis. We also focus on the impact of the spread of resistance to anthelmintics used to control F. hepatica and consider how vaccines might be developed and applied in the context of the immune-modulation driven by the parasite. Several major research gaps are identified which, when addressed, will contribute to providing focussed and where possible, bespoke, advice for farmers on how to integrate stock management and diagnosis with vaccination and/or targeted treatment to more effectively control the parasite in the face of increasing the prevalence of infection and spread of anthelmintic resistance that are likely to be exacerbated by climate change.

Abstract OT1-03-01: Chemotherapy-free trastuzumab and pertuzumab in HER2 [+] breast cancer: FDG-PET response-adapted strategy. The PHERGain study

BACKGROUND:

Several studies have confirmed that a significant subset of patients (pts) with early stage HER2[+]breast cancer (BC) achieve pathological complete response (pCR) with a dual HER2 neoadjuvant blockade without chemotherapy (chemo). Early metabolic evaluation using 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) might help to recognize those pts with a higher likelihood of obtaining a pCR and an excellent outcome with a chemo-free strategy.

TRIAL DESIGN:

This is a randomized, multicenter, non-comparative phase II trial. Pts age ≥ 18 years with centrally-confirmed, treatment-naïve, HER2 [+] operable BC will be randomized, in a 1:4 ratio, and stratified by HR status, to receive docetaxel, carboplatin, trastuzumab, and pertuzumab (TCHP) (cohort A), or trastuzumab and pertuzumab (HP) ± endocrine therapy (ET) according to HR status (cohort B). Centrally-reviewed 18F-FDG PET/CT scans will be performed prior to randomization and after 2 cycles of therapy. Pts allocated into cohort A will continue with the same therapy for a total of 6 cycles regardless of 18F-FDG PET/CT results. Pts enrolled into cohort B showing at least a 40% reduction of the SUVmax on 18F-FDG PET/CT respect to baseline (PET responders) will continue with the same therapy for a total of 8 cycles. PET non-responders pts will receive 6 cycles of TCHP. After surgery, cohort B/PET responders pts who do not achieve a pCR will receive 6 cycles of TCHP. Moreover, all pts from cohorts A/B must complete 18 cycles of HP, along with adjuvant ET and radiotherapy (RT) according to HR status and institutional practices, respectively. Pts with subclinic metastases will be assigned to cohort C to receive 6 cycles of TCHP. Surgery and RT will be evaluated on a case-by-case basis on cohort C, and all pts will continue with HP for at least 12 additional cycles ± ET according to HR status.

The first co-primary endpoint is to evaluate the rate of pCR defined as the absence of invasive disease in the breast and axilla (ypT0/isN0) achieved with HP ± ET in PET responders pts (cohort B/PET responders).The second co-primary endpoint is to evaluate 3-year (3-y) invasive disease-free survival (iDFS) rate defined as time from the first date of no disease to invasive recurrence, new invasive disease, or death by any cause in cohort B.

Total accrual will be 400 pts. Considering a 10% and 25% of drop-out rates at the time of first and second co-primary analysis, the study will be positive if ≥41 pts achieved a pCR in cohort B/PET responders; or if we observe ≤14 events of 3-y iDFS in cohort B. Decisions will be based on one-sided, exact binomial test. With a 2.5% type I error rate (H0: pCR ≤20% and 3-y iDFS ≤89%) and 80% power (HA: pCR ≥30% and 3-y iDFS ≥95%).

The secondary objectives are to evaluate other definitions of pCR, rates of breast-conserving surgery, tumor response by magnetic resonance imaging, optimal 18F-FDG PET cut-off for pCR and other 18F-FDG PET quantification parameters for pCR prediction, DFS, distant-DFS, overall survival, progression-free survival, and health-related quality of life. Translational sub-studies will analyze biomarkers that may be predictive of response to dual HER2 blockade with HP.

Citation Format: Llombart-Cussac A, Curigliano G, Gebhart G, Gligorov J, Khaldoun K, Marmé F, Prat A, Schmid P, Cortes J, Perez J. Chemotherapy-free trastuzumab and pertuzumab in HER2 [+] breast cancer: FDG-PET response-adapted strategy. The PHERGain study [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 OT1-03-01.

Freezing-induced self-assembly of amphiphilic molecules

The self-assembly of amphiphilic molecules usually takes place in a liquid phase, near room temperature. Here, using small angle X-ray scattering (SAXS) experiments performed in real time, we show that freezing of aqueous solutions of copolymer amphiphilic molecules can induce self-assembly below 0 °C.