Uracil in DNA and its processing by different DNA glycosylases

Uracil in DNA may result from incorporation of dUMP during replication and from spontaneous or enzymatic deamination of cytosine, resulting in U:A pairs or U:G mismatches, respectively. Uracil generated by activation-induced cytosine deaminase (AID) in B cells is a normal intermediate in adaptive immunity. Five mammalian uracil-DNA glycosylases have been identified; these are mitochondrial UNG1 and nuclear UNG2, both encoded by the UNG gene, and the nuclear proteins SMUG1, TDG and MBD4. Nuclear UNG2 is apparently the sole contributor to the post-replicative repair of U:A lesions and to the removal of uracil from U:G contexts in immunoglobulin genes as part of somatic hypermutation and class-switch recombination processes in adaptive immunity. All uracil-DNA glycosylases apparently contribute to U:G repair in other cells, but they are likely to have different relative significance in proliferating and non-proliferating cells, and in different phases of the cell cycle. There are also some indications that there may be species differences in the function of the uracil-DNA glycosylases.

Uracil-DNA glycosylases SMUG1 and UNG2 coordinate the initial steps of base excision repair by distinct mechanisms

DNA glycosylases UNG and SMUG1 excise uracil from DNA and belong to the same protein superfamily. Vertebrates contain both SMUG1 and UNG, but their distinct roles in base excision repair (BER) of deaminated cytosine (U:G) are still not fully defined. Here we have examined the ability of human SMUG1 and UNG2 (nuclear UNG) to initiate and coordinate repair of U:G mismatches. When expressed in Escherichia coli cells, human UNG2 initiates complete repair of deaminated cytosine, while SMUG1 inhibits cell proliferation. In vitro, we show that SMUG1 binds tightly to AP-sites and inhibits AP-site cleavage by AP-endonucleases. Furthermore, a specific motif important for the AP-site product binding has been identified. Mutations in this motif increase catalytic turnover due to reduced product binding. In contrast, the highly efficient UNG2 lacks product-binding capacity and stimulates AP-site cleavage by APE1, facilitating the two first steps in BER. In summary, this work reveals that SMUG1 and UNG2 coordinate the initial steps of BER by distinct mechanisms. UNG2 is apparently adapted to rapid and highly coordinated repair of uracil (U:G and U:A) in replicating DNA, while the less efficient SMUG1 may be more important in repair of deaminated cytosine (U:G) in non-replicating chromatin.

UNG-initiated base excision repair is the major repair route for 5-fluorouracil in DNA, but 5-fluorouracil cytotoxicity depends mainly on RNA incorporation

Cytotoxicity of 5-fluorouracil (FU) and 5-fluoro-2′-deoxyuridine (FdUrd) due to DNA fragmentation during DNA repair has been proposed as an alternative to effects from thymidylate synthase (TS) inhibition or RNA incorporation. The goal of the present study was to investigate the relative contribution of the proposed mechanisms for cytotoxicity of 5-fluoropyrimidines. We demonstrate that in human cancer cells, base excision repair (BER) initiated by the uracil–DNA glycosylase UNG is the major route for FU–DNA repair in vitro and in vivo. SMUG1, TDG and MBD4 contributed modestly in vitro and not detectably in vivo. Contribution from mismatch repair was limited to FU:G contexts at best. Surprisingly, knockdown of individual uracil–DNA glycosylases or MSH2 did not affect sensitivity to FU or FdUrd. Inhibitors of common steps of BER or DNA damage signalling affected sensitivity to FdUrd and HmdUrd, but not to FU. In support of predominantly RNA-mediated cytotoxicity, FU-treated cells accumulated ~3000- to 15 000-fold more FU in RNA than in DNA. Moreover, FU-cytotoxicity was partially reversed by ribonucleosides, but not deoxyribonucleosides and FU displayed modest TS-inhibition compared to FdUrd. In conclusion, UNG-initiated BER is the major route for FU–DNA repair, but cytotoxicity of FU is predominantly RNA-mediated, while DNA-mediated effects are limited to FdUrd.

The Vågå study; epidemiology of headache I: the prevalence of ultrashort paroxysms

In a large-scale study of headache epidemiology in Vågå, Norway, 1838 adult parishioners(18--65 years of age) were examined, and this represents 88.6% of the target group. Jabs and jolts syndrome/idiopathic stabbing headache (ISH) was verified in 35.2% of the questioned parishioners. This prevalence is much higher than previously observed ones. There were clearly more females than males, the female/male ratio being 1.49, as compared to a ratio of 1.06 in the study cohort (P-value: < 0.0001, chi(2) test). The ratio, 1.49, also differs clearly from a previously observed one: 6.6 (P-value = 0.0003, Fisher's exact test). Control studies included blinded re-check of 100 work-ups, with complete concurrence (kappa-value of 1.00 and blinded re-check of 41 individuals (kapp value of 0.841). Jabs and jolts/ISH are frequent and almost the sole shortlasting (generally < 3 s duration) cephalic paroxysms.

Repeatability of measurement of fetal nuchal translucency thickness

The aim of this prospective study was to assess the repeatability of measurement of fetal nuchal translucency thickness at 10-14 weeks' gestation. The nuchal translucency was measured by two of four operators in 200 pregnant women attending the Harris Birthright Research Centre for Fetal Medicine at 10-14 weeks' gestation. To assess repeatability of different components of variability, six measurements of nuchal translucency were made on each fetus, with a total of 1200 measurements. The data of this study demonstrate that 95% of the time the intraobserver, interobserver and caliper placement repeatability of measuring fetal nuchal translucency were less than 0.54 mm, 0.62 mm and 0.58 mm, respectively. In addition, the repeatability was unrelated to the size of the nuchal translucency. The findings of this study demonstrate that, when the nuchal translucency thickness is measured by well-trained operators, the measurement is highly reproducible.

Direct interaction between XRCC1 and UNG2 facilitates rapid repair of uracil in DNA by XRCC1 complexes

Uracil-DNA glycosylase, UNG2, interacts with PCNA and initiates post-replicative base excision repair (BER) of uracil in DNA. The DNA repair protein XRCC1 also co-localizes and physically interacts with PCNA. However, little is known about whether UNG2 and XRCC1 directly interact and participate in a same complex for repair of uracil in replication foci. Here, we examine localization pattern of these proteins in live and fixed cells and show that UNG2 and XRCC1 are likely in a common complex in replication foci. Using pull-down experiments we demonstrate that UNG2 directly interacts with the nuclear localization signal-region (NLS) of XRCC1. Western blot and functional analysis of immunoprecipitates from whole cell extracts prepared from S-phase enriched cells demonstrate the presence of XRCC1 complexes that contain UNG2 in addition to separate XRCC1 and UNG2 associated complexes with distinct repair features. XRCC1 complexes performed complete repair of uracil with higher efficacy than UNG2 complexes. Based on these results, we propose a model for a functional role of XRCC1 in replication associated BER of uracil.

Uracil-DNA glycosylase in base excision repair and adaptive immunity: species differences between man and mouse

Genomic uracil is a DNA lesion but also an essential key intermediate in adaptive immunity. In B cells, activation-induced cytidine deaminase deaminates cytosine to uracil (U:G mispairs) in Ig genes to initiate antibody maturation. Uracil-DNA glycosylases (UDGs) such as uracil N-glycosylase (UNG), single strand-selective monofunctional uracil-DNA glycosylase 1 (SMUG1), and thymine-DNA glycosylase remove uracil from DNA. Gene-targeted mouse models are extensively used to investigate the role of these enzymes in DNA repair and Ig diversification. However, possible species differences in uracil processing in humans and mice are yet not established. To address this, we analyzed UDG activities and quantities in human and mouse cell lines and in splenic B cells from Ung(+/+) and Ung(-/-) backcrossed mice. Interestingly, human cells displayed ∼15-fold higher total uracil excision capacity due to higher levels of UNG. In contrast, SMUG1 activity was ∼8-fold higher in mouse cells, constituting ∼50% of the total U:G excision activity compared with less than 1% in human cells. In activated B cells, both UNG and SMUG1 activities were at levels comparable with those measured for mouse cell lines. Moreover, SMUG1 activity per cell was not down-regulated after activation. We therefore suggest that SMUG1 may work as a weak backup activity for UNG2 during class switch recombination in Ung(-/-) mice. Our results reveal significant species differences in genomic uracil processing. These findings should be taken into account when mouse models are used in studies of uracil DNA repair and adaptive immunity.

The Vågå study of headache epidemiology II. Jabs: clinical manifestations

OBJECTIVES

To describe clinical characteristics of cephalic jabs.

MATERIAL AND METHODS

In a population study in Vågå, Norway, 1838 18-65-year-old-parishioners (88.6% of the target group) were subjected to a semi-structured interview, based on a headache questionnaire.

RESULTS

Of 627 cases of jabs, 68% had single jabs; 4% volleys, and 28% a mixture of volleys and singlets. Most individuals had experienced only few jabs. Exceptionally, there were multiple attacks per day, even per hour. The ratio between an anterior and posterior location was 2.6. Neck movements and Valsalva manoeuvres seemingly occasionally precipitated attacks. Attacks were generally of mild/moderate intensity. Unilaterality prevailed over bilaterality; but unilateral pain might shift side.

CONCLUSION

Cephalic jabs are generally solitary paroxysms, with rather long intervals between attacks. Jabs do not only occur in the trigeminal area. Occasionally vocalization and more frequently jolts accompany the paroxysm.

Concentrations, biomagnification and spatial variation of organochlorine compounds in a pelagic food web in the northern part of the Baltic Sea

Zooplankton, mysis (Mysis sp.) and herring (Clupea harengus) were collected at two pelagic locations in the northern part of the Baltic Sea, one in Bothnian Bay (BB) and the other in the Bothnian Sea (BS), in order to investigate concentrations, composition profiles, biomagnification features and spatial differences of organochlorine contaminants. Compounds included in this study are hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz), chlordanes (CHLs), dieldrin, mirex and polychlorinated biphenyls (PCBs). All groups of compound were detected in every sample investigated, with the exception of mirex that was detected only in the herring samples. The concentrations of organochlorine compounds in all samples ranged, e.g. from 250 to 1500 ng/g lipid for PCBs and from 6 to 150 ng/g lipid for CHLs. The biomagnification factor (BMF) is calculated as the concentration of the compounds in the organism divided by the concentration in food normalised to lipids. In the zooplankton-mysis-herring food web, large variations in BMFs between the different compound groups were observed. The highest BMFs were obtained for the CHLs followed by the DDTs and the lowest for the HCHs. Nonachlorinated CHLs had the highest BMFs within the group of CHLs and for the DDTs p,p'-DDT had a higher biomagnification potential than its metabolites p,p'-DDE and p,p'-DDD. Finally, concentration and biomagnification differences between the two stations were observed. The herring in the southernmost station (BS) displayed approximately two- to sixfold higher biomagnification than the herring from the north (BB).

Extracephalic jabs/idiopathic stabs. Vågå study of headache epidemiology

Ultrashort cephalic paroxysms are well known. In the parish of Vågå, Norway, 35.2% of the 18-65-year-old subjects (n = 1779) were recently found to have such jabs. In the present work, a search has been made for extracephalic 'jabs'. A questionnaire was in its entirety administered by the same investigator (O.S.) in a 'semistructured' way. Facial jabs were present in three women, and in one of them the pain spread to the head. Four subjects had jabs occurring at random throughout the body, also including the cephalic area. Pure nuchal jabs were present in 12 subjects, 10 of whom were males. This sex preponderance difference differs significantly from that in jabs in general (with 40.2% males). The characteristics of the extracephalic jabs, i.e. the duration and temporal pattern, do not seem to differentiate them essentially from jabs in general. The subjects were not asked specific questions regarding extracranial jabs. Most of the affected individuals gave information spontaneously about their jabs. For these reasons, this study is not a proper prevalence study. It does show, however, that extracranial jabs exist, and it gives some indications as to their frequency.

Long-Lasting Cephalic Jabs (?) The Vågå Study of Headache Epidemiology

Jabs (stabs) usually last ≤3 s and are located in the skull area, mostly anteriorly. In many cases, there are only a few jabs during lifetime. With this definition, jabs are frequent, thus at 35.2% in the Vågå study of headache epidemiology. Long-lasting jabs (?), i.e. paroxysms lasting 10-120 s, were present in six out of 1779 parishioners. These pain paroxysms seemed mainly to be side-locked, but could not be provoked. Possibly, these long-lasting jabs after all mainly are regular jabs. To include the ≤2-minute-long paroxysms among the jabs will necessitate a rather drastic change of criteria. This group of jabs may, nevertheless, be heterogeneous. In two parishioners, the paroxysms were associated with a migraine-like pain. The paroxysms occasionally became most intense (2-10 times the basal pain), and then, and only then, were they combined with stark, visual phenomena: wave-like movements ('undulation'), anopsia, but also: immense dizziness, nausea/vomiting. The nature of the side-locked basal pain, although migraine-like, remains unsolved.

Ductus venosus Doppler velocimetry in the first trimester: a new finding

OBJECTIVES

To establish reference curves for ductus venosus blood flow velocities during the first trimester and compare them with previously published curves.

METHODS

This was a cross-sectional and retrospective study performed between January 1998 and January 2003. The following inclusion criteria were used: singleton pregnancy, velocity measurements taken when the crown-rump length (CRL) was between 34 and 84 mm, absence of fetal anomalies, full-term pregnancy and newborn birth weight appropriate for gestational age. The following variables of the ductus venosus were measured: peak velocity during ventricular systole (S-wave) and diastole (D-wave), nadir during atrial contraction in late diastole (A-wave), time-averaged maximum velocity (TAMXV) and pulsatility index for veins (PIV).

RESULTS

A total of 843 fetuses were included. The mean CRL was 62 (range, 34-84) mm. The S-wave, D-wave, TAMXV and PIV were normally distributed, and logarithmic transformation was performed to achieve a normal distribution for the A-wave. S-wave, D-wave and A-wave and TAMXV increased with CRL. PIV increased up to a CRL of 63 mm and decreased thereafter. Regression analysis revealed a significant quadratic relationship between PIV and CRL.

CONCLUSIONS

S-wave, D-wave, A-wave velocities and TAMXV in the ductus venosus increase with CRL between 34 and 84 mm. The reference range for PIV has a biphasic pattern, with an initial non-significant increase up to a CRL of 63 mm and a fall thereafter.

Visual and digital assessment of Ki-67 in breast cancer tissue - a comparison of methods

Background

In breast cancer (BC) Ki-67 cut-off levels, counting methods and inter- and intraobserver variation are still unresolved. To reduce inter-laboratory differences, it has been proposed that cut-off levels for Ki-67 should be determined based on the in-house median of 500 counted tumour cell nuclei. Digital image analysis (DIA) has been proposed as a means to standardize assessment of Ki-67 staining in tumour tissue. In this study we compared digital and visual assessment (VA) of Ki-67 protein expression levels in full-face sections from a consecutive series of BCs. The aim was to identify the number of tumour cells necessary to count in order to reflect the growth potential of a given tumour in both methods, as measured by tumour grade, mitotic count and patient outcome.

Methods

A series of whole sections from 248 invasive carcinomas of no special type were immunohistochemically stained for Ki-67 and then assessed by VA and DIA. Five 100-cell increments were counted in hot spot areas using both VA and DIA. The median numbers of Ki-67 positive tumour cells were used to calculate cut-off levels for Low, Intermediate and High Ki-67 protein expression in both methods.

Results

We found that the percentage of Ki-67 positive tumour cells was higher in DIA compared to VA (medians after 500 tumour cells counted were 22.3% for VA and 30% for DIA). While the median Ki-67% values remained largely unchanged across the 100-cell increments for VA, median values were highest in the first 1-200 cells counted using DIA. We also found that the DIA100 High group identified the largest proportion of histopathological grade 3 tumours 70/101 (69.3%).

Conclusions

We show that assessment of Ki-67 in breast tumours using DIA identifies a greater proportion of cases with high Ki-67 levels compared to VA of the same tumours. Furthermore, we show that diagnostic cut-off levels should be calibrated appropriately on the introduction of new methodology.

Code-Free Development and Deployment of Deep Segmentation Models for Digital Pathology

Application of deep learning on histopathological whole slide images (WSIs) holds promise of improving diagnostic efficiency and reproducibility but is largely dependent on the ability to write computer code or purchase commercial solutions. We present a code-free pipeline utilizing free-to-use, open-source software (QuPath, DeepMIB, and FastPathology) for creating and deploying deep learning-based segmentation models for computational pathology. We demonstrate the pipeline on a use case of separating epithelium from stroma in colonic mucosa. A dataset of 251 annotated WSIs, comprising 140 hematoxylin-eosin (HE)-stained and 111 CD3 immunostained colon biopsy WSIs, were developed through active learning using the pipeline. On a hold-out test set of 36 HE and 21 CD3-stained WSIs a mean intersection over union score of 95.5 and 95.3% was achieved on epithelium segmentation. We demonstrate pathologist-level segmentation accuracy and clinical acceptable runtime performance and show that pathologists without programming experience can create near state-of-the-art segmentation solutions for histopathological WSIs using only free-to-use software. The study further demonstrates the strength of open-source solutions in its ability to create generalizable, open pipelines, of which trained models and predictions can seamlessly be exported in open formats and thereby used in external solutions. All scripts, trained models, a video tutorial, and the full dataset of 251 WSIs with ~31 k epithelium annotations are made openly available at https://github.com/andreped/NoCodeSeg to accelerate research in the field.

Compound dependence of the relationship log K(ow) and log BCF L : A comparison between chlorobenzenes (CBs) for rainbow trout and polycyclic aromatic hydrocarbons (PAHs) forDaphnia

Linear relatinships between log bioconcentration factor (BCF) and log K(ow) for a variety of compounds have been reported many times in the literature. Analysis of the thermodynamics of the two partition processes has, however, shown that they are not analogous and that linear relationships can be expected to have different slopes for structurally unrelated compounds. In this study a set of literature lipid normalized BCF (BCFL) values of chlorbenzenes (CBs) for rainbow trout and polycyclic aromatic hydrocarbons (PAHs) forDaphnia was put together with literature Kow values. The slopes of the regression lines for log BCFL versus log Kow for the two groups of compounds proved to differ significantly in a statistical test using analysis of variance (ANOVA). The difference, which is of significance for estimates of BCFs in environmental modelling of these types of compounds, is explained by the differences in chemical structure of the two groups of compounds.

Non-influence of fetal gender on ductus venosus Doppler flow in the first trimester

OBJECTIVES

Recent findings have suggested that ductus venosus blood flow may be influenced by fetal gender. The aim of this study was to investigate further the influence of fetal gender on ductus venosus Doppler flow in the first trimester.

METHODS

This was a cross-sectional and retrospective study performed between January 1998 and January 2003. A total of 932 fetuses at between 10 and 14 weeks' gestation were included. The following inclusion criteria were used: singleton gestation; crown-rump length between 39 and 84 mm; and absence of fetal anomalies. The following variables of the ductus venosus were evaluated: peak velocity during ventricular systole (S-wave) and diastole (D-wave); nadir during atrial contraction in late diastole (A-wave); pulsatility index for veins (PIV); peak velocity index for veins (PVIV); and time-averaged maximum velocity (TAMXV).

RESULTS

Four hundred and forty-eight (48.1%) female and 484 (51.9%) male fetuses were included in the study. Comparing males and females at between 10 and 14 weeks' gestation, there was no statistically significant difference in S-wave, D-wave, A-wave, PIV, PVIV or TAMXV.

CONCLUSIONS

Our study suggests that fetal gender does not influence ductus venosus blood flow in the first trimester.

Nuchal translucency: an ultrasound marker for fetal chromosomal abnormalities

CONTEXT

The literature shows an association between several ultrasound markers and chromosome abnormality. Among these, measurement of nuchal translucency has been indicated as a screening method for aneuploidy. The trisomy of chromosome 21 has been most evaluated.

OBJECTIVE

To define the best fixed cutoff point for nuchal translucency, with the assistance of the ROC curve, and its accuracy in screening all fetal aneuploidy and trisomy 21 in a South American population.

TYPE OF STUDY

Validation of a diagnostic test.

SETTING

This study was carried out at the State University of Campinas, Campinas, Brazil.

PARTICIPANTS

230 patients examined by ultrasound at two tertiary-level private centers, at 10 to 14 weeks of gestation.

DIAGNOSTIC TEST

The participants consisted of all those patients who had undergone ultrasound imaging at 10 to 14 weeks of gestation to measure nuchal translucency and who had had the fetal or neonatal karyotype identified.

MAIN MEASUREMENTS

Maternal age, gestational age, nuchal translucency measurement, fetal or neonatal karyotype.

RESULTS

Prevalence of chromosomal defects - 10 %; mean age - 35.8 years; mean gestational age - 12 weeks and 2 days; nuchal translucency (NT) thickness - 2.18 mm. The best balance between sensitivity and specificity were values that were equal to or higher than 2.5 mm for overall chromosomal abnormalities as well as for the isolated trisomy 21. The sensitivity for overall chromosomal abnormalities and trisomy 21 were 69.5 % and 75 %, respectively, and the positive likelihood ratios were 5.5 and 5.0, respectively.

CONCLUSION

The measurement of nuchal translucency was found to be fairly accurate as an ultrasound marker for fetal abnormalities and measurements equal to or higher than 2.5 mm were the best fixed cutoff points.

The impact of real-time feedback by deep learning during echocardiographic scanning on test-retest variability of left ventricular systolic function measurements

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Norwegian University of Science and Technology, St. Olavs University Hospital, Central-Norway Health Authority

OnBehalf

Department of Circulation and Medical imaging, Norwegian University of Science and Technology, Trondheim, Norway

Background/introduction

Left ventricular (LV) ejection fraction (EF) is the most widely used measure of systolic cardiac function. LV foreshortening is a common problem within echocardiography and cause inaccuracies in estimation of EF and end-diastolic volume (EDV). Guidance of LV length during scanning could improve quality but has not yet been available.

Purpose

To evaluate the impact of real-time feedback using a robust deep learning (DL) tool during echocardiographic scanning to reduce test-retest variability in assessment of EF and LV EDV.

Methods

Patients scheduled for echocardiography were included if they were in sinus rhythm and had no need for use of contrast. Three consecutive echocardiograms were performed, where the first and second by two of three experienced sonographers and the third (reference) by one of four cardiologists in random order. Data collection was divided into two periods. In the first period, sonographers were told to provide high quality echocardiograms for analyses of LV function and no additional tool was provided. Thereafter, the sonographers were trained in use of the DL algorithm on 10 patients each. In the second period of inclusion, the real-time DL was used during scanning by the sonographers performing the second exam (Sonographer 2), while the first (Sonographer 1) had participated in training but had no access to the DL tool. All exams included the standard apical views, and the reference exams included tri-plane recordings of the LV as well.

All measurements were done retrospectively blinded to the others. LV EF and EDV were measured in four- and two-chamber views and averaged by the method of discs’ formula. The coefficients of variation (CoV) were compared for both LV EF and EDV (two groups of sonographers vs cardiologist) before and after the introduction of DL.

Results

A total of 88 patients were included (45% women), 41 in period 1 and 47 in period 2. Mean (SD) age was 63 (16) years, LV EF was 53 (12) % and LV EDV was 126 (55) ml.

Main findings are shown in the table. There was no significant difference in CoV for neither LV EF nor EDV using the DL tool. Compared to the first period the sonographers not using the DL tool had poorer reproducibility of LV EDV in period 2 (p ≤0.02), while there was a trend for reduced CoV for LV EDV for those using the algorithm (p = 0.11). By using the DL algorithm, LV foreshortening was reduced by 2.4 mm (p &lt;0.001), and similarly, alignment of the mitral annulus was numerically improved (p = 0.10).  Whether other markers of image quality were changed is not known.

Conclusion

The novel real-time DL algorithm to reduce foreshortening provided more standardized recordings when used by experienced sonographers during scanning, but these changes did not result in significant improvement in test-retest variation. Further development and investigations are needed to significantly reduce test-retest variability. Abstract Table_1  Abstract Figure. DL_tool

Real-time automatic feedback by deep learning to reduce apical foreshortening in echocardiography

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Norwegian University of Science and Technology, St. Olavs University Hospital, Central-Norway Health Authority

Background

Left ventricular (LV) foreshortening is common in echocardiography and may impair reproducibility and estimation of LV function. Feedback of foreshortening metrics such as LV length during scanning could improve accuracy, however, such a tool has not been available.

Purpose

To evaluate the effect of feedback of LV length during imaging for experienced sonographers, measured in real-time using a robust deep learning (DL) based tool.

Methods

Consecutive patients (n = 108) with mixed cardiac pathology were included during two separate periods. Each patient underwent three echocardiograms. The first and second examinations were performed by two (of three) randomized sonographers and the third exam by one (of four) randomized cardiologists. All examinations included the three standard apical views and the cardiologists’ exam included tri-plane recordings for reference. The data collection was divided in two phases. In the first period, the sonographers were told to provide high quality echocardiograms for analyses of LV function. Subsequently, sonographers were trained in use of the real-time DL tool on 10 patients each. In period two, the algorithm was used during scanning by the sonographer performing the second exam. One expert reader measured LV length (subendocardial apex to mitral annular plane) in all exams. The cardiologists’ tri-plane recordings were analyzed and used as reference. LV foreshortening was calculated at end-diastole (reference minus the operators LV length). Each exam was classified as foreshortened if the difference was ≥4 mm.

Results

After excluding those not in sinus rhythm (n = 9) and with need for contrast echocardiography (n = 11), 88 patients (45% women) were included (41 in period 1 and 47 in period 2). Age was mean (SD) 63 (16) years (45% women). Main findings are shown in the Table. LV length by both sonographer groups was significantly foreshortened in period 1 (mean 2.6 and 3.5 mm), and both sonographer groups reduced LV foreshortening in period 2 (both p ≤0.02). Improvement was best for sonographers using the real-time DL algorithm. These were not significantly foreshortened compared to the reference (p = 0.53), and less foreshortened compared to sonographer 1 (p = 0.001). Similarly, sonographers had more foreshortened examinations than cardiologist in period 1 (sonographer groups; 15 (37%) and 13 (32%) vs. cardiologist; 5 (12%), both p ≤0.03). In period 2, there was no difference in proportion of foreshortening between cardiologists and sonographer 2 (cardiologist; 0 vs sonographer; 2 (4%, p = 0.5)), while sonographer 1 foreshortened more 11 (23%), p ≤0.003).

Conclusion

Feedback of LV length during imaging significantly reduced foreshortening in echocardiographic acquisitions by sonographers, and has the potential to improve image accuracy even in the hands of experienced operators. Abstract Table  Abstract Figure. Deep Learning foreshortening application

Tumour-associated macrophages in human meningiomas

Tumour-associated macrophages (TAMs) are regarded as potential therapeutic targets due to "pro-tumoral" and "anti-tumoral" phenotypes. Human meningiomas contain considerable number of TAMs, but their clinical impact is sparsely investigated in these tumours. The aim of this study was therefore to investigate the presence, morphology, and distribution of TAMs in human meningiomas, and relate these findings to histopathology, meningioma subtypes, World Health Organization (WHO) grade, risk of recurrence, and overall survival. In this study, 147 WHO grade 1 and 2 primary meningiomas prepared as tissue micro arrays were included. Standard immunohistochemistry, with the antibodies Iba1 as a pan-marker for "all TAMs", iNOS for M1 and Arginase 1 for M2 TAMs, was performed to investigate their infiltration in the meningioma tissue. The immunostainings were scanned and analysed digitally. TAMs were found in most of the meningiomas with varying amount of ramified and amoeboid appearances. The quantity of total TAMs (Iba1-stained) was found to be significantly higher in the age group ≥ 60 years compared with the younger age group. M2 cell dominated over M1 cell quantity, and a higher quantity of M2 TAMs was found in skull-base compared with non-skull base tumours. Meningothelial subtypes had a higher quantity of M2 TAMs compared with transitional and atypical ones. Furthermore, the M1/M2-ratio was higher in meningiomas linked to the convexities compared with tumours in the basal. No relations between TAMs and histological WHO grade or prognosis (time to recurrence and overall survival) were found. TAMs were common in our series of meningiomas. However, their infiltration showed no clinicopathological significance. Due to their complex dynamic characteristics and shifting phenotypes, the investigation of these immune cells is demanding. Therefore, the TAMs' definite role in human meningiomas in relation to clinicopathological parameters and prognosis need to be further investigated.