Generative modeling of living cells with SO(3)-equivariant implicit neural representations.

Data-driven cell tracking and segmentation methods in biomedical imaging require diverse and information-rich training data. In cases where the number of training samples is limited, synthetic computer-generated data sets can be used to improve these methods. This requires the synthesis of cell shapes as well as corresponding microscopy images using generative models. To synthesize realistic living cell shapes, the shape representation used by the generative model should be able to accurately represent fine details and changes in topology, which are common in cells. These requirements are not met by 3D voxel masks, which are restricted in resolution, and polygon meshes, which do not easily model processes like cell growth and mitosis. In this work, we propose to represent living cell shapes as level sets of signed distance functions (SDFs) which are estimated by neural networks. We optimize a fully-connected neural network to provide an implicit representation of the SDF value at any point in a 3D+time domain, conditioned on a learned latent code that is disentangled from the rotation of the cell shape. We demonstrate the effectiveness of this approach on cells that exhibit rapid deformations (Platynereis dumerilii), cells that grow and divide (C. elegans), and cells that have growing and branching filopodial protrusions (A549 human lung carcinoma cells). A quantitative evaluation using shape features and Dice similarity coefficients of real and synthetic cell shapes shows that our model can generate topologically plausible complex cell shapes in 3D+time with high similarity to real living cell shapes. Finally, we show how microscopy images of living cells that correspond to our generated cell shapes can be synthesized using an image-to-image model.

The Cell Tracking Challenge: 10 years of objective benchmarking.

The Cell Tracking Challenge is an ongoing benchmarking initiative that has become a reference in cell segmentation and tracking algorithm development. Here, we present a significant number of improvements introduced in the challenge since our 2017 report. These include the creation of a new segmentation-only benchmark, the enrichment of the dataset repository with new datasets that increase its diversity and complexity, and the creation of a silver standard reference corpus based on the most competitive results, which will be of particular interest for data-hungry deep learning-based strategies. Furthermore, we present the up-to-date cell segmentation and tracking leaderboards, an in-depth analysis of the relationship between the performance of the state-of-the-art methods and the properties of the datasets and annotations, and two novel, insightful studies about the generalizability and the reusability of top-performing methods. These studies provide critical practical conclusions for both developers and users of traditional and machine learning-based cell segmentation and tracking algorithms.

Secondary malignancies and survival of FCR-treated patients with chronic lymphocytic leukemia in Central Europe.

This is the first large-scale cross-country analysis of patients with chronic lymphocytic leukemia (CLL) aimed to evaluate the incidence, types, and key prognostic factors of secondary malignancies, and to assess the impact on overall survival based on retrospective claims data from three Central European countries. We analyzed 25,814 newly diagnosed CLL patients from Czechia, Hungary, and Poland; 10,312 (39.9%) patients were treated for CLL in study periods between 2004 and 2016. Out of the treated patients, 1986 (19.3%) received the FCR therapy in the first line and 779 (7.6%) received FCR in subsequent lines. We observed that 33.7% of treated patients developed secondary malignancies during the study. Based on country estimates, the probability to develop a secondary malignancy within 4 years since starting the first-line FCR therapy ranged between 28.0% and 36.8%. We found the age at diagnosis, male gender, any malignancy prior to the CLL diagnosis, and the CLL treatment to be the key risk factors for developing secondary malignancies. Specifically, the FCR therapy was a statistically significant (p < 0.001) prognostic factor for risk increase with the hazard ratio between 1.46 and 1.60. Across the three Central European countries, we observed consistent results indicating FCR increased the risk of secondary malignancies in CLL patients. We conclude that secondary malignancies are clearly an undervalued burden for CLL patients, caregivers, and the healthcare system. When evaluating new therapies in regulatory and reimbursement decision making, the factor of secondary malignancies deserves deeper considerations.

Memory outcomes of temporal lobe surgery in adults aged over 45 years.

OBJECTIVE: It is assumed that temporal lobe resection in older people is associated with worse seizure outcomes and potential postsurgical memory decline. We studied postsurgical memory development and surgical efficacy in patients over 45 years of age compared with younger patients. METHODS: We studied 88 patients (51 male and 37 female) after temporal lobe surgery, which involved hippocampal resection. The patients were evaluated before surgery and in the first (72 patients) and/or third (57 patients) postsurgical year. The Wechsler Memory Scale III test was performed to evaluate the MQ postsurgical development. Engel's classification was used to evaluate the postsurgical seizure outcome. RESULTS: The presurgical MQ (median 88) in ≥45 years age group was significantly lower than in both younger groups (median MQ = 100 for ≤30 years age group, p = 0.002; median MQ = 107 for 31-44 years age group, p = 0.002). Three years after the surgery, the MQ decreased significantly in ≤30 years age group (p = 0.012), while only non-significant MQ decline was observed in both older groups. We found no significant impact of age on the surgical outcome. CONCLUSION: Higher age at the time of surgery does not significantly increase the risk for postsurgical memory decline; however, older patients are more likely to have lowered presurgical MQ. We did not find significant differences in the impact of surgery on seizure outcome among the age groups. Epilepsy surgery appears to be a safe and effective method in the age over 45 years even though an earlier surgery should be preferred.

Dasatinib treatment long-term results among imatinib-resistant/intolerant patients with chronic phase chronic myeloid leukemia are favorable in daily clinical practice.

To evaluate long-term real-life results of dasatinib therapy among chronic phase chronic myeloid leukemia patients resistant or intolerant to imatinib, we retrospectively analyzed data of 118 patients treated in centers participating in the database INFINITY. With median follow-up of 37 months, estimated 5-year cumulative incidences of complete cytogenetic and major molecular responses were 78% and 68%, respectively. The estimated 5-year probability of overall survival (OS) and event-free survival (EFS) were 86% and 83%, respectively. Both OS and EFS were significantly improved among patients with BCR-ABL1 transcript level ≤10% at 3 months. Dasatinib toxicity was tolerable however persistent in almost half our patients, even after years of therapy. Pleural effusion occurred in 29% of patients and was responsible for 30% of dasatinib discontinuations. Our results confirmed very good efficacy and acceptable toxicity of dasatinib in second line setting and support the evidence and importance of high-quality real-life CML patient management.

Lactic Acidosis Interferes With Toxicity of Perifosine to Colorectal Cancer Spheroids: Multimodal Imaging Analysis.

Colorectal cancer (CRC) is a disease with constantly increasing incidence and high mortality. The treatment efficacy could be curtailed by drug resistance resulting from poor drug penetration into tumor tissue and the tumor-specific microenvironment, such as hypoxia and acidosis. Furthermore, CRC tumors can be exposed to different pH depending on the position in the intestinal tract. CRC tumors often share upregulation of the Akt signaling pathway. In this study, we investigated the role of external pH in control of cytotoxicity of perifosine, the Akt signaling pathway inhibitor, to CRC cells using 2D and 3D tumor models. In 3D settings, we employed an innovative strategy for simultaneous detection of spatial drug distribution and biological markers of proliferation/apoptosis using a combination of mass spectrometry imaging and immunohistochemistry. In 3D conditions, low and heterogeneous penetration of perifosine into the inner parts of the spheroids was observed. The depth of penetration depended on the treatment duration but not on the external pH. However, pH alteration in the tumor microenvironment affected the distribution of proliferation- and apoptosis-specific markers in the perifosine-treated spheroid. Accurate co-registration of perifosine distribution and biological response in the same spheroid section revealed dynamic changes in apoptotic and proliferative markers occurring not only in the perifosine-exposed cells, but also in the perifosine-free regions. Cytotoxicity of perifosine to both 2D and 3D cultures decreased in an acidic environment below pH 6.7. External pH affects cytotoxicity of the other Akt inhibitor, MK-2206, in a similar way. Our innovative approach for accurate determination of drug efficiency in 3D tumor tissue revealed that cytotoxicity of Akt inhibitors to CRC cells is strongly dependent on pH of the tumor microenvironment. Therefore, the effect of pH should be considered during the design and pre-clinical/clinical testing of the Akt-targeted cancer therapy.

Prediction Score for persisting perfusion defects after pulmonary embolism.

AIMS: Long-term persistence of perfusion defect after pulmonaryembolism (PE) may lead to the development of chronic thromboembolic pulmonary hypertension. Identification of patients at risk of such a complication using a scoring system would be beneficial in clinical practice. Here, we aimed to derive a score for predicting persistence of perfusion defects after PE. METHODS: 83 patients after PE were re-examined 6, 12 and 24 months after the PE episode. Data collected at the time of PE and perfusion status during follow-ups were used for modelling perfusion defects persistence using the Cox proportional hazards model and validated using bootstrap method. RESULTS: A simple scoring system utilizing two variables (hemoglobin levels and age at the time of PE) was developed. Patients with hemoglobin levels over 140 g/L who were older than 65 years were at the highest risk of perfusion defects; in patients with the same hemoglobin levels and age <65 years, the risk was reduced by 79%, and by 89% in patients with hemoglobin <140 g/L. CONCLUSION: The proposed scoring system may be useful in clinical practice for identifying patients with high risk of persisting perfusion defects, flagging them for closer follow up, thus improving the effectiveness of long-term treatment of patients after PE.

Drug Penetration Analysis in 3D Cell Cultures Using Fiducial-Based Semiautomatic Coregistration of MALDI MSI and Immunofluorescence Images.

In this paper, we present an easy-to-follow procedure for the analysis of tissue sections from 3D cell cultures (spheroids) by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) and laser scanning confocal microscopy (LSCM). MALDI MSI was chosen to detect the distribution of the drug of interest, while fluorescence immunohistochemistry (IHC) followed by LSCM was used to localize the cells featuring specific markers of viability, proliferation, apoptosis and metastasis. The overlay of the mass spectrometry (MS) and IHC spheroid images, typically without any morphological features, required fiducial-based coregistration. The MALDI MSI protocol was optimized in terms of fiducial composition and antigen epitope preservation to allow MALDI MSI to be performed and directly followed by IHC analysis on exactly the same spheroid section. Once MS and IHC images were coregistered, the quantification of the MS and IHC signals was performed by an algorithm evaluating signal intensities along equidistant layers from the spheroid boundary to its center. This accurate colocalization of MS and IHC signals showed limited penetration of the clinically tested drug perifosine into spheroids during a 24 h period, revealing the fraction of proliferating and promigratory/proinvasive cells present in the perifosine-free areas, decrease of their abundance in the perifosine-positive regions, and distinguishing between apoptosis resulting from hypoxia/nutrient deprivation and drug exposure.

First-line imatinib in elderly patients with chronic myeloid leukaemia from the CAMELIA registry: Age and dose still matter.

We retrospectively evaluated the role of age and dosage in 372 CML patients (170 women, 202 men) treated with first-line imatinib (IMA) from the records of the CAMELIA registry. The median follow-up of the patients was 82.3 (18.0-177.3) months. The treatment results of 80 elderly patients aged over 65 years at diagnosis were compared in analysis "A" with those of 292 younger patients and in analysis "B" with those of 90 patients younger than 40 and 202 patients aged 40-64. The elderly patients had statistically adverse values of the Sokal, ELTS, and ECOG scores and Charlson comorbidity index in both analyses (p from = 0.012 to ≤ 0.001). Despite a more frequent use of a daily dose lower than 400 mg - in 31 elderly patients (38.8%) than in 45 younger ones (15.4%) (p < 0.001), there were no statistically significant differences in the achievement of optimal haematological, cytogenetic, and molecular responses according to the ELN criteria in both the analyses, A and B. The comparisons of overall survival with CML-related death (OSCML) and event-free survival (EFS) were insignificant inanalysis A (p = 0.07 and 0.396, respectively) but progression-free survival (PFS) differed significantly (p = 0.007). In analysis B OSCML and PFS differed significantly (p = 0.027 and 0.003) but EFS was similar (p = 0.351). Elderly patients with a sustained dose of IMA of 400 mg/day have insignificantly better OS, PFS, and EFS compared to patients treated with a lower dosage of IMA. The results in the treatment of the elderly CML patients were comparable with those of the younger ones in terms of the probabilities of the achievement of optimal ELN responses. However, the results for the survival probabilities were influenced by age and the IMA dosage.

FiloGen: A Model-Based Generator of Synthetic 3-D Time-Lapse Sequences of Single Motile Cells With Growing and Branching Filopodia.

The existence of diverse image datasets accompanied by reference annotations is a crucial prerequisite for an objective benchmarking of bioimage analysis methods. Nevertheless, such a prerequisite is hard to satisfy for time lapse, multidimensional fluorescence microscopy image data, manual annotations of which are laborious and often impracticable. In this paper, we present a simulation system capable of generating 3-D time-lapse sequences of single motile cells with filopodial protrusions of user-controlled structural and temporal attributes, such as the number, thickness, length, level of branching, and lifetime of filopodia, accompanied by inherently generated reference annotations. The proposed simulation system involves three globally synchronized modules, each being responsible for a separate task: the evolution of filopodia on a molecular level, linear elastic deformation of the entire cell with filopodia, and the synthesis of realistic, time-coherent cell texture. Its flexibility is demonstrated by generating multiple synthetic 3-D time-lapse sequences of single lung cancer cells of two different phenotypes, qualitatively and quantitatively resembling their real counterparts acquired using a confocal fluorescence microscope.

Speech prosody impairment predicts cognitive decline in Parkinson's disease.

BACKGROUND: Impairment of speech prosody is characteristic for Parkinson's disease (PD) and does not respond well to dopaminergic treatment. OBJECTIVES: We assessed whether baseline acoustic parameters, alone or in combination with other predominantly non-dopaminergic symptoms may predict global cognitive decline as measured by the Addenbrooke's cognitive examination (ACE-R) and/or worsening of cognitive status as assessed by a detailed neuropsychological examination. METHODS: Forty-four consecutive non-depressed PD patients underwent clinical and cognitive testing, and acoustic voice analysis at baseline and at the two-year follow-up. Influence of speech and other clinical parameters on worsening of the ACE-R and of the cognitive status was analyzed using linear and logistic regression. RESULTS: The cognitive status (classified as normal cognition, mild cognitive impairment and dementia) deteriorated in 25% of patients during the follow-up. The multivariate linear regression model consisted of the variation in range of the fundamental voice frequency (F0VR) and the REM Sleep Behavioral Disorder Screening Questionnaire (RBDSQ). These parameters explained 37.2% of the variability of the change in ACE-R. The most significant predictors in the univariate logistic regression were the speech index of rhythmicity (SPIR; p = 0.012), disease duration (p = 0.019), and the RBDSQ (p = 0.032). The multivariate regression analysis revealed that SPIR alone led to 73.2% accuracy in predicting a change in cognitive status. Combining SPIR with RBDSQ improved the prediction accuracy of SPIR alone by 7.3%. CONCLUSIONS: Impairment of speech prosody together with symptoms of RBD predicted rapid cognitive decline and worsening of PD cognitive status during a two-year period.