Search Results (661)

The evolution of preimplantation genetic testing for aneuploidy (PGT-A) techniques has been crucial in assisted reproductive technologies (ARTs), improving embryo selection and increasing success rates in in vitro fertilization (IVF) treatments. Techniques ranging from fluorescence in situ hybridization (FISH) to next-generation sequencing (NGS) have relied on cellular material extraction through biopsies of blastomeres at the cleavage stage on day three or from trophectoderm (TE) cells of the blastocyst. However, this has raised concerns about its potential impact on embryo development. As a result, there has been growing interest in developing non-invasive techniques for detecting aneuploidies, such as the analysis of blastocoel fluid (BF), spent culture medium (SCM), and artificial intelligence (AI) models. Non-invasive methods represent a promising advancement in PGT-A, offering the ability to detect aneuploidies without compromising embryo viability. This article reviews the evolution and principles of PGT-A, analyzing both traditional techniques and emerging non-invasive approaches, while highlighting the advantages and challenges associated with these methodologies. Furthermore, it explores the transformative potential of these innovations, which could optimize genetic screening and significantly improve clinical outcomes in the field of assisted reproduction. Full article

Thyroid hormone receptor alpha (THRα) is a nuclear hormone receptor that binds triiodothyronine (T3) and acts as an important transcription factor in development, metabolism, and reproduction. The coding gene, THRA, has two major splicing isoforms in mammals, THRA1 and THRA2, which encode THRα1 and THRα1, respectively. The better characterized isoform, THRα1, is a transcriptional stimulator of genes involved in cell metabolism and growth. The less well-characterized isoform, THRα2, lacks the ligand-binding domain (LBD) and may act as an inhibitor of THRα1 activity. Thus, the ratio of THRα1 to THRα2 isoforms is critical for transcriptional regulation in various tissues and during development and may be abnormal in a number of thyroid hormone resistance syndromes. However, the complete characterization of the THRα isoform expression pattern in healthy human tissues, and especially the study of changes in the ratio of THRα1 to THRα2 in cultured patient cells, has been hampered by the lack of suitable tools to detect the isoform-specific expression patterns. Therefore, we developed a plasmid pCMV-THRA-RFP-EGFP splicing detector that allows the visualization and quantification of the differential expression of THRA1 and THRA2 splicing isoforms in living single cells during time-lapse and perturbation experiments. This tool enables experiments to further characterize the role of THRα2 and to perform high-throughput drug screening. Molecules that modify THRA splicing may be developed into drugs for the treatment of thyroid hormone resistance syndromes. Full article

Monitoring animal populations is crucial for assessing the health of ecosystems. Traditional methods, which require extensive fieldwork, are increasingly being supplemented by time-lapse camera-trap imagery combined with an automatic analysis of the image data. The latter usually involves some object detector aimed at detecting relevant targets (commonly animals) in each image, followed by some postprocessing to gather activity and population data. In this paper, we show that the performance of an object detector in a single frame of a time-lapse sequence can be improved by including spatio-temporal features from the prior frames. We propose a method that leverages temporal information by integrating two additional spatial feature channels which capture stationary and non-stationary elements of the scene and consequently improve scene understanding and reduce the number of stationary false positives. The proposed technique achieves a significant improvement of 24% in mean average precision ([email protected]:0.95) over the baseline (temporal feature-free, single frame) object detector on a large dataset of breeding tropical seabirds. We envisage our method will be widely applicable to other wildlife monitoring applications that use time-lapse imaging. Full article

Bright biocompatible fluorescent imaging dyes with red to near-infrared (NIR) emissions are ideal candidates for fluorescence microscopy applications. Pyrene–benzothiazolium hemicyanine dyes are a new class of lysosome-specific probes reported on recently. In this work, we conduct a detailed implementation study for a pyrene–benzothiazolium derivative, BTP, to explore its potential imaging applications in fluorescence microscopy. The optical properties of BTP are studied in intracellular environments through advanced fluorescence microscopy techniques, with BTP exhibiting a noticeable shift toward blue (λ_em ≈ 590 nm) emissions in cellular lysosomes. The averaged photon arrival time (AAT)-based studies exhibit two different emissive populations of photons, indicating the probe’s dynamic equilibrium between two distinctively different lysosomal microenvironments. Here, BTP is successfully utilized for time-lapse fluorescence microscopy imaging in real-time as a ‘wash-free’ imaging dye with no observed background interference. BTP exhibits an excellent ability to highlight microorganisms (i.e., bacteria) such as Bacillus megaterium through fluorescence microscopy. BTP is found to be a promising candidate for two-photon fluorescence microscopy imaging. The two-photon excitability of BTP in COS-7 cells is studied, with the probe exhibiting an excitation maximum at λ_TP ≈ 905 nm. Full article

Ice jamming is the primary mechanism that can generate overland flooding and recharge the isolated basins of the Peace–Athabasca Delta (PAD), a valuable ecosystem of international importance and the ancient homeland of the Indigenous Peoples of the region. Focusing on the regulated Peace River and the Peace Sector of the delta, which has been experiencing a drying trend in between rare ice-jam floods over the last ~50 years, this study describes recent notable breakup events, associated observational data, and numerical applications to determine river discharge during the breakup events. Synthesis and interpretation of this material provide a new physical understanding that can inform the ongoing development of a protocol for strategic flow releases toward enhancing basin recharge in years when major ice jams are likely to form near the PAD. Additionally, several recommendations are made for future monitoring activities and improvements in proposed antecedent criteria for early identification of “promising” breakup events. Full article

Corneal endothelium cells (CECs) regulate corneal hydration between the leaky barrier of the corneal endothelium and the ionic pumps on the surface of CECs. As CECs do not regenerate, loss of CECs leads to poor vision and corneal blindness. Corneal transplant is the only treatment option; however, there is a severe shortage of donor corneas globally. Cell therapy using propagated primary human CECs is an alternative approach to corneal transplantations, and proof of functionality is crucial for validating such CECs. Expression markers like Na-K-ATPase and ZO-1 are typical but not specific to CECs. Assessing the barrier function of the expanded CECs via electrical resistance (i.e., TEER and Ussing’s chamber) involves difficult techniques and is thus impractical for clinical application. Calcium has been demonstrated to affect the paracellular permeability of the corneal endothelium. Its absence alters morphology and disrupts apical junctions in bovine CECs, underscoring its importance. Calcium signaling patterns such as calcium waves affect the rate of wound healing in bovine CECs. Therefore, observing calcium waves in expanded CECs could provide valuable insights into their health and functional integrity. Mechanical or chemical stimulations, combined with Ca²⁺-sensitive fluorescent dyes and time-lapse imaging, can be used to visualize these waves, which could potentially be used to qualify expanded CECs. Full article

Recently, the use of click chemistry for localization of chemically modified cyanopeptides has been introduced, i.e., taking advantage of promiscuous adenylation (A) domains in non-ribosomal peptide synthesis (NRPS), allowing for the incorporation of clickable non-natural amino acids (non-AAs) into their peptide products. In this study, time-lapse experiments have been performed using pulsed feeding of three different non-AAs in order to observe the synthesis or decline of azide- or alkyne-modified microcystins (MCs) or anabaenopeptins (APs). The cyanobacteria Microcystis aeruginosa and Planktothrix agardhii were grown under maximum growth rate conditions (r = 0.35–0.6 and 0.2–0.4 (day⁻¹), respectively) in the presence of non-AAs for 12–168 h. The decline of the azide- or alkyne-modified MC or AP was observed via pulse-feeding. In general, the increase in clickable MC/AP in peptide content reached a plateau after 24–48 h and was related to growth rate, i.e., faster-growing cells also produced more clickable MC/AP. Overall, the proportion of clickable MC/AP in the intracellular fraction correlated with the proportion observed in the dissolved fraction. Conversely, the overall linear decrease in clickable MC/AP points to a rather constant decline via dilution by growth instead of a regulated or induced release in the course of the synthesis process. Full article

Nearshore sandbars are dynamic features that characterize shallow morphobathymetry and vary over a wide range of geometries and temporal lifespans. Nearshore sandbars influence beach geometry by altering the energy of incoming waves; thus, monitoring the evolution of sandbars is a fundamental approach in effective coastal planning. Due to several natural and technical limitations related to shallow seafloor mapping, there is a significant gap in the availability of high-resolution, shallow bathymetric data for monitoring the dynamic behaviour of nearshore sandbars effectively. This study introduces a novel image-processing technique that produces time series of pseudo-bathymetric data by utilizing multi-temporal (monthly) drone imagery, and it provides an assessment of local morphodynamics at a sandy beach in the southeast Mediterranean. The technique is called standardized-ratio bathymetric index (SRBI), and it transforms natural-colour drone imagery to pseudo-bathymetric data by applying an empirical formula used for satellite-derived bathymetry. This technique correlates well with laser altimetry depth measurements; however, it does not require in situ depth data for implementation. The resulting pseudo-bathymetric data allows for extracting cross-shore profiles and delineating the sandbar crest with 4 m horizontal accuracy. Stacking of temporal profiles allowed for the quantification of the sandbar’s crest and trough changes at different alongshore sections. The main findings suggest that the nearshore crescentic sandbar at Episkopi Beach (north Crete) shows strong seasonality regarding net offshore migration that is promoted by enhanced wave action during winter months. In addition, the crescentic sandbar is susceptible to morphology arrestment during prolonged weeks of low wave action. The average migration rate during winter is 10 m.month⁻¹, with some sections exhibiting a maximum of 60 m.month⁻¹. This study (a) offers a novel remote-sensing approach, suitable for nearshore seafloor monitoring with low computational complexity, (b) reveals sandbar geometry and temporal change in superior detail compared to other observational methods, and (c) advances knowledge about nearshore sandbar monitoring in the Mediterranean region. Full article

Background. Critical and progressive cachexia may be observed in numerous medical disciplines, but in patients with various diseases, several pathways overlap (endocrine, inflammatory and kidney diseases, heart failure, cancer). Methods. Unlike numerous cohort studies that examine thyroid cancer and risk factors, a different method was used to avoid bias and analyze the sequence of events, i.e., the pathway. A case-control analysis is presented on patients with initial immune-mediated thyroiditis complicated by cachexia, presenting pulmonary pathology coexisting with opportunistic infection, and ultimately diagnosed with cancer (TC—thyroid cancer, misdiagnosed as lung cancer). Results. Contrary to other patients with lung cancer, the presented patients were not active smokers and exclusively women who developed cachexia with existing autoimmune processes in the first phase. Furthermore, the coexistence of short overall survival without cancer progression in the most seriously ill patients, as well as correlation with sex (contrary to history of smoking) and predisposition to mycobacterial disease, are very suggestive. Although we describe three different autoimmune conditions (de Quervain’s, Graves’, and atrophic thyroiditis), disturbances in calcium and metabolic homeostasis, under the influence of hormonal and inflammatory changes, are crucial factors of cachexia and prognosis. Conclusions. The unique sequence sheds light on immune-mediated thyroid disease as a subclinical paraneoplastic process modified by various therapeutic regimens. However, it is also associated with cachexia, systemic consequences, and atypical sequelae, which require a holistic approach. The differential diagnosis of severe cachexia, adenocarcinoma with pulmonary localization, and tuberculosis reactivation requires an analysis of immunological and genetic backgrounds. Contrary to highly specialized teams (e.g., lung cancer units), immunotherapy and general medicine in aging populations require a multidisciplinary, holistic, and inquiring approach. The lack of differentiation, confusing biases, and discrepancies in the literature are the main obstacles to statistical research, limiting findings to correlations of common factors only. Time-lapse case studies such as this one may be among the first to build evidence of a pathway and an association between inflammatory and endocrine imbalances in cancer cachexia. Full article

Human pluripotent stem cells (hPSCs) attract tremendous attention due to their unique properties. Manual extraction of trajectories of cell colonies in experimental image time series is labor intensive and subjective, thus the aim of the work was to develop a computer semi-automated protocol for colony tracking. The developed procedure consists of three major stages, namely, image registration, object detection and tracking. Registration using discrete Fourier transform and tracking based on the solution of a linear assignment problem was implemented as console programs in the Python 3 programming language using a variety of packages. Object detection was implemented as a multistep procedure in the ProStack in-house software package. The procedure consists of more than 40 elementary operations that include setting of several biologically relevant parameters, image segmentation and performing of quantitative measurements. The developed procedure was applied to the dataset containing bright-field images from time-lapse recording of the human embryonic cell line H9. The detection step took about 6 h for one image time series with a resolution of 2560 by 2160; about 1 min was required for image registration and trajectories extraction. The developed procedure was effective in detecting and analyzing the time series of images with “good” and “bad” phenotypes. The differences between phenotypes in the distance in pixels between the starting and finishing positions of trajectories, in the path length along the trajectory, and the mean instant speed and mean instant angle of the trajectories were identified as statistically significant by Mann–Whitney and Student’s tests. The measured area and perimeter of the detected colonies differed, on average, for different phenotypes throughout the entire time period under consideration. This result confirms previous findings obtained by analyzing static images. Full article

To investigate the interaction effects of prolonged working periods and different task loads on response lapses, focusing on the mechanisms of delayed responses and error lapses. Professionals such as pilots, truck drivers, and nurses often face extended work hours and fluctuating task loads. While these factors individually affect performance, their interaction and its impact on response lapses remain unclear. Twenty participants completed the Uchida–Kraepelin (U–K) Psychological Test and a dual-task version with functional near-infrared spectroscopy. Independent variables were time-on-task and task load. Dependent variables included measures of fatigue, arousal, workload, task performance (delayed and error rates), and brain functional connectivity. Both time-on-task and task load significantly affected cerebral connectivity, response lapses, workload (frustration level), fatigue, and arousal. Arousal levels significantly decreased and reaction times increased after 60 min of work. Cognitive resource regulation became challenging after 90 min under high task load levels. A decline in the connection between the prefrontal and occipital cortex during high-load tasks was observed. The findings provide insight into the mechanisms of response lapses under different task load levels and can inform strategies to mitigate these lapses during extended work periods. This study’s findings can be applied to improve work schedules and fatigue management in industries like aviation, transportation, and healthcare, helping reduce response lapses and errors during extended work periods under high task load conditions. Full article

In this study, we used machine learning (ML) to estimate time-lapse velocity variations in a reservoir region using seismic data. To accomplish this task, we needed an adequate training set that could map seismic data to velocity perturbation. We generated a synthetic seismic database by simulating reservoirs of varying velocities using a 2D velocity model typical of the Brazilian pre-salt ocean bottom node (OBN) acquisition, located in the Santos basin, Brazil. The largest velocity change in the injector well was around 3% of the empirical velocity model, which mimicked a realistic scenario. The acquisition geometry was formed by the geometry of 1 shot and 49 receivers. For each synthetic reservoir, the corresponding seismic data were obtained by estimating a one-shot forward-wave propagation using acoustic approximation. We studied the reservoir illumination to optimize the input data of the ML inversion. We split the set of synthetic reservoirs into two subsets: training (80%) and testing (20%) sets. We point out that the ML inversion was restricted to the reservoir zone, which means that it was inversion-oriented to a target. We obtained a good similarity between true and ML-inverted reservoir anomalies. The similarity diminished for a situation with non-repeatability noise. Full article

Artificial intelligence applied to time-lapse microscopy may revolutionize embryo selection in IVF by automating data collection and standardizing the assessments. In this context, blastocyst expansion dynamics, although being associated with reproductive fitness, have been poorly studied. This retrospective study (N = 2184 blastocysts from 786 cycles) exploited both technologies to picture the association between embryo and inner-cell-mass (ICM) area in µm², the ICM/Trophectoderm ratio, and the zona pellucida thickness in µm (zp-T) at sequential blastocyst expansion stages, with (i) euploidy and (ii) live-birth per transfer (N = 548 transfers). A quantitative-standardized-expansion-assay (qSEA) was also set-up; a novel approach involving automatic annotations of all expansion metrics every 30 min across 5 h following blastulation. Multivariate regressions and ROC curve analyses were conducted. Aneuploid blastocysts were slower, expanded less and showed thicker zp. The qSEA outlined faster and more consistent zp thinning processes among euploid blastocysts, being more or as effective as the embryologists in ranking euploid embryo as top-quality of their cohorts in 69% of the cases. The qSEA also outlined faster and more consistent blastocyst expansion and zp thinning dynamics among euploid implanted versus not implanted blastocysts, disagreeing with embryologists’ priority choice in about 50% of the cases. In conclusion, qSEA is a promising objective, quantitative, and user-friendly strategy to predict embryo competence that now deserves prospective validations. Full article

Shear stress plays a crucial role in modulating cell adhesion and signaling. We present a microfluidic shear stress generator used to investigate the adhesion dynamics of Dictyostelium discoideum, an amoeba cell model organism with well-characterized adhesion properties. We applied shear stress and tracked cell adhesion, motility, and detachment using time-lapse videomicroscopy. In the precise shear conditions generated on-chip, our results show cell migration patterns are influenced by shear stress, with cells displaying an adaptive response to shear forces as they alter their adhesion and motility behavior. Additionally, we observed that DH1-10 wild-type D. discoideum cells exhibit stronger adhesion and resistance to shear-induced detachment compared to phg2 adhesion-defective mutant cells. We also highlight the influence of cell density on detachment kinetics. Full article

Background: Quiescin Sulfhydryl Oxidase 1 (QSOX1) is an enzyme that catalyzes the oxidation of free thiols to generate disulfide bonds in a variety of proteins, including the cell surface and extracellular matrix. QSOX1 has been reported to be upregulated in a number of cancers, and the overexpression of QSOX1 has been correlated with aggressive cancers and poor patient prognosis. Glioblastoma (GBM) brain cancer has been practically impossible to treat effectively, with cells that rapidly invade normal brain tissue and escape surgery and other treatment. Thus, there is a crucial need to understand the multiple mechanisms that facilitate GBM cell invasion and to determine if QSOX1 is involved. Methods and Results: Here, we investigated the function of QSOX1 in human glioblastoma cells using two cell lines derived from T98G cells, whose proliferation, motility, and invasiveness has been shown by us to be dependent on disulfide bond-containing adhesion and receptor proteins, such as L1CAM and the FGFR. We lentivirally introduced shRNA to attenuate the QSOX1 protein expression in one cell line, and a Western blot analysis confirmed the decreased QSOX1 expression. A DNA content/cell cycle analysis using flow cytometry revealed 27% fewer knockdown cells in the S-phase of the cell cycle, indicating a reduced proliferation. A cell motility analysis utilizing our highly quantitative SuperScratch time-lapse microscopy assay revealed that knockdown cells migrated more slowly, with a 45% decrease in migration velocity. Motility was partly rescued by the co-culture of knockdown cells with control cells, indicating a paracrine effect. Surprisingly, knockdown cells exhibited increased motility when assayed using a Transwell migration assay. Our novel chick embryo orthotopic xenograft model was used to assess the in vivo invasiveness of knockdown vs. control cells, and tumors developed from both cell types. However, fewer invasive knockdown cells were observed after about a week. Conclusions: Our results indicate that an experimental reduction in QSOX1 expression in GBM cells leads to decreased cell proliferation, altered in vitro migration, and decreased in vivo invasion. Full article