Radiation dose estimation with multiple artificial neural networks in dicentric chromosome assay.

PURPOSE: The dicentric chromosome assay (DCA), often referred to as the 'gold standard' in radiation dose estimation, exhibits significant challenges as a consequence of its labor-intensive nature and dependency on expert knowledge. Existing automated technologies face limitations in accurately identifying dicentric chromosomes (DCs), resulting in decreased precision for radiation dose estimation. Furthermore, in the process of identifying DCs through automatic or semi-automatic methods, the resulting distribution could demonstrate under-dispersion or over-dispersion, which results in significant deviations from the Poisson distribution. In response to these issues, we developed an algorithm that employs deep learning to automatically identify chromosomes and perform fully automatic and accurate estimation of diverse radiation doses, adhering to a Poisson distribution. MATERIALS AND METHODS: The dataset utilized for the dose estimation algorithm was generated from 30 healthy donors, with samples created across seven doses, ranging from 0 to 4 Gy. The procedure encompasses several steps: extracting images for dose estimation, counting chromosomes, and detecting DC and fragments. To accomplish these tasks, we utilize a diverse array of artificial neural networks (ANNs). The identification of DCs was accomplished using a detection mechanism that integrates both deep learning-based object detection and classification methods. Based on these detection results, dose-response curves were constructed. A dose estimation was carried out by combining a regression-based ANN with the Monte-Carlo method. RESULTS: In the process of extracting images for dose analysis and identifying DCs, an under-dispersion tendency was observed. To rectify the discrepancy, classification ANN was employed to identify the results of DC detection. This approach led to satisfaction of Poisson distribution criteria by 32 out of the initial pool of 35 data points. In the subsequent stage, dose-response curves were constructed using data from 25 donors. Data provided by the remaining five donors served in performing dose estimations, which were subsequently calibrated by incorporating a regression-based ANN. Of the 23 points, 22 fell within their respective confidence intervals at p < .05 (95%), except for those associated with doses at levels below 0.5 Gy, where accurate calculation was obstructed by numerical issues. The accuracy of dose estimation has been improved for all radiation levels, with the exception of 1 Gy. CONCLUSIONS: This study successfully demonstrates a high-precision dose estimation method across a general range up to 4 Gy through fully automated detection of DCs, adhering strictly to Poisson distribution. Incorporating multiple ANNs confirms the ability to perform fully automated radiation dose estimation. This approach is particularly advantageous in scenarios such as large-scale radiological incidents, improving operational efficiency and speeding up procedures while maintaining consistency in assessments. Moreover, it reduces potential human error and enhances the reliability of results.

Downregulation of DNA methylation enhances differentiation of THP-1 cells and induces M1 polarization of differentiated macrophages.

DNA methylation is an epigenetic modification that regulates gene expression and plays an essential role in hematopoiesis. UHRF1 and DNMT1 are both crucial for regulating genome-wide maintenance of DNA methylation. Specifically, it is well known that hypermethylation is crucial characteristic of acute myeloid leukemia (AML). However, the mechanism underlying how DNA methylation regulates the differentiation of AML cells, including THP-1 is not fully elucidated. In this study, we report that UHRF1 or DNMT1 depletion enhances the phorbol-12-myristate-13-acetate (PMA)-induced differentiation of THP-1 cells. Transcriptome analysis and genome-wide methylation array results showed that depleting UHRF1 or DNMT1 induced changes that made THP-1 cells highly sensitive to PMA. Furthermore, knockdown of UHRF1 or DNMT1 impeded solid tumor formation in xenograft mouse model. These findings suggest that UHRF1 and DNMT1 play a pivotal role in regulating differentiation and proliferation of THP-1 cells and targeting these proteins may improve the efficiency of differentiation therapy in AML patients.

Dicentric chromosome assay using a deep learning-based automated system.

The dicentric chromosome assay is the "gold standard" in biodosimetry for estimating radiation exposure. However, its large-scale deployment is limited owing to its time-consuming nature and requirement for expert reviewers. Therefore, a recently developed automated system was evaluated for the dicentric chromosome assay. A previously constructed deep learning-based automatic dose-estimation system (DLADES) was used to construct dose curves and calculate estimated doses. Blood samples from two donors were exposed to cobalt-60 gamma rays (0-4 Gy, 0.8 Gy/min). The DLADES efficiently identified monocentric and dicentric chromosomes but showed impaired recognition of complete cells with 46 chromosomes. We estimated the chromosome number of each "Accepted" sample in the DLADES and sorted similar-quality images by removing outliers using the 1.5IQR method. Eleven of the 12 data points followed Poisson distribution. Blind samples were prepared for each dose to verify the accuracy of the estimated dose generated by the curve. The estimated dose was calculated using Merkle's method. The actual dose for each sample was within the 95% confidence limits of the estimated dose. Sorting similar-quality images using chromosome numbers is crucial for the automated dicentric chromosome assay. We successfully constructed a dose-response curve and determined the estimated dose using the DLADES.

Regulation of UHRF1 acetylation by TIP60 is important for colon cancer cell proliferation.

BACKGROUND: Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is upregulated in colon cancer cells and associated with silencing tumor suppressor genes (TSGs) to promote colon cancer cell proliferation. OBJECTIVE: To investigate epigenetic modification of UHRF1 by TIP60. Whether UHRF1 acetylation by TIP60 can induce cell proliferation in colon cancer cells. METHODS: Acetylation sites of UHRF1 by TIP60 was predicted by ASEB (Acetylation Set Enrichment Based) method and identified by immunoprecipitation assay using anti-pan-acetyl lysine antibody and in vitro acetylation assay. Based on this method, UHRF1 acetylation-deficient mimic 4KR (K644R, K646R, K648R, K650R) mutant was generated to investigate effects of UHRF1 acetylation by TIP60. shRNA system was used to generate stable knockdown cell line of UHRF1. With transient transfection of UHRF1 WT and 4KR, the effects of UHRF1 4KR mutant on Jun dimerization protein 2 (JDP2) gene expression, cell proliferation and cell cycle were investigated by RT-qPCR and FACS analysis in shUHRF1 colon cancer cell line. RESULTS: Downregulation of TIP60-mediated UHRF1 acetylation is correlated with suppressed cell cycle progression. Acetylation-deficient mimic of UHRF1 showed poor cell growth through increased expression of JDP2 gene. CONCLUSIONS: Acetylation of UHRF1 4K residues by TIP60 is important for colon cancer cell growth. Furthermore, upregulated JDP2 expression by acetylation-deficient mutant of UHRF1 might be an important epigenetic target for colon cancer cell proliferation.

SET7-mediated TIP60 methylation is essential for DNA double-strand break repair.

The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is crucial for maintaining genomic integrity and is involved in numerous fundamental biological processes. Post-translational modifications by proteins play an important role in regulating DNA repair. Here, we report that the methyltransferase SET7 regulates HR-mediated DSB repair by methylating TIP60, a histone acetyltransferase and tumor suppressor involved in gene expression and protein stability. We show that SET7 targets TIP60 for methylation at K137, which facilitates DSB repair by promoting HR and determines cell viability against DNA damage. Interestingly, TIP60 demethylation is catalyzed by LSD1, which affects HR efficiency. Taken together, our findings reveal the importance of TIP60 methylation status by SET7 and LSD1 in the DSB repair pathway. [BMB Reports 2022; 55(11): 541-546].

Psychogenic coma after general anesthesia with remimazolam and remifentanil -a case report.

BACKGROUND: Delayed emergence from general anesthesia is associated with life-threatening conditions with pharmacological, neurological, metabolic, and rarely, psychiatric causes. This case report was presented to report psychogenic coma after recovery from anesthesia with remimazolam and remifentanil. CASE: An elderly woman was unresponsive after recovery from anesthesia with remimazolam and remifentanil. Physical examination, laboratory testing, and radiographic imaging did not reveal any obvious organic causes. Pharmacological or metabolic abnormalities were not found. Absence of those causes strongly suggests that prolonged unconsciousness is related to psychiatric origin. The patient spontaneously regained consciousness after 48 h without any neurological complications. CONCLUSIONS: Anesthesiologists should be aware of the possibility of psychogenic coma for patients with unexplained delay in emergence from anesthesia after the exclusion of other causes.

Feasibility Study on Automatic Interpretation of Radiation Dose Using Deep Learning Technique for Dicentric Chromosome Assay.

The interpretation of radiation dose is an important procedure for both radiological operators and persons who are exposed to background or artificial radiations. Dicentric chromosome assay (DCA) is one of the representative methods of dose estimation that discriminates the aberration in chromosomes modified by radiation. Despite the DCA-based automated radiation dose estimation methods proposed in previous studies, there are still limitations to the accuracy of dose estimation. In this study, a DCA-based automated dose estimation system using deep learning methods is proposed. The system is comprised of three stages. In the first stage, a classifier based on a deep learning technique is used for filtering the chromosome images that are not appropriate for use in distinguishing the chromosome; 99% filtering accuracy was achieved with 2,040 test images. In the second stage, the dicentric rate is evaluated by counting and identifying chromosomes based on the Feature Pyramid Network, which is one of the object detection algorithms based on deep learning architecture. The accuracies of the neural networks for counting and identifying chromosomes were estimated at over 97% and 90%, respectively. In the third stage, dose estimation is conducted using the dicentric rate and the dose-response curve. The accuracies of the system were estimated using two independent samples; absorbed doses ranging from 1- 4 Gy agreed well within a 99% confidential interval showing highest accuracy compared to those in previous studies. The goal of this study was to provide insights towards achieving complete automation of the radiation dose estimation, especially in the event of a large-scale radiation exposure incident.

The influence of surrounding land cover on wetland habitat conditions: a case study of inland wetlands in South Korea.

Wetland ecosystems have been globally degraded and lost due to rapid urbanization and climate change. An assessment of national scale inventory, including wetland types and conditions, is urgently required to understand the big picture of endangered wetlands, such as where they are and how they look like. We analyzed the spatial patterns of each inland wetland type (brackish wetland was included) in South Korea and the relative importance of land cover categories on wetland conditions. The wetlands were grouped into four dominant types (riverine, lake, mountain, and human-made) according to their topography. Riverine wetlands constituted the largest area (71.3%). The relative ratio of wetlands in a well-conserved condition (i.e., "A" rank) was highest in riverine wetlands (23.8%), followed by mountain wetlands (22.1%). The higher proportion of grasslands was related to a better condition ranking, but the increasing bareland area had a negative impact on wetland conditions. We also found that wetlands located near wetland protected areas tend to be in a better condition compared to remote sites. Our results further support the importance of the condition of surrounding areas for wetland conservation.