Ionizing radiation is one of the most effective tools in cancer therapy. In a previous study, we reported that protein tyrosine kinase (PTK) inhibitors modulate the radiation responses in the human chronic myelogenous leukemia (CML) cell line K562. The receptor tyrosine kinase inhibitor, genistein, delayed radiation-induced cell death, while non-recepter tyrosine kinase inhibitor, herbimycin A (HMA) enhances radiation-induced apoptosis. In this study, we focused on the modulation of radiation-induced cell death by genistein and performed PCR-select suppression subtractive hybridization (SSH) to understand its molecular mechanism. We identified human thymidine kinase 1 (TK1), which is cell cycle regulatory gene and confirmed expression of TK1 mRNA by Northern blot analysis. Expression of TK1 mRNA and TK 1 enzymatic activity were parallel in their increase and decrease. TK1 is involved in G1-S phase transition of cell cycle progression. In cell cycle analysis, we showed that radiation induced G2 arrest in K562 cells but it was not able to sustain. However, the addition of genistein to irradiated cells sustained a prolonged G2 arrest up to 120 h. In addition, the expression of cell cycle-related proteins, cyclin A and cyclin B1, provided the evidences of G1/S progression and G2-arrest, and their relationship with TK1 in cells treated with radiation and genistein. These results suggest that the activation of TK1 may be critical to modulate the radiation-induced cell death and cell cycle progression in irradiated K562 cells.

Purpose: To compare the image quality of CT obtained using a deep learning-based image reconstruction (DLIR) engine with images with adaptive statistical iterative reconstruction-V (AV). Materials and Methods: Using a phantom, the noise power spectrum (NPS) and task-based transfer function (TTF) were measured in images with different reconstructions (filtered back projection [FBP], AV30, 50, 100, DLIR-L, M, H) at multiple doses. One hundred and twenty abdominal CTs with 30% dose reduction were processed using AV30, AV50, DLIR-L, M, H. Objective and subjective analyses were performed. Results: The NPS peak of DLIR was lower than that of AV30 or AV50. Compared with AV30, the NPS average spatial frequencies were higher with DLIR-L or DLIR-M. For lower contrast objects, TTF in images with DLIR were higher than those with AV. The standard deviation in DLIR-H and DLIR-M was significantly lower than AV30 and AV50. The overall image quality was the best for DLIR-M ( p < 0.001 ). Conclusions: DLIR showed improved image quality and decreased noise under a decreased radiation dose.

목적 코로나바이러스감염증–19 영향으로 소아청소년과 내원 환자 수가 현저히 감소한 2020년에 소아 장중첩증에는 어떤 변화가 발생했는지 알아보고자 한다. 대상과 방법 2011년부터 2020년까지 고려대학교 안산병원에 내원하여 장중첩증 진단 후 관장정복술을 받은 18세 미만의 환자의 성별, 나이, 관장정복술의 연도별/월별/계절별 빈도, 관장정복술의 연도별/월별 실패율, 장중첩증의 연도별/월별 재발률을 조사하였다. 또한 2011–2019년에 내원한 환자군과 2020년에 내원한 환자군 사이에 평균 나이, 관장정복술 실패율 및 장중첩증 재발률에서 통계적 차이가 있는지 분석하였다. 결과 10년간 859건의 관장정복술은 남아에서 더 많이 시행되었고 평균 나이는 22.2개월, 연령별로는 1세 미만이 가장 많았다. 연도별 빈도는 2014년에 가장 높았고 2020년에 가장 낮았으며, 월별 빈도는 12월과 9월이 높았고 3월이 가장 낮았다. 2020년 환자군( n = 27)은 2011–2019년 환자군( n = 832)에 비해 평균 나이가 어리고(18.1개월 vs. 22.8개월) 관장정복술 실패율이 높고 (7.4% vs. 2.4%) 장중첩증 재발률이 높았으나(14.8% vs. 7.3%) 통계적 유의성을 보이지는 않았다( p = 0.07, p = 0.15, p = 0.14). 결론 코로나바이러스감염증–19가 유행한 2020년에는 장중첩증으로 관장정복술을 받은 환자 수가 급격히 감소하였고, 지난 10년의 기록과 비교할 때 환자의 나이가 더 어린 경향을 보였으며, 관장정복술의 실패율과 장중첩증 재발률은 가장 높은 수치를 기록하였다.