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Inhibition of cell division is an active response to DNA damage that enables cells to maintain genome integrity. However, how DNA damage arrests the plant cell cycle is largely unknown. Here, we show that the repressor-type R1R2R3-Myb transcription factors (Rep-MYBs), which suppress G2/M-specific genes, are required to inhibit cell division in response to DNA damage. Knockout mutants are resistant to agents that cause DNA double-strand breaks and replication stress. Cyclin-dependent kinases (CDKs) can phosphorylate Rep-MYBs in vitro and are involved in their proteasomal degradation. DNA damage reduces CDK activities and causes accumulation of Rep-MYBs and cytological changes consistent with cell cycle arrest. Our results suggest that CDK suppressors such as CDK inhibitors are not sufficient to arrest the cell cycle in response to DNA damage but that Rep-MYB-dependent repression of G2/M-specific genes is crucial, indicating an essential function for Rep-MYBs in the DNA damage response.

A cortical hyperintensity on fluid-attenuated inversion recovery images (FLAIR cortical hyperintensity (FCH)) is an abnormal finding after revascularization surgery for moyamoya disease. This study aimed to investigate the pathophysiology of FCH through genetic analyses of RNF213 p.R4810K polymorphism and perioperative hemodynamic studies using single-photon emission computed tomography. We studied 96 hemispheres in 65 adults and 47 hemispheres in 27 children, who underwent combined direct and indirect revascularization. Early or late FCH was defined when it was observed on postoperative days 0-2 and 6-9, respectively. FCH scores (range: 0-6) were evaluated according to the extent of FCH in the operated hemisphere. FCHs were significantly more prevalent in adult patients than pediatric patients (early: 94% vs. 78%; late: 97% vs. 59%). In pediatric patients, FCH scores were significantly improved from the early to late phase regardless of the RNF213 genotype (mutant median [IQR]: 2 [1-5] vs. 1 [0-2]; wild-type median: 4 [0.5-6] vs. 0.5 [0-1.75]). In adults, FCH scores were significantly improved in patients with the wild-type RNF213 allele (median: 4 [2-5.25] vs. 2 [2, 3]); however, they showed no significant improvement in patients with the RNF213 mutation. FCH scores were significantly higher in patients with symptomatic cerebral hyperperfusion than those without it (early median: 5 [4, 5] vs. 4 [2-5]; late median: 4 [3-5] vs. 3 [2-4]). In conclusion, the RNF213 p.R4810K polymorphism was associated with prolonged FCH, and extensive FCH was associated with symptomatic cerebral hyperperfusion in adult patients with moyamoya disease.

BACKGROUND: Surgical management of splenic flexure carcinoma remains controversial. OBJECTIVE: This study aimed to establish an expert international consensus on splenic flexure carcinoma management. DESIGN: A 3-round online-based Delphi study was conducted between September 2020 and April 2021. SETTING: The first round included 18 experts from 12 different countries. For the second and third rounds, each expert in the first round was asked to invite 2 more colorectal surgeons (n = 47). Out of 47 invited experts, 89% (n = 42) participated in the second and third rounds of the consensus. INTERVENTIONS: A total of 35 questions were created and sent via the online questionnaire tool. MAIN OUTCOME MEASURES: Levels of recommendation based on voting concordance were graded as follows: more than 75% agreement was defined as strong, between 50% and 75% as moderate, and below 50% as weak. RESULTS: There was moderate consensus on the definition of splenic flexure (55%) as 10 cm from either side where the distal transverse colon turns into the proximal descending colon. Also, experts recommended an abdominopelvic CT scan plus intraoperative exploration (moderate consensus, 72%) for tumor localization and cancer registry. Segmental colectomy was the preferred technique for the management of splenic flexure carcinoma in the elective setting (72%). Moderate consensus was achieved on the technique of complete mesocolic excision and central vascular ligation principles for splenic flexure carcinoma (74%). Only strong consensus was achieved on the surgical approach for minimally invasive surgery (88%). LIMITATIONS: Subjective decisions are based on individual expert clinical experience and not evidence based. CONCLUSIONS: This is the first internationally conducted Delphi consensus study regarding splenic flexure carcinoma. The definition of splenic flexure remains am, BACKGROUND: Surgical management of splenic flexure carcinoma remains controversial. OBJECTIVE: This study aimed to establish an expert international consensus on splenic flexure carcinoma management. DESIGN: A 3-round online-based Delphi study was conducted between September 2020 and April 2021. SETTING: The first round included 18 experts from 12 different countries. For the second and third rounds, each expert in the first round was asked to invite 2 more colorectal surgeons (n = 47). Out of 47 invited experts, 89% (n = 42) participated in the second and third rounds of the consensus. INTERVENTIONS: A total of 35 questions were created and sent via the online questionnaire tool. MAIN OUTCOME MEASURES: Levels of recommendation based on voting concordance were graded as follows: more than 75% agreement was defined as strong, between 50% and 75% as moderate, and below 50% as weak. RESULTS: There was moderate consensus on the definition of splenic flexure (55%) as 10 cm from either side where the distal transverse colon turns into the proximal descending colon. Also, experts recommended an abdominopelvic CT scan plus intraoperative exploration (moderate consensus, 72%) for tumor localization and cancer registry. Segmental colectomy was the preferred technique for the management of splenic flexure carcinoma in the elective setting (72%). Moderate consensus was achieved on the technique of complete mesocolic excision and central vascular ligation principles for splenic flexure carcinoma (74%). Only strong consensus was achieved on the surgical approach for minimally invasive surgery (88%). LIMITATIONS: Subjective decisions are based on individual expert clinical experience and not evidence based. CONCLUSIONS: This is the first internationally conducted Delphi consensus study regarding splenic flexure carcinoma. The definition of splenic flexure remains ambiguous. To more effectively compare oncologic outcomes among different cancer registries, guidelines need to be d

Any polymers composed of racemic repeating units are obviously optically inactive and hence chiral functions, such as asymmetric catalysis, will not be expected at all. Contrary to such a preconceived notion, we report an unprecedented helical polymer-based highly enantioselective organocatalyst prepared by polymerization of a racemic monomer with no catalytic activity. Both the right- and left-handed helical poly(biarylylacetylene)s (PBAs) composed of dynamically racemic 2-arylpyridyl-N-oxide monomer units with N-oxide moieties located in the vicinity of the helical polymer backbone can be produced by noncovalent interaction with a chiral alcohol through deracemization of the biaryl pendants. The macromolecular helicity and the axial chirality induced in the PBAs are retained (“memorized”) after complete removal of the chiral alcohol. Accordingly, the helical PBAs with dual static memory of the helicity and axial chirality show remarkable enantioselectivity (86% ee) for the asymmetric allylation of benzaldehyde. The enantioselectivity is slightly lower than that (96% ee) of the homochiral PBAs prepared from the corresponding enantiopure (R)- and (S)-monomers, but is comparable to that (88% ee) of the helical PBA composed of nonracemic monomers of ca. 60% ee.

OBJECTIVE: Cerebral angiography is the gold standard for diagnosing moyamoya disease (MMD), whereas mag-netic resonance (MR) imaging/angiography is becoming more popular in the field of cerebrovascular disease due to its low invasiveness. Although there are concerns about using only MR imaging/angiography for preoperative analysis of MMD, considering the underestimation of pre-existing transdural collateral circulations and dangerous collaterals related to the risk of hemorrhage, we retro-spectively reviewed our 10-year experience of MR imagingefirst diagnosis and analyzed the perioperative outcomes.METHODS: We analyzed 160 consecutive direct/indirect combined revascularization procedures for MMD preoper-atively assessed using MR imaging/angiography alone. Perioperative complications were assessed for up to 2 weeks after surgery. Locations of the lesions responsible for complications were further classified into the surgical field, the ipsilateral hemisphere outside the surgical field, and the contralateral hemisphere.RESULTS: Sixty-four revascularization procedures were performed in 38 children, and 96 procedures were per-formed in 68 adults. There was no difference in the inci-dence of perioperative ischemic complications between adults (6.3%) and pediatric patients (4.7%), but hemorrhagic complications were more frequently observed in adults (7.3%) than in children (0%) (P < 0.05). There was no spe-cific lesion deviation for ischemic complications; however, hemorrhagic complications predominantly occurred in the surgical field. CONCLUSIONS: Direct/indirect combined revasculari-zation surgery based on our preoperative diagnostic pro-tocol with the MR-first strategy resulted in favorable outcomes in pediatric MMD patients with relatively low complication rates. However, the validity of the MR-first diagnostic protocol should be further evaluated in adult patients with MMD.

Direct superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis combined with indirect pial synangiosis provides favorable surgical collaterals for Moyamoya disease (MMD), especially in adults; however, factors leading to the development of each direct and indirect collateral are not well documented. We aimed to investigate the association between RNF213 founder polymorphism (p.R4810K) and each direct and indirect collateral development. By qualitative and quantitative evaluations of direct and indirect surgical collaterals using time-of-flight MR angiography, postoperative development of each type of bypass was evaluated independently into two categories. Multivariate logistic regression analysis was performed to study the contributing factors for the development of each surgical collateral. Excellent development of postoperative direct and indirect bypass was observed in 65 hemispheres (70%) by qualitative evaluation, which was confirmed by quantitative evaluation. Multivariate logistic regression analysis of excellent indirect bypass development revealed a significant positive correlation with the p.R4810K (odds ratio, OR4.0; 95%-confidence interval, CI 1.2-16), advanced MR angiographic stage (OR9.5; 95%CI 1.7-73), and preoperative middle meningeal artery caliber (OR6.8; 95%CI 1.8-35), but a significant negative correlation was found with the excellent direct bypass development (OR0.17; 95%CI 0.03-0.75). No significant correlation was observed between excellent direct bypass development and the p.R4810K (OR0.95; 95%CI 0.37-2.4). In conclusion, excellent development of indirect collaterals after STA-MCA anastomosis combined with indirect pial synangiosis occurs more frequently in adult MMD with the RNF213 founder polymorphism, suggesting a role of the p.R4810K variant for marked in-growth of indirect collaterals and the utility of preoperative genetic analysis.