Thin cathode glass gas electron multiplier detector for carbon beam dose imaging

An optically read-out glass gas electron multiplier (G-GEM) detector is expected to simplify complicated quality assurance measurements for hadron therapies by imaging the dose distribution of the incident beam. However, the effect of secondary particles from the detector itself has not been well studied. In this paper, we evaluate a design that reduces the secondary particles from the cathode of a G-GEM detector. Specifically, we assembled detectors with thin cathodes and assessed their effect on the secondary particle production in simulations and experiments. The experiments were carried out under 290 MeV/u 12C ion bombardment at the Heavy Ion Medical Accelerator in Chiba. The clinical intensity of the thin cathode detector was compared with that of a conventional thick cathode G-GEM detector. The improved chamber design reduced the dose contributions of secondary particles from the cathode without degrading the dose imaging performance

Development and characterization of optical readout well-type glass gas electron multiplier for dose imaging in clinical carbon beams

The use of carbon ion beams in cancer therapy (also known as hadron therapy) is steadily growing worldwide; therefore, the demand for more efficient dosimetry systems is also increasing because daily quality assurance (QA) measurements of hadron radiotherapy is one of the most complex and time consuming tasks. The aim of this study is to develop a two-dimensional dosimetry system that offers high spatial resolution, a large field of view, quick data response, and a linear dose–response relationship.We demonstrate the dose imaging performance of a novel digital dose imager using carbon ion beams for hadron therapy. The dose imager is based on a newly-developed gaseous detector, a well-type glass gas electron multiplier. The imager is successfully operated in a hadron therapy facility with clinical intensity beams for radiotherapy. It features a high spatial resolution of less than 1 mm and an almost linear dose–response relationship with no saturation and very low linear-energy-transfer dependence. Experimental results show that the dose imager has the potential to improve dosimetry accuracy for daily QA

Impact of the COVID-19 pandemic on migraine in Japan: a multicentre cross-sectional study

Abstract Objectives To assess the impacts of social situation changes due to the coronavirus disease 2019 (COVID-19) pandemic on headache-related disability and other symptoms in patients with migraine in Japan. Methods We conducted a multicentre, cross-sectional study including 659 outpatients with migraine diagnosed by headache specialists. The participants were asked about the impacts of the first wave of the COVID-19 pandemic on headache-related disability, headache days, headache intensity, stress, physical activity, hospital access and their work and home lives. For headache-related disability, the total Migraine Disability Assessment (MIDAS) score and part A and B scores were analysed. Multivariate stepwise linear regression analysis was performed to identify the clinical predictors of changes in the total MIDAS score before and during the COVID-19 pandemic. Logistic regression analysis was performed to determine the factors related to new-onset headache during the COVID-19 pandemic. Results Finally, 606 migraine patients (73 M/533 F; age, 45.2 ± 12.0 years) were included in the study, excluding those with incomplete data. Increased stress, substantial concern about COVID-19 and negative impacts of the first wave of the COVID-19 pandemic on daily life were reported in 56.8 %, 55.1 and 45.0 % of the participants, respectively. The total MIDAS and A and B scores did not significantly change after the first wave of the COVID-19 pandemic. New-onset headache, which was observed in 95 patients (15.7 %), was associated with younger age and worsened mood and sleep in the logistic regression analysis. The multivariate stepwise linear regression analysis of changes in the total MIDAS score before and during the first wave of COVID-19 pandemic identified worsened sleep, increased acute medication use, increased stress, medication shortages, comorbidities, the absence of an aura and new-onset headache were determinants of an increased total MIDAS score during the first wave of the COVID-19 pandemic. Conclusions In this multicentre study, clinical factors relevant to headache-related disability, such as new-onset headache, stress and sleep disturbances, were identified, highlighting the importance of symptom management in migraine patients during the first wave of the COVID-19 pandemic

Homologous Recombination but Not Nucleotide Excision Repair Plays a Pivotal Role in Tolerance of DNA-Protein Cross-links in Mammalian Cells*

DNA-protein cross-links (DPCs) are unique among DNA lesions in their unusually bulky nature. The steric hindrance imposed by cross-linked proteins (CLPs) will hamper DNA transactions, such as replication and transcription, posing an enormous threat to cells. In bacteria, DPCs with small CLPs are eliminated by nucleotide excision repair (NER), whereas oversized DPCs are processed exclusively by RecBCD-dependent homologous recombination (HR). Here we have assessed the roles of NER and HR for DPCs in mammalian cells. We show that the upper size limit of CLPs amenable to mammalian NER is relatively small (8–10 kDa) so that NER cannot participate in the repair of chromosomal DPCs in mammalian cells. Moreover, CLPs are not polyubiquitinated and hence are not subjected to proteasomal degradation prior to NER. In contrast, HR constitutes the major pathway in tolerance of DPCs as judged from cell survival and RAD51 and γ-H2AX nuclear foci formation. Induction of DPCs results in the accumulation of DNA double strand breaks in HR-deficient but not HR-proficient cells, suggesting that fork breakage at the DPC site initiates HR and reactivates the stalled fork. DPCs activate both ATR and ATM damage response pathways, but there is a time lag between two responses. These results highlight the differential involvement of NER in the repair of DPCs in bacterial and mammalian cells and demonstrate the versatile and conserved role of HR in tolerance of DPCs among species

Probable rapid eye movement sleep behavior disorder, nocturnal disturbances and quality of life in patients with Parkinson’s disease: a case-controlled study using the rapid eye movement sleep behavior disorder screening questionnaire

<p>Abstract</p> <p>Background</p> <p>Increasing evidence provides a clear association between rapid eye movement sleep behavior disorders (RBD) and Parkinson’s disease (PD), but the clinical features that determine the co-morbidity of RBD and PD are not yet fully understood.</p> <p>Methods</p> <p>We evaluated the characteristics of nocturnal disturbances and other motor and non-motor features related to RBD in patients with PD and the impact of RBD on their quality of life. Probable RBD (pRBD) was evaluated using the Japanese version of the RBD screening questionnaire (RBDSQ-J).</p> <p>Results</p> <p>A significantly higher frequency of pRBD was observed in PD patients than in the controls (RBDSQ-J ≥ 5 or ≥ 6: 29.0% vs. 8.6%; 17.2% vs. 2.2%, respectively). After excluding restless legs syndrome and snorers in the PD patients, the pRBD group (RBDSQ-J≥5) showed higher scores compared with the non-pRBD group on the Parkinson’s disease sleep scale-2 (PDSS-2) total and three-domain scores. Early morning dystonia was more frequent in the pRBD group. The Parkinson’s Disease Questionnaire (PDQ-39) domain scores for cognition and emotional well-being were higher in the patients with pRBD than in the patients without pRBD. There were no differences between these two groups with respect to the clinical subtype, disease severity or motor function. When using a cut-off of RBDSQ-J = 6, a similar trend was observed for the PDSS-2 and PDQ-39 scores. Patients with PD and pRBD had frequent sleep onset insomnia, distressing dreams and hallucinations. The stepwise linear regression analysis showed that the PDSS-2 domain “motor symptoms at night”, particularly the PDSS sub-item 6 “distressing dreams”, was the only predictor of RBDSQ-J in PD.</p> <p>Conclusion</p> <p>Our results indicate a significant impact of RBD co-morbidity on night-time disturbances and quality of life in PD, particularly on cognition and emotional well-being. RBDSQ may be a useful tool for not only screening RBD in PD patients but also predicting diffuse and complex clinical PD phenotypes associated with RBD, cognitive impairment and hallucinations.</p