An abdominal spacer that does not require surgical removal and allows drainage of abdominal fluids in patients undergoing carbon ion radiotherapy.

Abdominal spacers are useful for maintaining the distance between the target tumors and surrounding tissues, such as the gastrointestinal tract, in patients treated with carbon ion radiotherapy. Surgical intervention to remove the spacers is sometimes necessary because of abdominal infections triggered by long-term spacer placement or intestinal perforation. Therefore, spacers that do not require surgical removal and provide effective drainage against abdominal infections are urgently needed. This study aimed to develop a spacer that could be removed non-surgically and one that provides the therapeutic effect of drainage in patients who receive carbon ion radiotherapy for abdominal tumors. A novel fan-shaped spacer was constructed from a film drain that was folded along the trigger line. Simple withdrawal of the trigger line caused the film drain to fold and the holding lines to become free. We performed laparoscopy-assisted insertion with pneumoperitoneum and blind removal of the spacer fourteen times using a porcine model. Saline in the abdominal cavity was effectively aspirated using the spacer. Our novel fan-shaped spacer could be removed safely without surgery and was able to drain fluid effectively from the abdominal cavity.

Sign-constrained linear regression for prediction of microbe concentration based on water quality datasets.

This study presents a novel methodology for estimating the concentration of environmental pollutants in water, such as pathogens, based on environmental parameters. The scientific uniqueness of this study is the prevention of excess conformity in the model fitting by applying domain knowledge, which is the accumulated scientific knowledge regarding the correlations between response and explanatory variables. Sign constraints were used to express domain knowledge, and the effect of the sign constraints on the prediction performance using censored datasets was investigated. As a result, we confirmed that sign constraints made prediction more accurate compared to conventional sign-free approaches. The most remarkable technical contribution of this study is the finding that the sign constraints can be incorporated in the estimation of the correlation coefficient in Tobit analysis. We developed effective and numerically stable algorithms for fitting a model to datasets under the sign constraints. This novel algorithm is applicable to a wide variety of the prediction of pollutant contamination level, including the pathogen concentrations in water.

Usefulness of coronary postmortem computed tomography angiography to detect lesions in the coronary artery and myocardium in cases of sudden death.

Coronary postmortem computed tomography angiography (coronary PMCTA) has been introduced as a routine examination procedure for autopsy at our department. Here, we reviewed eight autopsy cases in which apparent histopathological changes including acute myocardial infarction (AMI), anomalous aortic origin of a coronary artery (AAOCA), hypertrophic obstructive cardiomyopathy (HOCM) and acute myocarditis were involved in the cause of death. For investigation of the coronary artery and shape of the heart, coronary PMCTA was valuable in detecting narrowing or obstruction of coronary artery in AMI, indicating an anomalous aortic origin of the left coronary artery in AAOCA, and demonstrating septal hypertrophy and intracavitary obstruction in HOCM. However, it was debatable whether the hypervascularity demonstrated by coronary PMCTA in the case of acute myocarditis was more prominent than the vascular images obtained in other cases without inflammation. Thus, coronary PMCTA appeared to be useful not only for detection of coronary artery stenosis, but also for indicating other distinctive changes involved in AAOCA and HOCM.