Prognostic value of a mandibular canal staging system for primary lesions in patients with lower gingival squamous cell carcinoma: a multicenter, retrospective study.

BACKGROUND: The Union for International Cancer Control and American Joint Committee on Cancer tumor staging system is used globally for treatment planning. As it may be insufficient for tumor staging of lower gingival carcinomas, we proposed the mandibular canal tumor staging system. In this study, we aimed to compare the two systems for such tumor staging and to identify prognostic markers. METHODS: This multicenter, retrospective study included patients with lower gingival squamous cell carcinoma who underwent radical surgery during 2001-2018. We compared survival rates (Kaplan-Meier estimator) and patient stratification according to the two systems. RESULTS: The proposed system yielded more balanced patient stratification than the existing system. Progression in the tumor grade according to the proposed system was associated with a poorer prognosis. The 5-year overall and disease-specific survival rates for the entire cohort were 74.9% and 81.8%, respectively. Independent factors affecting overall survival were tumor stage according to the proposed system, excision margins, and number of positive nodes, whereas those affecting disease-specific survival were excision margins and number of positive nodes. CONCLUSIONS: Subsite-specific tumor classification should be used for patients with oral cancer, and our results suggest that mandibular canal tumor classification may be effective for patients with lower gingival carcinoma.

Precursor Radiographic Findings in Patients With Medication-Related Osteonecrosis of the Jaw.

BACKGROUND: Oral surgical treatment, such as tooth extraction, has been identified as a risk factor for the onset of medication-related osteonecrosis of the jaw (MRONJ). However, MRONJ may already be latent, and its manifestation may be triggered by extraction. PURPOSE: The purpose of this study was to examine the association between pre-extraction imaging and MRONJ. STUDY DESIGN, SETTING, SAMPLE: We performed a multicenter case-control analysis of patients receiving antiresorptive agents (ARAs) who underwent extraction between 2012 and 2016. We enrolled patients who had undergone tooth extraction in the setting of ARA exposure. PREDICTOR VARIABLES: The predictor variables comprised preoperative radiographic findings associated with MRONJ stage 0. These findings included alveolar bone loss, thickening or obscuring of the periodontal ligament, and osteosclerosis involving the alveolar bone. They were coded as present or absent before tooth extraction. MAIN OUTCOME VARIABLE: The primary outcome variable was MRONJ status coded as present or absent. COVARIATES: Sex, age, underlying diseases necessitating the administration of ARA, the type of ARA used, corticosteroid use, extraction region, and wound closure were analyzed. ANALYSES: Mann-Whitney U test, χ2 test, Fisher's exact test for univariate analysis, and multiple logistic regression analysis were performed. P values < .05 were significant. RESULTS: The subjects consisted of 26 patients and 110 controls (male: 8/36, female: 18/74). The mean ages of the MRONJ group and the control group were 77.0 ± 11.9 and 63.0 ± 15.8, respectively (P value = .001). The prevalence of osteosclerosis was significantly higher in the MRONJ group than in the control group (14/72, 53.9%/29.3%, P < .01). Multivariate analysis identified osteosclerosis (odds ratio: 8.4, 95% confidence interval: 2.133.9, P < .01) as a significant independent predictor associated with the development of MRONJ after extraction. CONCLUSION AND RELEVANCE: These findings suggest that a precursor to MRONJ is highly likely to be present in patients with osteosclerosis at the time of extraction. The majority of patients who developed MRONJ after extraction had imaging findings that suggested infection in the surrounding alveolar bone.

Prediction of patient-specific quality assurance for volumetric modulated arc therapy using radiomics-based machine learning with dose distribution.

PURPOSE: We sought to develop machine learning models to predict the results of patient-specific quality assurance (QA) for volumetric modulated arc therapy (VMAT), which were represented by several dose-evaluation metrics-including the gamma passing rates (GPRs)-and criteria based on the radiomic features of 3D dose distribution in a phantom. METHODS: A total of 4,250 radiomic features of 3D dose distribution in a cylindrical dummy phantom for 140 arcs from 106 clinical VMAT plans were extracted. We obtained the following dose-evaluation metrics: GPRs with global and local normalization, the dose difference (DD) in 1% and 2% passing rates (DD1% and DD2%) for 10% and 50% dose threshold, and the distance-to-agreement in 1-mm and 2-mm passing rates (DTA1 mm and DTA2 mm) for 0.5%/mm and 1.0%.mm dose gradient threshold determined by measurement using a diode array in patient-specific QA. The machine learning regression models for predicting the values of the dose-evaluation metrics using the radiomic features were developed based on the elastic net (EN) and extra trees (ET) models. The feature selection and tuning of hyperparameters were performed with nested cross-validation in which four-fold cross-validation is used within the inner loop, and the performance of each model was evaluated in terms of the root mean square error (RMSE), the mean absolute error (MAE), and Spearman's rank correlation coefficient. RESULTS: The RMSE and MAE for the developed machine learning models ranged from <1% to nearly <10% depending on the dose-evaluation metric, the criteria, and dose and dose gradient thresholds used for both machine learning models. It was advantageous to focus on high dose region for predicating global GPR, DDs, and DTAs. For certain metrics and criteria, it was possible to create models applicable for patients' heterogeneity by training only with dose distributions in phantom. CONCLUSIONS: The developed machine learning models showed high performance for predicting dose-evaluation metrics especially for high dose region depending on the metric and criteria. Our results demonstrate that the radiomic features of dose distribution can be considered good indicators of the plan complexity and useful in predicting measured dose evaluation metrics.

The effectiveness of a self-reported questionnaire on masticatory function in health examinations.

Periodontal diseases have been reported to be lifestyle-related and associated with metabolic syndrome (MetS). The introduction of dental checkups in a health checkup program may create a synergistic effect and aid the prevention of MetS. In Japan, a chewing function questionnaire has now been introduced into the national health checkup program. The purpose of this study was to investigate whether the questionnaire reflects dental and oral conditions and whether it helps improve general and oral health. A total of 6599 subjects who underwent health checkups or guidance specified by the National Health Insurance of Japan for two consecutive years were included. A single comprehensive question to evaluate masticatory function was asked. Medical and dental examinations and insurance data were collected and used for analysis. In terms of masticatory function during chewing, 82.3% of subjects experienced no problems, 17.3% experienced some difficulty, and 0.4% experienced severe problems. There was a significant relationship between the questionnaire response and dental examinations results for several items of examination. The overall dental consultation rate after health screening was 42.3%. Improvement in periodontal disease was achieved in those who reported some problems with chewing function. Improvement in blood pressure was also observed in those who reported some problem with chewing function and subsequently had a dental consultation. The results of this study indicate that questionnaires on masticatory function reflect the status of dental and oral health. In addition, the results suggested that questionnaire results are potentially linked to improvement in dental and oral health status, and improvement in MetS.

Response to mRNA SARS-CoV-2 vaccination evaluated by B-cell receptor repertoire after tixagevimab/cilgavimab administration.

The use of anti-SARS-CoV-2 antibody products like tixagevimab/cilgavimab represents an important strategy to protect immunocompromised patients with haematological malignancies from COVID-19. Although patients who receive these agents should still be vaccinated, the use of tixagevimab/cilgavimab can mask the production of anti-spike antibody after vaccination, making it hard to assess vaccine response. We have newly established a quantification method to assess the response to SARS-CoV-2 vaccination at the mRNA level using B-cell receptor (BCR) repertoire assay and the Coronavirus Antibody Database (CoV-AbDab). Repeated blood samples before and after vaccination were analysed for the BCR repertoire, and BCR sequences were searched in the database. We analysed the number and percentage frequency of matched sequences. We found that the number of matched sequences increased 2 weeks after the first vaccination and quickly decreased. Meanwhile, the number of matched sequences more rapidly increased after the second vaccination. These results show that the postvaccine immune response can be assessed at the mRNA level by analysing the fluctuation in matching sequences. Finally, BCR repertoire analysis with CoV-AbDab clearly demonstrated the response to mRNA SARS-CoV-2 vaccination even after tixagevimab/cilgavimab administration in haematological malignancy patients who underwent allogeneic haematopoietic stem cell transplantation.

Comparable efficacy and safety of COVID-19 vaccines for patients receiving tegafur-uracil as postoperative adjuvant chemotherapy.

PURPOSE: Many effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed, but a weaker response in individuals undergoing anticancer treatment has been reported. This study evaluates the immunogenic status and safety of SARS-CoV-2 vaccines for patients with non-small-cell lung cancer (NSCLC), receiving tegafur-uracil (UFT) as postoperative adjuvant chemotherapy. METHODS: The subjects of this prospective study were 40 patients who underwent surgery for NSCLC and received SARS-CoV-2 vaccines postoperatively. We compared the antibody titers of SARS-CoV-2 vaccines and the adverse events between patients who received adjuvant UFT and patients who did not. RESULTS: The mean anti-S1 IgG titers were not significantly different between the UFT and without-UFT groups (mean optimal density, 0.194 vs. 0.205; P = 0.76). Multivariate analysis identified the period after the second vaccination as an independent predictor of anti-S1 IgG titer (P = 0.049), but not the UFT status (with or without-UFT treatment; P = 0.47). The prevalence of adverse events did not differ significantly between the groups, and no severe adverse events occurred. CONCLUSIONS: The efficacy and safety of the SARS-CoV-2 vaccines for NSCLC patients who received postoperative adjuvant UFT chemotherapy were comparable to those for NSCLC patients who did not receive postoperative adjuvant UFT chemotherapy. CLINICAL TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Network (UMIN) in Japan (UMIN000047380).

Deep learning-based detection and classification of multi-leaf collimator modeling errors in volumetric modulated radiation therapy.

PURPOSE: The purpose of this study was to create and evaluate deep learning-based models to detect and classify errors of multi-leaf collimator (MLC) modeling parameters in volumetric modulated radiation therapy (VMAT), namely the transmission factor (TF) and the dosimetric leaf gap (DLG). METHODS: A total of 33 clinical VMAT plans for prostate and head-and-neck cancer were used, assuming a cylindrical and homogeneous phantom, and error plans were created by altering the original value of the TF and the DLG by ± 10, 20, and 30% in the treatment planning system (TPS). The Gaussian filters of σ = 0.5 $\sigma = 0.5$ and 1.0 were applied to the planar dose maps of the error-free plan to mimic the measurement dose map, and thus dose difference maps between the error-free and error plans were obtained. We evaluated 3 deep learning-based models, created to perform the following detections/classifications: (1) error-free versus TF error, (2) error-free versus DLG error, and (3) TF versus DLG error. Models to classify the sign of the errors were also created and evaluated. A gamma analysis was performed for comparison. RESULTS: The detection and classification of TF and DLG error were feasible for σ = 0.5 $\sigma = 0.5$ ; however, a considerable reduction of accuracy was observed for σ = 1.0 $\sigma = 1.0$ depending on the magnitude of error and treatment site. The sign of errors was detectable by the specifically trained models for σ = 0.5 $\sigma = 0.5$ and 1.0. The gamma analysis could not detect errors. CONCLUSIONS: We demonstrated that the deep learning-based models could feasibly detect and classify TF and DLG errors in VMAT dose distributions, depending on the magnitude of the error, treatment site, and the degree of mimicked measurement doses.

Safety and immunogenicity of the COVID-19 vaccine BNT162b2 in patients undergoing chemotherapy for solid cancer.

BACKGROUND: Although COVID-19 severity in cancer patients is high, the safety and immunogenicity of the BNT162b2 mRNA COVID-19 vaccine in patients undergoing chemotherapy for solid cancers in Japan have not been reported. METHODS: We investigated the safety and immunogenicity of BNT162b2 in 41 patients undergoing chemotherapy for solid cancers and in healthy volunteers who received 2 doses of BNT162b2. We evaluated serum IgG antibody titers for S1 protein by ELISA at pre-vaccination, prior to the second dose and 14 days after the second vaccination in 24 cancer patients undergoing cytotoxic chemotherapy (CC group), 17 cancer patients undergoing immune checkpoint inhibitor therapy (ICI group) and 12 age-matched healthy volunteers (HV group). Additionally, inflammatory cytokine levels were compared between the HV and ICI groups at pre and the next day of each vaccination. RESULTS: Anti-S1 antibody levels were significantly lower in the ICI and CC groups than in the HV group after the second dose (median optimal density: 0.241 [0.063-1.205] and 0.161 [0.07-0.857] vs 0.644 [0.259-1.498], p = 0.0024 and p < 0.0001, respectively). Adverse effect profile did not differ among the three groups, and no serious adverse event occurred. There were no differences in vaccine-induced inflammatory cytokines between the HV and ICI groups. CONCLUSION: Although there were no significant differences in adverse events in three groups, antibody titers were significantly lower in the ICI and CC groups than in the HV group. Further protection strategies should be considered in cancer patients undergoing CC or ICI.

Impact of upgraded radiotherapy system on outcomes in postoperative head and neck squamous cell carcinoma patients.

Background: This study was performed to evaluate the impact of upgrade of radiotherapy system, including launch of intensity-modulated radiation therapy (IMRT), on the therapeutic outcomes. Materials and methods: Patients with head and neck (H&N) squamous cell carcinoma (SCC) who underwent postoperative radiotherapy at our hospital between June 2009 and July 2019 were retrospectively reviewed. In July 2014, we converted the radiotherapy technique for these patients from a 3-dimensional conformal radiotherapy (3D-CRT) to IMRT, along with the adoption of a meticulous planning policy and a few advanced procedures, including online imaging guidance. Results: A total of 136 patients (57 treated with the previous system and 79 treated with the upgraded system) were reviewed. There were significantly more patients with extracapsular extension in the upgraded-system group than the previous-system group (p = 0.0021). There were significantly fewer patients with ≥ Grade 2 acute and late adverse events in the upgraded-system group than the previous-system group. The differences in progression-free survival (PFS), distant metastasis-free survival (DFFS), locoregional progression-free survival (LRPFS), and overall survival (OS) between the two groups were not statistically significant (p = 0.8962, 0.9926, 0.6244, and 0.4827, respectively). Multivariate analysis revealed that the upgrade had neither positive nor negative impact on survival outcomes. Extracapsular extension was independently associated with decreased LRPFS and OS (p = 0.0499 and 0.0392, respectively). Conclusions: The IMRT-centered upgrade was beneficial for the postoperative patients with H&N SCC, because survival outcomes were sustained with less toxicities.

Relationship between dry mouth and hypertension.

OBJECTIVES: Salivary dysfunction, such as reduced salivary flow and an altered salivary composition, is caused by several diseases, medical conditions, and medications. The purpose of the present study was to clarify the relationship between hypertension and morphological changes in the submandibular glands. MATERIALS AND METHODS: An epidemiological study was conducted to elucidate the relationship between hypertension and dry mouth. The effects of hypertension on morphological changes and the intima thickness of arteries in the submandibular glands were histopathologically investigated. RESULTS: Among 1933 subjects in the epidemiological study, 155 (8.0%) had dry mouth. A multivariate analysis revealed that dry mouth correlated with age (p < 0.001), sex (p < 0.001), and hypertension (p < 0.05). No significant differences were observed in the size of the submandibular glands between patients with or without hypertension. The average area of acinar cells was smaller in patients with than in those without hypertension (0.366 ± 0.153 vs. 0.465 ± 0.178, p < 0.05). The arteriosclerotic index was significantly higher in patients with than in those without hypertension (0.304 ± 0.034 vs 0.475 ± 0.053, p < 0.05). CONCLUSIONS: Hypertension may contribute to the degeneration of the submandibular glands by decreasing the number of acinar cells and promoting fatty infiltration and stenosis of the arteries. CLINICAL RELEVANCE: There may be a correlation between hypertension and the degeneration of the submandibular glands by decreasing the number of acinar cells and promoting fatty infiltration and stenosis of the arteries.

Expression of an alcohol dehydrogenase gene in a heterotrophic bacterium induces carbon dioxide-dependent high-yield growth under oligotrophic conditions.

Sphingobium japonicum strain UT26, whose γ-hexachlorocyclohexane-degrading ability has been studied in detail, is a typical aerobic and heterotrophic bacterium that needs organic carbon sources for its growth, and cannot grow on a minimal salt agar medium prepared without adding any organic carbon sources. Here, we isolated a mutant of UT26 with the ability to grow to visible state on such an oligotrophic medium from a transposon-induced mutant library. This high-yield growth under oligotrophic conditions (HYGO) phenotype was CO2-dependent and accompanied with CO2 incorporation. In the HYGO mutant, a transposon was inserted just upstream of the putative Zn-dependent alcohol dehydrogenase (ADH) gene (adhX) so that the adhX gene was constitutively expressed, probably by the transposon-derived promoter. The adhX-deletion mutant (UT26DAX) harbouring a plasmid carrying the adhX gene under the control of a constitutive promoter exhibited the HYGO phenotype. Moreover, the HYGO mutants spontaneously emerged among the UT26-derived hypermutator strain cells, and adhX was highly expressed in these HYGO mutants, while no HYGO mutant appeared among UT26DAX-derived hypermutator strain cells, indicating the necessity of adhX for the HYGO phenotype. His-tagged AdhX that was expressed in Escherichia coli and purified to homogeneity showed ADH activity towards methanol and other alcohols. Mutagenesis analysis of the adhX gene indicated a correlation between the ADH activity and the HYGO phenotype. These results demonstrated that the constitutive expression of an adhX-encoding protein with ADH activity in UT26 leads to the CO2-dependent HYGO phenotype. Identical or nearly identical adhX orthologues were found in other sphingomonad strains, and most of them were located on plasmids, suggesting that the adhX-mediated HYGO phenotype may be an important adaptation strategy to oligotrophic environments among sphingomonads.

Effect of setup error in the single-isocenter technique on stereotactic radiosurgery for multiple brain metastases.

In conventional stereotactic radiosurgery (SRS), treatment of multiple brain metastases using multiple isocenters is time-consuming resulting in long dose delivery times for patients. A single-isocenter technique has been developed which enables the simultaneous irradiation of multiple targets at one isocenter. This technique requires accurate positioning of the patient to ensure optimal dose coverage. We evaluated the effect of six degrees of freedom (6DoF) setup errors in patient setups on SRS dose distributions for multiple brain metastases using a single-isocenter technique. We used simulated spherical gross tumor volumes (GTVs) with diameters ranging from 1.0 to 3.0 cm. The distance from the isocenter to the target's center was varied from 0 to 15 cm. We created dose distributions so that each target was entirely covered by 100% of the prescribed dose. The target's position vectors were rotated from 0°-2.0° and translated from 0-1.0 mm with respect to the three axes in space. The reduction in dose coverage for the targets for each setup error was calculated and compared with zero setup error. The calculated margins for the GTV necessary to satisfy the tolerance values for loss of GTV coverage of 3% to 10% were defined as coverage-based margins. In addition, the maximum isocenter to target distance for different 6DoF setup errors was calculated to satisfy the tolerance values. The dose coverage reduction and coverage-based margins increased as the target diameter decreased, and the distance and 6DoF setup error increased. An increase in setup error when a single-isocenter technique is used may increase the risk of missing the tumor; this risk increases with increasing distance from the isocenter and decreasing tumor size.

Hypozincemia is associated with human hepatocarcinogenesis in hepatitis C virus-related liver cirrhosis.

AIM: Hypozincemia is associated with the progression of chronic liver diseases, but it is unknown whether hypozincemia promotes human hepatocarcinogenesis. Our aim is to evaluate the serum zinc levels in liver cirrhosis (LC) patients and clarify the relationship between the serum zinc levels and the development of hepatocellular carcinoma (HCC). METHODS: Cirrhotic patients without HCC (n = 299) were enrolled from 14 medical institutes in Japan as a multicenter prospective study (No. 2028). Of the 299 patients, 157 were included in the present study based on reliable and consistent serum zinc levels and no history of oral zinc supplementation. Clinical parameters associated with the development of HCC were determined. Furthermore, the cumulative incidence of HCC was analyzed using Kaplan-Meier methods and was calculated using the log-rank test. A Cox regression analysis was utilized for the multivariate analysis to evaluate the predictors of hepatocarcinogenesis. RESULTS: Thirty of 157 patients (19.1%) developed HCC during an observation period of 3 years. Serum zinc levels were significantly decreased in hepatitis C virus-related LC (C-LC) patients with HCC (0.0180). The risk factors for incidence of HCC were hypozincemia (0.0014), high α-fetoprotein (0.0080), low branched chain amino acids-to-tyrosine ratio (0.0128), or female sex (0.0228). Hypozincemia (hazard ratio 1.61, 0.0324) was the only significant predictor of hepatocarcinogenesis by multivariate Cox regression analysis. CONCLUSIONS: Hypozincemia is associated with hepatocarcinogenesis in C-LC patients.

The impact of the three degrees-of-freedom fiducial marker-based setup compared to soft tissue-based setup in hypofractionated intensity-modulated radiotherapy for prostate cancer.

PURPOSE: We evaluated the setup accuracy of a three-degree-of-freedom fiducial marker (3DOF-FM)-based setup compared to a soft tissue (ST)-based setup in hypofractionated intensity-modulated radiotherapy (IMRT) for prostate cancer. MATERIALS AND METHODS: We analyzed the setup accuracy for 17 consecutive prostate cancer patients with three implanted FMs who underwent hypofractionated IMRT. The 3DOF-ST-based setup using cone-beam computed tomography (CT) was performed after a six DOF-bony structure (BS)-based setup using an ExacTrac x-ray system. The 3DOF-FM-based matching using the ExacTrac x-ray system was done during the BS- and ST-based setups. We determined the mean absolute differences and the correlation between the FM- and ST-based translational shifts relative to the BS-based setup position. The rotational mean shifts detected by the ExacTrac x-ray system were also evaluated. RESULTS: The mean differences in the anterior-posterior (AP), superior-inferior (SI), and left-right (LR) dimensions were 0.69, 0.0, and 0.30 mm, respectively. The Pearson correlation coefficients for both shifts were 0.92 for AP, 0.91 for SI, and 0.68 for LR. The percentages of shift agreements within 2 mm were 85% for AP, 93% for SI, and 99% for LR. The absolute values of rotational shifts were 0.1° for AP, 0.3°, and 1.2° for LR. CONCLUSIONS: The setup accuracy of the 3DOF-FM-based setup has the potential to be interchangeable with a ST-based setup. Our data are likely to be useful in clinical practice along with the popularization of the hypofractionated IMRT in prostate cancer.

[Investigation of Estimation Accuracy of Phantom Scatter Factor by Clarkson Method Considering Depth in MLC Irregular Field].

In monitor unit (MU) independent verification by calculation for irregular field (MLC field) using multileaf collimator in X-ray therapy, it has become common to use collimator scatter factor (Sc) and phantom scatter factor (Sp) instead of total scatter factor (Sc, p). It is usually expressed as Sc, p (A)=Sc (A)×Sp (A), and the field size A is considered but the depth d is not. Sc is data of in-air output, and measure with a mini-phantom at constant depth to remove electron contamination. On the other hand, Sp is obtained from measurement data of Sc, p and Sc, and can be expressed as Sc, p (d, A)=Sc (constant depth, A)×Sp (d, A) at an arbitrary depth d, thus Sp depends on the depth of Sc, p. Therefore, Sp needs to consider depth. In addition, a linear accelerator equipped with the tertiary MLC has two field sizes, that are collimator field by upper and lower collimators and MLC field by tertiary MLC below them. In MU independent verification by calculation, it is often used that the estimated value of Sp obtained by converting MLC field to equivalent square field and referring to data of Sp in square field. To convert the MLC field to equivalent square field, a conversion formula from sector radius r to equivalent square field L by Clarkson's sector integration (Clarkson method) is used. In this study, using 24 types of MLC fields to evaluate estimation accuracy due to the difference of conversion formula in Clarkson method, we estimated value of Sp using r=0.5611L of B-Clarkson method and using r=0.5580L of A-Clarkson method. And the difference with the measured value of Sp obtained by measuring Sc, p and Sc in the same MLC fields was compared. While, to evaluate estimation accuracy due to the different depths using these Clarkson methods, the difference between estimated value and measured value of Sp similarly obtained at depth of 5, 10 and 15 cm was compared. As results, estimated value of Sp using A-Clarkson method than using B-Clarkson method was close to measured value, and it was the same trend at depth of 5, 10 and 15 cm. Therefore, it was suggested that estimation accuracy of Sp by A-Clarkson method is higher than B-Clarkson method when verifying beams with different depths in MU independent verification by calculation for MLC field.

[Investigation of the Influence of the Conversion Method to Equivalent Square Field on the Depth Direction of Phantom Scatter Factor].

In X-ray therapy, equivalent square field (side of equivalent square field) is important because it influences the accuracy of independent verification of monitor unit (MU) by calculation. To calculate the side of equivalent square field for rectangular fields, we often use a table of domestic standard measurement method (Day's method), or A/P method calculated by area-perimeter ratio. The sides of equivalent square fields of these methods are assumed to be unchanged by depth and energy, but there are reports that it is not valid. Therefore, the depth dependency of side of equivalent square fields of Day's method, A/P method, and area ratio correction (ARC) method was compared by measuring phantom scatter factors (Sp). From the analysis of Sp measured at different depths, the estimated value of Sp on the equivalent square side of the Day's method and A/P method had a depth dependency that the difference from the measured value was large when the measurement depth was deep. The estimated value of Sp on the equivalent square side of the ARC method had a small difference from the measured value even when the measurement depth was deep, and the depth dependency was small compared with the Day's method and the A/P method. Side of equivalent square field of ARC method had a smaller difference of depth dependency than in the case of Day's method and A/P method. Therefore, in the independent verification of MU for rectangular field, using the equivalent square side of the ARC method is better.

Branched-chain amino acids prevent hepatocarcinogenesis and prolong survival of patients with cirrhosis.

BACKGROUND & AIMS: Although a low plasma level of branched-chain amino acids (BCAAs) is a marker of cirrhosis, it is not clear whether BCAA supplements affect disease progression. We performed a multicenter study to evaluate the effects of BCAA supplementation on hepatocarcinogenesis and survival in patients with cirrhosis. METHODS: We enrolled 299 patients from 14 medical institutions in Japan in a prospective, multicenter study in 2009; 267 patients were followed through 2011. Patients were given BCAA supplements (5.5-12.0 g/day) for more than 2 years (n = 85) or no BCAAs (controls, n = 182). The primary end points were onset of hepatocellular carcinoma (HCC) and death. Factors associated with these events were analyzed by competing risk analysis. RESULTS: During the study period, 41 of 182 controls and 11 of 85 patients given BCAAs developed HCC. On the basis of the Cox and the Fine and Gray models of regression analyses, level of α-fetoprotein, ratio of BCAA:tyrosine, and BCAA supplementation were associated with development of HCC (relative risk for BCAAs, 0.45; 95% confidence interval, 0.24-0.88; P = .019). Sixteen controls and 2 patients given BCAAs died. Factors significantly associated with death were Child-Pugh score, blood level of urea nitrogen, platelet count, male sex, and BCAA supplementation (relative risk of death for BCAAs, 0.009; 95% confidence interval, 0.0002-0.365; P = .015) in both regression models. CONCLUSIONS: On the basis of a prospective study, amino acid imbalance is a significant risk factor for the onset of HCC in patients with cirrhosis. BCAA supplementation reduces the risk for HCC and prolongs survival of patients with cirrhosis.

Reaction analysis for deprotonation of the sulfonic group of perfluorosulfonic acid molecules at low hydration levels.

A reaction analysis for deprotonation of the sulfonic group in a model molecule of perfluorosulfonic acid (PFSA) at low hydration levels was performed. PFSA is usually adopted as a polymer electrolyte membrane in polymer electrolyte fuel cells. In hydration level three, the deprotonation reaction certainly occurs. The deprotonated state produced is more stable than the predeprotonated state by 3.72 kcal/mol. In addition, its activation energy is very low. Although quantitative discussion of this activation energy is difficult considering the computational error, it can be said qualitatively that H(+) is abstracted smoothly from the sulfonic group because of a low activation energy. From the results of bond-order analysis, the produced H3O(+) is strongly bound by the SO3(-) group. Thus, diffusivity of H3O(+) would be low. In hydration level four or more, we found a possibility that the diffusivity of H3O(+) increases because the hydrogen-bond strength between H3O(+) and SO3(-) is lower or SO3(-) cannot bind H3O(+) directly by forming an Eigen cation.

Screening of aspiration pneumonia using the modified Mallampati classification tool in older adults.

Pneumonia is a major cause of morbidity and mortality in older adults. In the aging society, screening methods for predicting aspiration pneumonia are crucial for its prevention. Changes in the oropharyngeal morphology and hyoid bone position may increase the risk of aspiration pneumonia. This multicenter study aimed to investigate a simple and effective screening method for predicting dysphagia and aspiration pneumonia. Overall, 191 older adults (aged 65 years or older) were randomly sampled using the simple random sampling technique. Oropharyngeal morphology was assessed using the modified Mallampati classification, which reflects the size of the tongue in the oropharyngeal cavity. The hyoid position was measured as the distance between the menton and laryngeal prominence to evaluate aging-related changes in the muscles of the laryngopharynx. Dysphagia was assessed using the repetitive saliva swallowing test (RSST), which measures the number of swallowing movements in 30 seconds; dysphasia is defined as less than 3 swallowing movements in 30 seconds. The aspiration signs were assessed based on history of choking or coughing reflex during eating or drinking and medical history of pneumonia. The study findings revealed that the modified Mallampati classification was significantly correlated with a medical history of pneumonia. A higher incidence of pneumonia was evident in the lower Mallampati classification, which shows the smaller size of the tongue base in the oropharyngeal cavity. The results of this study suggest that the modified Mallampati classification may be a possible screening method to predict the occurrence of pneumonia.

Dental and oral management in the perioperative period of surgery: A scoping review.

Dental and oral management (DOM) is a long-established treatment modality. This scoping review aimed to narratively review previous studies, examine the effects of perioperative DOM, and identify the available evidence. A literature search was conducted using the PubMed electronic database for studies published between January 1, 2000, and March 8, 2022. The search yielded 43 studies, most of which were published in the last 10 years. The results of this study confirmed that improved perioperative oral hygiene is effective in preventing postoperative pneumonia. Our results also suggested that preoperative DOM is effective in preventing postoperative surgical site infections. Perioperative DOM is effective in reducing the incidence of postoperative pneumonia, SSI, and postsurgical complications. Further studies are needed to elucidate the various mechanism of DOM and to examine efficient intervention methods and timing.