Energetics of the H-Bond Network in Exiguobacterium sibiricum Rhodopsin.

Exiguobacterium sibiricum rhodopsin (ESR) functions as a light-driven proton pump utilizing Lys96 for proton uptake and maintaining its activity over a wide pH range. Using a combination of methodologies including the linear Poisson-Boltzmann equation and a quantum mechanical/molecular mechanical approach with a polarizable continuum model, we explore the microscopic mechanisms underlying its pumping activity. Lys96, the primary proton uptake site, remains deprotonated owing to the loss of solvation in the ESR protein environment. Asp85, serving as a proton acceptor group for Lys96, does not form a low-barrier H-bond with His57. Instead, deprotonated Asp85 forms a salt-bridge with protonated His57, and the proton is predominantly located at the His57 moiety. Glu214, the only acidic residue at the end of the H-bond network exhibits a pKa value of ∼6, slightly elevated due to solvation loss. It seems likely that the H-bond network [Asp85···His57···H2O···Glu214] serves as a proton-conducting pathway toward the protein bulk surface.

pH-Dependent Binding and Releasing Mechanism of Acetate in the Inner Water Cavity of Heliorhodopsin.

The high-resolution structure of heliorhodopsin crystallized at low pH reveals the presence of a planar triangle molecule, acetate, in the inner water cavity. Here, we investigate how the acetate molecule is stabilized at the counterion Glu107 moiety, using molecular dynamics (MD) simulations and a quantum mechanical/molecular mechanical (QM/MM) approach. QM/MM calculations indicate that the density is best described as acetate among triangle acids, including nitric acid and bicarbonate. The calculated protonation state indicates that protonated acetate donates an H-bond to deprotonated Glu107 in the low-pH crystal structure. The observed red-shift of ∼30 nm in the absorption wavelength with pKa ≈ 4 is likely due to the His23/His80 protonation, rather than the Glu107 protonation. MD simulations also show that acetate can exist at the Glu107 moiety only when it is protonated. When ionized, acetate is released from the Glu107 moiety via Asn101 at the channel bottleneck and Arg91 on the intracellular protein surface. These observations could explain how acetate binds at low pH and releases at high pH.

Proton transfer and conformational changes along the hydrogen bond network in heliorhodopsin.

Heliorhodopsin releases a proton from the Schiff base during the L-state to M-state transition but not toward the protein bulk surface. Here we investigate proton transfer and induced structural changes along the H-bond network in heliorhodopsin using a quantum mechanical/molecular mechanical approach and molecular dynamics simulations. Light-induced proton transfer could occur from the Schiff base toward Glu107, reorienting Ser76, followed by subsequent proton transfer toward His80. His80 protonation induces the reorientation of Trp246 on the extracellular surface, originating from the electrostatic interaction that propagates along the transmembrane H-bond network [His80…His23…H2O[H23/Q26]…Gln26…Trp246] over a distance of 15 Å. Furthermore, it induces structural fluctuation on the intracellular side in the H-bond network [His80…Asn16…Tyr92…Glu230…Arg104…Glu149], opening the inner cavity at the Tyr92 moiety. These may be a basis of how light-induced proton transfer causes conformational changes during the M-state to O-state transition.

Measuring Muscle Activity in Sprinters Using T2-Weighted Magnetic Resonance Imaging.

PURPOSE: This study aimed to investigate the level of muscle activity during sprint running using T2-weighted magnetic resonance imaging. METHODS: Fourteen male sprinters (age 21.2 [4.0] y; height 171.8 [4.2] cm, weight 65.5 [5.3] kg, 100-m personal record 11.01 [0.41] s; mean [SD]) performed 3 sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3 T magnetic resonance imaging scans were performed to obtain the T2 values of the 14 athletes' lower-extremity muscles. RESULTS: After the 60-m round-trip sprints, the T2 value of the gluteus maximus, long head of biceps femoris, semitendinosus, semimembranosus, adductor brevis, adductor longus, adductor magnus, and gracilis increased significantly. The rate of change in the T2 values before and after the 60-m round-trip sprints was notably higher in the semitendinosus and gluteus maximus than in the other muscles. CONCLUSIONS: These findings demonstrate the specific physiological metabolism of the lower-extremity muscles during fast sprinting. There are particularly high levels of muscle activity in the gluteus maximus and semitendinosus during sprint performance.

Differences between junior and senior male sprinters in physiological variables associated with sprint performance.

BACKGROUND: The physiological variables associated with sprint performance have been extensively studied. However, little information is available on how the corresponding physiological variables differ between junior and senior sprinters. This study aimed to examine this subject. METHODS: In addition to the maximal running velocity achieved while sprinting over 60-m, body composition, muscle thicknesses of the trunk and lower limbs, performance scores of four jumping tasks (countermovement, rebound, standing long, and standing five-step jumps), and 10-s maximal anaerobic pedaling power were determined in 17 junior and 22 senior male sprinters. RESULTS: In the junior and senior sprinters, most of the measured variables were significantly correlated with the maximal running velocity. Analysis of covariance showed that only the maximal pedaling power relative to the body mass was significantly different between the two groups in the regression equation slope of the relationship with maximal running velocity (0.20 for junior and 0.64 for senior sprinters). Additionally, multiple regression analysis revealed that while the standing five-step jump distance (40%) and the size of the psoas major muscle (23%) were selected as explanatory factors for maximal running velocity in the junior sprinters, maximal pedaling power relative to the body mass (63%) was selected in the senior sprinters. CONCLUSIONS: This study suggests that the following physiological factors associated with sprint running performance differ between the junior and senior sprinters: the ability of repetitive jumping in the horizontal forward direction and muscularity of hip flexors in the junior sprinters versus the anaerobic capacity in senior sprinters. Therefore, coaches and athletes need to take into consideration that the physiological variables to be focused on are different for each generation.

Long-term treatment outcome of type 1 thyroplasty using novel titanium medialization laryngoplasty implant combined with arytenoid adduction for unilateral vocal cord paralysis: single-arm interventional study at a single institution.

OBJECTIVE: To evaluate the long-term treatment outcome of type 1 thyroplasty with novel rearrangeable titanium medialization laryngoplasty implant (TMLI) combined with arytenoid adduction (AA) for unilateral vocal cord paralysis (UVFP) in the authors' institution. METHODS: A total of 16 Japanese patients with UVFP who received type 1 thyroplasty using TMLI with arytenoid adduction was enrolled in this single-arm, non-randomized interventional study. The results of the auditory perceptual assessment, aerodynamic examination, acoustic measurement, and patient-based survey on these patients were evaluated preoperatively and at 3, 6, and 12 months postoperatively. RESULTS: Type 1 thyroplasty using TMLI with arytenoid adduction for our patient series presented significant improvements in maximum phonation time, mean flow rates, GRBAS scale, the Voice Handicap Index and the Voice-Related Quality of Life score over the 12-month postoperative period. CONCLUSION: Type 1 thyroplasty using TMLI with arytenoid adduction was quite effective for obtaining satisfactory postoperative voice improvement without any surgical complication over the long-term period.

Ten-second maximal pedaling power as a representative measure for assessing sprint performance.

BACKGROUND: There is no evidences concerning the relative contribution of physiological parameters to maximal sprinting velocity and acceleration ability. The aim of this study is to elucidate the associations between physiological variables and sprint performance. METHODS: Twenty-six male sprinters performed a 60-m sprint twice. Maximal sprint velocity (Vmax) and running distance after 4 s from the start (D4) were measured as indices of sprint performance during the sprint using a laser distance measurement device. Body composition, jump performance in the countermovement jump, the rebound jump, the standing long jump and the standing 5-step jump, and 10-s maximal anaerobic pedaling power were measured as physiological variables. RESULTS: All measured variables were significantly related to Vmax (r=0.49-0.71, P<0.05) and D4 (r=0.39-0.72, P<0.05), expect for anthropometric variables. Multiple regression analysis indicated that the 10-s maximal anaerobic pedaling power relative to body mass was the only variable that significantly explained Vmax and D4. CONCLUSIONS: The 10-s maximal anaerobic pedaling power relative to body mass can be a representative measure for assessing the sprint performance of male sprinters.

Postoperative Bio-Chemoradiotherapy Using Cetuximab and Docetaxel in Patients With Cis-Platinum-Intolerant Core High-Risk Head and Neck Cancer: Protocol of a Phase 2 Nonrandomized Clinical Trial.

BACKGROUND: We confirmed the safety of postoperative bio-chemoradiotherapy using cetuximab and docetaxel in a small number of patients with cis-platinum-intolerant core high-risk head and neck cancer. OBJECTIVE: To assess treatment efficacy, we planned a phase 2 study of postoperative bio-chemoradiotherapy for patients with cis-platinum-intolerant core high-risk head and neck cancer and will compare the results to those of previously collected radiotherapy data. METHODS: Patients who underwent definitive surgery for oral cavity, laryngeal, oropharyngeal, or hypopharyngeal advanced cancer, whose postoperative pathological results indicated core high risk for recurrence (eg, positive margin in the primary site or extranodal extension) and who were cis-platinum-intolerant, will undergo postoperative bio-chemoradiotherapy. The primary end point is 2-year disease-free survival. RESULTS: The expected 2-year disease-free survival is set at 55%, and the calculated sample size is 35 patients, according to a statistical analysis based on previous reports. CONCLUSIONS: This treatment method is expected to improve the survival rate of patients with severe head and neck cancer. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000031835; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ ctr_view.cgi?recptno=R000036355 (Archived by WebCite at http://www.webcitation.org/71fejVjMr).

Predictive value of the Hyodo score in endoscopic evaluation of aspiration during swallowing.

OBJECTIVE: The Hyodo scoring system during the endoscopic procedure has been proposed as a new tool for evaluating oral intake feasibility. However, the effectiveness of the information obtained from this procedure in predicting aspiration is not fully elucidated. The aim of this study was to assess the significance of clinical factors, including Hyodo scores, for predicting the risk of aspiration. METHODS: Five hundred and twenty-eight endoscopic swallowing examinations were performed. Clinical factors, including age, sex, disease type, history of aspiration pneumonia, cognitive function, presence of tracheostomy, presence of vocal cord paralysis, consciousness level on the Japan Coma Scale, ECOG Performance Status, serum albumin level and Hyodo score, were obtained for each examination. The relationship between each of these factors and the presence of aspiration during endoscopic procedure was evaluated. RESULTS: Three hundred and thirty-two patients (62.9%) were scored less than 5, 153 (29.0%) were scored between 5 and 8, and 43 (8.1%) were scored above 8. The number of patients with aspiration was 133 (25.2%). ROC analysis revealed that a cut-off point of 6 for Hyodo score was effective for predicting aspiration, with a sensitivity of 0.65 and a specificity of 0.86. History of aspiration pneumonia (OR 1.87, P<0.001), vocal cord paralysis (OR 2.23, P<0.001), PS≥3 (OR 2.47, P<0.001) and Hyodo score>6 (OR 9.08, P<0.001) were found to be independent predictive factors for aspiration. CONCLUSION: The Hyodo scoring method was easy for otolaryngologists to perform and the scores were useful for predicting aspiration with moderate sensitivity and high specificity. Hyodo score>6, history of aspiration pneumonia, vocal cord paralysis, and PS≥3 were independent predictive factors for aspiration and that a Hyodo score above 6 was the statistically strongest predictor for aspiration.

The applicability of new TNM classification for humanpapilloma virus-related oropharyngeal cancer in the 8th edition of the AJCC/UICC TNM staging system in Japan: A single-centre study.

OBJECTIVE: The purpose of this study is to validate the applicability of new TNM classification for human papillomavirus (HPV)-related oropharyngeal cancer (OPC) in the 8th edition of the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) TNM staging system in Japan. METHODS: A total of 91 OPC patients treated with radiation-based therapy between November 2001 and July 2015 were analyzed retrospectively in this study. HPV infection status was evaluated using tumor p16 expression. RESULTS: 40 OPC patients (44.0%) had HPV-positive disease in this study. The distribution of disease stage of HPV-positive OPC patients dramatically changed from the 7th edition to the 8th edition of AJCC/UICC TNM classification. However, neither the 8th edition nor the 7th edition of the AJCC/UICC TNM staging system could adequately predict outcomes of HPV-positive OPC patients in our patient series. On the other hand, our multivariate analysis indicated that matted nodes and age ≥63 were independent prognostic factors for progression-free survival. In addition, HPV-positive OPC patients with stage I without matted nodes showed significantly better overall and progression-free survival compared with those with stage I with matted nodes and stages II and III in the 8th edition of the AJCC/UICC TNM staging system (P=0.008, and P=0.043, respectively). CONCLUSION: Our results suggested that matted nodes of HPV-positive OPC patients might be additionally examined to apply the 8th edition of AJCC/UICC TNM classification for more adequate predicting outcomes of HPV-positive OPC patients.

Lymph node ratio as a prognostic factor for survival in patients with head and neck squamous cell carcinoma.

OBJECTIVE: The purpose of this study is to validate the concept of lymph node ratio (LNR) in head and neck squamous cell carcinoma (HNSCC). METHODS: A total of 63 patients with HNSCC who underwent resection of the primary tumor combined with neck dissection in our institution were analyzed in this study. LNR was defined as the number of positive lymph nodes divided by the total number of lymph nodes excised. LNR was categorized into two groups (<0.068 and ≥0.068) according to the results of receiver-operating characteristic plots for determination of the cut-off value. RESULTS: LNR≥0.068 was associated with poor overall survival (OS), progression-free survival (PFS) and locoregional recurrence-free survival (LRFS) after resection of the primary tumor combined with neck dissection in patients with HNSCC. Univariate and multivariate data analysis showed that LNR≥0.068 was an independent prognostic factor for OS, PFS and LRFS. Both pathological T stage status (pT3 or 4) and ≥3 positive LNs were also an independent prognostic factors for PFS in patients with HNSCC in our univariate and multivariate analysis. CONCLUSION: These results suggested that LNR could be useful tools in identifying HNSCC patients with poor outcomes.

The Second-Look Procedure for Transoral Videolaryngoscopic Surgery for T1 and T2 Laryngeal, Oropharyngeal, and Hypopharyngeal Cancer Patients: Protocol for a Nonrandomized Clinical Trial.

BACKGROUND: Transoral videolaryngoscopic surgery (TOVS) has been widely applied for early T stage head and neck cancer. The resection is performed with a minimum safety margin for function preservation under a limited surgical field of view, making it difficult to be certain of complete resection. OBJECTIVE: Our aim is the evaluation of the completeness of resection by initial TOVS resection, and the possibility of primary control by TOVS alone, allowing for repeat procedures for function preserving treatment in early T stage laryngeal, oropharyngeal, and hypopharyngeal cancer patients. METHODS: Patients are treated by TOVS for the primary site with or without neck dissection. Patients are divided in two groups based on the results of the pathological evaluation of the surgical specimen; the control group in which the resection is considered to be complete, and the intervention (second-look procedure) group in which incomplete tumor resection is suspected. The predictive factors for the possibility of complete resection by TOVS will then be analyzed. RESULTS: Patient enrollment started on January 1, 2014, and closed on March 31, 2016, with 54 patients. The control group consists of 27 patients, the intervention group is 21 patients, and 6 patients were excluded. There were no clinical differences between the control and intervention groups. The observation period will end on December 31, 2018. CONCLUSIONS: TOVS has potential for both definitive resection and function preservation with minimal invasiveness. Identifying the limitations of TOVS is beneficial to ensure accurate treatment selection in early T stage head and neck cancer patients. TRIAL REGISTRATION: UMIN Clinical Trials Registry: UMIN000012485; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi? recptno=R000014472 (Archived by WebCite at http://www.webcitation.org/6v1b741Iw).

Efficacy and safety of postoperative bio-chemoradiotherapy using cetuximab and docetaxel for high-risk head and neck cancer patients in Japan.

PURPOSE: To confirm the efficacy and safety of cetuximab and docetaxel in postoperative radiotherapy for high-risk head and neck cancer patients who cannot to be administered high-dose cisplatin. PATIENTS AND METHODS: The eligibility criteria required stage III-IVB head and neck cancer patients who had undergone total resection, and for whom pathological evaluation revealed positive or close margins in the primary site and/or extracapsular nodal extension and/or two or more nodal metastases. In each case, the patients general condition prevented the use of high-dose cisplatin. Instead, they received cetuximab and docetaxel every week during a 66.6 Gy course of postoperative radiotherapy. RESULTS: Eleven patients were enrolled; the median follow-up period was 22 months, and the 1- and 2-year disease free survival rates were 91 and 55%, respectively. Grade 3 adverse events included oral mucositis, radiation dermatitis, reduced white blood cell and neutrophil counts, lung infection, aspiration, and hyponatremia; however, no grade 4 adverse events were observed. CONCLUSION: Administration of cetuximab and docetaxel during postoperative radiotherapy for high-risk poor condition head and neck cancer patients in poor general condition was both feasible and tolerable. With the safety of this treatment confirmed, we propose a phase trail to further clarify the efficacy of cetuximab and docetaxel use for high-risk cisplatin-intolerant patients.

Surgery-based versus radiation-based treatment strategy for a high metabolic volume laryngeal cancer.

OBJECTIVE/HYPOTHESIS: We previously reported that the metabolic tumor volume (MTV) of a primary tumor was an independent prognostic factor for survival in laryngeal carcinoma treated by radiotherapy (RT)-based protocol. The purpose of this study was to evaluate the difference in survival outcomes between surgery-based and RT-based treatment in patients with a MTV laryngeal cancer. STUDY DESIGN: An individual retrospective cohort study. METHODS: We reviewed the records of 63 patients with laryngeal cancer showing a primary tumor with a high MTV value (≥ 4.9 mL). The patients were separated into two groups by primary treatment strategy: 22 patients were included in the surgery group, and 41 patients were included in the RT group. Clinical factors and treatment modalities were analyzed for their association with survival. RESULTS: Multivariate analysis, including age, sex, subsite, T classification, nodal metastasis, and treatment modality, showed that the subsite (hazard ratio [HR] 2.55, P = 0.043) and treatment modality (HR 3.98, P = 0.019) were independent predictors for survival. The Kaplan-Meier curves for 2-year relapse-free survival rates and overall survival rates for patients in the surgery and RT groups were 74.2% versus 38.8% (P = 0.025) and 80.1% versus 66.7% (P = 0.078). CONCLUSIONS: Patients with a high metabolic volume laryngeal cancer treated by a surgery-based protocol showed better relapse-free survival and overall survival than did those undergoing RT-based treatment. Pretreatment MTV assessment could be useful in planning the treatment strategy for patients with a laryngeal cancer. LEVEL OF EVIDENCE: 2b. Laryngoscope, 127:862-867, 2017.

Prognostic significance of metabolic tumor volume in patients with piriform sinus carcinoma treated by radiotherapy with or without concurrent chemotherapy.

BACKGROUND: The purpose of this study was to elucidate the prognostic significance of the pretreatment metabolic tumor volume (MTV) in patients with piriform sinus carcinoma treated by radiation-based therapy. METHODS: This retrospective study included 100 patients with piriform sinus carcinomas who had received treatment by radiation-based therapy. The MTV values were obtained from pretreatment positron emission tomography (PET). The association between clinical factors, including the MTV, and survival was analyzed. RESULTS: Kaplan-Meier estimates revealed the 5-year disease-free survival (DFS) rates were significantly poorer for patients with a high MTV compared to those with a low MTV. In the multivariate analysis, MTV (p < .001), nodal metastasis (p = .011), and applied chemotherapy regimen (p = .004) were found to be independent prognostic factors for DFS. CONCLUSION: The locoregional MTV is a prognostic factor for DFS in patients with piriform sinus carcinoma treated by radiation-based therapy. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

Reduction surgery using a combination of a stereolithographic model and navigation system for ossifying fibroma with secondary central giant cell granuloma.

Both central giant cell granuloma (CGCG) and ossifying fibroma (OF) are relatively common diseases. The synchronous presentation of CGCG and OF is, however, an extremely rare occurrence. We present an unusual case with the synchronous presentation of these two diseases in the maxilla and introduce a surgical strategy based on a combination of the stereolithographic model and navigation system for the treatment of gigantic OF with secondary CGCG.

Predictive markers, including total lesion glycolysis, for the response of lymph node(s) metastasis from head and neck squamous cell carcinoma treated by chemoradiotherapy.

BACKGROUND: Chemoradiotherapy (CRT) is used to treat cervical lymph node(s) metastatic head and neck cancer patients. Evaluation and treatment of lymph node(s) after CRT is important to improve the prognosis. METHODS: Prior to CRT, we determined the TNM stage by visual and imaging examinations. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated from the results of fluorodeoxyglucose-positron emission tomography (FDG-PET). After CRT, the patients were divided in two groups-complete response (CR) and non-CR-and their responses were compared with the clinical characteristics. RESULTS: T4, N2b, N2c and TLG2.5 ≥ 18.8 were statistically significant predictive indices before CRT. The odds ratio, 95 % confidence interval and p value were, respectively-T4: 2.73, 1.15-6.51, 0.0230; N2b: 6.96, 1.50-32.3, 0.0132; N2c: 11.80, 2.37-58.50, 0.00258; and TLG2.5 ≥ 18.8: 6.25, 2.17-18.00, 0.000672. CONCLUSIONS: TLG was found to be a good predictive factor for metastatic lymph node(s) prior to CRT treatment. After CRT treatment, FDG-PET was found to be highly specific and useful for negative screening.

Imaging strategy for response evaluation to chemoradiotherapy of the nodal disease in patients with head and neck squamous cell carcinoma.

BACKGROUND: Definitive chemoradiotherapy (CRT) is used to treat lymph node metastatic head and neck cancer patients. Regional control of the neck disease is important to improve the prognosis, and the accuracy of the method used to evaluate the metastatic lymph node(s) after CRT is crucial to the decision-making process for any following salvage surgery. METHODS: Patients undergoing CRT were divided in two groups of patients of those showing complete clinical response (CR) and those showing clinical non-response (non-CR), as assessed by computed tomography (CT) and/or magnetic resonance imaging (MRI), ultrasonography, fluorodeoxyglucose-positron emission tomography (FDG-PET), and fine needle aspiration cytology. The responses (CR vs. non-CR) were compared with the actual clinical outcomes. For the interim analysis, the study period was broken down into two periods, namely, the exploratory phase (patients treated between January 2002 and April 2012) and the validating phase (patients treated between May 2012 and January 2014). RESULTS: The sensitivity, specificity, and accuracy were as follows: CT and/or MRI, 66.7, 73.8, and 72.8 %, respectively, in the exploratory phase; ultrasonography, 91.7, 70.6, and 73.4 %, respectively, in the exploratory phase and 80.0, 82.8, and 82.4 %, respectively, in the validating phase; FDG-PET, 50.0, 97.5, and 91.3 %, respectively, in the exploratory phase and 60.0, 100, and 94.1 %, respectively, in the validating phase; cytology, 68.4, 95.9, and 90.3 %, respectively, in the exploratory phase and 66.7, 100, and 85.7 %, respectively, in the validating phase. CONCLUSIONS: Based on our results, CT and/or MRI appear to be inadequate methods for the evaluation of the response of lymph node(s) to CRT. In contrast, ultrasonography appears to be a highly sensitive and useful tool for positive screening at 6-8 weeks after CRT, and FDG-PET appears to be a highly specific and useful tool for negative screening at 8-12 weeks after CRT.