Automated evaluation of masseter muscle volume: deep learning prognostic approach in oral cancer.

BACKGROUND: Sarcopenia has been identified as a potential negative prognostic factor in cancer patients. In this study, our objective was to investigate the relationship between the assessment method for sarcopenia using the masseter muscle volume measured on computed tomography (CT) images and the life expectancy of patients with oral cancer. We also developed a learning model using deep learning to automatically extract the masseter muscle volume and investigated its association with the life expectancy of oral cancer patients. METHODS: To develop the learning model for masseter muscle volume, we used manually extracted data from CT images of 277 patients. We established the association between manually extracted masseter muscle volume and the life expectancy of oral cancer patients. Additionally, we compared the correlation between the groups of manual and automatic extraction in the masseter muscle volume learning model. RESULTS: Our findings revealed a significant association between manually extracted masseter muscle volume on CT images and the life expectancy of patients with oral cancer. Notably, the manual and automatic extraction groups in the masseter muscle volume learning model showed a high correlation. Furthermore, the masseter muscle volume automatically extracted using the developed learning model exhibited a strong association with life expectancy. CONCLUSIONS: The sarcopenia assessment method is useful for predicting the life expectancy of patients with oral cancer. In the future, it is crucial to validate and analyze various factors within the oral surgery field, extending beyond cancer patients.

Bioresorbable Poly (L-Lactic Acid) Flow Diverter Versus Cobalt-Chromium Flow Diverter: In Vitro and In Vivo Analysis.

BACKGROUND: Permanent metallic flow diverter (FD) implantation for treatment of intracranial aneurysms requires antiplatelet therapy for an unclear duration and restricts postprocedural endovascular access. Bioresorbable FDs are being developed as a solution to these issues, but the biological reactions and phenomena induced by bioresorbable FDs have not been compared with those of metallic FDs. METHODS: We have developed a bioresorbable poly (L-lactic acid) FD (PLLA-FD) and compared it with an FD composed of cobalt-chromium and platinum-tungsten (CoCr-FD). FD mechanical performance and in vitro degradation of the PLLA-FD were evaluated. For in vivo testing in a rabbit aneurysm model, FDs were implanted at the aneurysm site and the abdominal aorta in the PLLA-FD group (n=21) and CoCr-FD group (n=15). Aneurysm occlusion rate, branch patency, and thrombus formation within the FD were evaluated at 3, 6, and 12 months. Local inflammation and neointima structure were also evaluated. RESULTS: Mean strut, porosity, and pore density for the PLLA-FD were 41.7 µm, 60%, and 20 pores per mm2, respectively. The proportion of aneurysms exhibiting a neck remnant or complete occlusion did not significantly differ between the groups; however, the complete occlusion rate was significantly higher in the PLLA-FD group (48% versus 13%; P=0.0399). Branch occlusion and thrombus formation within the FD were not observed in either group. In the PLLA-FD group, CD68 immunoreactivity was significantly higher, but neointimal thickness decreased over time and did not significantly differ from that of the CoCr-FD at 12 months. Collagen fibers significantly predominated over elastic fibers in the neointima in the PLLA-FD group. The opposite was observed in the CoCr-FD group. CONCLUSIONS: The PLLA-FD was as effective as the CoCr-FD in this study and is feasible for aneurysm treatment. No morphological or pathological problems were observed with PLLA-FD over a 1-year period.

Collision-induced torque mediates the transition of chiral dynamic patterns formed by active particles.

Controlling the patterns formed by self-propelled particles through dynamic self-organization is a challenging task. Although varieties of patterns associated with chiral self-propelled particles have been reported, essential factors that determine the morphology of the patterns have remained unclear. Here, we explore theoretically how torque formed upon collision of the particles affects the dynamic self-organization of the particles and determine the patterns. Based on a particle-based model with collision-induced torque and torque associated with self-propulsion, we find that introducing collision-induced torque turns the homogeneous bi-directionally aligned particles into rotating mono-polar flocks, which helps resolve a discrepancy in the earlier observations in microfilament gliding assays.

Monopolar flocking of microtubules in collective motion.

Flocking is a fascinating coordinated behavior of living organisms or self-propelled particles (SPPs). Particularly, monopolar flocking has been attractive due to its potential applications in various fields. However, the underlying mechanism behind flocking and emergence of monopolar motion in flocking of SPPs has remained obscured. Here, we demonstrate monopolar flocking of kinesin-driven microtubules, a self-propelled biomolecular motor system. Microtubules with an intrinsic structural chirality preferentially move towards counter-clockwise direction. At high density, the CCW motion of microtubules facilitates monopolar flocking and formation of a spiral pattern. The monopolar flocking of microtubules is accounted for by a torque generated when the motion of microtubules was obstructed due to collisions. Our results shed light on flocking and emergence of monopolar motion in flocking of chiral active matters. This work will help regulate the polarity in collective motion of SPPs which in turn will widen their applications in nanotechnology, materials science and engineering.

Solvent effect for an effective attraction between like-charged macroions immersed in an electrolyte solution: The intensification mechanism of the effective attraction caused by the translational motion of solvent particles.

The effective interaction between macroanions immersed in an electrolyte solution was calculated using an integral equation theory of liquids to study the solvent granularity effect on the effective attraction mediated by cations. Explicit and implicit solvent models were examined. The effective attraction for the explicit solvent model was found to be stronger than that for the implicit solvent model. This solvent effect was remarkably enhanced only when the effective attraction between macroanions was strong; this means that the solvent effect is not a usual excluded volume effect. The intensification mechanism of the attraction by the solvent granularity is analyzed in the present study, and an indirect mechanism is proposed.

Lateral depletion effect on two-dimensional ordering of bacteriorhodopsins in a lipid bilayer: A theoretical study based on a binary hard-disk model.

The 2D ordering of bacteriorhodopsins in a lipid bilayer was studied using a binary hard-disk model. The phase diagrams were calculated taking into account the lateral depletion effects. The critical concentrations of the protein ordering for monomers and trimers were obtained from the phase diagrams. The critical concentration ratio agreed well with the experiment when the repulsive core interaction between the depletants, namely, lipids, was taken into account. The results suggest that the depletion effect plays an important role in the association behaviors of transmembrane proteins.

Solvation effects on diffusion processes of a macromolecule: Accuracy required for radial distribution function to calculate diffusion coefficient.

We investigate the dependence of the diffusion coefficient of a large solute particle on the solvation structure around a solute. The diffusion coefficient of a hard-sphere system is calculated by using a perturbation theory of large-particle diffusion with radial distribution functions around the solute. To obtain the radial distribution function, some integral equation theories are examined, such as the Percus-Yevick (PY), hypernetted-chain (HNC), and modified HNC theories using a bridge function proposed by Kinoshita (MHNC) closures. In one-component solvent systems, the diffusion coefficient depends on the first-minimum value of the radial distribution function. The results of the MHNC closure are in good agreement with those of calculation using the radial distribution functions of Monte Carlo simulations since the MHNC closure very closely reproduces the radial distribution function of Monte Carlo simulations. In binary-solvent mixtures, the diffusion coefficient is affected by the larger solvent density distribution in the short-range part, particularly the height and sharpness of the first peak and the depth of the first minimum. Since the HNC closure gives the first peak that is higher and sharper than that of the MHNC closure, the calculated diffusion coefficient is smaller than the MHNC closure result. In contrast, the results of the PY closure are qualitatively and quantitatively different from those of the MHNC and HNC closures.

Confined Space Enables Spontaneous Liquid Separation by Molecular Size: Selective Absorption of Alkanes into a Polyolefin Cast Film.

The depletion force has been used to explain phase separation phenomena in colloidal systems. Here, we showed that depletion force can explain not only phase separation of large and small colloidal particles but also preferential absorption of larger molecules from a mixture of large and small molecules in a liquid state. When a polyolefin cast film was immersed in a mixture of long and short normal alkanes, the longer molecules were selectively absorbed into the film. This experimental result was explained from the viewpoint of depletion force. The main finding was the use of confined space to emphasize the separation tendency caused by the force. In general, the increase in entropy may serve as a driving force to mix molecules. However, if sufficiently narrow pores are present, large and small molecules are separated naturally by size as the entropy increases. This finding will lead to size exclusion chromatography of low-mass molecules, similar to gel permeation chromatography of macromolecules. In order to demonstrate the effect of depletion force, we selected and experimented with a system based on a polyolefin isotactic poly(4-methyl-1-pentene) (P4MP1) film and a normal alkane mixture and realized high molecular selectivity. The P4MP1 film we used can be prepared simply by evaporating the solvent from the solution and casting the film. On the basis of the Asakura-Oosawa theory, we concluded that spontaneous and high molecular selectivity is attributed to the depletion force provided by the small sub-nanopores with uniform size in the film.

Reduced density profile of small particles near a large particle: Results of an integral equation theory with an accurate bridge function and a Monte Carlo simulation.

Solute-solvent reduced density profiles of hard-sphere fluids were calculated by using several integral equation theories for liquids. The traditional closures, Percus-Yevick (PY) and the hypernetted-chain (HNC) closures, as well as the theories with bridge functions, Verlet, Duh-Henderson, and Kinoshita (named MHNC), were used for the calculation. In this paper, a one-solute hard-sphere was immersed in a one-component hard-sphere solvent and various size ratios were examined. The profiles between the solute and solvent particles were compared with those calculated by Monte Carlo simulations. The profiles given by the integral equations with the bridge functions were much more accurate than those calculated by conventional integral equation theories, such as the Ornstein-Zernike (OZ) equation with the PY closure. The accuracy of the MHNC-OZ theory was maintained even when the particle size ratio of solute to solvent was 50. For example, the contact values were 5.7 (Monte Carlo), 5.6 (MHNC), 7.8 (HNC), and 4.5 (PY), and the first minimum values were 0.48 (Monte Carlo), 0.46 (MHNC), 0.54 (HNC), and 0.40 (PY) when the packing fraction of the hard-sphere solvent was 0.38 and the size ratio was 50. The asymptotic decay and the oscillation period for MHNC-OZ were also very accurate, although those given by the HNC-OZ theory were somewhat faster than those obtained by Monte Carlo simulations.

[Treatment Strategies for Unruptured Multiple Intracranial Aneurysms].

OBJECTIVE: Unruptured aneurysms are often discovered incidentally on MRI. In some patients, multiple aneurysms cannot be treated with only craniotomy or endovascular surgery. When both craniotomy and endovascular surgery are deemed necessary, craniotomy is generally performed first because of the use of antiplatelet agents involved, followed by endovascular surgery several months later. However, no clear criteria for this treatment policy have been elicited. We investigated therapeutic outcomes in patients with aneurysms treated by craniotomy followed by endovascular surgery at our hospital. PATIENTS AND METHODS: This was a retrospective study including patients undergoing craniotomy clipping of one or more unruptured aneurysms at one site and endovascular surgery for those at a different site, between January 2012 and May 2018 in our hospital. The types of treatment, interval between treatments, complications, and other factors were analyzed. RESULTS: This study included 22 patients who underwent a total of 25 craniotomies and 23 endovascular surgeries. The mean time from final craniotomy to initial endovascular surgery was 118 days. Although treatment-related complications occurred in three patients, they were not associated with the time interval between craniotomy and endovascular surgery or the timing of the start of the antiplatelet therapy. CONCLUSIONS: The treatment was successful and was carried out safely and appropriately by first performing the craniotomy, followed by a set interval of time before starting the antiplatelet therapy, and then performing the endovascular surgery. Further studies analyzing more cases are required to establish the criteria better, such as the appropriate interval time between treatments.

Theoretical approaches for dynamical ordering of biomolecular systems.

BACKGROUND: Living systems are characterized by the dynamic assembly and disassembly of biomolecules. The dynamical ordering mechanism of these biomolecules has been investigated both experimentally and theoretically. The main theoretical approaches include quantum mechanical (QM) calculation, all-atom (AA) modeling, and coarse-grained (CG) modeling. The selected approach depends on the size of the target system (which differs among electrons, atoms, molecules, and molecular assemblies). These hierarchal approaches can be combined with molecular dynamics (MD) simulation and/or integral equation theories for liquids, which cover all size hierarchies. SCOPE OF REVIEW: We review the framework of quantum mechanical/molecular mechanical (QM/MM) calculations, AA MD simulations, CG modeling, and integral equation theories. Applications of these methods to the dynamical ordering of biomolecular systems are also exemplified. MAJOR CONCLUSIONS: The QM/MM calculation enables the study of chemical reactions. The AA MD simulation, which omits the QM calculation, can follow longer time-scale phenomena. By reducing the number of degrees of freedom and the computational cost, CG modeling can follow much longer time-scale phenomena than AA modeling. Integral equation theories for liquids elucidate the liquid structure, for example, whether the liquid follows a radial distribution function. GENERAL SIGNIFICANCE: These theoretical approaches can analyze the dynamic behaviors of biomolecular systems. They also provide useful tools for exploring the dynamic ordering systems of biomolecules, such as self-assembly. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.

Effective potential between negatively charged patches on acidic proteins immersed in various electrolyte solutions.

Effective interactions between O-sized anions in various electrolyte solutions were calculated by using the integral equation theory with some simple models. The results indicated that only multivalent cations mediated a strong effective attraction between O-sized anions at a certain concentration. The effective interaction turned from repulsive to attractive as the electrolyte concentration increased, and the effective attraction decreased when more electrolyte was added. Moreover, the effective interactions between O-sized anions in the electrolyte solution did not present a long repulsive tail, although the effective attraction caused by the divalent cations appeared. By contrast, the effective attraction mediated by monovalent cations and the reentrant behavior did not appear and the effective interaction was basically repulsive. These behaviors agree with the experimental results for reentrant condensation of acidic proteins in various electrolyte solutions. The calculated results suggest that the dissociated carboxylic acidic groups on the proteins form attractive patches between proteins under certain concentration conditions.

Stick boundary condition at large hard sphere arising from effective attraction in binary hard-sphere mixtures.

We have studied the diffusion of a large hard-sphere solute immersed in binary hard-sphere mixtures. We reveal how the boundary condition at the solute surface is affected by the solvent density around the solute. Solving equations for a binary compressible mixture by perturbation expansions, we obtain the boundary condition depending on the size ratio of binary solvent spheres. When the size ratio is 1:2, the boundary condition lies close to the slip boundary condition. By contrast, when the size ratio becomes large, the boundary condition approaches the stick boundary condition with the addition of larger solvent spheres. We find that the transition to the stick boundary condition is caused by the increase in the solvent density around the solute due to an entropic effect.

Isotactic poly(4-methyl-1-pentene) melt as a porous liquid: Reduction of compressibility due to penetration of pressure medium.

A pressure-induced structural change of a polymer isotactic poly(4-methyl-1-pentene) (P4MP1) in the melted state at 270 °C has been investigated by high-pressure in situ x-ray diffraction, where high pressures up to 1.8 kbar were applied using helium gas. The first sharp diffraction peak (FSDP) position of the melt shows a less pressure dependence than that of the normal compression using a solid pressure transmitting medium. The contraction using helium gas was about 10% at 2 kbar, smaller than about 20% at the same pressure using a solid medium. The result indicates that helium entered the interstitial space between the main chains. The helium/monomer molar ratio was estimated to be 0.3 at 2 kbar from the FSDP positions. These results suggest that the compressibility of the P4MP1 melt can be largely dependent on the pressure transmitting media. As the pore size is reversibly and continuously controllable by compression, we suggest that the P4MP1 melt can be an ideal porous liquid for investigating a novel mechanical response of the pores in a non-crystalline substance.

[Two Cases of Ruptured Blood Blister-like Aneurysm Treated with X-ray Angiography Perfusion(XAP)Analysis].

Two cases of ruptured blood blister-like internal carotid artery aneurysms for which low flow bypass was sufficient to attain successful treatment of trapping are reported. In the acute stage of rupture, it is troublesome to perform accurate examinations of tolerance to ischemia like balloon occlusion test(BOT)for estimating the required amount of bypass flow. In our cases, X-ray angiography perfusion(XAP)analysis was introduced, which could be performed in a couple dozen seconds without room-to-room transfer of patients, following the ordinary examination of diagnostic digital subtraction angiography. The perfusion index(PI)ratio measured in this analysis is equivalent to the laterality of cerebral blood flow between the right and left hemispheres. The PI ratio of 0.85 approximately corresponds to the mean stump pressure(MSTP)of 40mmHg, on the basis of the correlation diagram between the PI ratio and MSTP(approximate straight line:PI ratio%=0.6×MSTP+60). Even though the PI ratio of the cases was superior to this threshold of tolerance for parent artery occlusion, complementary low flow bypass was added in the acute case for the overwhelming succeeding vasospasm and for securing the flow to peripheral perforators, which resulted in a successful treatment without any ischemic events.

Machine Learning Analysis of Gaze Data for Enhanced Precision in Diagnosing Oral Mucosal Diseases.

The diagnosis of oral mucosal diseases is a significant challenge due to their diverse differential characteristics. Risk assessment of lesions by visual examination is a complex process due to the lack of definitive guidelines. This study aimed to improve this process by creating a diagnostic algorithm using gaze data acquired during oral mucosal disease examinations. A total of 78 dentists were included in this study. Tobii Pro Nano® (Tobii Technology) was used to acquire gaze data during clinical photographic visual examinations. Advanced analysis tools such as support vector machines and heatmaps were used to visualize the gazing tendencies of a group of skilled oral surgeons, focusing on the number of gazes per region and the gazing time ratios. The preliminary findings showed the possibility of visualizing gazing tendencies and identifying areas of importance for diagnosis. The classification of intraoral photographs based on gross features revealed the existence of an optimal examination method for each category and diagnostically significant areas. This novel approach to analyzing gaze data has the potential to refine diagnostic techniques and increase both accuracy and efficiency.

Partially thrombosed giant basilar artery aneurysm with attenuated contrast enhancement of the intraluminal thrombus on vessel wall MRI after flow diversion treatment: illustrative case.

BACKGROUND: The effect of vessel wall magnetic resonance imaging (VW-MRI) enhancement in partially thrombosed aneurysms has previously indicated aneurysmal instability and a rupture risk. However, whether the contrast effect of the wall changes before or after flow diversion treatment is still under investigation. OBSERVATIONS: The authors report a case of a partially thrombosed basilar artery aneurysm that increased in size over a short period, worsened brainstem compression symptoms, and was treated with a flow diverter stent with good results. In this case, VW-MRI after surgery showed a reduced contrast effect on the intraluminal thrombus within the aneurysm. The aneurysm thrombosed and markedly regressed over the next 5 months, with remarkable improvement in the brainstem compression symptoms. LESSONS: This finding on VW-MRI may indicate an attenuation of neovascularization in the thrombus wall and be a sign of aneurysm stabilization.

Predictors of aneurysm shrinkage after flow diversion treatment for internal carotid artery aneurysms: quantitative volume analysis with MRI.

Background and purpose: Although aneurysm shrinkage often occurs after flow diversion treatment for intracranial aneurysms, no reports have addressed the factors associated with aneurysm shrinkage. Materials and methods: This retrospective single-center study was performed to examine patients with unruptured internal carotid artery aneurysms who were treated using flow diversion and followed up by imaging for at least 12 months. The study outcome was aneurysm shrinkage (volume reduction of ≥10%) 12 months after treatment. Aneurysm volume was quantitatively assessed using the MRIcroGL software. Patient and aneurysm characteristics were statistically analyzed. Results: This study involved 81 patients with 88 aneurysms. At the 6 months, 12 months, and last follow-ups, the proportion of aneurysms that had shrunk was 50, 64, and 65%, respectively. No adjunctive coiling (odds ratio, 56.7; 95% confidence interval, 7.03-457.21; p < 0.001) and aneurysm occlusion (odds ratio, 90.7; 95% confidence interval, 8.32-988.66; p < 0.001) were significantly associated with aneurysm shrinkage. In patients treated by flow diversion with adjunctive coiling, only the volume embolization rate was a factor significantly associated with aneurysm shrinkage (p < 0.001). Its cutoff value was 15.5% according to the receiver operating characteristic curve analysis (area under the curve, 0.87; sensitivity, 0.87; specificity, 0.83). Conclusion: The rate of aneurysm shrinkage after flow diversion increased during the first 12 months after treatment, but not thereafter. No adjunctive coiling and aneurysm occlusion were predictors of aneurysm shrinkage, respectively. If adjunctive coiling is required, a volume embolization rate of ≤15.5% may be suggested for aneurysm regression.

Onset-to-treatment time and aneurysmal regression predict improvement of cranial neuropathy after flow diversion treatment in patients with symptomatic internal carotid artery aneurysms.

BACKGROUND: Although flow diversion plays a pivotal role in treating internal carotid artery aneurysms presenting with cranial neuropathy, predictors of symptom improvement have not been established. OBJECTIVE: To investigate improvement of symptoms after flow diversion treatment in patients with internal carotid artery aneurysms causing cranial neuropathy, with sufficient follow-up period. Additionally, to examine factors associated with improvement of symptoms. METHODS: This retrospective multicenter study examined patients with unruptured internal carotid artery aneurysms presenting with cranial neuropathy who were treated using flow diversion and followed up for at least 12 months. Study outcomes were transient worsening of symptoms and symptom status 12 months after treatment. Patient and aneurysm characteristics were statistically analyzed. RESULTS: Seventy-seven patients were included. Data needed for outcome analysis were available for 66 patients. At the 1-, 3-, 6-, 12-month, and last follow-ups, the proportion of patients with resolved or improved symptoms was 26% (20/77), 51% (39/77), 74% (57/77), 83% (64/77), and 79%(62/77), respectively. Symptom onset-to-treatment time <6 months (OR=24.2; 95% CI 3.09 to 188.84; p=0.002) and aneurysmal regression (OR=23.1; 95% CI 1.97 to 271.75; p=0.012) were significantly associated with symptom improvement. Transient symptom worsening and worse symptoms at 12 months occurred in 19/77 (25%) and 2/77 (3%) patients, respectively. CONCLUSIONS: The rate of cranial neuropathy symptom improvement after flow diversion increased over the first 12 months after treatment, but not thereafter. Treatment within 6 months of symptom onset and aneurysmal regression were predictors of symptom improvement.

Ruptured thrombosed vertebral artery dissecting aneurysm treated with staged flow diverter after prediction of the rupture point by vessel wall MRI.

The safety and feasibility of using staged flow diverter (FD) for ruptured cerebral aneurysms, in which coil embolization is performed in the acute phase and FD is deployed in the subacute phase, has recently been reported. This strategy requires assuming the rupture point and performing coil embolization. Although vessel wall magnetic resonance imaging (VW-MRI) has been reported to be useful in predicting the rupture point of aneurysms, its use with staged FD has not yet been reported. We report the first case of staged FD with preoperative contrast-enhanced VW-MRI to predict the rupture point for partially thrombosed vertebral artery dissecting large aneurysm involving posterior inferior cerebellar artery (PICA) origin. This approach achieved a very good outcome, not only completely occluding the aneurysm, but also reconstructing the parent artery while maintaining the patency of the PICA.