Mental workload during endoscopic sinus surgery is associated with surgeons' skill levels

Introduction

Surgeons' mental workload during endoscopic sinus surgery (ESS) has not been fully evaluated. The assessment was challenging due to the great diversity of each patient's anatomy and the consequence variety of surgical difficulties. In this study, we examined the mental workload of surgeons with various surgical skill levels during ESS under the standardized condition provided by novel-designed 3D sinus models.

Materials and methods

Forty-seven participants performed a high-fidelity ESS simulation with 3D-printed sinus models. Surgeons' mental workload was assessed with the national aeronautics and space administration-task load index (NASA-TLX). Associations between the total and subscales score of NASA-TLX and surgical skill index, including the board certification status, the number of experienced ESS cases, and the objective structured assessment of technical skills (OSATS), were analyzed. In addition, 10 registrars repeated the simulation surgery, and their NASA-TLX score was compared before and after the repetitive training.

Results

The total NASA-TLX score was significantly associated with OSATS score (p = 0.0001). Primary component analysis classified the surgeons' mental burden into three different categories: (1) the skill-level-dependent factors (temporal demand, effort, and performance), (2) the skill-level-independent factors (mental and physical demand), and (3) frustration. After the repetitive training, the skill-level-dependent factors were alleviated (temporal demand; z = -2.3664, p = 0.0091, effort; z = -2.1704, p = 0.0346, and performance; z = -2.5992, p = 0.0017), the independent factors were increased (mental demand; z = -2.5992, p = 0.0023 and physical demand; z = -2.2509, p = 0.0213), and frustration did not change (p = 0.3625).

Conclusion

Some of the mental workload during ESS is associated with surgical skill level and alleviated with repetitive training. However, other aspects remain a burden or could worsen even when surgeons have gained surgical experience. Routine assessment of registrars' mental burdens would be necessary during surgical training to sustain their mental health.

Basic Experiments Toward Mixed Reality Dynamic Navigation for Laparoscopic Surgery

Laparoscopic surgery is a minimally invasive procedure that is performed by viewing endoscopic camera images. However, the limited field of view of endoscopic cameras makes laparoscopic surgery difficult. To provide more visual information during laparoscopic surgeries, augmented reality (AR) surgical navigation systems have been developed to visualize the positional relationship between the surgical field and organs based on preoperative medical images of a patient. However, since earlier studies used preoperative medical images, the navigation became inaccurate as the surgery progressed because the organs were displaced and deformed during surgery. To solve this problem, we propose a mixed reality (MR) surgery navigation system in which surgical instruments are tracked by a motion capture (Mocap) system; we also evaluated the contact between the instruments and organs and simulated and visualized the deformation of the organ caused by the contact. This paper describes a method for the numerical calculation of the deformation of a soft body. Then, the basic technology of MR and projection mapping is presented for MR surgical navigation. The accuracy of the simulated and visualized deformations is evaluated through basic experiments using a soft rectangular cuboid object.

Development of Haptic Interface for Neurosurgical Simulators with Micro Scissors Module for Displaying the Cutting Force

Introduction of surgical simulators, which enable repeated learning of new surgical techniques, is advancing and they are desired in the field of neurosurgery. This study aims to make a two-fold contribution. First is the development of a haptic interface, which can be used while changing the operative tools necessary for training the cerebral fissure opening technique while using both the hands. Second is to develop a module for the haptic interface, which can display the cutting force when using micro scissors. To realize the operation with both the hands, the haptic interfaces for the right and left hands are designed so that they do not interfere. In addition, surgical tools, such as retractors, micro dissectors, and micro scissors, can be exchanged. In the cutting experiment carried out prior to the development of the haptic interface, it was clarified that the force when the dura mater was cut using micro scissors was 0.5 N. For comparison, the cutting forces required to cut two and three sheets of paper were measured to be 0.4 N and 0.6 N, respectively. The developed micro scissors module was designed using one motor and planetary gear mechanism. The gear mechanism is designed such that the right and left handles rotate in reverse directions around the rotation axis of the micro scissors using only one motor. This mechanism enables the micro scissors to cut the virtual tissues in the middle of the blade. The developed module could display a force of 0.4 N.

Moving Particle Semi-Implicit and Finite Element Method Coupled Analysis for Brain Shift Estimation

Neuronavigation is a computer-assisted technique for presenting three-dimensional images of a patient’s brain to facilitate immediate and precise lesion localization by surgeons. Neuronavigation systems use preoperative medical images of patients. In neurosurgery, when the dura mater and arachnoid membrane are incised and the cerebrospinal fluid (CSF) drains out, the brain loses the CSF buoyancy and deforms in the direction of gravity, which is referred to as brain shift. This brain shift yields inaccurate neuronavigation. To reduce this inaccuracy, an intraoperative brain shift should be estimated. This paper proposes a dynamic simulation method for brain-shift estimation combining the moving-particle semi-implicit (MPS) method and the finite element method (FEM). The CSF was modeled using fluid particles, whereas the brain parenchyma was modeled using finite elements (FEs). Node particles were attached to the surface nodes of the brain parenchyma in the FE model. The interaction between the CSF and brain parenchyma was simulated using the repulsive force between the fluid particles and node particles. Validation experiments were performed using a gelatin block. The gelatin block was dipped into silicone oil, which was then gradually removed; the block deformation owing to the buoyancy loss was measured. The experimental deformation data were compared with the results of the MPS-FEM coupled analysis. The mean absolute error (MAE) between the simulated deformation and the average across the four experiments was 0.26 mm, while the mean absolute percentage error (MAPE) was 27.7%. Brain-shift simulations were performed using the MPS-FEM coupled analysis, and the computational cost was evaluated.

Automatic assessment of laparoscopic surgical skill competence based on motion metrics

The purpose of this study was to characterize the motion features of surgical devices associated with laparoscopic surgical competency and build an automatic skill-credential system in porcine cadaver organ simulation training. Participants performed tissue dissection around the aorta, dividing vascular pedicles after applying Hem-o-lok (tissue dissection task) and parenchymal closure of the kidney (suturing task). Movements of surgical devices were tracked by a motion capture (Mocap) system, and Mocap-metrics were compared according to the level of surgical experience (experts: ≥50 laparoscopic surgeries, intermediates: 10-49, novices: 0-9), using the Kruskal-Wallis test and principal component analysis (PCA). Three machine-learning algorithms: support vector machine (SVM), PCA-SVM, and gradient boosting decision tree (GBDT), were utilized for discrimination of the surgical experience level. The accuracy of each model was evaluated by nested and repeated k-fold cross-validation. A total of 32 experts, 18 intermediates, and 20 novices participated in the present study. PCA revealed that efficiency-related metrics (e.g., path length) significantly contributed to PC 1 in both tasks. Regarding PC 2, speed-related metrics (e.g., velocity, acceleration, jerk) of right-hand devices largely contributed to the tissue dissection task, while those of left-hand devices did in the suturing task. Regarding the three-group discrimination, in the tissue dissection task, the GBDT method was superior to the other methods (median accuracy: 68.6%). In the suturing task, SVM and PCA-SVM methods were superior to the GBDT method (57.4 and 58.4%, respectively). Regarding the two-group discrimination (experts vs. intermediates/novices), the GBDT method resulted in a median accuracy of 72.9% in the tissue dissection task, and, in the suturing task, the PCA-SVM method resulted in a median accuracy of 69.2%. Overall, the mocap-based credential system using machine-learning classifiers provides a correct judgment rate of around 70% (two-group discrimination). Together with motion analysis and wet-lab training, simulation training could be a practical method for objectively assessing the surgical competence of trainees.

Tracking of Overlapped Vehicles with Spatio-Temporal Shared Filter for High-Speed Stereo Vision

In this study, we propose a method for measuring the distance and velocity of overlapping vehicles using high-speed stereo vision. The method is based on the correlation filter called MOSSE and is improved by balancing the computation cost and accuracy using the features of high-frame-rate images. To achieve stable tracking, the tracking window was adjusted for each vehicle according to the vehicle distance and the overlapping state. Experiments on the images acquired by the cameras mounted on an actual vehicle were performed to validate the proposed method.

Repetitive simulation training with novel 3D ‐printed sinus models for functional endoscopic sinus surgeries

Background

The purpose of this study was to find a utility of a newly developed 3D‐printed sinus model and to evaluate the educational benefit of simulation training with the models for functional endoscopic sinus surgery (FESS).

Material and methods

Forty‐seven otolaryngologists were categorized as experts (board‐certified physicians with ≥200 experiences of FESS, n = 9), intermediates (board‐certified physicians with <200 experiences of FESS, n = 19), and novices (registrars, n = 19). They performed FESS simulation training on 3D‐printed models manufactured from DICOM images of computed tomography (CT) scan of real patients. Their surgical performance was assessed with the objective structured assessment of technical skills (OSATS) score and dissection quality evaluated radiologically with a postdissection CT scan. First we evaluated the face, content, and constructive values. Second we evaluated the educational benefit of the training. Ten novices underwent training (training group) and their outcomes were compared to the remaining novices without training (control group). The training group performed cadaveric FESS surgeries before and after the repetitive training.

Results

The feedback from experts revealed high face and content value of the 3D‐printed models. Experts, intermediates, and novices demonstrated statistical differences in their OSATS scores (74.7 ± 3.6, 58.3 ± 10.1, and 43.1 ± 11.1, respectively, p < .001), and dissection quality (81.1 ± 13.1, 93.7 ± 15.1, and 126.4 ± 25.2, respectively, p < .001). The training group improved their OSATS score (41.1 ± 8.0 to 61.1 ± 6.9, p < .001) and dissection quality (122.1 ± 22.2 to 90.9 ± 10.3, p = .013), while the control group not. After training, 80% of novices with no prior FESS experiences completed surgeries on cadaver sinuses.

Conclusion

Repeated training using the models revealed an initial learning curve in novices, which was confirmed in cadaveric mock FESS surgeries.

Level of evidence

N/A

Objective evaluation of laparoscopic surgical skills in wet lab training based on motion analysis and machine learning

BACKGROUND

Our aim was to build a skill assessment system, providing objective feedback to trainees based on the motion metrics of laparoscopic surgical instruments.

METHODS

Participants performed tissue dissection around the aorta (tissue dissection task) and renal parenchymal closure (parenchymal-suturing task), using swine organs in a box trainer under a motion capture (Mocap) system. Two experts assessed the recorded movies, according to the formula of global operative assessment of laparoscopic skills (GOALS: score range, 5-25), and the mean scores were utilized as objective variables in the regression analyses. The correlations between mean GOALS scores and Mocap metrics were evaluated, and potential Mocap metrics with a Spearman's rank correlation coefficient value exceeding 0.4 were selected for each GOALS item estimation. Four regression algorithms, support vector regression (SVR), principal component analysis (PCA)-SVR, ridge regression, and partial least squares regression, were utilized for automatic GOALS estimation. Model validation was conducted by nested and repeated k-fold cross validation, and the mean absolute error (MAE) was calculated to evaluate the accuracy of each regression model.

RESULTS

Forty-five urologic, 9 gastroenterological, and 3 gynecologic surgeons, 4 junior residents, and 9 medical students participated in the training. In both tasks, a positive correlation was observed between the speed-related parameters (e.g., velocity, velocity range, acceleration, jerk) and mean GOALS scores, with a negative correlation between the efficiency-related parameters (e.g., task time, path length, number of opening/closing operations) and mean GOALS scores. Among the 4 algorithms, SVR showed the highest accuracy in the tissue dissection task ([Formula: see text]), and PCA-SVR in the parenchymal-suturing task ([Formula: see text]), based on 100 iterations of the validation process of automatic GOALS estimation.

CONCLUSION

We developed a machine learning-based GOALS scoring system in wet lab training, with an error of approximately 1-2 points for the total score, and motion metrics that were explainable to trainees. Our future challenges are the further improvement of onsite GOALS feedback, exploring the educational benefit of our model and building an efficient training program.

Improved 3D Human Motion Capture Using Kinect Skeleton and Depth Sensor

Kinect has been utilized as a cost-effective, easy-to-use motion capture sensor using the Kinect skeleton algorithm. However, a limited number of landmarks and inaccuracies in tracking the landmarks’ positions restrict Kinect’s capability. In order to increase the accuracy of motion capturing using Kinect, joint use of the Kinect skeleton algorithm and Kinect-based marker tracking was applied to track the 3D coordinates of multiple landmarks on human. The motion’s kinematic parameters were calculated using the landmarks’ positions by applying the joint constraints and inverse kinematics techniques. The accuracy of the proposed method and OptiTrack (NaturalPoint, Inc., USA) was evaluated in capturing the joint angles of a humanoid (as ground truth) in a walking test. In order to evaluate the accuracy of the proposed method in capturing the kinematic parameters of a human, lower body joint angles of five healthy subjects were extracted using a Kinect, and the results were compared to Perception Neuron (Noitom Ltd., China) and OptiTrack data during ten gait trials. The absolute agreement and consistency between each optical system and the robot data in the robot test and between each motion capture system and OptiTrack data in the human gait test were determined using intraclass correlations coefficients (ICC3). The reproducibility between systems was evaluated using Lin’s concordance correlation coefficient (CCC). The correlation coefficients with 95% confidence intervals (95%CI) were interpreted substantial for both OptiTrack and proposed method (ICC > 0.75 and CCC > 0.95) in humanoid test. The results of the human gait experiments demonstrated the advantage of the proposed method (ICC > 0.75 and RMSE = 1.1460°) over the Kinect skeleton model (ICC < 0.4 and RMSE = 6.5843°).

Construction of a detachable artificial trachea model for three age groups for use in an endotracheal suctioning training environment simulator

Tracheal suctioning is an important procedure to maintain airway patency by removing secretions. Today, suctioning operators include not only medical staff, but also family caregivers. The use of a simulation system has been noted to be the most effective way to learn the tracheal suctioning technique for operators. While the size of the trachea varies across different age groups, the artificial trachea model in the simulation system has only one fixed model. Thus, this study aimed to construct multiple removable trachea models according to different age groups. We enrolled 20 patients who had previously received proton beam therapy in our institution and acquired the treatment planning computed tomography (CT) image data. To construct the artificial trachea model for three age groups (children, adolescents and young adults, and adults), we analyzed the three-dimensional coordinates of the entire trachea, tracheal carina, and the end of the main bronchus. We also analyzed the diameter of the trachea and main bronchus. Finally, we evaluated the accuracy of the model by analyzing the difference between the constructed model and actual measurements. The trachea model was 8 cm long for children and 12 cm for adolescents and young adults, and for adults. The angle between the trachea and bed was about 20 degrees, regardless of age. The mean model accuracy was less than 0.4 cm. We constructed detachable artificial trachea models for three age groups for implementation in the endotracheal suctioning training environment simulator (ESTE-SIM) based on the treatment planning CT image. Our constructed artificial trachea models will be able to provide a simulation environment for various age groups in the ESTE-SIM.

Relationship Between Tracheal Suctioning Catheter Motion and Secretion Amount Based on Viscosity

Background

To provide safe tracheal suctioning, the American Association of Respiratory Care guideline discusses the length of suctioning catheter, but the most effective tracheal suctioning catheter technique is still unknown.

Objective

The aim of this study is to compare the amount of simulated secretion produced by five different handlings of a catheter at two different viscosities and in two different models to discover the most effective suctioning maneuver in the various mucus conditions.

Design

In vitro experimental design.

Methods

The amount of secretion aspirated by our researcher's manipulation of a suctioning catheter was measured. The tip of the catheter was recorded using a high-speed video camera to visualize the secretion motion.

Results

The most effective suctioning technique differed depending on the viscosity of the secretion. There were no significant differences between five suctioning methods applied to high-viscosity phlegm in a tracheal membrane model, but the flexion technique was the most efficient for low-viscosity secretion.

Conclusions

Our results imply that the flexion technique was reasonably safe and the most effective of these five methods for low-viscosity secretion.

A Wearable Encounter-Type Haptic Device Suitable for Combination with Visual Display

[abstFig src='/00280006/02.jpg' width='260' text='The encounter type wearable haptic device' ] This paper describes a wearable encounter-type haptic device suitable for combined usage with a visual display. The features of the device lie in a driving mechanism that enables an encounter-type haptic display and the compact implementation of the entire device including the driving mechanism. The driving mechanism displays a natural haptic sense based on a smooth transition between follow-up and constraint of finger movements. The compactness is important because it contributes to preserving the quality of visual information when used together with a visual display. To test the basic performance of the device, the response of the driving mechanism was evaluated. The haptic display function was evaluated by a simulation in which the device is used to touch an object in a computer graphics (CG) space.

An Approach Toward an Automated Object Retrieval Operation with a Two-Arm Flexible Manipulator

The recent developments in space technology demand various services to uncontrollable satellites, such as refueling and repairing, in order to extend their lifespans. However, there has so far been no research on such practical applications with flexible manipulators. In this paper, we address automated object capture with a two-arm flexible manipulator, which is a basic technology for such services in space. This object capturing strategy includes symmetric cooperative control, visual servoing, the resolution of the inverse kinematics problem and the optimization of the configuration of a two-arm redundant flexible manipulator. For the performance improvement on the rise time of the internal forces at the instant of making contact, a transition control strategy is also proposed considering the resultant mechanical compliance associated with the internal forces. Moreover, we present the control system configuration for this task. This control system is based on IBM-compatible personal computers (PCs), and the computational loads for the task execution are distributed to several PCs connected to each other through the Ethernet. The effectiveness of the proposed control system and task sequence is validated with the experiments.

Configuration- Dependent Vibration Controllability of Flexible-Link Manipulators

In this article, the structural vibration controllability of flexible- link manipulators is discussed. For some spatial flexible- link manipulators, the structural vibration controllability is configuration-dependent. Therefore, the flexible-link manipulator may have some vibration-uncontrollable configurations. To un derstand the physical interpretation of vibration-uncontrollable configurations, we propose the modal accessibility concept, which indicates how well the actuators can affect the structural vibration modes. The configuration in which all of the actua tors cannot affect at least one of the manipulator's vibration modes is vibration uncontrollable. Main contributions of this article are the following two points: first, interesting structural vibration-uncontrollable configurations are found within the two-link, three-joint-type manipulator's workspace, and are verified experimentally; second, the modal accessibility index is introduced to indicate how well the corresponding vibration mode is controllable. Experimental results show that even in the controllable configurations, it becomes difficult to suppress vibration if the modal accessibility is small.

Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus-the 'D-shuttle' project

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter 'D-shuttle' for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the terrestrial background radiation level of other regions/countries.

Link between inflammation and aquaporin-5 distribution in submandibular gland in Sjögren's syndrome?

OBJECTIVE

To determine whether a link exists between inflammation and aquaporin-5 distribution in submandibular glands from three animal models for Sjögren's syndrome: IQI/JIC, r1ΔT/r2n and non-obese diabetic mice.

METHODS

Mice of different ages were used. Inflammatory infiltrates were quantified using the focus score. Acinar aquaporin-5 subcellular distribution was determined by immunohistochemistry and quantified using labelling indices.

RESULTS

  Minor inflammatory infiltrates were present in r1f/r2n mice. Massive inflammatory infiltrates and acinar destruction were observed in 24-week-old non-obese diabetic mice, 10-and 13-month-old IQI/JIC mice and some r1ΔT/r2n mice. Aquaporin-5 immunoreactivity was primarily apical in submandibular glands from 8- and 24-week-old Balb/C mice, 8-week-old non-obese diabetic mice, 2-, 4- and 7-month-old IQI/JIC mice and r1f/r2n mice. In contrast, decreased apical aquaporin-5 labelling index with concomitant increased apical-basolateral, apical-cytoplasmic and/or apical-basolateral-cytoplasmic aquaporin-5 labelling indices was observed in 24-week-old non-obese diabetic, 10- and 13-month-old IQI/JIC and r1ΔT/r2n mice with a focus score≥1.

CONCLUSIONS

  Altered aquaporin-5 distribution in submandibular acinar cells from IQI/JIC, non-obese diabetic and r1ΔT/r2n mice with a focus score≥1 appears to be concomitant to the presence of inflammatory infiltrates and acinar destruction.

Development of a Wire Harness Assembly Motion Planner for Redundant Multiple Manipulators

This article discusses a motion planner for manipulating deformable linear objects with multiple manipulators. When multiple manipulators grip a rigid body, hand positions and postures of those manipulators are dependent variables of the positions and postures of the gripped rigid body. On the other hand, when multiple manipulators grip a deformable linear object, constraint conditions are eased compared to those for a rigid body. However, there is another problem: the need for consideration of deformation of a deformable linear object by the motion plan of a robot. In this research, in order to grip and operate such deformable linear objects with multiple manipulators, we developed a sampling-based robot motion planner. By combining basic motions generated by the developed robot motion planner, we will show that a complicated task, such as the assembly of a deformable linear object with the multiple manipulators, is possible. Using the example of a wire harness assembly work on an automobile production line, we perform motion planning using the developed motion planner, and we verify its effectiveness through simulations.

A Human-Like Approach Towards Humanoid Robot Footstep Planning

Humanoid robots posses the unique ability to cross obstacles by stepping over or upon them. However, conventional 2D methods for robot navigation fail to exploit this ability and thus design trajectories only by circumventing obstacles. Recently, global algorithms have been presented that take into account this feature of humanoids. However, due to high computational complexity, most of them are very time consuming. In this paper, we present a novel approach to footstep planning in obstacle cluttered environments that employs a human-like strategy to terrain traversal. Design methodology for obstacle stepping over motion designed for use with this algorithm is also presented. The paper puts forth simulation results of footstep planning as well as experimental results for the stepping over trajectory designed for use with hardware execution of the footstep plan.

Stable Soft-Tissue Fracture Simulation for Surgery Simulator

Soft-tissue fracture simulation is a key to surgery simulation virtually reproducing cutting, dissection, and removal. Soft-tissue fracture is modeled by finite element fracture in which elements are removed if their stress exceeds a specified fracture stress. Removing elements without considering connection to adjacent elements may produce structurally unstable elements, that cause computational instability. We propose geometric limitation and element fracture method to avoid this instability. We confirmed the feasibility of our proposals by comparing blunt dissection simulation results to blunt dissection experiment results using agar.

An impact dynamics model and sequential optimization to generate impact motions for a humanoid robot

When a human needs to generate a large force, they will try to apply an impulsive force with dynamic cooperation of the whole body. In this paper we first discuss impact dynamics of humanoid robots and then propose a way to generate impact motions for a humanoid robot to exert a large force while keeping a balance. In the impact motion generation, Sequential Quadratic Programming (SQP) is used to solve a non-linear programming problem in which an objective function and constraints may be non-linear functions of the motion parameters. Impact motions are generated using SQP so that the impact force is maximized while the angular momentum is minimized. Breaking wooden boards with a Karate chop is taken as a case study because it is a typical example of tasks that utilize impulsive force. A humanoid robot motion for the Karate chop is generated by the proposed method. In order to validate the designed motion, experiments are carried out using a small humanoid robot Fujitsu HOAP-2. The Karate-chop motion generated by the proposed method is compared with the motion designed by a human. The results of breaking the wooden boards experiments clearly show the effectiveness of the proposed method.

MPID Control Tuning for a Flexible Manipulator Using a Neural Network

This paper studies the use of neural networks as a tuning tool for the gain in Modified Proportional-Integral-Derivative (MPID) control used to control a flexible manipulator. The vibration control gain in the MPID controller has been determined in an empirical way so far. It is a considerable time consuming process because the vibration control performance depends not only on the vibration control gain but also on the other parameters such as the payload, references and PD joint servo gains. Hence, the vibration control gain must be tuned considering the other parameters. In order to find optimal vibration control gain for the MPID controller, a neural network based approach is proposed in this paper. The proposed neural network finds an optimum vibration control gain that minimizes a criteria function. The criteria function is selected to represent the effect of the vibration of the end effector in addition to the speed of response. The scaled conjugate gradient algorithm is used as a learning algorithm for the neural network. Tuned gain response results are compared to results for other types of gains. The effectiveness of using the neural network appears in the reduction of the computational time and the ability to tune the gain with different loading condition.

Onset of autoimmune glomerulonephritis derived from the telomeric region of MRL-chromosome 1 is associated with the male sex hormone in mice

Female B6.MRLc1(82-100) congenic mice develop more severe autoimmune glomerulonephritis (AGN) than males. We assessed the effects of gonadectomy on the pathogenesis of AGN in these mice. One-month-old male and female mice were divided into sham-operated group (SG) and gonadectomized group (GG), and the pathological changes were investigated at 8 months. SG females showed higher spleen and thymus weights, serum total IgG and autoantibody levels, glomerular damage scores and percent IgG- and CD3-positive glomeruli as compared with SG males. Gonadectomy showed more remarkable effects in males than in females. Spleen and thymus weights, urinary albumin excretion, glomerular damage scores, percent IgG- and CD3-positive glomeruli, and CD3-positive areas in the spleen were significantly higher in GG males than in SG males. CD3-positive cells were observed in both the thymic cortex and medulla in all animals except SG males. The expression ratio of active Fc gamma receptor (Fcgr) 3 to inhibitory Fcgr2b in the kidneys, which we have previously demonstrated to have a great impact on pathogenesis in B6.MRLc1(82-100), was significantly higher in GG males than in SG males. These results suggested that the differences in the pathogenesis of AGN are primarily because of the inhibitory roles of the male sex hormones.

Hovering Control of a Tail-Sitter VTOL Aerial Robot

This paper describes system development and hovering control of a tail-sitter VTOL aerial robot. The tail-sitter VTOL aerial robot developed from model aircraft parts, sensors, microcomputers, and other components hovers autonomously thanks to attitude, altitude, and position control. Attitude control error averages 1-2°and altitude control error several centimeters. The aerial robot demonstrated both fixed-point hovering and trajectory tracking in hover mode.

Beneficial effects of leukotriene receptor antagonists in the prevention of cedar pollinosis in a community setting

BACKGROUND

In recent years, many countries have experienced an increase in the prevalence of allergic rhinitis. No effective approach is currently available to prevent the onset of symptoms in allergic individuals. Pranlukast, a leukotriene receptor antagonist with a good safety and efficacy record for the management of allergic inflammation, may be appropriate for early intervention in the management of pollinosis.

OBJECTIVE

To investigate the efficacy of pranlukast as an early intervention in the control of cedar pollinosis.

METHODS

In a double-blind comparative study, pranlukast (n = 102) or placebo (n = 91) was administered to cedar pollinosis patients immediately before the start of the dispersion season and continued for 4 weeks. Subsequently, pranlukast was administered to all patients for 2 weeks until the end of the cedar pollen dispersion season (mid-March). All patients were carefully monitored for severity of nasal symptoms, symptom scores, medication scores, symptom-medication scores, and quality of life (QOL).

RESULTS

Compared with placebo, therapy with pranlukast before and during the dispersion of cedar pollen in these patients significantly improved nasal symptoms (paroxysmal sneezing, rhinorrhea, and nasal congestion), symptom scores, and symptom-medication scores. The drug also significantly reduced deterioration of QOL, and improved nasal symptoms and QOL throughout the dispersion period.

CONCLUSION

Administering pranlukast immediately before the beginning of cedar pollen dispersion is effective in reducing symptoms of allergic rhinitis throughout the dispersion period.