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The relation between the low-dose radiation and the cognitive decline remains limited and controversial. However, the increasing use of high-dose radiation for medical purposes and some historical radiation-related accidents indicated that the low-dose radiation reduced cognitive ability, suggesting the reconsideration of the central nervous system’s low sensitivity to radiation, which has been advocated by conventional radiation biology. Although the continuous stimulation of low-dose radiation is known to be an environmental stressor that causes a critical decline in cognition during space exploration, the overall mechanisms from radiation exposure to cognitive alteration is still lacking. One of its main reasons is the inconsistent empirical results, and there are various possibilities to cause the contradictory consequences, such as the hormesis effect of low-dose radiation, the cellular adaptive responses, the radiation resistance, the bystander effects, and the genomic instability. In this review, we survey the low-dose radiation-induced cognitive studies, targeting learning achievement, emotional changes as well as fundamental cognitive behaviors in both humans and animals. Also, some relevant molecular studies are reappraised to understand the low-dose radiation-induced effects on the cognitive function. [ABSTRACT FROM AUTHOR]

Purpose: The medical certification for pilots is required by the aviation safety authority based with the aviation safety act. Methods: In this study, medical examination items of the year of 2021 performed during the aviation medical examination in Korea were reviewed by retrospective analysis. Results: Data from a total of 27 hospitals were collected. The number of inspection items ranged from a minimum of 22 items to a maximum of 57 items, showing a difference of more than double. Data from tertiary general hospitals and large airlines showed a tendency to perform more items of test compared to clinic-level institutions. The ratios for each inspection item are as follows: 1) 100% inspection items: urine test, ophthalmic test (except fundus test), fasting blood sugar, general blood test (complete blood count), electrocardiogram, electoencephalography, chest posterior anterior, pure tone audiometry, and total cholesterol; 2) 65%-74% inspection items: triglyceride, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, blood urea nitrogen/creatinine, and hepatitis B surface antigen; 3) 57% inspection items: hepatitis B surface antibody, human immunodeficiency virus, and venereal disease research laboratory; 4) 50% inspection items: urate and fundus examination. Conclusion: There have been many changes in the medical field over the past 40 years, but in terms of examination items, the aviation physical examination does not reflect the flow of change. Over the past years, the number of pilots has increased significantly, the flight environment has changed, and medical examination methods have been developed and diversified. In accordance with this, it is necessary to change the test items. [ABSTRACT FROM AUTHOR]

The space environment is a harsh space for humans who have evolved for a long time by adapting to the earth environment. The cosmic conditions that humans experience in outer space including the moon and Mars, such as altered gravity, exposure to cosmic radiation, changes in atmospheric pressure, and lunar dust, not only make the human body uncomfortable but also threaten survival. Space medicine is one of a field of environmental medicine that aims to clarify the physiology and response of body to these harmful space conditions. The primary purpose of space medicine is to protect the health and life of astronauts, and to support mission performance to succeed in space exploration. In addition, it contributes to mankind by utilizing and industrializing the knowledge and technology acquired in the process of developing knowledge about medical countermeasures, basic life support in the space. [ABSTRACT FROM AUTHOR]

Aircraft accidents caused by dizziness of aviation workers are so common that they account for 5% to 10% of the total, and in most cases, have fatal consequences. Therefore, it is essential to diagnose and treat the dizziness of aviation workers properly. Common diseases caused by abnormal vestibular function include benign paroxysmal positional vertigo, Meniere's disease, and vestibular neuritis. In this paper, we first proposed an overview of these diseases' pathophysiology, diagnosis, and treatment. Also, we evaluated the importance of these diseases in aerospace medicine and presented aerospace medical dispositions for aviation medical examiners. [ABSTRACT FROM AUTHOR]

The medical certification for pilots is required by the aviation safety authority in most countries based with the International Civil Aviation Organization (ICAO) recommendation. In this study, medical data of the year of 2015 for the Korean rotary-wing pilot population, including examination findings and reasons of unfitness were reviewed by retrospective analysis. Among the total 591 cases, 64 (10.8%) were determined to be conditioned fit as a consequence of abnormal findings. Three (0.5%) were denied certification as unfit. Hearing loss (32.8%) was the most common cause of disqualification differing from that of fixed-wing pilots. It is not surprising data in that helicopter is notorious for its noise and vibration when flying compared with fixed-wing aircraft. Hypertension (23.9%) and diabetes (9%) were following causes. There was an increasing variation in medical unfitness as pilots' age and total flight time are increased respectively. Rate of the conditioned fit tends to be significantly increasing the age of 55 or more or the flight time of 5,000 hours. These results suggest that aeromedical decision should be made under understanding of the influence of age, total flight time and aircraft type flight environment to ensure flight safety. [ABSTRACT FROM AUTHOR]

Microgravity could exert significant health effect for astronauts, by weakening his or her immune function. Opportunistic infection by viruses, bacteria or fungi and their resistance to antibiotics or other treatment could cause significant health problem to astronauts. Therefore, it is essential that we perform research about change of immune function in microgravity condition. However, performing biological research under microgravity condition is extremely difficult on Earth. Therefore, several researchers have developed machinery and methods such as bioreactors (for cell culture study) and anti-orthostatic hindlimb unloading model (for rodents). In this review, we evaluated the usefulness of these models for simulated microgravity research. We also aimed to review recent literatures, which studied the immunological effects of long-term simulated microgravity. [ABSTRACT FROM AUTHOR]

There have been many advances in Japan aviation medicine, starting with establishment of the Civil Aeronautics Act in 1952 until now. The aviation medical examination system has been periodically revised and in recent years, the age limit has been extended. As the emerging concerns about aviation safety after an aircraft accident, the Japanese aeromedical research center has been developed in earnest. This article reviews the overall situation of Japanese aviation medicine and presents the direction of Korean aviation medicine to go forth through this. [ABSTRACT FROM AUTHOR]

It is essential to study the effects of hypergravity on the human body in the research field of aerospace medicine. Previous studies have shown that hypergravity could act in a harmful way to the human body. However, recent studies have shown that moderate degree of hypergravity can act in a beneficial way to the human body. The authors have in particular been studying the effects of hypergravity on immune diseases, especially allergic asthma and rhinitis. Therefore, this review paper will introduce the results of recent studies on hormetic (health promotion) effect of hypergravity. In addition, this review paper also examines the mechanism by which hormetic effect of hypergravity could be possible. Furthermore, we will also discuss how to apply these hormetic effects in clinical practice. [ABSTRACT FROM AUTHOR]

Several ground-based facilities have been developed for the study of hyper-gravity on Earth. Gravitational accelerator uses centrifugal force to make hyper-gravity condition. This machinery could be used not only for humans (for training of pilots), but also for experimental animals (basic research about its effect in vivo). In order to study the effect of long-term as well as short-term hyper-gravity on experimental animals, we developed Gravitational accelerator using rotatory centrifugal force. With 1 meter-long arms on both sides and with the rotational speed of 120 rpm, we could reproduce 15 Gz of hyper-gravity. We assured its stability and safety by operating it during 7 continuous days. After we made it certain that our Gravitational accelerator was well operated during that period, we performed additional study about the effect of hyper-gravity on the immune status of experimental animals. [ABSTRACT FROM AUTHOR]

The vestibular system is the only organ controlled by positive feedbacks in human. Since it calculates the exact positional signals of the head, it analogizes three dimensional relationships between the human body and the objects in a real space, and it helps the ability to correct object's clear vision and postures. A certain quantity of external stimulation such as rotation, galvanic, temperature, pressure and sounds is given to observe the responses of effectors and to be able to figure out the characteristics of nervous system. The rotation stimulation would be used the most exquisite input data. In the vestibular system, there is a range that responses to linear frequency, hence reasonable rotation stimulation can be applied as a stabilized evaluation tool for vestibular science. In this article, it explains how the rotational stimulation affects the vestibular system and how it will distinguish its significance. [ABSTRACT FROM AUTHOR]

We aimed to study about the effect of acute hyper-gravity (HG) on the allergic immune response in a murine model of allergic asthma. Thirty-two BALB/c mice were used. In Group A (control group, n=8), mice were sensitized and challenged with saline. Group B (HG control group, n=8) were exposed to HG (10 Gz, 1 hour) after intraperitoneal and intranasal saline challenge. Group C (asthma group, n=8) received intraperitoneal and intranasal ovalbumin (OVA) challenge. Group D (HG asthma group, n=8) were exposed to HG after intraperitoneal and intranasal OVA challenge. We evaluated serum total and OVA-specific IgE; serum titers of cytokines; and histopathologic examination of lung. As a result, titers of Serum total and OVA-specific IgE were not significantly different between groups. Compared to Group C, mice in Group D showed significant increase of Th2 cytokines (IL-4, IL-13), cytokines involved in eosinophilia (IL-3, IL-5, GM-CSF) and those involved in cell-medicated immunity (IFN-γ). In histopathologic examination, lungs of Group D showed significantly more infiltration of inflammatory cells compared to Group C. However, these differences were not so significant between Groups A and B. In conclusion, acute HG could exacerbate allergic asthma in experimental animals. [ABSTRACT FROM AUTHOR]