BACKGROUND: Glial cells are generally known to support normal neuronal functions tightly regulating the extracellular environment and providing energy substrates such as glucose. Therefore, dysfunction or loss of glial cells will lead to neuonal death. Since manganese (Mn2+) is known to be sequestered in glial cells, we investigated whether nitric oxide (NO) production in the activated glial cells is potentiated by manganese and the relationship between increased NO production and manganese-induced cytotoxicity of glial cells. METHODS: Manganese toxicity was assessed by morphological examination and by measuring the release of lactate dehydrogenase. Cultured glial cells were stimulated by lipopolysaccharide (1mug/mL). NO production was determined by measuring nitrites, a stable oxidation product of NO. RESULTS: Neither a LPS nor a MnCl2 altered the viability of glial cells. A 24 hr stimulation both LPS and MnCl2, however, markedly potentiated the manganese-induced death of glial cells. Manganese significantly increased the bacterial LPS-induced NO production. Manganese-induced NO release was markedly reduced by NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 1 mM), and potentiation of manganese-induced cell death by activated glial cells was partially prevented by L-NNA. CONCLUSION: It is concluded that manganese could induce sustained production of neurotoxic nitric oxide by the activated glial cells and manganese-induced cytotoxicity is partially mediated by potentiation of LPS-induced nitric oxide in the glial cell culture model.
Cell Death ; Glucose ; L-Lactate Dehydrogenase ; Manganese* ; Neuroglia* ; Neurons ; Nitric Oxide* ; Nitrites

BACKGROUND: Head-down suspension (HDS) of rats has been used as a model for the simulation of a microgravity environment. Atrial natriuretic peptide (ANP), C-type natriuretic peptides (CNP) and their receptors are found in the kidney, suggesting that these peptides could play a significant physiological role in the kidney. Therefore, this study was investigated the changes in the adaptations of renal natriuretic peptides and their receptors syntheses after 4 weeks of HDS in rats. METHODS: Unanesthetized, unrestrained, male Sprague-Dawley rats were subjected to either a horizontal position (control rats) or a -45degreeshead-down tilt using the tail-traction technique (HDS rats). This study observed the renal syntheses of natriuretic peptides as a expression of ANP and CNP mRNA, and also determined the expression of A-type natriuretic peptide receptor (NPR-A) mRNA and B-type NPR (NPR-B) mRNA. The expressions of natriuretic peptide and NPR mRNA were measured by reverse transcription-polymerase chain reaction with [(32)P]-dCTP following 4 weeks of HDS in the kidney of both control and HDS rats. RESULTS: After 4 weeks of HDS, the expression of ANP mRNA significantly (P<0.01) decreased, while CNP mRNA expression was showed the non-significant increasing trend in the kidney of HDS rats. NPR-A, which binds with ANP, was significantly (P<0.001) decreased in renal mRNA expression of HDS rats compared with controls. Expression in mRNA of NPR-B, which binds with CNP, showed a slightly decreasing trend in the kidney of rats following HDS. CONCLUSION: These results suggest that the renal adaptation following 4 weeks of HDS exerts to maintain the blood volume and electrolyte balance through attenuation of syntheses in the natriuretic peptide and its binding receptor, especially in ANP rather than in CNP systems.
Animals ; Atrial Natriuretic Factor ; Blood Volume ; Humans ; Kidney ; Male ; Natriuretic Peptides* ; Peptides ; Rats* ; Rats, Sprague-Dawley ; Receptors, Peptide ; RNA, Messenger* ; Water-Electrolyte Balance ; Weightlessness

BACKGROUND: It is known that depression and anxiety tendency causes physical or social dysfunction. Nowadays, the air travel is increasing as the life condition has been improved so the health of pilots who are in charge of passengers become a very important issue. However, few studies have been done on this issue, especially the relationship between depression & anxiety and medical diseases among them. This study was performed to know the factors affection pilots' sick leave and the correlation between depression & anxiety and sick leave. METHODS: Self administered questionaires were obtained from 123 pilots of one of the airline companies at Seoul from 1st April to 30th may 2003. Depression tendency was measured based upon BDI, the level of anxiety was measured by the standardised STAI and obesity was diagnosed if a BMI is over 25 kg/m2. The data on the subjects' age, position, airlines and the days of sick leave were obtained from personal record. RESULTS: All the study subjects were male with the average age of 40.23+/-7.48 (ranging from 30 to 60). The average age for those who had sick leave was 34.58+/-3.50 and that for those who had not was 40.48+/-7.55 and these two average ages showed difference with statistical significance (P value <0.001), and the odd ratio of sick leave about age was 0.796 (95% CI: 0.645-0.938). Whether a pilot had sick leave or not, however, was not statistically related to the level of BDI, STAI, flying duty, flying route, and body mass index (P value >0.05). CONCLUSION: This study shows that the average age of sick leave group was lower than that of non-sick leave group (P<0.001). The level of depression and anxiety were not related to the sick leave. The reasons for this seems to be the fact that pilots are healthier than general population and also they pay more attention to their own health. The younger pilots tended to have more days of sick leave, which might be explain that the older pilots were more cautious about the disadvantages of having sick leave but, the younger pilots tend to have strong individualistic personalities.
Anxiety* ; Body Mass Index ; Depression* ; Diptera ; Humans ; Male ; Obesity ; Seoul ; Sick Leave*

In order to assess the five-year external quality control programs for clinical chemistry tests of an aviation industrial infirmary, this study was done using data files related to commercial control sera in 1992-1996 by korean Association of Quality Assurance for clinical laboratory. Varlence. index score(VIS) of each items by the our group were calculated using data files of the salute testing method group. The clinical chemistry testing items were Na, K, BUN, Glucose, Ca, Inorgantic phosphorus, Uric acid, Creatinine, Total Bilirubin, Total Protein, Albumin, Total cholesterol, Triglyceride, AST, ALT, ALP, and LDH. The major findings were as follows. 1) The average range of VIS for 5 years was 89-53 for 18 items. This was shown our center is much improved by the external quality control program. 2) There were 6 testing items which VIS is bigger than 100 in 1992 and then appeared decreased trend of VIS until 1996. 3) The most variable items of VIS were K, Na, Albumin, and BUH. 4) The most stable items of VIS were Glucose, Total bilirebin, and LDH.
Information Storage and Retrieval ; Aviation* ; Bilirubin ; Chemistry, Clinical* ; Cholesterol ; Clinical Chemistry Tests* ; Creatinine ; Follow-Up Studies* ; Glucose ; Phosphorus ; Quality Control* ; Triglycerides ; Uric Acid

The aim of this study was to determine the adaptation of atrial natriuretic peptide(ANP) to simulated weightlessness. The level of immunoreactive plasma ANP level and the expression of right atrial ANP mRNA were assessed in male Sparague-Dawley rats during 2 weeks of head-down suspension(HDS) The rats were placed in a -45 degrees anti-orthostatic position. The plasma ANP level was investigated by radioimmunoassay and ANP mRNA was expressed by Northern blot analysis. The changes in daily water intake, body weight and arterial hematocrit did not show the statistical significances during HDS. The plasma ANP level slightly increased after 1 day of HDS, the response was transient and then decreased below the control levels. The expression of the ANP mRNA increased after 1 day, the peak value occurred at 3 days of HDS and thereafter ANP mRNA showed the similar patterns compared to the changes of plasma level. On the basis of these findings, we conclude that the initial adaptation of ANP to increased control blood volume in rats occurs between 3 and 7 days of HDS, and the ANP acts an important role during regulatory process to central hypervolemia at both synthetic and secretory levels within the early stage of HDS.
Animals ; Atrial Natriuretic Factor ; Blood Volume ; Blotting, Northern ; Body Weight ; Drinking ; Hematocrit ; Humans ; Male ; Plasma ; Radioimmunoassay ; Rats* ; RNA, Messenger* ; Weightlessness

The ROKAF(Republic of Korea Air Force ) has been conducting high G-training with new centrifuge training equipment at Aeromedical Research and Training Center(AMRTC) to enhance G-tolerance since July 1995. All trainees routinely have received ECG monitoring during High G training, both for safety and medical evaluation. The purpose of this study was to estimate the incidence of cardiac dysrhythmia among the fighter pilots of ROKAF and other countries and to investigate the relationship between G-induced loss of consciousness (G-LOC) and the presence of dysrhythmia during High-G training. The electrocardiographic responses of 417 fighter pilots exposed to the standard centrifuge high-G training profile were analysed. Dysrhythmias were observed in 204(42.7%) of the sessions, Ventricular ectopy occurred In 143(29.9% ) and supraventricular ectopy showed in 56(11.7%) of the sessions. G-induced loss of consciousness(G-LOC) occurred in 15%(62 pilots) of the trainees. Dysrhythmias associated with G-LOC were recorded In 23(37%), however, aeromedically serious arrhythmias were not observed. 41%(25/61) of dysrhythmias appeared in ROR(Rapid Onset Rate), whereas 27.9%(17/61) of them in GOR (Gradual Onset Rate). Although riding the centrifuge is a stressful experience in aircrews, the presence of the serious arrhythmias could potentially result in sudden incapacitation during flight. Therefore, ECG monitoring of aircrews during centrifuge training is hlghly recommended for their safety as well as aeromedical policy.
Arrhythmias, Cardiac ; Electrocardiography* ; Incidence ; Korea ; Unconsciousness

Head-down tilt (HDT) has been commonly used as the simulation of a microgravity to evaluate the hemodynamic and the hormonal responses to the central blood shift observed during the spaceflight. But there were some differences in the systemic responses according to species or angle of tilt, and there are few reports in the hemodynamic response and the regulation on polmonary vascular bed during the early stage of HDT. This study was attempted to clarify the regulatory mechanism on the systemic and pulmonary vascular responses through the low pressure receptor, and the hormonal changes to the -6 degrees HDT, and to investigate the effect of anticholinergic agent, glycopyrrolate, on the hemodynamic and the hormonal responses. In 28 anesthetized dogs(8~14 kg), 15 dogs(TILT group) were tilted from the supine position to the -6 degrees head-down position(HDP ) for 30 minutes, then back to the supine recovery position for the next 30 minutes, and the same tilt procedure was taken at 20 minutes after the intra venous administration of 0.2g glycopyrrolate. The rest 13 dogs were kept in the supine position without tilt as the control group(CONT group ) for the same time course of the TILT group. Cardiac output(Q), heart rate(HR), stroke volume(SV), index of contractility(IC) and thoracic fluid volume(TFV) were deterkuned by the impedance cardiograph. Systemic arterial pressure (SAP) and pulmonary arterial pressure(PAP) were measured at the brachial and pulmonary arteries respectively, and central venous pressure(CVP) also at the right atrium. And systemic and pulmonary vascular resistances (SVR and PVR) were calculated. The concentration of plusma ANP and ADH in the arterial blood were measured by the radioimmunoassay in 8 dogs in each group at 5 minutes before, and 25 and 55 minutes after begining of the tilt. During the HDP, Q, SV and TFV increased to 9%,10.6% and 12.6ml respectively in the TILT group, where as they decreased by 10%, 13.8% and 7.5ml respectively in the CONT group. SAP, PAP and HR did not change significantly in the TILT group, but SAP and HR increased in the CONT group. At the same time, SVR and PVR reduced significantly by 4.5% and 8.9% respectively at 15 minutes of HDP in the TILT group, where as they elevated gradually to 21.8% and 13.4% respectively at the first 30 runutes In the CONT group. There were no significant differences in the changes of HR, PAP and CVP between the TILT and the CONT group. And the plasma ANP and ADH did not change significantly in the both groups. After the administration of glycopyrrolate, SAP and SVR Increased to 3.7mmHg and 5.1% respectively, and PAP, PVR, Q, HR, and SV did not change significantly during the HDP in the TILT group. There was no significant difference in the change of each hemodynamic parameter between the TILT and the CONT group, except in TFV, which showed the same change as that before the administration of glycopyrrolate in the both groups. The plsma ANP showed nonslgnificant increased trend at the HDP in the TILT group but did not change In the CONT group, and the plasma ADH showed nonsignificant decreased trend in the both groups. In summary, the cardiopulmonary baroreceptors induced the vasodilations of both systemic and pulmonary vessels by the expansion of thoracic fluid volume at the head-down tilt, and the anticholinergic agent(glycopyrrolate) tended to attenuate the hemodynamic responses to the tilt. The concentration of the plasma ANP and ADH did not show significant changes in this study. It is suggested that the regulatory mechanism inducing the systeruc and pulmonary vats odilation during the early phase of the head-down tilt is mediated by the cholinergic vasodilator fiber in the dog.
Animals ; Arterial Pressure ; Atrial Natriuretic Factor ; Dogs ; Electric Impedance ; Glycopyrrolate ; Head-Down Tilt* ; Heart ; Heart Atria ; Hemodynamics* ; Plasma ; Pressoreceptors ; Pulmonary Artery ; Radioimmunoassay ; Space Flight ; Stroke ; Supine Position ; Thoracic Surgery, Video-Assisted ; Weightlessness

No abstract available.

Thibeault C. Special Committee Report : Cabin Air Quality Aviat Space Environ Med 1997 ;68 : 80-2. Cabin Air Quality has generated considerable public and workers' concern and controversy in the last few years. To clarify the situation, AsMA requested the Passenger Health Subcommittee of the Air Transport Medicine Committee to review the situation and prepare a position statement. After identifying the various sources of confusion, we review the scientifically accepted facts In the different elements involved in Cabin Air Quality : pressurization, ventilation, contaminants, humidity and temperature. At the same time, we identify areas that need more research and make recommendations accordingly.
Humidity ; Ventilation

No abstract available.
Aerospace Medicine* ; Korea* ; Publications*