Cerebral arterial air embolism (CAAE), although infrequent, is a complication that can occur at any time during an invasive medical procedure. We experienced two cases of CAAE during cerebral angiography accidentally. The author reports the two cases of CAAE wherein air emboli dissolved spontaneously and immediately under normal atmospheric pressure, not under therapeutic hyperbaric environment. One of the cases shows entire dissolution of the air embolus on the moving image. This report shows that arterial air embolus can be absorbed spontaneously, and air embolus size is one of the factors that influence air embolus dissolution besides hyperbaric oxygen condition.
Absorption* ; Atmospheric Pressure ; Cerebral Angiography ; Embolism* ; Embolism, Air ; Oxygen

Aerospace neurology concentrate on the function of nervous system exposed to environmental conditions other than those encountered in our normal standard conditions. Clinical factors in these environments include the toxic effects of changes in atmospheric pressure and considerations of safety for pilot with neurologic disease. This article gives a brief overview of the environmental factors experienced in aviation and space environments that are most associated in neurologic dysfunction.
Atmospheric Pressure ; Aviation ; Nervous System ; Neurologic Manifestations ; Neurology

Nonthermal atmospheric pressure plasma has attracted great interest for biomedical applications. The plasma consists of charged particles, radicals, and a strong electric field as the fourth state of matter. This study evaluated the change in the surface roughness after tooth bleaching by plasma in combination with a low concentration (15%) of carbamide peroxide, specifically whether the application of plasma produced detriments, such as demineralization and structural change, with the goal of efficient and safe tooth bleaching. After being combined with plasma and 15% carbamide peroxide, the hydroxyapatite surface was significantly smoother with a low roughness average value. Tooth bleaching with 15% carbamide peroxide alone produced an irregular surface and increased the surface roughness with high roughness average value. Tooth bleaching with plasma resulted in no significant variations in hydroxyapatite in terms of change in surface roughness and surface topography. The application of tooth bleaching with plasma is not deleterious to dental hard tissue, implicating it as a safe tooth bleaching technique.
Atmospheric Pressure* ; Durapatite* ; Plasma* ; Streptococcus mutans ; Tooth Bleaching* ; Urea

BACKGROUND: Spontaneous pneumothorax is a common respiratory condition and has been postulated that it develops because of rupture of subpleural blebs. Although the morphology and ultrastructure of causative lesions are well known, the reason for rupture of sbupleural blebs is not absolutely clear. Broad consensus concerning the role of meteorological factors in spontaneous pneumothorax dose not exist. The aim of the study was to examine the influence of change of atmospheric pressure and temperature on the occurrence of spontaneous pneumothorax. MATERIAL AND METHOD: One hundred twenty eight consecutive spontaneous pnemothorax events that occurred between January 2003 and December 2004 were selected. Changes of meteorological factors of particular days from the day before for 5 consecutive days were calculated and compared between the days with pneumothorax occurrence (SP days) and the days without pneumothorax occurrence (Non SP days). The correation between change of pressure and temperature and the occurrence of SP was evaluated. RESULT: SP occurred on 117 days (16.0%) in the 2-year period. Although there was no significant differences in change of pressure factors prior 4 days of SP occurrence compare to the 4 days prior Non SP day, change of mean pressure was higher (+0.934 vs. -0.191hPa, RR 1.042, CI 1.003~1.082, p=0.033), and change of maximum pressure fall was lower (3.280 vs. 4.791 hPa, RR 1.051, CI 1.013~1.090, p=0.009) on the 4 days prior SP day. There were significant differences in change of temperature factors prior 2 days and the day of SP, Changes of mean temperature (-0.576 vs.+0.099 degrees C, RR 0.886, 95% CI 0.817~0.962, p=0.004) and maximum temperature rise (7.231 vs. 8.079 degrees C, RR 0.943 CI 0.896~0.993, p=0.027) were lower on the 2 days prior SP. But changes of mean temperature (0.533 vs. -0.103 degrees C, RR 1.141, CI 1.038~1.255, p=0.006) and maximum temperature rise (9.209 vs. 7.754 degrees C, RR 1.123, CI 1.061~1.190, p=0.000) were higher on the SP days. CONCLUSION: Change of atmospheric pressure and temperature seems to influence the chance of occurrence of SP. Meteorological phenomena that pressure rise 4 day prior to SP and following temperature fall and rise might explain the occurrence of SP. Further studies should be continued in the future.
Atmospheric Pressure* ; Blister ; Consensus ; Meteorological Concepts ; Pneumothorax* ; Rupture

Present study deals with the straight impact of hypobaric hypoxia on the quantity and composition of some predominant fecal microflora and its functional aspects. For that, isolated fecal contents of rat were exposed to two different simulated air pressures (70 kPa and 40 kPa) for different time durations (1, 3, and 5 h) and the bacterial community composition was compared with normobaric groups (101.3 kPa). It was found that the total anaerobes, Escherichia coli, Enterbacters spp., Bifidobacterium spp., Clostridium spp. were increased whereas total aerobes were decreased at both hypobaric treatments. The increased number of amplicon was detected in the pressure-treated groups than the control that clearly mentioned the disruption of microbiota structure at different simulated hypobaric-hypoxia. The amylase, protease, tannase, β-glucuronidase, and alkaline phosphatase activities were increased at these atmospheric pressures. Thus, the present investigation demonstrates that the hypobaric hypoxia is an important environmental factor which can strongly modulate the composition of intestinal flora as well as microflora-derived functional aspects.
Animals ; Atmospheric Pressure ; Bacteria, Aerobic ; Feces ; Hypoxia ; Microbiota ; Rats

BACKGROUND: The hostile environment experienced in flying high performance aircraft, including changes in acceleration, atmospheric pressure, vibration, and temperature, may affect cardiac function of the pilot. It is not known, however, whether different mission scenarios with different workloads and emotional stress would differentially affect the heart. To evaluate the effects of four different types of light missions on cardiac function, we analyzed echocardiograms of pilots that were recorded baseline and within 30 min. after flight. METHODS: 78 healthy male pilots (mean age 29 years, range 22-43) who fly high performance aircraft in F-4D fighter squadrons (SQs) were included in this study. Their mean F-4D flight time was 452 h (range 1 1690). These subjects were divided into four groups based on the type of mission they flew: combat air patrol mission (N=20, Group I), air to ground mission (N=19, Group II), air to air mission including combat maneuver (N=22, Group III) and night flight mission (N=17, Group IV). Baseline echocardiograms and questionnaire were recorded at some previous day before actual flight. Echocardiograms and individual questionnaire were repeated within 30 min. after actual flight. Each subject served as his own control. We compared baseline and post-flight measurements and also compared the magnitude of changes among four groups from 18 echocardiographic variables. RESULTS: No echocardiographic variables differed significantly between baseline and post-flight measurements in any of the variables (at paired-t test) at each group. There were no significant differences among four groups for any changes in echocardiographic variables (Change=baseline data-post-flight data). CONCLUSION: We conclude that there were no significant differences in changes in cardiac functions among groups from before to after their missions.
Acceleration ; Aircraft ; Atmospheric Pressure ; Diptera ; Echocardiography* ; Heart ; Humans ; Male ; Missions and Missionaries* ; Stress, Psychological ; Vibration ; Surveys and Questionnaires

PURPOSE: This study evaluated the effect of polishing techniques on surface roughness of polymethyl methacrylate (PMMA), as well as the influence of light-cured surface glaze and subsequent brushing on surface roughness. MATERIALS AND METHODS: A total of 60 PMMA specimens (10x10x5 mm) were made and then divided into 6 groups of 10 each according to the polymerization methods (under pressure or atmosphere) and the surface polishing methods (mechanical or chemical polishing) including 2 control groups. The mechanical polishing was performed with the carbide denture bur, rubber points and then pumice and lathe wheel. The chemical polishing was performed by applying a light-cured surface glaze (Plaquit(R); Dreve-Dentamid GmbH). Accura 2000(R), a non-contact, non-destructive, optical 3-dimensional surface analysis system, was used to measure the surface roughness (Ra) and 3-dimensional images were acquired. The surface roughness was again measured after ultrasonic tooth brushing in order to evaluate the influence of brushing on the surface roughness. The statistical analysis was performed with Mann-Whitney test and t-test using a 95% level of confidence. RESULTS: The chemically polished group showed a statistically lower mean surface roughness in comparison to the mechanically polished group (P = .0045) and the specimens polymerized under the atmospheric pressure presented a more significant difference (P = .0138). After brushing, all of the groups, except the mechanically polished group, presented rougher surfaces and showed no statistically significant differences between groups. CONCLUSION: Although the surface roughness increased after brushing, the chemical polishing technique presented an improved surface condition in comparison to the mechanical polishing technique.
Atmospheric Pressure ; Dentures ; Polymerization ; Polymers ; Polymethyl Methacrylate ; Rubber ; Silicates ; Tooth ; Ultrasonics

PURPOSE: This study examined the influence of meteorological phenomena on the development of spontaneous pneumothorax (SP). METHODS: We conducted this study from January to November 2004. We obtained the daily SP incidence from data requested by the National Health Insurance office from general hospital in Daejon, and we got the meteorological data from the Daejon Regional Meteorologic office. The difference in meteorological phenomena between cluster days (3 or more SP) and no SP days was analyzed using a generalized additive model (GAM) that used a specialized form of the non-parametric, non-linear regression test. RESULTS: Five hundred sixty-six SP patients were included. There were 369 male patients and 74 female patients. SP patients were associated with significantly lower atmospheric pressure and with broad swings of daily atmospheric pressure for 4-7 days prior to the hospital visits. More clouds had gathered for several days before cluster days than had gathered on days with no SP. CONCLUSION: Development of SP is related with meteorological phenomena. SP occurs when lower atmospheric pressure, broad swings of atmospheric pressure, and cloudy weather are collectively exprienced for several days before the hospital visit.
Atmospheric Pressure ; Daejeon ; Female ; Hospitals, General ; Humans ; Incidence ; Male ; Meteorological Concepts ; National Health Programs ; Pneumothorax* ; Weather

OBJECTIVE: We have observed, anecdotally, that the incidence of primary spontaneous intracerebral hemorrhage (sICH), as well as spontaneous subarachnoid hemorrhage, varies in accordance with seasonality and meteorological conditions. This retrospective single-hospital-based study aimed to determine the seasonality of sICH and the associations, if any, between the occurrence of sICH and meteorological parameters in Incheon city, which is a northwestern area of South Korea. METHODS: Electronic hospital data on 708 consecutive patients admitted with primary sICH from January 2008 to December 2010 was reviewed. Traumatic and various secondary forms of ICHs were excluded. Average monthly admission numbers of sICH were analyzed, in relation with the local temperature, atmospheric pressure, humidity, and daily temperature range data. The relationships between the daily values of each parameter and daily admission numbers of sICH were investigated using a combination of correlation and time-series analyses. RESULTS: No seasonal trend was observed in sICH-related admissions during the study period. Furthermore, no statistically significant correlation was detected between the daily sICH admission numbers and the meteorological parameters of temperature, atmospheric pressure and humidity. The daily temperature range tended to correlate with the number of daily sICH-related admissions (p = 0.097). CONCLUSION: This study represents a comprehensive investigation of the association between various meteorological parameters and occurrence of spontaneous ICH. The results suggest that the daily temperature range may influence the risk of sICH.
Atmospheric Pressure ; Cerebral Hemorrhage ; Electronics ; Electrons ; Humans ; Humidity ; Incidence ; Meteorology ; Retrospective Studies ; Seasons ; Subarachnoid Hemorrhage ; Weather

OBJECTIVE: We have observed, anecdotally, that the incidence of primary spontaneous intracerebral hemorrhage (sICH), as well as spontaneous subarachnoid hemorrhage, varies in accordance with seasonality and meteorological conditions. This retrospective single-hospital-based study aimed to determine the seasonality of sICH and the associations, if any, between the occurrence of sICH and meteorological parameters in Incheon city, which is a northwestern area of South Korea. METHODS: Electronic hospital data on 708 consecutive patients admitted with primary sICH from January 2008 to December 2010 was reviewed. Traumatic and various secondary forms of ICHs were excluded. Average monthly admission numbers of sICH were analyzed, in relation with the local temperature, atmospheric pressure, humidity, and daily temperature range data. The relationships between the daily values of each parameter and daily admission numbers of sICH were investigated using a combination of correlation and time-series analyses. RESULTS: No seasonal trend was observed in sICH-related admissions during the study period. Furthermore, no statistically significant correlation was detected between the daily sICH admission numbers and the meteorological parameters of temperature, atmospheric pressure and humidity. The daily temperature range tended to correlate with the number of daily sICH-related admissions (p = 0.097). CONCLUSION: This study represents a comprehensive investigation of the association between various meteorological parameters and occurrence of spontaneous ICH. The results suggest that the daily temperature range may influence the risk of sICH.
Atmospheric Pressure ; Cerebral Hemorrhage ; Electronics ; Electrons ; Humans ; Humidity ; Incidence ; Meteorology ; Retrospective Studies ; Seasons ; Subarachnoid Hemorrhage ; Weather