Epstein-Barr virus shedding by astronauts during space flight.

Patterns of Epstein-Barr virus (EBV) reactivation in 32 astronauts and 18 healthy age-matched control subjects were characterized by quantifying EBV shedding. Saliva samples were collected from astronauts before, during, and after 10 space shuttle missions of 5-14 days duration. At one time point or another, EBV was detected in saliva from each of the astronauts. Of 1398 saliva specimens from 32 astronauts, polymerase chain reaction analysis showed that 314 (23%) were positive for EBV DNA. Examination by flight phase showed that 29% of the saliva specimens collected from 28 astronauts before flight were positive for EBV DNA, as were 16% of those collected from 25 astronauts during flight and 16% of those collected after flight from 23 astronauts. The mean number of EBV copies from samples taken during the flights was 417 per mL, significantly greater (p<.05) than the number of viral copies from the preflight (40) and postflight (44) phases. In contrast, the control subjects shed EBV DNA with a frequency of 3.7% and mean number of EBV copies of 40 per mL of saliva. Ten days before flight and on landing day, titers of antibody to EBV viral capsid antigen were significantly (p<.05) greater than baseline levels. On landing day, urinary levels of cortisol and catecholamines were greater than their preflight values. In a limited study (n=5), plasma levels of substance P and other neuropeptides were also greater on landing day. Increases in the number of viral copies and in the amount of EBV-specific antibody were consistent with EBV reactivation before, during, and after space flight.

Antibody responses to bacteriophage phi X-174 in human subjects exposed to the antarctic winter-over model of spaceflight.

BACKGROUND: It has been proposed that exposure to long-term spaceflight conditions (stress, isolation, sleep disruption, containment, microbial contamination, and solar radiation) or to ground-based models of spaceflight will alter human immune responses, but specific antibody responses have not been fully evaluated. OBJECTIVE: We sought to determine whether exposure to the 8-month Antarctic winter-over model of spaceflight would alter human antibody responses. METHODS: During the 1999 Australian National Antarctic Research Expeditions, 11 adult study subjects at Casey, Antarctica, and 7 control subjects at Macquarie Island, sub-Antarctica, received primary and secondary immunizations with the T cell-dependent neoantigen bacteriophage phi X-174. Periodic plasma samples were analyzed for specific antibody function. RESULTS: All of the subjects from Casey, Antarctica, cleared bacteriophage phi X-174 normally by 1 week after primary immunization, and all had normal primary and secondary antibody responses, including immunologic memory amplification and switch from IgM to IgG antibody production. One subject showed a high normal pattern, and one subject had a low normal pattern. The control subjects from Macquarie Island also had normal immune responses to bacteriophage phi X-174. CONCLUSIONS: These data do not support the hypothesis that de novo specific antibody responses of subjects become defective during the conditions of the Antarctic winter-over. Because the Antarctic winter-over model of spaceflight lacks the important factors of microgravity and solar radiation, caution must be used in interpreting these data to anticipate normal antibody responses in long-term spaceflight.

One year in Antarctica: mucosal immunity at three Australian stations.

The effect of a year's isolation in Antarctica on the human mucosal immune system was assessed during the winter of 1992 at three Australian Antarctic stations: Casey, Davis and Mawson. Saliva samples were collected from each expeditioner prior to their departure from Australia and during each month in Antarctica. The concentrations of salivary immunoglobulins IgA and IgG were significantly different between the three stations, but there were no differences for salivary IgM and albumin. The mean concentrations of IgA were higher at Mawson (P < 0.008), and the mean concentrations of IgG were lower at Davis (P < 0.001) compared with the other stations. Ranges of values observed at the stations over the 12-13 months were similar. The variability of values within individuals showed station differences for salivary IgM and IgG only. The study revealed significant changes in salivary immunoglobulin values over the period in Antarctica, with similar patterns at the three Australian stations. The salivary IgA and IgM levels were lower in the first 4 months in Antarctica (January-April) and increased to maximum values in July-August, before returning to mean levels when isolation was broken in October-November. The patterns of salivary IgA and IgM suggest that stressors due to isolation may play a role in alterations of mucosal immunity in expeditioners in Antarctica.

Is it really so bad? A comparison of positive and negative experiences in Antarctic winter stations.

This study examined the range of positive and negative themes reported by 104 Australian Antarctic winter personnel at four stations during two austral winters. Reports from the expeditioners were subjected to a content analysis using the TextSmart software from SPSS, Inc. Results indicated that, although the list of negative experiences is lengthy, most events are relatively rare. On the other hand, although the list of positive experiences is short, the frequencies with which they are reported are much greater than for most of the problems. Possible explanations for these themes and for future directions are discussed.

Psychological changes in hundred-day remote Antarctic field groups.

Psychological adaptation to extreme environments has been examined from several perspectives. In this study, two Australian teams, each consisting of six male crew members, completed computer-administered questionnaires twice weekly during 100-day traverses around the Lambert Glacier Basin, Antarctica. Only small trends were noted when data were aggregated at the group level, which is consistent with the findings of others. Data were then analyzed using pooled time-series regression. These analyses incorporated personality characteristics, environmental factors, and interpersonal factors as predictors of Group Tensions, Personal Morale, Emotional State, Cognitive Readiness, and the Team's Work Life. Most of the psychological discomfort and problems that occurred appeared to be within the individual or between individuals. They did not affect all members of the group equally.

The measurement of solar ultraviolet radiation.

High skin cancer rates, stratospheric ozone depletion and increased public interest and concern have resulted in a strong demand for solar ultraviolet radiation measurements and information. The Australian Radiation Laboratory (ARL) has been involved since the mid-1980s in the measurement of solar ultraviolet radiation (UVR) using spectroradiometers (SRM) and a network of broadband detectors at 18 sites in Australia and Antarctica and in Singapore through a collaborative agreement with the Singapore Institute of Science and Forensic Medicine. Measurement locations range from equatorial (Singapore, 1.3 degrees N) through tropical (Darwin, 12.4 degrees S) to polar (Mawson, 67.6 degrees S) and as a result there are many difficulties associated with maintenance and calibration of the network detectors, and transfer of data to ensure an accurate and reliable data collection. Calibration procedures for the various detectors involve the comparison with simultaneous spectral measurements using a portable SRM incorporating a double monochromator, calibrated against traceable standard lamps. Laboratory measurements of cosine response and responsivity are also made. Detectors are intercompared at the Yallambie site for a number of months before installation at another location. As an additional check on the calibrations, computer models of solar UVR at the earth's surface for days with clear sky and known ozone are compared with the UV radiometer measurements.

Telemedicine: have technological advances improved health care to remote Antarctic populations?

Telemedicine has been used in remote areas for decades. In recent years the information superhighway has been a catalyst for the rapid growth of telemedicine; development of new technologies; and proliferation of subspecialties, journals and abstracts, and centers for telemedicine law. It has further promoted conferences of clinicians and managers planning telemedicine to advance remote health care, as well as the generation of revenue from business opportunities. This "rediscovered" telemedicine is seen by many as the answer to the unavailability of professional health care in geographically isolated areas. Failures of some well established networks and the high costs of establishing and running others have stimulated calls for thorough evaluations to be made, especially of the use of appropriate technology rather than the latest and most sophisticated. I review here 50 years of telemedicine in Antarctica and make an assessment of its role in the improvement of health care services.

Antarctic isolation: immune and viral studies.

Stressful environmental conditions are a major determinant of immune reactivity. This effect is pronounced in Australian National Antarctic Research Expedition populations exposed to prolonged periods of isolation in the Antarctic. Alterations of T cell function, including depression of cutaneous delayed-type hypersensitivity responses and a peak 48.9% reduction of T cell proliferation to the mitogen phytohaemagglutinin, were documented during a 9-month period of isolation. T cell dysfunction was mediated by changes within the peripheral blood mononuclear cell compartment, including a paradoxical atypical monocytosis associated with altered production of inflammatory cytokines. There was a striking reduction in the production by peripheral blood mononuclear cells of the predominant pro-inflammatory monokine TNF-alpha and changes were also detected in the production of IL-1, IL-2, IL-6, IL-1ra and IL-10. Prolonged Antarctic isolation is also associated with altered latent herpesvirus homeostasis, including increased herpesvirus shedding and expansion of the polyclonal latent Epstein-Barr virus-infected B cell population. These findings have important long-term health implications.

Seasonal cutaneous immune responses in an Antarctic wintering group: no association with testosterone, vitamin D metabolite or anxiety score.

Immune function is modulated by a complex set of neuroendocrine factors including sex hormones, vitamin D metabolites and stress. Antarctic expeditioners exhibit reduced cell mediated immunity. Studies have also shown a reduction in testosterone levels in wintering expeditioners and suggested a correlation between levels of anxiety and reduced immune function in brief trip expeditioners. Nineteen male Antarctic expeditioners were followed by 3 monthly assessments of cell mediated immunity, levels of testosterone and vitamin D metabolite and psychological indicators of anxiety. There was a significant reduction in immune function during the study period, consistent with previous Antarctic studies. Levels of testosterone, anxiety and the immunoregulatory metabolite of vitamin D did not alter significantly. In this group the reduction in immune function did not show a correlation with levels of anxiety or the hormones studied.

Effect of seasonal ultraviolet radiation fluctuations on vitamin D homeostasis during an Antarctic expedition.

Antarctica is a unique and challenging environment where members of expeditions face a range of conditions not normally experienced. Ultraviolet (uv) radiation levels show marked variation during the year. The 25-hydroxy metabolite of vitamin D [25(OH)D] is largely produced by sunlight and shows a yearly variation in concentration that corresponds to uv radiation levels. The active metabolite 1,25-dihydroxyvitamin D [1,25(OH)2D] does not generally show any such variation provided 25(OH)D concentrations are sufficient. Previous studies have shown a seasonal variation in 25(OH)D with a significant winter drop. No other study of 1,25(OH)2D has been reported on members of Antarctic expeditions. A group of 19 men wintering at Davis Station (68 degrees 34' S) had four blood samples taken at 3-monthly intervals beginning in the Antarctic summer. Analysis for 25(OH)D showed a drop in concentration for each of the latter three sampling periods (P < 0.005). This correlated with uv radiation levels and would suggest that endogenous production of 25(OH)D ceases for at least the duration of the Antarctic winter. There were no significant alterations in 1,25(OH)2D or calcium concentrations over the same period. Providing that individuals with pre-existing vitamin D deficiencies are detected before departure for Antarctica and missions are limited in duration, clinical deficiency is unlikely to occur.

Cell mediated immunity in Antarctic wintering personnel; 1984-1992.

Cell-mediated immune responses were studied in 12 Antarctic and sub-Antarctic wintering groups at quarterly intervals over the period 1984-1992, using the cutaneous CMI Multitest. These populations are among the most isolated on earth. While the sub-Antarctic population at Macquarie Island had levels of responsiveness and hypoergy (9%) comparable to healthy populations in temperate zones, the Antarctic Continental group showed a level of hypoergy of 36%. There was no seasonal variation in the pattern of responses. It is concluded that the extreme and isolated environment and stress factors are responsible for the decreased immunological responsiveness but the mechanisms are presently unclear. On review, one factor appears to be perceived anxiety. The high rate of hypoergy in Antarctica, where medical care is limited, may have health implications. These groups provide an excellent analogue for immunological investigations in longer term space flight.

Immune responses during an Antarctic summer.

The immune status of 29 members of the Australian National Antarctic Research Expeditions (ANARE) was investigated before, during, and after a 56 day summer voyage to Antarctica and correlated with psychological and physiological parameters. All subjects were healthy. Expedition personnel demonstrated decreased cell mediated immune responses (CMI) assessed by the CMI Multi-test; 21% were hypoergic. The major associated observation was a significant negative correlation with anxiety in Antarctica. However, perceived anxiety was greater before and after the voyage. No significant changes were found in T and B lymphocyte subsets, immunoglobulin and complement components and cutaneous blood flow, nor was there any clinical evidence of illness. Of the hormones examined only cortisol was low predeparture which may reflect increased perceived anxiety at that time. Changes in immune control mechanism were apparent as shown by reduced CMI responses and lowered tetanus antibody levels. Stress factors are postulated to induce depression of the immune response in Antarctica. The association with anxiety suggests that brain peptides or associated cytokines may have a role in mediating these immune events. Such alterations in immune status have implications for health management in isolated and extreme conditions.

Cell-mediated immunity in healthy adults in Antarctica and the sub-Antarctic.

Cell-mediated immune responses were studied in 2 Antarctic and sub-Antarctic groups at quarterly intervals over a wintering year, using the cutaneous CMI Multitest. The sub-Antarctic population at Macquarie Island (M.I.) had levels of responsiveness and hypoergy comparable to other healthy populations in temperate regions. The Antarctic group at Mawson showed decreased scores and total number of positive responses to antigens, and a significantly elevated incidence of anergy and hypoergy. Quarterly skin testing showed considerable variability in subject responsiveness to specific antigens at different times over the year. However, only 2 antigens at M.I., trichophyton and proteus, showed a significant seasonal variation in score. There was no statistically significant seasonal variation in antigen scores at Mawson. It is concluded that environment and stress factors in Antarctic expeditions are responsible for the decreased immunological responsiveness.