Recent advances in medical research

Expeditioners are tested my medical staff in an extremely cold room prior to heading south
Testing expeditioners in the cold room at the AAD's Kingston headquarters before they head south (Photo: Glenn Jacobson)
An expeditioner takes a radio temperature pill to measure his deep core temperature

Thirty years ago Australian Antarctic Division (AAD) medical practitioners commenced the first immunological studies on the Australian National Antarctic Research Expeditions (ANARE). In the intervening years many research projects have been performed1,2,3 in collaborative studies between AAD and international and national universities and agencies.

One such recent collaboration, under the leadership of Professor William Shearer of Baylor College of Medicine, Houston, Texas, USA, saw doctors from AAD collect thousands of specimens of blood, cells, urine, and saliva from volunteers at all ANARE stations during winter 1999 for later processing at that institute, the University of Texas MD Anderson Cancer Center, Houston and the University of Washington, Seattle. Support for the study came from AAD and NASA through the National Space Biomedical Research Institute (NSBRI).

The eight-month total physical isolation at Casey was employed as an analogue for longer duration space flight and the T cell-dependent neo-antigen f X 174 bacteriophage was used to determine if this isolation would alter human antibody responses. Macquarie Island subjects were used as a control group.

Bacteriophage f X 174 is a virus which infects bacteria but which does not replicate or cause illness in humans. It can induce antibody responses in humans and over the past 30 years has been used to identify abnormalities in the primary (IgM) and secondary (IgG) antibody responses in immunodeficient and immunosuppressed patients.

All the subjects at Casey cleared the bacteriophage normally by one week after primary immunization and all had normal primary and secondary antibody responses, including immunologic memory amplification and a switch from IgM to IgG antibody production. The data did not support the hypothesis that de novo antibody responses of subjects become defective during conditions of winter in Antarctica4. This is an important finding for Antarctic expeditions as, although no disease could be associated with altered immune changes in ANARE groups in the past5,6 such immune changes may have important long-term health implications.

Mucosal immunity studies were conducted at all ANARE continental stations in 1992 to address the concern that immuno-suppression may occur in expedition staff and be associated with the anecdotal observation of an increased incidence of infections in staff when winter isolation is broken. The study just published revealed significant changes in salivary immunoglobulin values over the period in Antarctica, with similar patterns at all three Australian stations. Immunoglobulin levels (IgA and IgM) were lower in the first four months in Antarctica, with increases to maximum values after midwinter, before returning to mean levels when isolation was broken and new expeditioners arrived. The pattern suggests that stressors due to isolation may play a role in alterations of mucosal immunity.

Further work is proceeding at all stations in 2001 on the role of environmental stressors (cold) in altered immune responses as well as into cold adaptation. This was made possible by the signing of a Cooperative Research and Development Agreement in April 2000 between the AAD and the United States Army Research Institute of Environmental Medicine (USARIEM) for long-term collaborative research into areas such as thermal physiology, cold climate clothing, stress and adaptation, predictive modelling, and the role of environmental stressors in altered immune responses.

The first studies under this new Agreement were performed in September/October 2000 in Hobart, when shortly before sailing south, 35 volunteers from the 2001 ANARE were exposed in a cold room at 5°C for 120 minutes while dressed only in underwear and a light paper smock (see photographs). Deep core temperature of each was collected via a radio temperature pill and stored in a small data logger. Skin temperatures were measured with thermistors attached to the chest, arms, and thighs and connected to an continuous monitoring system. Rate of oxygen uptake was determined every 20 minutes during the 120 minutes cold stress test and samples of blood were taken for assay of factors such as catecholamines, vasopressin, anti-diuretic hormone, immunoglobulins, neuropeptides and melatonin.

The purposes of this protocol are:

  1. to quantify shivering thermogenesis associated with deep core temperature and specific skin temperatures during a standardised cold stress test, prior to and following an Antarctic expedition;
  2. to confirm if there is a reduction in specific cytokines during prolonged Antarctic exposure. A major goal is to document whether such changes have a direct association with depressed thermoregulatory responses following prolonged Antarctic exposure;
  3. to develop specific algorithms applicable for the cold acclimatised state that can be used to validate cold stress prediction models.

The results of the pre-departure phase of this study have already been accepted for presentation at the International Thermal Physiology Symposium in Wollongong in September 2001.

Monthly blood collections are currently in progress at all four stations, and a repeat of the cold room stress test will be conducted on the volunteers when they return to Australia in early 2002.

DJ Lugg and P Sullivan
Polar Medicine,
Australian Antarctic Division

References

  1. Lugg DJ. ANARE Medical Research: what did happen to all those specimens, Doc? In: Proceedings of the ANARE Jubilee Science Symposium, Hobart, July 1997. In Press.
  2. Lugg DJ, Shepanek M. Space analogue studies in Antarctica. Acta Astronautica 1999; 44: 693-699.
  3. Muller HK, Lugg DJ, Quinn D. Cell mediated immunity in Antarctic personnel: 1984-1992. Immunol Cell Biol 1995; 73: 316-320.
  4. Shearer WT, Lugg DJ, Rosenblat HM, Nickolls PM, Sharp RM, Reuben JM, Ochs HD. Antibody responses to bacteriophage f X 174 in humans exposed to the Antarctic winter-over model of space flight. J Allergy Clin Immunol 2001; 107: 160-164.
  5. Tingate TR, Lugg DJ, Muller HK, Stowe RT, Pierson DL. Antarctic isolation: immune and viral studies. Immunol Cell Biol 1997; 75: 275-283.
  6. Mehta SK, Pierson DL, Cooley HN, Dubow R, Lugg DJ. Epstein-Barr reactivation associated with diminished cell-mediated immunity in Antarctic expeditioners. J Med Virol 2000; 61: 235-240.
  7. Gleeson M, Francis JL, Lugg DJ, Clancy RL, Ayton JM, Reynolds JA, McConnell CA. A year in Antarctica: mucosal immunity at three Australian stations. Immunol Cell Biol 2000; 78: 616-622.
This page was last modified on 20 March 2001.