The sixth volume in Space Biology and Medicine is a volume with contributors from all spacefaring nations. Although all space agencies must currently operate under server budgetary restraints, progress in the field of space biology and medicine continues. The preparations for the International Space Station, in which Russia is going to participate with the United States, Europe, Japan, and Canada, are also continuing. For the longer term, studies for a Lunar Station are in progress. The contributions to this volume are witness of all these activities.
Two chapters deal with the effects of weightlessness on the immune system. Taylor and colleagues review the effects in vivo, indicating a reduction of the immune function in space. The blunting of the immune function after short-term flights resembles that after acute stress on the ground, while long-term effects compare to those caused by chronic stress. Cogoli and Cogoli-Greuter describe studies on single cells, which show that proliferation and cytokine expression of T-lymphocytes are reduced in microgravity, possibly through a non-equilibrium thermodynamic effect.
Preparation for long-term space missions is the express purpose of four contributions in this volume. Kanas considers the usefulness of space simulation studies by means of extended isolation and confinement on Earth, and points to be examined in future projects of this kind. Volumes 3 and 5 in this series were dedicated to two ESA projects of this nature. Grigoriev and Egorov describe a medical monitoring system for long-term missions. Schwartzkopf reports on the design of life support systems using plant cultivation for food and oxygen regeneration, with particular reference to a future Lunar base. Wolf describes a small-scale bioregenerative system based on an algal bioreactor.
The use of medicinal drugs by astronauts is the subject of two chapters by Pavy-Le Traon, Saivin and colleagues. The resistance of bacteria to antibiotics can be changed in weightlessness, and no suitable drug against bone demineralisation in space is available. The pharmacokinetics of drugs is also changed, mainly due to the fluid shift in space. Smith and colleagues provide a comprehensive review of our present knowledge of the regulation of body fluid volume and electrolyte levels and the hormonal regulation mechanisms involved. The effects of weightlessness on the function of the vestibular system, which are the cause of space motion sickness in astronauts during the first week in space, are reviewed by Kornilova.
Finally there are two chapters on the effects of gravity on non-human creatures. Izumi-Kurotani describes behaviour and stature of frogs during spaceflight, as well as some histological and biochemical changes in organs and tissues after return to Earth. Merkys and Darginaviciene have studied the mechanism of the plant gravitropic response (spatial orientation along the gravity vector) in space an on Earth, and conclude that flows of calcium ions and the growth hormone indole acetic acid in opposite directions appear to be involved.