medicina

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Medicine & Space     

have described elsewhere how the recent scientific discoveries of repeated mass extinctions due to small solar system bodies, and the archaeological findings of previous ecological catastrophes engendered by human overcrowding, notably at Easter Island, have made the colonization of space essential for human survival, let alone development. As a doctor, it is, of course, relevant to look at this most far-reaching development in human affairs frombio-medical point of view - there is indeed much to learn and gain from the long-term settlement of Space. 

Medical interest in the Humanization of Space centres around two main areas - the consequences, hazards, and adaptations to be made by the human organism to the new conditions ion the one hand, and industrial applications in the production of new treatments and therapies. In the early days, before any living organisms - apart from some highly secret Soviet dogs sent aloft in sounding rockets - had experienced spaceflight, there was no knowledge in the west, and much apprehension, about the capacity of humans to withstand the high G forces (acceleration), or weightlessness entailed in rocket trips to orbit. Some medical authorities felt that high acceleration would cause cardiac arrest, or coma, while the rapid arrival at micro-gravity was expected to lead to heart failure, and in the case of one authority, blindness due to loss of lubrication from the eye-socket. To answer these unknown, tele-instrumentation of animals, and then humans, was essential and led to considerable advances in medical technology. 

In the event, these dire scenarios failed to materialise. The main issues to date can be divided into those of short duration flights, such as in the Mercury, Gemini, Vostok, Apollo, and early Soyuz flights, of less than 30 days' duration, and the longer space station flights on Skylab, Salyut, and Mir. The first and major problem encountered in these short flights was that of "Space sickness". This occurs from an absence of stimulation to the semi-circular canals - the organs of balance inside the inner ear. These enable a cat, for example, to land on its feet, and a human to walk upright; when overstimulated, they cause sea-sickness, and the re-cycling of Chinese dinners at fairgrounds! Thus, in some ways, space sickness is a mirror image of motion sickness. About 40% of subjects experience this problem, usually as a form of exhaustion and nausea rather than outright vomiting. It lasts from 1 to 5 days, and training in centrifuges helps to identify the worst potential sufferers, and offers some prophylaxis. As we have seen, it has not prevented some pretty fancy footwork by Shuttle astronauts within hours of lift-off. Various treatments have and are being evaluated, ranging from drugs like cinnarizine to mental techniques such as Yoga. Adaptation takes place by bringing into play two other senses that help us in orientation - touch or propriception, in which we ascribe an arbitrary ground to the perceived surface beneath our feet, and sight. The brain seems to impose a set of co-ordinates upon its surroundings; upon entering another docked spacecraft, there is frequently a recrudescence of the space-sickness until the new habitat becomes familiar. The increase in the use of sight has an interesting and, for astronomers , a welcome side-effect. Several astronauts have noted an ability to pick up objects on Earth which,. theoretically well beyond their powers of resolution - for example, planes' vapour trails, and ships' engine wakes - as the song has it; "I can see for miles and miles and miles". This bodes well for future tourists, who will enjoy God's eye views of Earth
from one lounge, and the Heavens from a second lounge, deployed opposite the Earth room. More seriously, detecting and studying the earliest moments in the birth of hurricanes may be of great importance. 

The longer term effects of spaceflight came to light with the era of space stations., Skylab, Salyut, and Mir, and, with the tendency of 5-6 month stints by multinational crews on Mir, are being studied on both sexes and people of varying ages - 30 to55, and origins, including Americans and Europeans. The main areas involved are the heart and circulation, muscles, and skeleton. Over the first 6 weeks, the heart, subjected to micro-gravity, learns to work less hard, and eventually, reduces to one-third normal size - a testament to the remorseless struggle gravity imposes upon us. Fluids have a tendency to recycle from the legs to the "upper" regions of the body, resulting in a feeling of fullness in the head, and increased cycling of water and salts.

The real problem came on re-entry to Earth's gravity, where the severely deconditioned heart would experience failure. Early Russian cosmonauts had to be lifted out of their craft, and whisked off to recuperate in stretchers. The judicious use of increased fluids in the last three weeks of a mission, and the use of "Chibis" exercise suits has gone a long way to overcoming this situation, with the result that Romanenko was in better condition after his 12 month mission in the late 1980's than with his 4.5 month mission in 1979. The Russians fell that, as far as trips to Mars are concerned, the cardiovascular problems are soluble. Musculature and bone calcium mass are both reduced over long space missions, in proportion to their duration, and both result from lack of stress, be it gravitational or exercise - the same result occurs in immobility of Earth. Muscle mass can fall 10%on a six month trip, while body calcium is lost at about 1% per month (Skylab), Fears of possible fracture on re-entry have not thus far materialised , but worries about 2 year missions have led to intense study of these problems. Measures so far tried , with some success, include dietary, fluoridation, and rigorous exercise regimes, supplemented with elastic leggings and boots to increase the workload. For the longer term, one should realise that. as space habitats become larger, as they must do in order to support larger numbers for longer periods, - more imaginative sports and exercises will reduce the tedium of simple treadmill activity. Muscle powered flight, acrobatics, and ballet are only some of the activities which can be covered under the rubric of the more intimidating word "exercise". Dr Newt Gingrich, I understand, has altogether racier ideas in mind for his tourists! There are two other possible answers to this issue - firstly, artificial gravity, in which all or part of the habitat is spun at 1-2 revs per minute to produce centrifugal force as substitute for gravity, and, more intriguingly, electrostimulation of muscle groups and bones, with alpha rhythm induced sleep to obviate any discomfort. This last idea was described in Marshall T Savage's "The Millennial Project", and deserves serious study. The healing effect of electric fields on bone have long been known, and, under computer control, could surely be applied to this problem. More prosaically, hormone replacement therapy is now used by millions of women to strengthen ageing bones against future hip fractures, and is likely to offer a tried and tested preventive for the female colonists , at least. Exposure to solar and cosmic radiation is a potential long-term hazard, but is amenable to shielding by either lunar or asteroidal slag left over from mining, or even by water stored in an outer shell around the habitats of the future. Water, after all, is an bulky necessity of life, and will be readily available from comets, certain asteroids, many outer planets' satellites, and perhaps even the lunar South Pole; if we must have it, why not put it to dual use? The second principal medical issue I raised was the possibility of new manufactures in the new environment. Space offers the biochemist and manufacturer a hard vacuum, microgravity, free solar energy, quarantine conditions, and a limitless heat sink for industrial processes. Much work has been carried out on the Space shuttle and Mir space station into materials processing. In particular, the separation of complex chemicals such as hormones, antibodies, and proteins from a pre-existing "soup" by electrophoresis - the use of electric fields to attract charged molecules differentially - has been shown to yield products of exceptional purity and in great concentrations. The E.O.S (Electrophoretic Operations System) is at the stage where it is eligible for large scale operations once a space station and a cheap and reliable space transportation system comes into service. Approximately 40-50 useful pharmacological agents can be made to exceptional standards by E.O.S. of which the highly costly and controversial interferon for Multiple Sclerosis is but one. Purified vaccines for the former soviet health service were one example from Salyut 7. 

Perhaps one of the most exciting possibilities being investigated is a one-shot cure for diabetes. As readers know, diabetes results from a failure of the pancreas to manufacture the hormone Insulin; this leads to an overflow of sugar into the blood and urine, body wasting, and death in coma without treatment. As it is, Insulin injections provide at best an imperfect remedy, since long-term complications such as blindness, kidney failure, circulatory failure up to and including gangrene, strokes and heart disease are all hazards facing diabetics. Good control and obsessive attention to dietary detail help, but impose great burdens on many sufferers. 

Pancreatic transplants seem like an obvious answer, except that the pancreas is exceptionally difficult for surgical access ,as well as having all the handling qualities of blancmange! Quite apart from this, only the beta cells - 2% of the population of the pancreas, scattered about in "islands", are relevant to diabetes - the rest merely provides fodder for rejecting white cells. If a pure extract of beta cells in suspension could be injected by wide bore needle, perhaps these could colonize the patient's pancreas, and provide a one, or at least an infrequent, shot cure. 

Besides, the beat cells would be responsive to the normal control mechanisms, and the whole tedious business of regular testing and finicky diets be rendered obsolete. Tests by astronaut Charles Walker on the Shuttle in the 1980's demonstrated that beta cells could, in principle, be produced at 500 times greater yield, and with fivefold increase in purity over any comparable Earthbound process. Since the world boasts at least 50 million diabetics, whose cost, let alone suffering, is enormous, the ability to use third generation spaceships and an orbital manufacturing facility to bring these results back to earth on an industrial scale would surely justify the entire cost of human spaceflight thus far. This is far from being the only product relevant to medicine. New alloys, and large protein crystals,, grown in space, for characterization by X-ray diffraction techniques, will surely spell advances in many fields of medicine.,. The dreaded prions of B.S.E will surely need to be grown in large pure crystals for further study leading to the development of effective therapies if any of the dire predictions for that condition are even remotely true.

The isolated conditions of medical labs in Space would provide a useful layer of quarantine in the study of some of the deadliest viruses, as well, again, as the putative agents of B.S.E. More controversial experiments in genetic engineering may well be deemed safer at a distance from the human population! Thus biomedical work on the International Space Station,, as well, as paving the way for the development and colonization of space on the grand scale, as our future demands, will be of direct benefit to te health of millions here below. It is not too much, perhaps, to expect that revenues from biomedical research and applications will, along with tourism , electronics research and development, and energy generation, be a major driver in the development of cheap access to Space, and the opening up of new frontiers. 

One of our earliest myths, the Epic of Gilgamesh, tells of a hero's quest for Immortality, Wisdom, and Power. Significantly, even in those far-off days, it was to the gods of Heaven that Gilgamesh turned in his search. We are learning, in the conquest of Space, that he was correct. In summary, people have actually adapted to the alien weightless environment remarkably well, considering the early forebodings, and, moreover, have accomplished much work, physical and mental, while aloft. Many have also acquired an enduring sense of the brotherhood of all peoples, and the precious fragility of our blue planet. For our future cultural and mental health, such lessons are surely worthwhile. The lack of metabolic demand by deconditioned hearts and muscles may well allow greater and more balanced development of our brains, eyes , and psyches in the new environment. Such thoughts at the moment are speculative, but, given Nature's known sense of economy and ability to convert wasted assets to new uses, and the demands of the new medium, make a good deal of sense. In retrospect, the early fears seem to have been overplayed - the strangeness and hazards of space are surely no worse than those faced by our marine ancestors. Forsaking the 3 billion year security of the Mother Ocean, they faced the burdens of gravity, solar radiation, dessiccation , and capricious climate on a hitherto barren land. The step was momentous, and doubtless many perished en route, but the road to the Infinite Ocean of the Cosmos required the relatively brief (300 million years') passage across the harsh and dangerous lands of earth. In the future, as human settlements become dispersed across the solar system, and later the galaxy, we may expect the human stock to diverge into new species. As with earlier radiations into unoccupied niches, it is likely that there will be a spurt, and that, in a few million years, we may have many evolutionary descendants from hominid stock, just as the earlier Proconsul ancestor apes have spawned whole families of ape and hominid species today. Some of these post-human species, by natural; selection, are likely to be well suited to their Cosmic environment, and may well have left behind some of our less attractive traits. Human improvement by evolution seems inherently more credible than improvement by ideology with political or religious coercion, which have all been tried with tragic results in the last few millennia. I cannot be sure that this would happen, but at least this route buys us time and a chance. Confinement to Earth would be a counsel of despair, since extinction is certain. If Man has any meaning at all, it is surely to be, as Nietzsche said" a rope stretched between ape and superman"; all our highest instincts, as shown in our earliest mythologies, as well as the latest discoveries of several sciences , shows that this road leads to the skies above. 

by Dr Michael Martin-Smith, 
President of Space Age Associates, 

http://www.astronist.demon.co.uk/index.html author of the book "Man Medicine and Space" to be published later this year in the USA by www.iuniverse.com, and published also in Italian as "Salto nello Spazio" by Giulio Gelibter, Tre Editori, 35 via Umberto, 00185 Roma, for 28,000 liras