Low gravities and colonization. A show stopper? - Any suggestions apart from exercising?

karov · 2004-07-18 15:34:34

From the huge database collectec for human bodies in microgravity it appears that may be there is some kind of 'gravity sence' -- that`s why extensive excersises are not sufficient for sustaining normal phisiological condition in normal humanm body. Indeed it is assumed that gravity is 'feeled' by the body rather as pressure gradient in a bag filled with liquids. This 'feeling' may be is on cellular level. When the pressure gradient disappears, some mechanism in the body comands the calcium cycle to stop filling the bones.

This gives us another perspective -- if the calcium and muscle deteoration command (neurological/genetical?)mechanism is found and followed, than we could easily LIE the body on cellular level that it is in normal G, an has to keep the calcium levels in proper parameters.

This is the major point -- the lenght of the diurnal cycle, the orientation in the living space... everithing else is a matter of psychological training and conditioning, a thing in which even now we are good, without direct neurological interface or other 'fantastic' technologies...

dicktice · 2004-07-19 18:20:51

karov: Interesting.
re. your first paragraph, if the organism were a bag of sea water containing a live jellyfish and the necessary nutriants (instead of your bag filled with liquids) in microgravity, would the jellyfish survive without your "pressure gradiant"? Would the bag of water be a factor?
re. your second paragraph, I don't quite follow but with a little more explaination perhaps I shall.
re. I don't know about psychology overcoming the diurnal cycle (which I don't understand either) but I do know that when I miss a night's sleep, I just take a melatonin pill just before I want to sleep and my "body clock" drops right into synch again.
Please continue with your thoughts along these lines.

Shaun Barrett · 2004-07-20 07:56:20

Yes, Dicktice, the "train idea for g-conditioning is brilliant"!
To the best of my knowledge, Bill White was the first to suggest it. He claims he comes up with too many wacky ideas and worries about being ostracised for them. But wacky ideas are the life-blood of invention and I think Bill should never be afraid to speak up, even about the craziest ideas he gets!
His very next idea could be the 'next big thing' ... who knows?!

karov · 2004-07-20 10:06:38

karov: Interesting.
re. your first paragraph, if the organism were a bag of sea water containing a live jellyfish and the necessary nutriants (instead of your bag filled with liquids) in microgravity, would the jellyfish survive without your "pressure gradiant"? Would the bag of water be a factor?
re. your second paragraph, I don't quite follow but with a little more explaination perhaps I shall.
re. I don't know about psychology overcoming the diurnal cycle (which I don't understand either) but I do know that when I miss a night's sleep, I just take a melatonin pill just before I want to sleep and my "body clock" drops right into synch again.
Please continue with your thoughts along these lines.

-The land animals have in the most cases some vertical stance, even those who criple like the gators and snakes - at least evolved from vertebrate species opposing the gravity by muscle effort onto sceleton. The immediate scent of gravity comes, if you see at wikipedia, from the counteraction of the surface. The vertical stance makes the hydraulic presure gradient within the body to exist, because the different parts are in different hight. May be, some chemical mechanism within the body organisation, is responcible to react with the internal presure signals and to comand the body to loose or gain calcium in its bones. The body errect is namely the water bag. Less presure up, more down. Patients with long stay on beds loose calcium, because they lack the normal presure gradient within the body. That`s why, perhubs, the results between bed`s patients and real microgravity differ in important details.

- About the second paragraph -- it is connected indeed with your notion about the water animals -- the jellifish is not a vertebrate, but the fishes, cetaceans, some reptiles ARE swimming/ living in water vertebrates. The question is -- they actually live whole life in microgravity, cause of the buyoiancy exactly negates the gravity when the whole body is in water -- how these animals don`t loose they calcium andd muscles. Except extensive constant excercise, which honestly is not the answer, we should accept that certain genetic mechanism exists for regulation of the bone loss/gain cycle in water vertebrate organisms.
Hence, we have to understand exactly how the body 'understands' that it is not any more in vertical stance with internal presure gradient caused by gravity. After we follow all this mechanism, we could easily with medication or even transcribing some genes from , say, the dolfins, on say special even number service-chromosome as many times was proposed -- in order mature organisms to be reversibly conditioned...

...to LIE the machanism that the body is under 1 G and it should make it to keep the parameters of calcium cycle as on Earth...

This will give us every place -- from 0 G to some Gees over the earth level if such planets has solid surface, and if it is not more easier to produce artificial earth-like surface on 1 G hight.

- From that point - overcoming the physiological limits, it remains in the realms of the psychology the problems connected with the everyday living in different gravity, air presure, temperature, diurnal cycle... everything within the tolerability boundaries for humans. About the different diurnal cycle adaptation, you could see the numerous experiments for longtime cave dwelling -- the cycle tends to become different than the normal 24-hours, up to two times bigger or smaller... See also 'Arctic sindrome' about inhabiting the 6-month day/night cycle in the polar regions...

If we tame the body from trying to selfdestruct by homeostatic overmeasures, than as we know the brain is too programable -- after human 'hardware' is saved, the 'software' is easier.

EarthWolf · 2004-07-20 16:10:58

Hello,

I'm curious. I've heard of these centrifugal trains to keep people Earth-ready. But, how would you enter or leave these trains if these trains are constantly moving? Sorry, if this question seems inane.

Cordially,

EarthWolf

dicktice · 2004-07-20 16:39:16

Hello,
I'm curious. I've heard of these centrifugal trains to keep people Earth-ready. But, how would you enter or leave these trains if these trains are constantly moving? Sorry, if this question seems inane.
Cordially,
EarthWolf

Off the top of my head: Build a parallel track concentric with the first, for a separate railcar to start from a regular passenger station, match velocity with the gravity-train, transfer passengers and then return to the station. Voila!

dicktice · 2004-07-20 17:38:29

karov: I think you are saying that crawling vertebrates, like alligators and snakes, would deteriorate in orbit the same as us, since even their prone-height exposed to Earth's gravity is greater than cellular dimensions. That is too basic a problem to solve for my purpose which is to be able live and work in microgravity, right now. In other words, I guess I am looking for an engineering, rather than biological, solution to body conditioning in orbit.
I am not sure you if believe a jellyfish could survive within an ocean water environment in the absence of gravity. The gravity gradient must apply to bouyed as well as unbouyed organisms alike. You mention dolfins. Surely, they would deteriorate in orbit the same as scuba-equipped humans in a tank of water?
I doubt that our brain has the capability you suggest, to "fool" cells of the body into "thinking" a gravity-gradient exists where there is none. That must be at the level of the cellular machinery (accessible chemically, in theory, I admit) if what you suggest is true.
But, don't give up yet: We may still be able to think up some sort of engineering approach. At this early stage in orbital habitation planning, we are only a bunch of amateurs.

karov · 2004-07-21 04:11:40

karov: I think you are saying that crawling vertebrates, like alligators and snakes, would deteriorate in orbit the same as us, since even their prone-height exposed to Earth's gravity is greater than cellular dimensions. That is too basic a problem to solve for my purpose which is to be able live and work in microgravity, right now. In other words, I guess I am looking for an engineering, rather than biological, solution to body conditioning in orbit.
I am not sure you if believe a jellyfish could survive within an ocean water environment in the absence of gravity. The gravity gradient must apply to bouyed as well as unbouyed organisms alike. You mention dolfins. Surely, they would deteriorate in orbit the same as scuba-equipped humans in a tank of water?
I doubt that our brain has the capability you suggest, to "fool" cells of the body into "thinking" a gravity-gradient exists where there is none. That must be at the level of the cellular machinery (accessible chemically, in theory, I admit) if what you suggest is true.
But, don't give up yet: We may still be able to think up some sort of engineering approach. At this early stage in orbital habitation planning, we are only a bunch of amateurs.

We have quite well working 'engineering' solution to the microgravity issue -- the centrofuges. But you see they`ll be difficult and unconvenient to use omn low gravity bodies with atmosphere - I mean the discussed above part-of-a-cone centrifuges.

I never said the the brain could be lied to think that the body is in normal G when it is not. But psychollogical training should be sufficient to overcome and adapt to the necessary different ways of moving, diurnal cycles and so on. Off course the mechanism which comands the calcium exchange mechanism is on cellular level, out of the range of the neurological control. We have to tickle this regulatory system biochemically to force the body to pretend that it is in full G in order not to deteriorate.

All the walking vertebrates were designed to stay in 1 G -- even those who returned to crawling or swiming. So all they have the genetic set for developing enough of bones to stay. It just should be switched on or off in different programmed conditions.

We consider the humans as fully land animals, with deffinite vertical stance, hence the calcium mechanism is adjusted to keep the amount of calcium high enough. But, notice that all we were in water immersed state before birth. In prenatal state the baby has more soft and elastic bones in order to be able to pass. Put in gravity it rapidly switches on to harder bones and miscles regime. A mature human devoit of G -- in matter of months returns in prenatal state of muscle and bone tissue condition.

Perhubs the crawling and water vertebrates have another genetic/biochemical mechasnism to harden themseves without the intrinsic inbody presure gradient of the vertical stance land animals. WE, regarding the baby-phase should also have such. SO, bone-muscle loss regulator which activates in microgravity should be regulable with biochemical ( pharmaceutical or genetic transcriptional) mechanism, without to be necessary the excersise to be more intense than in the eveyday life.

Centrifuges are OK. This is the only way to produce earth-like environment in naked space, having in hand raw masterials and energy. The space colonies will rotate to produce ~1 G...

But in zero-G and lower-G places the inhabitants could be biochemically 'fooled' THEIR BODY to 'think' that it is not in pre-natal state and that the bone-muscle mass and quality should be preserved.

I think with the advance ( so fast !!! ) of the genomics and nanotechnology, my proposition if appear to be true is even more simple and cheap approach for solving the microgravity problem than to rotate each the habitats. Only the biggest ones of the space colonies -- with radius bigger than the 1 G troposphere hight ( between ~10 km up to ~2500 km - the theoretical maximum for the strongest materials )-- would be rotated in order to be provided really earth-like environment.

dicktice · 2004-07-21 10:15:53

I'm not prepared yet to draw conclusions: this is too much fun. The question of "vector" regarding gravity perhaps needs to be addressed first. For example, if you were able to walk on your hands for a month, with your feet in the air, would the bones in your spine maintain their strength? If you are held secure in a horizontal "bed" rotating about your height axis, will your bones deterioriate different, from inactivity, than if it were not rotating? I would say: not.
Now, reverting to the strategum of vibrating your body vertically for short periods between much longer bedridden periods, as has been posted not only by me in the past year of so: How does this cause recovery, if true, of deterioration due by the bedridden inactive periods? The essential vibration amplitudes, waveforms, frequencies or repetition rates, for were said to vary for diferent organisms, such a mice or turkeys, and not human subjects had been tried when I last looked into this. . . .
Have to go now.

karov · 2004-07-21 15:26:35

I'm not prepared yet to draw conclusions: this is too much fun. The question of "vector" regarding gravity perhaps needs to be addressed first. For example, if you were able to walk on your hands for a month, with your feet in the air, would the bones in your spine maintain their strength? If you are held secure in a horizontal "bed" rotating about your height axis, will your bones deterioriate different, from inactivity, than if it were not rotating? I would say: not.
Now, reverting to the strategum of vibrating your body vertically for short periods between much longer bedridden periods, as has been posted not only by me in the past year of so: How does this cause recovery, if true, of deterioration due by the bedridden inactive periods? The essential vibration amplitudes, waveforms, frequencies or repetition rates, for were said to vary for diferent organisms, such a mice or turkeys, and not human subjects had been tried when I last looked into this. . . .
Have to go now.

The 'vector sence' explanation about why the body deteriorate when is not in vertical position under G is just something that occured to me. I`m not so scientifically preapared in the field to be able to lead real argue ( I`m a lawyer ), but you understand my urge to share with you what came in my mind.

From other hand I don`t see any contradiction between your examples and what I ment. May be my poor and not skilled english is the reason - but:
-if you walk on hands the vector of gravity is still along the hight line of your body, but 'bottom-up' - your vascular system shall be very stressed because it evolved so the blood presure to be higher in the feet not the head. Indeed you will die as those hanged up-side-down -- it resembles microgravity effect of harmfull relative increase of the blood presure in the head where the vessels are thinner, but worse cause full G pumps the blood in the scull veins and arteries, and capilars...
-for the bed instance -- if the axis is vertical, the bed horisontal and the vector of centrifugal force pointing towards your feet, than indeed it is simulated gravity and your body will react as in 1 G ( + some dizzines from the Coriolis force...)
- about the vibration simulation + bedridding it should depend on the relation between the time lenght of the two regimes. Vertical vibration puts the body under force acting along the body hight the same way as the gravity. Bedridden the patient is not under such force, swinged - it is and recovers. Generally this resembles to the plain day/night cycle of sleep and vertical stance/walking. Too much bed + too less swing -- more bone/muscle loss than recovery...
-The specifics in the vibrations should depend on the shear size and hight ( along the force ) of the animal.
But constant force - centrifuging or real gravity is better.

My point is only that IT SEEMS that acceleration due to gravity or rotation with vector along the body`s hight is essencial for the calcium homeostatic mechanism in the bones to work properly. A body immersed in fluid or just on bed has no presure gradient due to acceleration and 'softens', vertically - 'hardens'.
The mentioned examples seem to confirm this.

Please, explain me why I`m wrong?

dicktice · 2004-07-21 17:15:56

korov: By "vector sense," I meant, by means of the hypothetical example of inverting the body, to illustrate that up and down regardless of position head to toe is what maintains the body's condition of strength on Earth.
Rotating the bed about the horizontal axis, was my other hypothetical example,to illustrate the same thing, parallel to the head/toe axis.
And, I have been recommending sleep periods in orbit (when cellular regeneration is supposed happen) strapped to a centrifuge bed with your head "up" and feet "down" to avoid bodily deterioration..
Still another means: vibration, has not in the popular press recently, so here is the lastest about that, newly Googled:

Cosmonaut shaken back to health
Roberto Vittori would love to go to Mars
By Dr Chris Riley
in Star City, Moscow
The Italian cosmonaut who flew with space tourist Mark Shuttleworth last month is completing an experiment that could have major implications for the way we treat osteoporosis sufferers.
Flight engineer Roberto Vittori is back at Star City near Moscow this week attempting to shake the strength back into his bones using a simple vibrating plate which he stands on to exercise.
Bone wastage is a big problem for anyone who spends even just a short time in orbit - and would certainly blight any manned trip to Mars unless researchers can find a way to counteract it.
Vittori's work should help doctors find the solutions they need to better prepare long-flight space crews. The experimental results should also feed back into the treatment of ordinary, osteoporotic people who live on the surface of the planet.
The BBC's Tomorrow's World programme will be discussing this story online on Wednesday, 15 May, at 1930 BST. Click here to join the forum.
New bone
Even in their short 10-day trip into space, the Soyuz crew's bone mass will have dropped by 0.3-0.6% - in a kind of accelerated ageing. And despite a rigorous exercise programme on board the International Space Station (ISS), the Expedition Four crew they have left on board could return to Earth next month after over five months in space with the first stages of osteoporosis.
Vittori at work: The experiment has big spin-offs
The long duration flights on Mir in the 1990s caused irreversible 20% bone loss in one cosmonaut.
Such levels of bone wasting are among the greatest stumbling blocks to a human flight to Mars, says Vittori, who hopes to be on a future Mars mission.
But if the vibration therapy being tested works, these potentially debilitating conditions incurred on long-duration space flights might soon be cured.
For just a few minutes a day for two months before the flight, Roberto trained on the plates which shake his leg bones at between 20 and 55 hertz. The vibrations create a so called "hypergravity" environment which seems to encourage new bone to grow.
Sheep and rats
"Bones are dynamic," says Filippo Ongaro, the European Space Agency doctor leading the study. "Osteoblasts build bone and osteoclasts destroy it. This happens in perfect balance most of the time on Earth - but in space the osteoblasts stop working and bone mass decreases," he explains.
Now he is back on Earth, Roberto's rehabilitation is being speeded up by training on the plates again. Ongaro thinks that the vibrations are triggering the osteoblasts to start working overtime again - replacing the bone lost in space.
Ironically, this discovery tumbled out of studies on the harmful effects of vibration on the body, when certain frequencies of shaking were found to have beneficial effects.
An attempt to impact the heel of a German cosmonaut on Mir to simulate the strains of walking for 10 minutes a day managed to fend off a 7% bone loss during a 140-day flight in 1995. And further studies on sheep and rats in the last year have shown just how much extra bone mass can be encouraged to grow by subjecting bones to vibrations.
Optimum frequency
This latest cosmonaut study comes off the back of a recent trial of the technique by Ongaro iwith 11 osteoporotic women in Rome.
Mark Shuttleworth ® is the control in the experiment
"We turned their bones from osteoporotic back to a healthy bone density in four months," declares Ongaro. "So we wanted to see if the technique could also help our astronauts, too."
Ongaro has found a way of selecting the optimum frequency for subjects by measuring the electrical output of the leg muscles during their exercise on the plates.
"The right vibration frequency seems to encourage extra muscular activity too, and when the muscles are working hardest that is the vibration frequency we apply to the bone. It turns out to be 30 hertz for Roberto."
New trials
He believes the shaking stimulates not only the bone, but muscles, blood vessel growth, and nervous system health as well.
Roberto's recovery will be compared with control subject Mark Shuttleworth, who flew the same mission length without the benefit of vibration therapy. These first experiments back on Earth will be followed by parabolic flights in the autumn to see if the technique works in microgravity, too.
If it still looks promising, the team hope to fly one of the plates up to the ISS next year - to fend off the effects of microgravity-induced osteoporosis for later crews.
Back on Earth, vibrations have already been used in Manchester, England, to strengthen the bones of children with cerebral palsy and a clinical trial of 200 osteoporotic women is about to begin in the United States.
Science on the BBC
See also:
05 May 02 | Sci/Tech
Space tourist returns to Earth
08 Aug 01 | Sci/Tech
Sheep yield osteoporosis clues
17 Dec 01 | Sci/Tech
Space workers get out of bed
Internet links:
Roberto Vittori (BBC)
National Osteoporosis Society
Roberto Vittori's Mission To The ISS
Osteoporosis (Nasa)
The BBC is not responsible for the content of external internet sites.

karov · 2004-07-22 05:24:57

Quote: "Bones are dynamic," says Filippo Ongaro, the European Space Agency doctor leading the study. "Osteoblasts build bone and osteoclasts destroy it. This happens in perfect balance most of the time on Earth - but in space the osteoblasts stop working and bone mass decreases," he explains.
=============================================
That`s it - what 'tells' the osteoblatsts to stop working in lower G? How the body 'understands' that it is in lower vertical-vector acceleration?

There should be a mechanism, a perceptors which percieves that the body is in micrtogravity and commands the osteoblast to decrease their activity. The detectors should be on cellular level. The osteoblast/osteoclast balance is chemical machinery. Biochemically it should be possible for regulation, without centrifuges, vibrating plates, etc. Biochemically 'fooling' the body that it is in full G, it shall keep the balance of build/destroy bone tissue as on Earth.

Just input in the bone balance receptors the falce, but necessary data.

Rxke · 2004-07-22 06:07:12

I don't understand why they didn't do the vibration excercise in orbit, where the body might benefit from it the most?
Maybe because they already did these kinds of experiments in Spacelab? It's probably quite a big machine to have around, and w/o the Shuttles...

Great stuff, anyhow.

karov: biochemical has the drawback of the need of extensive medical tests, before you can use it on humans, but the possible payback for a company developing an effective countermeasure would be huge, osteoporosis is a big problem, thus a potential goldmine for the pharmaceutical industry. Maybe Bigelows station will see the first big-scale experiments by private companies?

MarsDog · 2004-07-22 10:21:08

There are vibrators in armchairs, beds, and some barbers scalp massage with one.
There are motor driven vibrators, the belt goes around your waist.
Even the silent call alert in a cell phone has a small virator.
-
I am thinking of hooking up weighted solenoids to a large mosfet audio amp, and maybe a used washing machine motor to a piece of plywood, suspended from the ceiling. Would make an unusual music listening transducer bed.

dicktice · 2004-07-22 17:20:10

korov: By the way, did I mention that any lawyer interested in space exploration can't be all bad? Also, your English writing isn't anywhere near as bad as my writing in my own second lauguage, which happens to be Swedish.

dicktice · 2004-07-23 08:26:31

korov: My own snap judgement of the above "vibration therapy" experimental program is that it may duplicate the essential aspect of gravity to the extent needed to stimulate growth in the direction of the vibrational axis (vertical in this case) and that the steady-state we experience on Earth isn't actually necessary--that being the crux of the experimental technique. Frequency is selectively beneficial, whereby damage (the initial incentive for the investigation) is caused by random industrial vibrations, such as a jackhammer produces. The initial control experiments cleverly build upon the two space tourists who already have experienced weightlessness (and therefore bodily deteriation) in orbit: using one as the "guinea pig" and the other as the "control." It is too early for fullblown, in-orbit experiments yet. If this proves out, parabola-flight weightlessness simulations will still will be necessary to test the functioning of the flight-hardware in simulated microgravity conditions. In particular, how to strap the body upright onto the vibration plate may require a great number of flights, to get it right. Iam, in any case, greatly encouraged by the initiative shown by this international team of experimenters. It represents another example of how space research ultimately contributes to quality of life on Earth, as well as in orbit and beyond.

karov · 2004-07-24 20:12:00

korov: By the way, did I mention that any lawyer interested in space exploration can't be all bad? Also, your English writing isn't anywhere near as bad as my writing in my own second lauguage, which happens to be Swedish.

Thank you!

About the bad lawyers, I should defend myself and my colegues worldwide with the very humanistic notion, that:

Even now there are great money in the space. In the future - the next several centuries - almost every cent of the human economy will be off-earth.

I whis you luck!

karov · 2004-07-24 20:25:30

korov: My own snap judgement of the above "vibration therapy" experimental program is that it may duplicate the essential aspect of gravity to the extent needed to stimulate growth in the direction of the vibrational axis (vertical in this case) and that the steady-state we experience on Earth isn't actually necessary--that being the crux of the experimental technique. Frequency is selectively beneficial, whereby damage (the initial incentive for the investigation) is caused by random industrial vibrations, such as a jackhammer produces. The initial control experiments cleverly build upon the two space tourists who already have experienced weightlessness (and therefore bodily deteriation) in orbit: using one as the "guinea pig" and the other as the "control." It is too early for fullblown, in-orbit experiments yet. If this proves out, parabola-flight weightlessness simulations will still will be necessary to test the functioning of the flight-hardware in simulated microgravity conditions. In particular, how to strap the body upright onto the vibration plate may require a great number of flights, to get it right. Iam, in any case, greatly encouraged by the initiative shown by this international team of experimenters. It represents another example of how space research ultimately contributes to quality of life on Earth, as well as in orbit and beyond.

The situation is not new. Even in the martial arts there are two schools of thought which in great degree complement one another: external, 'hardware' one - pointed towards increasing the body strenght and internal, 'software' way to be harnessed the whole present potential of the body through 'mind-control'.
In the case of our low-G issue - the centrifuging of environments and upright cradles will be used as well as some ways of biochemical control of the osteoblast/osteoclast balance. AS you said the bone biochemical terapy is quite usefull here in 1 G to heal osteoporosis. The conventional medicine researches are just another way to achieve what I tryed to talkin' about.

Later after some google-ing I`ll post s.t. more about the 'internal', 'software' way or treating and preventing the harmfull effects of low-G on humans.

WE should be able to colonize all these many smaller round bodies in the Solar system and abroad, for Gods sake!!!

karov · 2004-07-26 03:41:26

Osteoblast/osteoclast differentiation:

http://www.blackwell-synergy.com/links/ … nks....abs
=============================================
..."6. Prospects for regenerative biology of bone
A. Biological: bone grafting, stem cell transplant, osteoinductive matrices (ceramics, collagen scaffold, biodegradable polymers), growth factors (BMP, FGF, TGF, IGF) B. Regional gene therapy: viral vectors (in vivo, ex vivo), DNA injection into fracture site with gene activated matrix" ... from:

http://ags.frycomm.com/handouts/2004/do … /troen.pdf
==============================================
ESPECIALLY ( as possible path from contra-bone loss-measures without external simulation of gravity, but biochemical way - via hormonal, ensime and imunological regulation intervention - of emulating that the body is under acceleration...):

- ..." The ratio of osteoblasts to osteoclasts is partially controlled by a complex hormonal system. Some of the hormones in this system, such as parathyroid hormone (PTH), control bone formation and destruction based on blood calcium levels. If calcium levels become too low, PTH works to stimulate osteoclasts. Conversely, calcitonin is released when blood calcium levels become too high, stimulating the osteoblasts. This simple hormonal system works by the principle of negative feedback. The osteoblast/osteoclast ratio is also controlled as a function of the loading and stresses on a bone. For instance, the femur (thigh bone) is very thick and strong (increased osteoblast activity) as a result of the high loads on it, whereas the wrist bones are much more delicate, as they rarely have high loads exerted on them."...
-----------------------------------------------------------
- ..."When in space, the complex balance of the skeletal system is disrupted. The much-reduced loading on portions of the skeletal system leads to a decrease in further bone formation. This yields a higher calcium level in the urine as excess minerals are excreted from the blood, triggering a hormonal reaction, increasing osteoclast activity and upsetting the balance between bone deposition and resorption. This causes a quick reduction in BMD, up to 2-9% in the first 2 weeks of flight."...
------------------------------------------------------------
-..."The exact physiological pathways by which this happens are unknown, but it has been theorized that differential fluid shear in the bone and reduced piezoelectric currents because of different loading in microgravity may cause a hormonal reaction.".., from:

http://paperairplane.mit.edu/16.423J/Sp … ...ug.html
==============================================
..."All other known physiological changes settle into a new stability after a few days or weeks, but there is no evidence that bone loss will stop after a certain point."..., from the last link!!!

The task, hence is: Follow comprehensivelly the hormonal machinery responsable for the bone regulation. Catch the input channel who 'tells' the calcuim homeostatic mechanism that the bones are in lower G. Feed the input piece of the regulatory chain with false "full-G" signals on biochemical level.

Regarding the cases of osteoporisis here on Earth where the osteoclasm predominates in otherwise normal external conditions, than it appears possible that OUT of the normal accelerational conditions ( in lower or zero G ) via biochemical "hacking" the body could be made to function as it is in normal G.

Again , my humble non-specialist`s oppinion is that the key should be in some perinatal gene-activation, when the body of the newborn is prepared for living in gravitated environment, after it spent the embrional phase with softer bones ( during and after their formation ) in order to be elastic enough to pass the narrow birth tunnel. This 'gene' is active untill the body is under gravity, acceleration, impacts - producing the proteins for the hormones responsible for normal osteoblast/osteoclast differentiation... and may be, reactivates in pre-natal mode when the body is in microgravity. Or simply the machine brakes down 'cause of genetic/hormonal disorder in younger humans or seizes work due to the aging, here on earth.

When invented such biochemical treatment: anti-osteoporosis 'pils' or direct vector-viral or other gene-trabscript method applied only over the bones of mature human organism; will give us, unchanged - the plethora of smaller worlds and the microgravity of the free-fall space for life-long habitation -- without to be necessary to create low-G human versions, adapted only to low G worlds and unable to visit the Earth and other heavly-pulling bodies. Centrifuging and upright cradles than will remain only as 'hardware' means of terraforming rotating colonies and for sports excersises.
++++++++++++++++++++++++++++++++++++++++++++++

A glimpse toward 'brute force' method of direct substitution of the osteoblast/osteoclast activity gives you the nanorobotical R&D works of R.Freitas and Zyvex corp. :

http://www.foresight.org/Nanomedicine/R … cytes.html
http://www.imm.org/Reports/Rep018.html] … ep018.html
http://www.zyvex.com/Publications/artic … vores.html

All these examples substitute and enchance the blood functions, but similar osteoclast/osteoblast cellular machine sustitute could be used to keep the basic-design human body off the deterioration in micro- or lower-G, by directly build up permanently the lost bone mass, retaining the calcium levels, as well.

dicktice · 2004-07-26 18:01:04

I don't agree with your wanting to tinkerwith the human (at least) genome for the purpose of living and reproducing somewhere over time and maintain Earth-normal body strength. Too risky too, for short-term convenience (so called) that are bound to propagate uncontrollably with time. Better, for those who intend to return to Earth (in any case, one-gee environments) to maintain their condition artificially by means of hardware. Those who remain where less gravity than one-gee is the norm, will become optimum in body strength I assume, and those whose occupations take them into microgravity conditions for extended periods will of course have to undergo the same (spaceshipworthy) devices and procedures. I'm inclined to believe that we, having come from the sea, have evolved such that our bodies (given time) will adapt to more as well as less than one-gee, naturally. We don't know enough to do the things you suggest before its time to colonize, and to hold up colonization while we do medical research into them first would just play into the hands of those oput there who don't really want to go "out there" anyway.

karov · 2004-07-27 09:06:14

I don`t agree that such low-G adaptation is feasible and the reverse full-g readaptation is more convenient, than the humans to be pharmaceutically or via regional ( bone ) gene terapy made to preserve their normal-g body strenght. Indeed our goal could be achieved with only tickling the highest level of bidy-structure regulation - ensimes+hormones, without goind deeper to tickle the chromosomes themselves. The human body has built-in mechanism to grow/loss bones&muscles, no genetic alteration is necessary to make the body to stay constantly in ready-for-full-earth-gravity osteo-state. Just ensure that there will be constant input of 1-G signals in the genetic-proteomical chain of the bone-regulator, and the body will retain its normal strenght EVERYWHERE !!!

Notice, what I mean in NO sense means to be modified the basic human genome, but as it is now all the humans to have the option to stay within the present continuum of a single genome space, hence - the human condition as it is to have full access - free of adaptational procedures - to each point of the human-habitable environments. If the body strenght is made to persists no matter what the ambient acceleration is, than one can live and go anywhere one wants. Say, a person born on Mars, could migrate on Titan , latter spend decades living&working in the microgravity of asteroides (+ some 1 G centrifuging in the earth-like resorts) and to retire on Earth, WITHOUT: to differ even in a single gene from the inheritance of its ancestors (i.e. from us), to need adaptation through sophisticated and time-consuming and health-hazardous and painfull measures, ONLY by retaining everywhere its original earthcompatible body ( bones&muscles) strenght; just like with little climatic and diurnal psichological accomodations - one could be born in Australa, migrate to Alaska, spend years on petrol platforms and retire in South Africa...

What you mean is based on the asumption that the humans will adapt in bone-condition to lower-g environments, say terraformed Luna or Mars, and than to go through full-g accomodation in order to visit Earth or Venus or 1 G rotating habitat. In the best cases this would take months if at all is possible, and highly would discourage home-returns even with the aid of the proposed by you 'hardware' devices ( wheelchairs, exosceletons? )... It is highly improbable that the basic human condition will act properly with lunar-g bones, and that it will be able to retain full-lifecycle functionality without further necessary changes.

I believe that anything that leads to separation of the mankind in 'gravitational races' shall be avoided.

Human beings remaining normal in abnormal sites is better, than humans becoming abnormal - adapted to abnormal places - and trying to reverse back to normality if one decide to visit the higher-G normal human planets.

All this , of course, is led by the assumption that it represents a virtue, to keep all our progeny within the boundaries of the present prototipe and the mankind itself as a whole to retain genetical unity. My idea is that in the future when we`ll have all the means to change at will our bodies and minds, at least small part of the post-humanity will remain traditionalist. Our species will become Infinity in diversity and techno-evolutional trends played, but this Infinity will contain smaller Infinity including the present humans and their favourite strategy: Don`t change your body, change the environment to fit you!

Rxke · 2004-07-27 11:04:48

problem with chemicals: how do you do the dosage in this case?

Too little: not effective enough, too much: unnecc. bone growth (wich is probably worse than osteoporosis...)

And... Some regions in the body metabolise faster than the rest, so chemicals might have effect locally, not 'whole-body' etc.

Phew, tricky. Thus interesting!

Again: *this* might be the gold mountain for business. Spin-offs for Earth will be a *huge* and steadily growing market. (with increasing life expectancy etc...)

karov · 2004-07-27 12:26:26

From Wikipedia:
=====================================
..."Osteocytes originate from osteoblasts which have migrated into and become trapped and surrounded by bone matrix which they themselves produce. The space which they occupy is known as a lacuna. Osteocytes have many processes which reach out to meet osteoblasts probably for the purposes of communication. Their functions include to varying degrees: formation of bone, matrix maintenance and calcium homeostasis. They possibly act as mechano-sensory receptors - regulating the bones response to stress."

==============================================
...more comments latter!

Rxke · 2004-07-27 12:38:31

BTW, from what i remember from the lessons i picked up as a freeloader at the medical dept. of the uni, fairly recent research seems to show that we build up our 'calcium reserve' in our bones in our younger years: so doing excercises or labour before your 20th year pays off tremendeously later in life.
Physicians are quite a bit concerned with the couch-potato culture of the younger generation (not kidding, they're afraid those people might get into trouble as early as in their 40's, and a 'bad diet' AND overweight doesn't help either.

Again (sorry 'bout the repeating) : this will be a *very* important branch of research, the coming years.

dicktice · 2004-07-27 18:32:13

karov: Very nicely put, regarding maintenance of "standard humans" away from Earth, and I tend to go along with you at least until my time is up and don't care any more--wish I could go on a little longer though, to see how it all comes out. But--and here is my connumdrum--if living on the moon at 1/6th-gee turns out to increase my (generically speaking) lifespan, I would most assuredly choose to stay and give up any thought of rever returning physically to Earth. (Remote presence, after all, is still feasible to and from there. I would be able to witness the expansion of humanity into space, which is all I've really ever wanted, anyway.
The lawyer meets the dreamer, eh?

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