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oemBiology oemBiology
wrote...
Posts: 1245
7 years ago
Referring to following video, I would like to know on how our body repair crystalline lens from UV rays and what kind of body reaction responds to UV rays.

Does anyone have any suggestions?
Thanks in advance for any suggestions


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wrote...
Valued Member
Educator
7 years ago
Interesting video, I love the graphics.

I don't think the lens is repairable, which is the reason it becomes cloudy and cataracts form.

http://rstb.royalsocietypublishing.org/content/366/1568/1278

Quote
Cataract is a visible opacity in the lens substance, which, when located on the visual axis, leads to visual loss. Age-related cataract is a cause of blindness on a global scale involving genetic and environmental influences. With ageing, lens proteins undergo non-enzymatic, post-translational modification and the accumulation of fluorescent chromophores, increasing susceptibility to oxidation and cross-linking and increased light-scatter. Because the human lens grows throughout life, the lens core is exposed for a longer period to such influences and the risk of oxidative damage increases in the fourth decade when a barrier to the transport of glutathione forms around the lens nucleus. Consequently, as the lens ages, its transparency falls and the nucleus becomes more rigid, resisting the change in shape necessary for accommodation. This is the basis of presbyopia. In some individuals, the steady accumulation of chromophores and complex, insoluble crystallin aggregates in the lens nucleus leads to the formation of a brown nuclear cataract. The process is homogeneous and the affected lens fibres retain their gross morphology. Cortical opacities are due to changes in membrane permeability and enzyme function and shear-stress damage to lens fibres with continued accommodative effort. Unlike nuclear cataract, progression is intermittent, stepwise and non-uniform.

For your next question, you want to know how UV rays generally interact with our body?
oemBiology Author
wrote...
7 years ago

For your next question, you want to know how UV rays generally interact with our body?

When UV rays attack our body, such as eye and skin, our body would trigger any chemical reactions to repair our cells.  There are so many chemical reactions within our body during sunbathe / sunburn, let take one example of vitamin D,  do you have any suggestions on which parts of body generate vitamin D and how the process relates between Sunbathe and vitamin D?

Thank you very much for any suggestions :>

wrote...
Valued Member
Educator
7 years ago
I do know that vitamin D is generated by the second layer of our skin and that repeated exposure to UV generates melanin, to prevent further sunburn for example... will comment further on this tomorrow
wrote...
7 years ago
Light-tissue interactions

Like sunlight on water, UV, visible and IR radiation can be partially reflected from the outer surface of the skin and eyes, and as it penetrates the tissue it can be scattered in various directions (including backwards) from microscopic particles and structures such as fibers (e.g., present in the dermis of the skin). In the tissue, radiation may also be absorbed by various molecules. In comparison to UV and long-wavelength IR radiation, visible radiation is generally not strongly absorbed by the bulk tissue, but it is strongly absorbed by certain components like pigments and blood. The net result of backscattered and absorbed visible radiation determines skin color, the white of our eyes, and the multi-colored irises that we see (too little light re-emerges from the pupil, except on photographs taken with a strong flash light directed straight into the eyes). The long-wavelength IR radiation is not scattered but strongly absorbed by water – the main constituent of soft tissues – and this contributes to the heat sensation when the skin is exposed to sunlight. Ultraviolet radiation, especially with short wavelengths, is strongly absorbed by bulk tissue, i.e. by organic molecules like proteins, lipids and DNA. Most of the UV-B radiation is therefore absorbed in the outermost superficial layer (the epidermis of the skin). The absorbed energy from UV radiation is not only converted into ‘heat’ (i.e. thermal energy from increased movement of molecules), as is the case with IR radiation, but it can also drive photochemical reactions. In the eye, visible radiation is absorbed by special photo-pigments that trigger electrochemical stimuli to optical nerves, enabling us to see, but potentially also mediating adverse effects.

With a few exceptions (most notably the formation of pre-vitamin D3), most photochemical reactions caused by UV radiation in the skin and eyes are detrimental: proteins and DNA become damaged and dysfunctional, either by directly absorbing UV radiation or by being damaged through an intermediary step, such as reactive oxygen species generated from another UV-absorbing molecule. Hence, UV radiation can be considered harmful. Overly damaged cells will die and disassemble in a well-orchestrated manner (a process dubbed apoptosis). Large numbers of cells in apoptosis may cause notable defects that literally surface after a few days in a process we know as ‘peeling’. Fortunately, our skin is well adapted to UV-induced damage which also arises upon exposure to the sun. Cells react, alarm signals are produced (i.e. stress responses mediated through cascades of molecular reactions), and the damaged molecules and cells are repaired or replaced. The UV-induced damage and alarm signals can evoke an inflammatory reaction (attracting immune cells from the blood to the site of the toxic insult) as part of a normal sunburn reaction in the skin, or snow blindness (or welder’s flash) in the eyes (the redness is caused by widening of superficial blood vessels, and some swelling occurs because of a higher permeability of the vessel walls facilitating the trafficking of white blood cells). In some cases such sunburn reactions may already arise after extremely low UV exposures, revealing an enhanced UV toxicity. Alternatively abnormal allergy-like skin reactions may occur, indicating a pathologic immune response to UV exposures.
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When you like a flower, you just pluck it out.
But when you love a flower, you water it daily.
The one who understands this, understands life.

- That's the difference between I like you and I love you.
oemBiology Author
wrote...
7 years ago Edited: 7 years ago, oem7110
I would like to know on how long our body takes to generate vitamin D3 within our body, since vitamin D deficiency can cause serotonin levels in the brain to drop, which is one potential contributor to depression.

If I take a sunbath, how long does it take to raise the serotonin levels within my body in general?

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>


"Vitamin D3 is one of the most useful nutritional tools we have at our disposal for improving overall health. This vitamin is unique because cholecalciferol (Vitamin D3) is a vitamin derived from 7-dehyrocholesterol; however, Vitamin D3 acquires hormone-like actions when cholecalciferol (Vitamin D3) is converted to 1,25-dihydroxy Vitamin D3 (Calcitriol) by the liver and kidneys. As a hormone, Calcitriol controls phosphorus, calcium, and bone metabolism and neuromuscular function. Vitamin D3 is the only vitamin the body can manufacture from sunlight (UVB)."

http://www.vrp.com/bone-and-joint/vitamin-d3-higher-doses-reduce-risk-of-common-health-concerns

"Vitamin D activates genes in your body responsible for the release of neurotransmitters, including serotonin, according to James M. Greenblatt, M.D., writing for the Psychology Today website. A vitamin D deficiency can cause serotonin levels in the brain to drop, which is one potential contributor to depression, Greenblatt notes. Increasing intake of vitamin D can help boost serotonin production. Milk, cheese, other dairy foods and mushrooms are good sources of vitamin D. Getting some unprotected sun exposure will also raise vitamin D levels, but always ask your doctor how much time you should spend in the sun without protection."

http://www.livestrong.com/article/286759-vitamins-that-increase-serotonin/
Post Merge: 7 years ago

If I take a sunbath, how long does vitamin D3 take to raise the serotonin levels within my body in general?

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>
wrote...
Valued Member
Educator
7 years ago
It's *extremely hard* to put a time frame on how quickly enzymes convert their reactants into products. Many factors play a role in the speed of this sort of reaction, namely a person's diet, as that determines if the subject has all the appropriate coenzymes, etc. for the enzymes to work correctly and efficiently.

oemBiology Author
wrote...
7 years ago Edited: 7 years ago, oem7110
Based on the following chemical reactions,
  • when 7-dehydrocholesterol converts into cholecalciferol (vitamin D3), does it release H-bonding (+ charge) to body?
  • when 25-hydroxyvitamin D converts into 1,25-dihydroxyvitamin D2, does it take OH-bonding (-charge) from body?

If yes, during above processes, body is losing electron and generating free radicals, would it be correct?

Furthermore, there is a missing link on chemical reactions between vitamin D3 and serotonin and how vitamin D3 raise the serotonin levels within my body.

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>
Post Merge: 7 years ago

Quote
With a few exceptions (most notably the formation of pre-vitamin D3), most photochemical reactions caused by UV radiation in the skin and eyes are detrimental: proteins and DNA become damaged and dysfunctional, either by directly absorbing UV radiation or by being damaged through an intermediary step, such as reactive oxygen species generated from another UV-absorbing molecule.

During the photochemical reactions, referring to following statement, I would like to know on whether blue light is better than red light on formation of pre-vitamin D3.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>


"Forget about red for seasonal affective disorder light therapy. White and blue are better for SAD ...
It's clear that whether blue light is better than green light is better than white light as the best light therapy still needs more research to determine...
They're free from UV light, which is absolutely critical in choosing a light box for SAD...

In the meantime however, just do something about your seasonal depression! "
http://www.sleeppassport.com/best-light-therapy.html
wrote...
Valued Member
Educator
7 years ago
Based on the following chemical reactions,
when 7-dehydrocholesterol converts into cholecalciferol (vitamin D3), does it release H-bonding (+ charge) to body?
when 25-hydroxyvitamin D converts into 1,25-dihydroxyvitamin D2, does it take OH-bonding (-charge) from body?

If yes, during above processes, body is losing electron and generating free radicals, would it be correct?

Check this out: https://books.google.ca/books?id=VS9YWqnMpNsC&pg=PA167&lpg=PA167&dq=7-dehydrocholesterol+converts+into+cholecalciferol&source=bl&ots=vc7l5d5p7J&sig=Enf1Y5r_RavoWcE7EnzlmonSZU0&hl=en&sa=X&ved=0ahUKEwjOlvWmyJHMAhWJlIMKHX45CT4Q6AEINjAE#v=onepage&q&f=false

If yes, during above processes, body is losing electron and generating free radicals, would it be correct?

Losing H+ doesn't lead to free-radicals. Hydrogen ions are almost infinitely abundant everywhere inside of us.

Quote
Furthermore, there is a missing link on chemical reactions between vitamin D3 and serotonin and how vitamin D3 raise the serotonin levels within my body.

There might actually be a link:

Keycap Digit One http://www.ncbi.nlm.nih.gov/pubmed/25713056

Keycap Digit Two https://www.sciencedaily.com/releases/2015/02/150225094109.htm
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oemBiology Author
wrote...
7 years ago Edited: 7 years ago, oem7110



Referring to above image, during the photochemical reactions, I would like to confirm on whether blue light (UVB) is better than red light on formation of pre-vitamin D3 or not, so there is no formation of pre-vitamin D3 during sunrise and sunset period when we take a sunbath.

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>
wrote...
7 years ago
Wouldn't it be neither?

UVB is required for the conversion, not visible light. Correct me if I'm wrong Face with Rolling Eyes
When you like a flower, you just pluck it out.
But when you love a flower, you water it daily.
The one who understands this, understands life.

- That's the difference between I like you and I love you.
wrote...
Valued Member
Educator
7 years ago
Found this on Wikipedia:

Vitamin D3 is produced photochemically from 7-dehydrocholesterol in the skin of most vertebrate animals, including humans. The precursor of vitamin D3, 7-dehydrocholesterol is produced in relatively large quantities. 7-Dehydrocholesterol reacts with UVB light at wavelengths between 270 and 300 nm, with peak synthesis occurring between 295 and 297 nm. These wavelengths are present in sunlight, as well as in the light emitted by the UV lamps in tanning beds (which produce ultraviolet primarily in the UVA spectrum, but typically produce 4% to 10% of the total UV emissions as UVB). Exposure to light through windows is insufficient because glass almost completely blocks UVB light.

Adequate amounts of vitamin D can be produced with moderate sun exposure to the face, arms and legs, averaging 5–30 minutes twice per week, or approximately 25% of the time for minimal sunburn. The darker the skin, and the weaker the sunlight, the more minutes of exposure are needed. Vitamin D overdose is impossible from UV exposure; the skin reaches an equilibrium where the vitamin degrades as fast as it is created.

https://en.wikipedia.org/wiki/Vitamin_D
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