LIGHT SCIENCES - PART 2

In this image below, we can see that the visible range of light to the human eye is only a small portion of the entire spectrum of light. Think of it.....all those millions of colors that we DO see.......but so many more lights that we do not. Light, however, can be dangerous to us, in the form of variant radiations. Once we start climbing into the range of Gamma radiations, and then lower into the Microwave range, it can then become highly "mutating" to the system.

The argon pumped tunable dye laser (A.P.T.D.L.) is a liquid medium laser that can be "tuned" to generate wavelengths of coherent light desirable for the treatment of skin lesions. An ionized gas (argon) laser is used to "pump" the liquid medium to generate a continuous laser beam output. This is in distinction to "pulsed" dye lasers that are pumped by intense flash lamps, and generate a pulsed mode output.

Current Application Of The Argon Pumped Tunable Dye Lasers:
I. Vascular Skin Lesions
Port Wine Stain
Telagiectasias
Spider Ectasia
Chronic Radiation Dermatitis
CRST3
Hereditary Hemorrhagic
Telangiectasia
Rosacea
Cherry Angiomas
Angiokeratomas
Venous Lake4
Glomus Tumors

II. Pigmented Skin Lesions:
Café-au-lait Spots
Lentigines
Nevus of Ota5

Most face and trunk telangiectasias including spider angiomas respond extremely well to tunable dye laser therapy. Tunable dye laser treatment has also been shown to improve the telangiectasias and erythematous component of rosacea.

Ultra-Violet Light
In Europe and North America, there's a mid-March peak in "schizophrenic births" - babies who grow up to develop schizophrenia. Up to 10 per cent more are born between February and April than in any other three-month period of the year. That might not sound like a lot, but with an estimated 60 million cases of schizophrenia worldwide, a 10 per cent seasonal increase represents a huge amount of additional suffering. What's more, most studies suggest that season of birth accounts for more cases of schizophrenia than almost any other known risk factor - including a person's genetic heritage. The only risk factor worse than a spring birth is being born in a city.

Now, an Australian psychiatrist believes he has cracked it. According to John McGrath of the Queensland Centre for Schizophrenia Research in Brisbane, all the evidence suggests that a lack of UV light during pregnancy is the key to the spring peak in schizophrenic births. If his controversial hunch is right, we may one day be able to stop schizophrenia in the womb, before it begins. And we might, just might, be able to do it with nothing more sophisticated than vitamin supplements or a sunlamp In the southern hemisphere, people tend to live closer to the equator than in the northern hemisphere. "To reach the latitudes inhabited by northern Europeans," says McGrath, "you have to go to the southern tip of South America." When McGrath and Welham pooled data from 170,000 people with schizophrenia living in the northern hemisphere, the seasonal peak in schizophrenic births grew bigger the further north they went Differences in UV light could explain the lack of a seasonal birth effect in the southern hemisphere, says McGrath. Besides the fact that people tend to live closer to the equator on that side of the world, the southern hemisphere also gets about 15 per cent more UV light than equivalent latitudes in the north, thanks to a combination of factors, including the relative lack of pollution and the position of the Earth relative to the Sun. A lack of UV light could even explain those bizarre correlations between schizophrenic births, Brazilian rainfall, and the El Nino effect in Queensland: rain means cloud, and cloud soaks up UV like a sponge.

The next question was how a lack of UV light could so alter the course of a baby's development that years later she would develop a disease as devastating as schizophrenia. Besides giving you a tan, UV light has another major impact on the body - it converts a cholesterol-like molecule in the skin to vitamin D.

At first glance, vitamin D, best know for its role in building healthy bones, seems like a feeble candidate for triggering a brain disease. But the circumstantial evidence compelled McGrath to take a second look. It turns out that a surprisingly large number of women are deficient in vitamin D - about 12 per cent among 20 to 39-year-olds, according to a large US survey. What's more, harking back to that urban birth risk factor for schizophrenia, city women are more likely to be vitamin D deficient than their country cousins. Finally, Afro-Caribbean immigrants to England and Surinamese immigrants to Holland have between three and four times the number of schizophrenic births than other populations in the same areas - and because of their dark skin, they are more likely to run low on vitamin D.

Seasonal Affective Disorder:(SAD's):
Some people experience an exaggerated form of these symptoms. Their depression and lack of energy become debilitating. Work and relationships suffer. This condition, known as Seasonal Affective Disorder (SAD) may affect over 10 million Americans while the milder, "Winter Blues" may affect a larger number of individuals.

The typical symptoms of SAD include depression, lack of energy, increased need for sleep, a craving for sweets and weight gain. Symptoms begin in the fall, peak in the winter and usually resolve in the spring. Some individuals experience great bursts of energy and creativity in the spring or early summer. Susceptible individuals who work in buildings without windows may experience SAD-type symptoms at any time of year. Some people with SAD have mild or occasionally severe periods of mania during the spring or summer. If the symptoms are mild, no treatment may be necessary. If they are problematic, then a mood stabilizer such as Lithium might be considered. There is a smaller group of individuals who suffer from summer depression. SAD is recognized in the DSM-IV (The American Psychiatric Association's diagnostic manual) as a subtype of major depressive episode. The classic major depression involves decreased appetite, decreased sleep, and often, poor appetite and weight loss. It has long been recognized that some depressed individuals had a "atypical depression" with increased sleep and appetite along with decreased energy. Some, but not all of these atypical individuals also had a seasonal pattern. Some people with winter depression also have mild or occasionally severe manic mood swings in the spring and summer. If these episodes are severe, the individual might be diagnosed with Bipolar Disorder. (formerly called manic depressive illness) Theories about how light affects mood and sleep.

In 1984, a psychiatrist at NIMH, Norman Rosenthal, published a paper on the use of bright light therapy in patients with this disorder. Since then, a large number of well-designed studies have confirmed and refined these findings. Researchers are still investigating mode by which bright light can lift depression or reset a sleep cycle. One theory is that an area of the brain, near the visual pathway, the suprachiasmatic nucleus responds to light by sending out a signal to suppress the secretion of a hormone called melatonin. Brain studies suggest that there is impairment serotonin function in neurons leading to the suprachiasmatic nucleus.

Initial theories suggested a pathway from the retina to the suprachiasmatic nucleus. However some recent research indicated that bright light applied to the back of an individual's knee could shift human circadian rhythms. (Daily sleep-wake cycle) This suggests that the bloodstream, not just the neurons of the visual pathways, might mediate the biological clock.

Light Sciences - Part 1

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