Vision consequences

Retinoid acid is a transcription factor. Retinoids play significant roles in dermatology, in the prevention of some cancers, and in the chemistry of vision. Consequently, many works have been dedicated to fluorinated analogues of retinoids. 

With regard to choice and consumption of food, all human sensory perceptions are involved. Among them, vision is the most important one for selecting food and appreciating its quality. Color is an intrinsic property of food. A color change of food often is caused by a quality change. Consumers are attracted by the color of a food product. This imphes three main consequences for food producers ... 

Thus far in this book we have discussed one- or two-component photochemical systems which because of their relative simplicity lend themselves quite well to laboratory study. Consequently the mechanisms of many of the photoreactions we have discussed have been elucidated in exquisite detail. As we turn our attention in this chapter to some photochemical aspects of living systems, we shall find much more complex situations in which mechanistic details are just now beginning to be obtained. In some systems, such as those which exhibit phototaxis or phototropism, so little is known that our treatment must as a consequence be limited to only a brief discussion of these phenomena. The topics we will consider here are photosynthesis, vision, phototaxis and phototropism, and damage and subsequent repair of damage by light. Due to space limitations, a discussion of the very fascinating area of bioluminescence must be omitted. 

Increases in the concentration of calcium in the cytosol provides a signal that can initiate muscle contraction, vision, and other signaling pathways. The response depends on the cell type. In muscle, a transient rise in the cytosolic calcium levels (from opening calcium channels in the sarcoplasmic reticulum) causes contraction. This signaling in contraction is a direct consequence of electrical activation of the voltage-gated channel. 

The great majority of untreated galactosemic subjects who survive more than a few weeks develop lenticular cataracts. These first appear as a faint milkiness of the anterior capsule of the lens between the fourth and eighth week. Opacity of the lens increases rapidly unless the infant is fed a galactose-free diet. On such a diet, early cataracts regress but rarely vanish completely, though in the best cases vision is little affected (B16, B19, H10, K13, W4). If treatment has been delayed and, in consequence,... 

This vision cannot wait. Mankind is facing several major energy-related challenges this century the threat and consequences of climate change, the reconcentration of crude-oil production in the Middle East, and the energy price risks of peaking oil production. 

One aspect to be addressed in order to obtain a realistic vision of the toxicity of these kinds of compounds is their environmental behaviour. Surfactants tend to be adsorbed on particulate matter and thus subsequently to sediment. Consequently, the highest surfactant concentrations are found in sediments, although their distribution is dependent on the partitioning equilibrium between the substrate and interstitial water. This results in two possible routes for uptake (bioaccumulation) and effect. The relative importance of each of these routes depends on the special habits of each benthic organism. 

Conditions caused by mutations in mitochondrial DNA often involve multiple organ systems. The effects of these conditions are most pronounced in organs and tissues that require a lot of energy (such as the heart, brain, and muscles). Although the health consequences of inherited mitochondrial DNA mutations vary widely, frequently observed features include muscle weakness and wasting, problems with movement, diabetes, kidney failure, heart disease, loss of intellectual functions (dementia), hearing loss, and abnormalities involving the eyes and vision. 

The study of the mechanism of vision in vertebrates 23>24) has progressed to the point where the first consequence of photon absorption has been described as an activation of the isomerization of the 11 -cis retinal chromophore of rhodopsin to all-trans. That triggers a complex sequence of reactions leading to the mysterious inside of the brain. Brrr, I had better get back — it looks dark in there. But the brain can generate sensations of light. Maybe, one day, we will be able to see enough to understand, but we ll go back just the same to a safer subject. 

Conjunctivitis, or pink eye, is an inflammation of the conjunctiva and probably the most widespread form of ailment in this tissue. If left untreated, it can have serious consequences on vision and overall health. There are many forms of conjunctivitis, and symptoms can range from itchy, burning, or teary eyes (allergic conjunctivitis) to more severe cases of bacterial and viral conjunctivitis (commonly known as pink eye ). Each type requires... 

In the absence of sufficient vitamin A, one consequence is a vision defect termed night blindness or, more technically, xerophthalmia. The rod cells in the retina are largely responsible for vision in low light. If they have too little retinal, they cannot do their job and night blindness, the inability to see in low light, results. If the condition persists, it is characterized by extreme dryness of the conjunctiva and can result in permanent blindness. 

Jimson weed contains the naturally occurring compounds atropine and scopolamine, which can interfere with the activity of the nervous system by blocking the action of a key chemical known as acetylcholine. This interference can produce hallucinations. Ingestion of the plant can also cause dilation of the pupils, blurred vision, rapid heart beat, reduction of salivation, as well as sedation and all of these effects are potentially useful in the practice of medicine. Consequently, by the early 1800s people the world over were buying Jimson weed from their local apothecaries. This included the citizens of Mecca. 

One of the most worrisome aspects of aging is memory loss. We can put up with wrinkles, sagging skin, aches and pains, but the first time we forget a name it conjures up horrific visions of Alzheimer s disease. Most people, of course, do not go on to develop this dreaded disease, but they may very well have to put up with some memory loss as a consequence of senior citizenship. Can we do anything about it Is there some pill we can pop to improve memory ... 

Seeing visions or hearing voices can only be attractive if the social context rewards and supports them and the individual believes that such experiences are valuable. Accusatory voices that arise unbidden cause fear and suspicion, leading to the belief that one is being persecuted by an external agency like the devil, Martians, or the FBI. In this case, we call the perceptions hallucinations and the beliefs delusions, and in so doing label them symptoms of mental illnesses like schizophrenia. The person with this kind of psychosis becomes a patient, with the most dire personal and social consequences. 

John and Louisa Aiken founded the Church of the Awakening. The Church of the Awakening is the oldest psychedelic church. In presenting the account of its founding and development, John Aiken presents a contemporary account of an age-old problem common to all who develop a new religious vision. Parts of the account are reminiscent of some of the accounts of the difficulties of the early Christians and of the early history of any new sect. This is probably no accident, but is rather part of the sociological consequence of trying to... 

---