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《英国眼科学杂志》
"Light, Einstein said, always travels by us at the same measured speed—300,000 kmps no matter how fast the light source is traveling. This was certainly not how every day objects behaved. A train approaches and the conductor throws a mail bag forward toward a station; it goes without saying that someone standing on the station platform sees the bag approach at the speed of the train plus the speed at which the conductor habitually hurls mail. Einstein insisted that light was different: stand, your lantern raised, at a fixed distance from me and I see the light travel by me at 300,000 kmps. Hurtle toward me on a train, even one moving at 150,000 kmps (half the speed of light), and I still see the light from your lantern go by me at 300,000 kmps. According to Einstein’s second postulate, the speed of the source does not matter to the velocity of light." ( Galison, Peter. Einstein’s Clocks, Poincaré’s Maps. New York: WW Norton & Co, 2003:17)
The fibulins are a family of proteins that are associated with basement membranes and elastic extracellular matrix fibres. It is evident that the fibulins are an ancient family of proteins which are highly conserved in species as evolutionarily distinct as worms and humans. Recent findings indicate the involvement of fibulins in inherited eye disorders. Fibulins 1 and 4 are candidate genes for retinopathies that map the chromosomes 22 and 11. A mutation in the fibulin free gene has been linked to a macular dystrophy (ML). In age related macular degeneration there are no associated fibulin 3 mutations; nevertheless, fibulin 3 accumulates between the retinal pigment epithelium and the drusen. Expression of fibulins 3 and 1 are elevated in a murine retinopathy model of rod degeneration. ( EMBO Reports 2003;4:1127–31)
Recent studies suggest that chronic pain may produce irreversible damage to the brain. In studies of patients with chronic back pain investigators from Northwestern University demonstrated with magnetic imaging techniques that the brain chemical N-acetylaspartate is reduced in the frontal cortex in patients with chronic back pain. This chemical correlates with the density of neurons in the involved area. Whether or not this apparent loss of cells in the brain is permanent has yet to be determined. ( Scientific American 2004;290:23–4)
Atopic dermatitis is a chronic disorder often treated with topical corticosteroids. Some concerns have been raised about possible side effects of chronic use of these ointments. Previous reports have suggested that atopic dermatitis might be treated with evening primrose oil extract (containing 8–10% of linolenic acid). Moreover, no side effects were noted with this treatment. However, several independent studies have failed to show any efficacy of the use of primrose oil treatment in atopic dermatitis. Questions have been raised about whether the conflicting results were dose related. Now, however, a study from England in which adults with atopic dermatitis received four capsules of oil tablets twice daily (920 mg of linolenic acid) has been completed. This study fails to document any benefits in the treatment of atopic dermatitis in this manner. ( BMJ 2003;327:1385–7)
All countries are forced to restrict the amount spent on health care. This may be done in an overt fashion or in a less overt but clearly rationing fashion, as in the case of managed health care. The question therefore that needs to be answered concerning individual healthcare procedures is whether cost utility analyses suggest that these procedures are of substantial benefit. Concerns have been raised that cost utility analysis of patients undergoing cataract surgery in the second eye will not document this as a cost effective procedure. However, in a study from Wills Eye Hospital, it was demonstrated that second eye cataract surgery is an extremely cost effective procedure when compared with other interventions across medical subspecialties. The cost effectiveness of second eye surgery diminishes only slightly from the 2000 per QALY gained from first eye cataract surgery. ( Ophthalmology 2003;110:2310–17)
Since 11 September 2001 considerable concern has been raised that terrorists might use smallpox as a form of biological terrorism. This has prompted some authorities in the United States to advocate an extensive smallpox vaccination programme. Many scientists with experience of smallpox challenge the wisdom of this programme. J Michael Lane, former director of the smallpox eradication programme at the Centers for Disease Control and Prevention, points out that smallpox is rarely transmitted to more than two or three contacts and most are only infected after prolonged exposure. Moreover, the virus is not transmissible until physical symptoms in the infected patient are apparent. By that time the patient is usually bedridden and the diagnosis of the disorder is clear. Lane suggests therefore that, rather than vaccinating large populations, a core group of people who would be involved in healthcare and emergency services should undergo a limited vaccination programme. ( Scientific American 2004;290:18–20)
The results of two large scale studies on the health risks and benefits of hormone replacement for post-menopausal women have been so depressing that it would seem unlikely that hormone replacement therapy would even be considered for this group of patients. However, some scientists suggest that hormone replacement therapy has obvious benefits and the studies’ failure to show protection against cardiovascular disease can be blamed on the late age of initiating treatment. Intervening for heart disease 10 years after menopause is viewed as being too late by these authorities. These authors cite experiments in monkeys that show that female monkeys with their ovaries removed and given a high fat diet to reduce coronary disease had a reduction in the number of heart attacks if given hormone replacement therapy. These scientists suggest that further research is necessary with attention to the root of administration (oral or local) and age of initiating therapy. ( EMBO Reports 2003;4:1112–15)
Active emmetropisation describes the process by which young eyes regulate their growth to eliminate refractive errors. Previous studies have suggested that a retina-brain link and/or an impact ciliary nerve are required for this emmetropisation process to occur. In a study from the University of California at Berkeley, investigating the development of the eye in chickens, investigators have demonstrated emmetropisation is possible in the absence of a retina-brain link, although the profiles of the eyes are different from normal. In other words, the affected eyes have a change in the set point for emmetropisation. This may point to a role of the retina-brain link as a fine tuning mechanism in establishing the refractive error. These experiments also indicated an important role for the ciliary nerve as a conduit for signals that exercise a restraining influence on eye growth. Together these data suggest there is more than one pathway regulating the choroidal and scleral contributions to emmetropisation. ( Current Eye Research 2003;27:371–85)(Editor)
The fibulins are a family of proteins that are associated with basement membranes and elastic extracellular matrix fibres. It is evident that the fibulins are an ancient family of proteins which are highly conserved in species as evolutionarily distinct as worms and humans. Recent findings indicate the involvement of fibulins in inherited eye disorders. Fibulins 1 and 4 are candidate genes for retinopathies that map the chromosomes 22 and 11. A mutation in the fibulin free gene has been linked to a macular dystrophy (ML). In age related macular degeneration there are no associated fibulin 3 mutations; nevertheless, fibulin 3 accumulates between the retinal pigment epithelium and the drusen. Expression of fibulins 3 and 1 are elevated in a murine retinopathy model of rod degeneration. ( EMBO Reports 2003;4:1127–31)
Recent studies suggest that chronic pain may produce irreversible damage to the brain. In studies of patients with chronic back pain investigators from Northwestern University demonstrated with magnetic imaging techniques that the brain chemical N-acetylaspartate is reduced in the frontal cortex in patients with chronic back pain. This chemical correlates with the density of neurons in the involved area. Whether or not this apparent loss of cells in the brain is permanent has yet to be determined. ( Scientific American 2004;290:23–4)
Atopic dermatitis is a chronic disorder often treated with topical corticosteroids. Some concerns have been raised about possible side effects of chronic use of these ointments. Previous reports have suggested that atopic dermatitis might be treated with evening primrose oil extract (containing 8–10% of linolenic acid). Moreover, no side effects were noted with this treatment. However, several independent studies have failed to show any efficacy of the use of primrose oil treatment in atopic dermatitis. Questions have been raised about whether the conflicting results were dose related. Now, however, a study from England in which adults with atopic dermatitis received four capsules of oil tablets twice daily (920 mg of linolenic acid) has been completed. This study fails to document any benefits in the treatment of atopic dermatitis in this manner. ( BMJ 2003;327:1385–7)
All countries are forced to restrict the amount spent on health care. This may be done in an overt fashion or in a less overt but clearly rationing fashion, as in the case of managed health care. The question therefore that needs to be answered concerning individual healthcare procedures is whether cost utility analyses suggest that these procedures are of substantial benefit. Concerns have been raised that cost utility analysis of patients undergoing cataract surgery in the second eye will not document this as a cost effective procedure. However, in a study from Wills Eye Hospital, it was demonstrated that second eye cataract surgery is an extremely cost effective procedure when compared with other interventions across medical subspecialties. The cost effectiveness of second eye surgery diminishes only slightly from the 2000 per QALY gained from first eye cataract surgery. ( Ophthalmology 2003;110:2310–17)
Since 11 September 2001 considerable concern has been raised that terrorists might use smallpox as a form of biological terrorism. This has prompted some authorities in the United States to advocate an extensive smallpox vaccination programme. Many scientists with experience of smallpox challenge the wisdom of this programme. J Michael Lane, former director of the smallpox eradication programme at the Centers for Disease Control and Prevention, points out that smallpox is rarely transmitted to more than two or three contacts and most are only infected after prolonged exposure. Moreover, the virus is not transmissible until physical symptoms in the infected patient are apparent. By that time the patient is usually bedridden and the diagnosis of the disorder is clear. Lane suggests therefore that, rather than vaccinating large populations, a core group of people who would be involved in healthcare and emergency services should undergo a limited vaccination programme. ( Scientific American 2004;290:18–20)
The results of two large scale studies on the health risks and benefits of hormone replacement for post-menopausal women have been so depressing that it would seem unlikely that hormone replacement therapy would even be considered for this group of patients. However, some scientists suggest that hormone replacement therapy has obvious benefits and the studies’ failure to show protection against cardiovascular disease can be blamed on the late age of initiating treatment. Intervening for heart disease 10 years after menopause is viewed as being too late by these authorities. These authors cite experiments in monkeys that show that female monkeys with their ovaries removed and given a high fat diet to reduce coronary disease had a reduction in the number of heart attacks if given hormone replacement therapy. These scientists suggest that further research is necessary with attention to the root of administration (oral or local) and age of initiating therapy. ( EMBO Reports 2003;4:1112–15)
Active emmetropisation describes the process by which young eyes regulate their growth to eliminate refractive errors. Previous studies have suggested that a retina-brain link and/or an impact ciliary nerve are required for this emmetropisation process to occur. In a study from the University of California at Berkeley, investigating the development of the eye in chickens, investigators have demonstrated emmetropisation is possible in the absence of a retina-brain link, although the profiles of the eyes are different from normal. In other words, the affected eyes have a change in the set point for emmetropisation. This may point to a role of the retina-brain link as a fine tuning mechanism in establishing the refractive error. These experiments also indicated an important role for the ciliary nerve as a conduit for signals that exercise a restraining influence on eye growth. Together these data suggest there is more than one pathway regulating the choroidal and scleral contributions to emmetropisation. ( Current Eye Research 2003;27:371–85)(Editor)