Contragestion and other clinical applications of RU 486, an antiprogesterone at the receptor

Article Abstract:

The drug known as RU 486 was developed in France during the late 1970s and introduced in September, 1988 by the pharmaceutical firm Roussel-Uclaf for use in terminating early pregnancy. Its uses and effects and how it works on a molecular and physiological level are discussed. RU 486 blocks the normal action of the hormone progesterone, critical in maintaining pregnancy. Progesterone stimulates thickening of the uterine lining so that the embryo can implant; it also prevents contractions and strengthens the cervix, which holds the fetus inside. To produce its effects, progesterone must bind to special sites called receptors in the cells. RU 486 binds to the progesterone receptors instead, physically stopping progesterone. The result is bleeding and contractions with termination of the pregnancy. In France, over 2,000 women per month have taken RU 486 to achieve abortion since January, 1989. The procedure is more than 95 percent effective and produces symptoms similar to heavy menstruation. Strong analgesics derived from opium are needed for ten percent of patients and blood transfusion in one out of 1,000 cases. Incomplete abortions and continued pregnancies rarely occur. No long-term effects have been identified and several patients who took RU 486 have since conceived and delivered healthy infants. The drug may be especially beneficial to women in countries where surgical expertise is lacking. RU 486 may have future applications as a contraceptive pill and treatment for certain brain tumors (meningiomas) and some breast cancers. A new term, contragestion, a contraction of contra and gestation (on the model of contraception, a contraction of contra and conception) is proposed. The concept emphasizes the continuous nature of human reproduction, which can be interrupted at many points. Several current procedures besides abortion interrupt the process after conception; these include the IUD and hormonal contraception that uses progestin only. RU 486 offers women opportunities to exercise greater responsibility concerning their fertility, and that the public deserves access to the best methods science can provide.

Health aspects, Research, International aspects, Ethical aspects, Hormone antagonists, Abortion, Progesterone, Abortion services, Mifepristone

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Fibroblast growth factor receptor is a portal of cellular entry for herpes simplex virus type 1

Article Abstract:

Many viruses initiate their attack on target cells by attaching to specific receptors on the cell surface. Epstein-Barr virus attaches to the complement receptor C3d on T cells, for example, and the AIDS virus infects cells primarily by attaching to CD4. Now, investigators have shown that Herpes simplex virus type 1, the form associated primarily with persistent infections and recurring mouth sores, infects some target cells by attaching to the fibroblast growth factor (FGF) receptor. This was demonstrated in several ways, including the observation that the mere presence of fibroblast growth factor inhibited the infection of the cells, as did the presence of protein antagonist molecules known to block the FGF receptor. Furthermore, cultured cells that did not express the FGF receptor were relatively resistant to infection with herpes simplex; when the same cells were transfected with the FGF receptor gene, they became susceptible to infection. Although the binding of a virus to a specific receptor is far from unusual, the herpes simplex virus may accomplish this task in a peculiar manner. While the viral molecule that accomplishes the binding has not yet been established, purified virus preparations contain a large amount of fibroblast growth factor. The authors speculate that during the growth of the virus, the virus accumulates significant amounts of FGF; the infection of new host cells is then begun by the binding of the accumulated FGF to its natural receptor on the target cell surface. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, Growth factor receptors, Herpes simplex virus, Fibroblast growth factors, Herpes simplex

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Shared human T cell receptor V-beta usage to immunodominant regions of myelin basic protein

Article Abstract:

Multiple sclerosis (MS) is a disease of the nervous system which is characterized by the destruction of myelin, a fatty substance which surrounds the nerve fibers of the brain and spinal cord. It is thought that MS is an autoimmune disease, in which the body recognizes its own components as foreign and mounts an immune response against them. A subset of lymphocytes, known as T cells, is thought to react against and destroy the myelin basic protein (MBP), which might contribute to the disease state in MS. T cells from both patients with MS and healthy individuals, as controls, were examined for their reactivity against two portions of the MBP which are known to be immunogenic, meaning able to cause an immune response. The types of T cell receptors, structures which are involved in the recognition of antigen and the initiation of the interactions necessary for an immune response to occur, were examined. It was found that one particular type of T cell receptor (V-beta 17) and to a lesser extent another type (V-beta 12) were often used in the recognition of one of the immunogenic regions of MBP, known as MBP (84-102), but not the other immunogenic site, MBP (143-168), by many of the patients with MS. Since the same type of T cell receptors are used to recognize the myelin protein, these receptors may be important as targets for therapy against MS. Drugs can be directed to act on these receptors, or the receptors can be blocked or altered. (Consumer Summary produced by Reliance Medical Information, Inc.)

Development and progression, Autoimmune diseases, Multiple sclerosis, T cells, Demyelination, Demyelinating diseases

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