Central nervous system indications

Potential central nervous system indications for calcium channel antagonists... 

The advantages of MR scanning have been especially pronounced in imaging of the brain and spinal cord. At the present time a large fraction, perhaps around 70%, of all MR studies are done for central nervous system indications. 

Alkyl mercury compounds in the blood stream are found mainly in the blood cehs, and only to a smah extent in the plasma. This is probably the result of the greater stabhity of the alkyl mercuric compounds, as well as their pecuflar solubiUty characteristics. Alkyl mercury compounds affect the central nervous system and accumulate in the brain (17,18). Elimination of alkyl mercury compounds from the body is somewhat slower than that of inorganic mercury compounds and the aryl and alkoxy mercurials. Methylmercury is eliminated from humans at a rate indicating a half-life of 50—60 d (19) inorganic mercurials leave the body according to a half-life pattern of 30—60 d (20). Elimination rates are dependent not only on the nature of the compound but also on the dosage, method of intake, and the rate of intake (21,22). 

The effects of occupational exposure to lindane have been investigated extensively (96—100). These studies indicated that occupational exposure to lindane resulted in increased body burdens of this chemical however, toxic effects associated with these exposures were minimal and no central nervous system disorders were observed. This is in contrast to the polyneuropathies that are often observed after exposure to other haloorganic solvents. 

Morphine. This alkaloid exerts both a depressing and a stimulating action on the central nervous system, the depression affecting the brain especially the sensation of pain and the respiration the cerebral motoi functions are less affected. The stimulant action in the cord is best seen in the cold-blooded animals, when it may develop into tonic convulsions. In higher animals, but rarely in man, there may be some indication of this stimulant action. In cats it may also involve the motor areas, and they... 

If tlie pollutant causes iui acute non carcinogenic risk, tlie inaximuin one hour concentration is used for C, and tlie acute reference exposure limit is used for tlie REL. Likewise, if tlie pollutant causes a clironic non carcinogenic risk, tlie one year average concentration is used, as is tlie clironic reference exposure limit. In tliis procedure, a Iiazard index is calculated for each pollutant separately, and tlien tlie indices are summed for each toxicological endpoint (i.e., tlie respiratory system, tlie central nervous system, etc.). Finally, tlie total hazard index is tlien compared to a value wliich is considered significant. 

Diuretics This indicates the unique property of capsaicin-sensitive primary afferent neurons to release mediators (neuropeptides and others) from both peripheral and central nervous system terminals upon adequate stimulation. Capsaicin and other chemical (protons) or physical (heat) stimuli release mediators from both peripheral and... 

The substance is irritating to the eyes, the skin and the respiratory tract. The substance may cause effects on the central nervous system, resulting in impaired functions. Exposure may result in death. The effects may be delayed. Medical observation is indicated. 

In the past, trichloroethylene was used as a human anesthetic. Trichloroethylene has also been used by individuals who intentionally inhale it for its narcotic properties. Therefore, most of the information regarding the effects of trichloroethylene in humans comes from case studies and experiments describing effects of trichloroethylene after inhalation exposure. These studies indicate that the primary effect of exposure to trichloroethylene is on the central nervous system. Effects include headache, vertigo, fatigue, short-term memory loss, decreased word associations, central nervous system depression, and anesthesia. 

Endogenous estrogens are known to be active in a number of areas of the brain. There are indications that estrogens may play a role in mood, locomotor activity, pain sensitivity, vulnerability to neurodegenerative diseases and cognition (McEwan, 1999). In humans, the blood brain barrier is not fiilly developed at birth and, for this reason, the central nervous system (CNS) may be more sensitive to phytoestrogens in utero or at birth. As ERs are expressed in the CNS, phytoestrogens may also be active in this area. 

Phytosterols have been demonstrated as being anti-cancer components in the diet (Awad and Fink 2000). Scientific studies indicate that phytosterols may offer profection against colon, breast and prostate cancers (Vanderhaeghe and Bouic, 2000). The possible mechanisms, as reported by these authors, include the effect of phytosterols on membrane structure and function and on the signal transduction pathways that regulate tumor growth and apoptosis. The rice bran derived phytosterol-cycloartenol-ferulic acid ester on the central nervous system has been studied by Hiraga et al. (1993). 

The presence of particles in the brains of experimental rats and humans exposed to asbestos has been reported (Pontefiart and Cunningham, 1973 Auerbach et al., 1980). In experimental studies, particles of Teflon, a reflux paste, enter the brain via intravascular transport when injected into the bladder (Aaronson et al., 1993). Encephalitic reactions to accumulated calcium oxalate crystals in the brain as a result of infusions of glucose surrogate polyol solutions have been described (PciflPcr etal., 1984). Such studies indicate the capacity of particulates to enter the brain and thus pose a potential pathological threat to the functioning of the central nervous system (CNS). 

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