Sensitivity effect

Administration of lL-12 before lethal y-kradiation of mice protects against hemopoietic death and increases the number of BM cells at six days after kradiation, but sensitizes for G1 injury (189). The protective effects are abrogated by anti-lL-1 receptor or anti-SCE antibodies but not by anti-lEN- y antibodies. The sensitizing effect of lL-12 may be due to its abiUty to prime for TNE and lL-6, and can be aboHshed by anti-lEN antibody. 

Notch sensitivity Effect of low temperature Maximum transition temperature ( O... 

Polymers in Schemes 12 and 13 were the first examples of the preparation of pyridinium and iminopyridinium ylide polymers. One of the more recent contributions of Kondo and his colleagues [16] deals with the sensitization effect of l-ethoxycarbonyliminopyridinium ylide (IPYY) (Scheme 14) on the photopolymerization of vinyl monomers. Only acrylic monomers such as MMA and methyl acrylate (MA) were photoinitiated by IPYY, while vinylacetate (VA), acrylonitrile (AN), and styrene were unaffected by the initiator used. A free radical mechanism was confirmed by a kinetic study. The complex of IPYY and MMA was defined as an exciplex that served as a precursor of the initiating radical. This ylide is unique in being stabilized by the participation of a... 

No acute oral MRL was derived for methyl parathion because data regarding the most sensitive effect that was observed after acute oral exposure are conflicting. Increased pup mortality and altered behavior occurred in offspring of rats exposed to 1 mg/kg/day methyl parathion during, but no effects on pup survival or on sensitive electrophysiological indices of neurotoxicity were seen at virtually the same dose, 0.88 mg/kg/day, in a similar developmental toxicity study. 

Self-assembly of functionalized carboxylate-core dendrons around Er +, Tb +, or Eu + ions leads to the formation of dendrimers [19]. Experiments carried out in toluene solution showed that UV excitation of the chromophoric groups contained in the branches caused the sensitized emission of the lanthanide ion, presumably by an energy transfer Forster mechanism. The much lower sensitization effect found for Eu + compared with Tb + was ascribed to a weaker spectral overlap, but it could be related to the fact that Eu + can quench the donor excited state by electron transfer [20]. 

Disregarding structure sensitivity effects, further works... 

No acute, intermediate, or chronic MRLs have been derived for any route of exposure because of the lack of a clear threshold for the most sensitive effects in humans. However, ATSDR has developed a framework to provide health guidance at lead sites (see appendix D). 

Carey R., Dai H., Krost M., Huston J. The NMDA Receptor and cocaine evidence that MK-801 can induce behavioral sensitization effects. Pharmacol. Biochem. Behav. 51 901, 1995. 

The chemical sensitization effect was 0.006 (calculated from the quantum yield of the photochemical transformation of 130 to 131, the yield of 131 obtained with the oxalate/hydrogen peroxide reaction, and the moles of oxalate employed). Higher chemical sensitization efficiencies (about 0.04) were observed when the oxalate/hydrogen-peroxide system was used in the addition of ethyl vinyl ether onto phenanthrene quinone... 

The most sensitive effect of in ovo exposures was induction of hepatic ethoxyresorufin O-deethylase (EROD) activity in 1-day-old chicks, with an ED50 dose of 0.312 pg/kg FW egg. 

Adequate data were available for development of the three AEGL classifications. Inadequate data were available for determination of the relationship between concentration and exposure duration for a fixed effect. However, based on the rapidity with which blood concentrations in humans approached equilibrium, the similarity in lethality values in rats exposed for 4 or 6 hours (h), and the fact that the cardiac sensitization effect is based on a concentration threshold rather than exposure duration, a single AEGL value was used across all time periods for each AEGL classification. Some experimental exposure durations in both human and animal studies were generally long, 4 to 6 h, which lends confidence to using the same value for all exposure durations. 

No information is available on the effects of intermediate-duration oral exposure in humans, but two animal studies (Boorman et al. 1986 Danse et al. 1984) provide sufficient data to identify the main target tissue (the stomach epithelium) and to define the dose-response relationship for this effect. These studies are suitable for derivation of an intermediate oral MRL, but further studies would still be helpful to search more specifically for possible subclinical neurological effects. This is important since neurological effects appear to be the most sensitive effect by the inhalation route, and people may be exposed to low levels of bromomethane in drinking water drawn from contaminated groundwater sources. No information is available on intermediate- duration dermal exposure to bromomethane. However, humans are not likely to experience significant dermal exposures to bromomethane near waste sites, so research in this area does not appear to be essential. 

Toxic psychosis Several monoamine stimulants including cocaine are known to produce a temporary or even a lasting psychotic state after heavy use. Reviews of numerous clinical case reports have shown amphetamine to produce a chronic psychotic state, sometimes persisting for months after cessation. There appears to be a sensitization effect in this regard, because after recovery, psychotic states may recur with minimal use of amphetamine or alcohol. When compared to schizophrenic patients, people with amphetamine-induced psychosis demonstrate fewer negative symptoms (Boutros and Bowers 1996). 

Antispermatogenic effects of 1,2-dibromoethane have been observed in humans occupationally exposed to 1,2-dibromoethane (Ratcliffe et al. 1987 Takahashi et al. 1981 Ter Haar 1980). These effects include changes in sperm velocity and count. Whether or not these effects are associated with reduced fertility in humans cannot be totally addressed, since the epidemiologic study (Wong et al. 1979) was not capable of detecting such a sensitive effect. Although this study had several limitations, it indicates a potential for adverse effects of 1,2-dibromoethane on fertility. 

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