Mouse system, naturally occurring

Molinate has a low toxicity to rats, oral LDso=720 mg/kg, and is rapidly metabolized by plants to CO2 (1) (5) and naturally occurring plant constituents (1). Molinate is also readily metabolized by soil microorganisms (6). After incubation of molinate with Bacillus sp. 24, Nocardia sp. 119, and Micrococcus sp. 22r which were isolated from Russian garden soils and rice field drains (7,8), it was found that molinate was completely degraded into various hydroxy and oxidized products in the medium. Molinate can be metabolized to its corresponding sulfoxide in the mouse in vivo and by the microsome-NADPH system of mouse liver (9, 10). Hubbell et al. (11) and DeBaun et al. (12) also found molinate sulfoxide along with other polar and nonpolar metabolites in rat urine. 

The classical experimental approach to study the mechanisms that govern the development of such a system is to explore naturally occurring disorders, the so called experiments of nature , in which there was an interception of such development. In the case of the particular subject of this chapter these would be the disorders in which there was either no formation of the bone marrow cavities and consequently bone marrow or this process was significantly impaired. This has brought me a quarter of century ago to osteopetrosis (Wiktor-Jedrzejczak et al., 1981). At that time already several genes whose mutations produced osteopetrosis have been provisionally identified both in the mouse and the rat as well as in man. 

Bretillon et al. (15) were the first to report that fl0,cl2 CLA inhibited the A9 desaturation of stearic acid to oleic acid by rat liver microsomes. This finding was confirmed and extended by Park et al. (16) who demonstrated that SCD activity in mouse liver microsomes was inhibited not only by fl0,cl2 CLA but also by the naturally occurring oxygenated derivatives of Unoleic acid 9-hydroxy-fl0,cl2-octadecadienoic acid (9-HODE) and 9-hydroperoxy-fl0,cl2-octadecadienoic add (9-HOO). The c9,t CLA isomer had no effect in this system. The fl0,cl2 CLA has also been shown to inhibit SCD activity in the bovine mammary gland (5). 

Virus is found worldwide. The natural reservoir is the common house mouse (Mus musculus) and the virus is shed in their urine. Infection occurs after inhalation of dust contaminated with excreta from infected mice or from aerosol of animal blood or fluids. Disease can be passed to rodent pets such as mice and hamsters. Does not produce disease in animals. The virus normally has little effect on healthy people but can be deadly for people whose immune system has been weakened. This is a biosafety level 3 agent. 

The immunobiology of this family has been reviewed by Hopkins (332) and Ito Smyth (353), the species most studied being Hymenolepis diminuta, H. nana, H. microstoma, and H. citelli, in that order. Much of the experimental work has been carried out on what must be considered to be artificial host-parasite systems, i.e. those not occurring naturally. As discussed below, H. diminuta grows readily in rats (Fig. 11.5) but in the mouse host it develops to some extent and is then rejected without reaching maturity. In these... 

---