1. Lake Takem and Lake Krankesjon, two moderately eutrophic, shallow lakes in southern Sweden, have during the past few decades shifted several times between a clear-water state with abundant submerged vegetation and a turbid state with high phytoplankton densities. 2. Between 1985 and 1991, Lake Takem was in a clear state, whereas Lake Krankesjon shifted from a turbid to a clear state. During this shift, the area covered by submerged macrophytes expanded, followed by an increase in water transparency, plant-associated macroinvertebrates, and piscivorous fish. Nutrient concentrations, phytoplankton biomass and abundance of planktonic cladocerans decreased. 3. In both lakes, water level fluctuations were the most common factor causing shifts, affecting submerged macrophytes either through changes in light availability or through catastrophic events such as dry-out or mechanical damage by ice movement. 4. Our data give further support for the existence of two alternative stable states in shallow lakes maintained by self-stabilizing feedback mechanisms.

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The effects of planktivorous and benthivorous fish on benthic fauna, zooplankton, phytoplankton and water chemistry were studied experimentally in two eutrophic Swedish lakes using cylindrical enclosures . In enclosures in both lakes, dense fish populations resulted in low numbers of benthic fauna and planktonic cladocerans, high concentration of chlorophyll, blooms of bluegreen algae, high pH and low transparency . In the soft-water Lake Trummen, total phosphorus increased in the enclosure with fish, but in the hard-water Lake Bysjon total phosphorus decreased simultaneously with precipitation of calcium carbonate . Enclosures without fish had a higher abundance of benthic fauna and large planktonic cladocerans, lower phytoplankton biomass, lower pH and higher transparency .The changes in enclosures with fish can be described as eutrophication, and those in enclosures without fish as oligotrophication . The possibility of regulation of fish populations as a lake restoration method is discussed .

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Roquinimex-related 3-quinolinecarboxamide derivatives were prepared and evaluated for treatment of autoimmune disorders. The compounds were tested in mice for their inhibitory effects on disease development in the acute experimental autoimmune encephalomyelitis model and selected compounds in the beagle dog for induction of proinflammatory reaction. Structure-activity relationships are discussed. Compound 8c, laquinimod, showed improved potency and superior toxicological profile compared to the lead compound roquinimex (1b, Linomide) and was selected for clinical studies (currently in phase II).