Compounds of formula I: or a pharmaceutically acceptable salt, hydrate, and/or solvate thereof, wherein: R.sub.1 is a pharmaceutically acceptable polymeric moiety comprising a pharmaceutically acceptable polymer chain such that the carbonyl group is linked to R.sub.1 through an ester, amide, carbonate or carbamate bond; R.sub.2 is hydrogen, or —(C═O)Rs wherein R.sub.5 is a C.sub.1-3 straight or branched chain alkyl group; and R.sub.3 and R.sub.4 are independently selected from hydrogen, C.sub.1-3 straight or branched chain alkyl group, or —(C=0)Re wherein R.sub.6 is —(O—CH.sub.2—CH.sub.2).sub.n—OCH.sub.3 or a C1-3 straight or branched chain alkyl group, and n is 1 to 5. The compositions are useful for the treatment of Parkinson's disease when administered alone or in combination with carbidopa and/or entacapone.

##STR00001##

An object of the present invention is to provide a layered body of cells that is used in a co-culture technique and that is capable of recognizing as paracrine effect of each cell and detecting the effect with high intensity. The layered body of the present invention is a layered body 1A having a layered structure in which a gel layer 20a containing a hydrogel is disposed between at least two cell layers 10a and 10b containing cells of different types from each other, wherein the hydrogel is a multi-branched polymer hydrogel formed by a reaction of: Liquid A containing a multi-branched polymer A, the polymer containing, as a backbone, a polyethylene glycol containing at least three branches, the branches containing one or more electrophilic functional groups in at least one of a side chain(s) and an end(s); and Liquid B containing a multi-branched polymer B, the polymer containing, as a backbone, a polyethylene glycol containing at least three branches, the branches containing one or more nucleophilic functional groups in at least one of a side chain(s) and an end(s), the concentration of components derived from the multi-branched polymers A and B in the hydrogel is from 0.6 to 8% by weight, and the thickness is from 0.02 mm to 2 mm.

The invention provides compound of the general formula: ##STR00001##
in which each X independently represents a polymer chain; n represents an integer greater than 1; Q represents a linker; Y represents an amide group; and Z represents either CH.(CH.sub.2L).sub.2 or C(CH.sub.2L)(CH.sub.2), in which each L independently represents a leaving group. The compounds are useful reagents for the conjugation of polymers to proteins, the resulting conjugates being novel and also forming part of the invention.

Disclosed are multi-arm polyethylene glycol derivatives having structure of formula I or formula VI. Compared with straight chain polyethylene glycol, multi-arm polyethylene glycol has a plurality of terminal groups, thus has a plurality of introducing points of functional groups and can support a plurality of reactive terminal groups, thereby enabling multi-arm polyethylene glycol to have more flexibility and wider range of application. ##STR00001##

The invention provides compound of the general formula:

##STR00001##

in which each X independently represents a polymer chain; n represents an integer greater than 1; Q represents a linker; Y represents an amide group; and Z represents either CH.(CH.sub.2L).sub.2 or C(CH.sub.2L)(CH.sub.2), in which each L independently represents a leaving group. The compounds are useful reagents for the conjugation of polymers to proteins, the resulting conjugates being novel and also forming part of the invention.

The invention provides compound of the general formula: ##STR00001##
in which each X independently represents a polymer chain; n represents an integer greater than 1; Q represents a linker; Y represents an amide group; and Z represents either CH.(CH.sub.2L).sub.2 or C(CH.sub.2L)(CH.sub.2), in which each L independently represents a leaving group. The compounds are useful reagents for the conjugation of polymers to proteins, the resulting conjugates being novel and also forming part of the invention.