Abstract: A transgenic mouse whose genome comprises a DNA sequence encoding the carboxy-terminal 100 amino acids of the human .beta.-amyloid precursor protein C-100 APP) inserted into exon I of the neurofilament gene such that all or part of exon I has been deleted is disclosed. Expression of the nucleic acid sequence is under the control of neurofilament L-gene regulatory region. The mouse as a result of the expression exhibits a brain morphology of an increased amyloid accumulation, and increase in reactive astrocytes, an increased microglial activation and a decreased number of neurons, and also exhibits spatial memory impairment.

Abstract: Light-emitting compounds of the formula: ##STR1## where R.sub.1 is a light-emitting moiety and R.sub.2 is a somatostatin-based peptide featuring a first amino acid sequence -Phe-Phe-Trp-Lys-Thr- or (SEQ ID NO:1) or -Phe-Phe-D-Trp-Lys-Thr-. The peptide is linked at a first amino acid position to (C-X), and the light-emitting compound exhibits substantial biological activity in the presence of a receptor having affinity for somatostatin-based peptides.

Abstract: Light-emitting compounds of the formula: ##STR1## where R.sub.1 is a light-emitting moiety and R.sub.2 is a somatostatin-based peptide featuring a first amino acid sequence --Phe--Phe--Trp--Lys--Thr-- (SEQ ID NO:1) or --Phe--Phe--D--Trp--Lys--Thr--. The peptide is linked at a first amino acid position to (C--X), and the light-emitting compound exhibits substantial biological activity in the presence of a receptor having affinity for somatostatin-based peptides.

Abstract: An improved modular prosthetic joint has a stem portion embedded in a bone with a removable bearing head frictionally mounted on the stem portion. The bearing head has a bore which mates with a tapered shaft of the stem portion. The bearing head has a generally thin wall defining its continuous and unbroken bearing outer surface, with a wall portion extending directly over the tapered shaft which is thinner than the remainder of the bearing head wall. A puller engages an annular shoulder of the bearing head to pierce through the thinner wall portion of the bearing head, engage the tapered shaft and urge the bearing head away from the tapered shaft. Thus, the bearing head is pierced and removed from its associated stem portion, and second replacement bearing head is then mountable on the tapered shaft by impaction.