The Webcam system: a simple, automated, computer-based video system for quantitative measurement of movement in nonhuman primates.

Investigations using models of neurologic disease frequently involve quantifying animal motor activity. We developed a simple method for measuring motor activity using a computer-based video system (the Webcam system) consisting of an inexpensive video camera connected to a personal computer running customized software. Images of the animals are captured at half-second intervals and movement is quantified as the number of pixel changes between consecutive images.

Aging of the nigrostriatal system in the squirrel monkey.

Increasing incidence of Parkinson's disease with advancing age suggests that age-related processes predispose the nigrostriatal dopaminergic system to neurodegeneration. Several hypotheses concerning the effects of aging on nigrostriatal neurons were assessed in this study using a non-human primate model. First, we examined the possibility that the total number of dopaminergic neurons decline in the substantia nigra as a function of age.

Novel observations with FDOPA-PET imaging after early nigrostriatal damage.

Striatal 6-[18F]fluoro-L-DOPA (FDOPA) kinetic rate constants were measured by positron emission tomography (PET) in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated squirrel monkeys. After scanning, stereological counts of dopaminergic neurons were done in substantia nigra, and dopamine (DA) and metabolite concentrations were determined in the caudate, putamen, and substantia nigra. Graded doses of MPTP produced animals with mild to moderate reductions (10-35%) in dopaminergic neurons, where the percent of cell loss was proportional to the amount of MPTP given.

Nigrostriatal reduction of aromatic L-amino acid decarboxylase activity in MPTP-treated squirrel monkeys: in vivo and in vitro investigations.

Aromatic L-amino acid decarboxylase (AAAD) activity was examined in vivo with positron emission tomography (PET) using 6-[18F]fluoro-L-DOPA (FDOPA) in squirrel monkeys lesioned with graded doses of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In vitro biochemical determinations of AAAD activity in caudate, putamen, substantia nigra, and nucleus accumbens were performed in the same animals to establish a direct comparison of in vivo and in vitro measurements. In vivo and in vitro AAAD activities in caudate/ putamen were substantially reduced in animals treated with the highest dose of MPTP (2.

Cutaneous mastocytomas in the neotenic caudate amphibians Ambystoma mexicanum (axolotl) and Ambystoma tigrinum (tiger salamander).

Spontaneous mastocytomas studied in 18 axolotls (Ambystoma mexicanum) and six tiger salamanders (Ambystoma tigrinum) were gray-white, uni- to multilobular cutaneous protrusions from 2 mm to 2 cm in diameter. Tumors were moderately cellular unencapsulated masses that usually infiltrated the dermis and hypodermis with the destruction of intervening tissues. Some tumors were invading superficial bundles of the underlying skeletal muscle.