Ultrasound images taken over the next 50 weeks showed that the artificial blood vessels grew at a normal rate as the animals aged.
We used male animals aged 20 weeks, weighing 25 30 g.
Animals aged 40 60 days were used in all experiment (adapted from OECD guideline to obtain only adults, which are more tolerant to the sucking device during collection than juveniles).
Statistical analysis revealed that prevalence in animals aged >4 years (20.4%) was significantly higher than in the age ranges <2 years (9.6%) and 2 4 years (11.4%) (P < 0.01).
The levels then exhibited a gradual decline at P60 (75% of the peak level) and at 6 months (67%) and a drastic decrease as the animals aged to 19 months (only 5%).
There is no distinct leader of the female herd, though animals aged five years or more may move independently.
The weight differences continually increased as the animals aged.
As a baseline, we studied 44 animals aged between 3 and 11 months, denoted as young in the following.
These were compared to 43 animals aged between 24 and 39 months of age denoted as old.
However, argyrophilic neurites, tangles or neuropil threads were not observed even in animals aged up to 20 months.
Muscles were recovered from animals aged 140 145 days at which time symptoms begin to appear on average.
