I have matrices on my workpace and i need to take the first element from each one

and produce new vector. In other words, i have the matrices D1,D2,D3....D36 on my workspace and by using a For loop i want to generate a new vector:

d=[D1(1,1) D2(1,1)...D3(1,1)].

does anyone know how to that in For loop?

Thanks,

Omri