[OS X TeX] theorem names

[George Gratzer]

I use the book document style and load the AMS packages, in particular, amsthm. Therefore,
theorems with names, e.g.

Theorem 5 (Fundamental theorem of AbelianGroups).

is typeset with 

Theorem 5

and the period in bold, 

(Fundamental Theorem of AbelianGroups)

not. Of course, it is easy to make 

Fundamental Theorem of AbelianGroups

bold, but I would need the parenthesis bold also.

The amslatex distribution has a file called testmath.pdf in 

amslatex/doc/latex/amsmath

On p.6 of this file there are two theorems with everything in bold. Unfortunately, there
is no source provided or explanation given.

Does anybody know the trick?

GG