Louis, Missouri, USA), ITS (6.25 [micro]g/mL insulin, 6.25 [micro]g/ mL transferrin, 6.25 [micro]g/mL
selenous acid) (Gibco, Thermo Fisher Scientific, Monza, Italy) for 7, 14, 21, and 28 days.
Copper chloride (Cu[Cl.sub.2] anhydrous 98%), indium chloride (In[Cl.sub.3] anhydrous 98%), gallium chloride (Ga[Cl.sub.3] anhydrous 99%), and
selenous acid ([H.sub.2]Se[O.sub.3] anhydrous 98%) were used as precursors and anhydrous ethylenediamine, triethanolamine, oleylamine, polyetheramine, and oleic acid were used as organic solvents.
ITS: insulin, transferrin and
selenous acid, bovine serum albumin, linoleic acid.
Se[O.sub.2] dissolves in water to form
selenous acid (Se[O.sub.2.sup.-3]).
The islets 75-150 [micro]m in diameter were cultured for 24 hr in CMRL1066 medium containing 5.5 mM glucose, 10% fetal bovine serum, 100 U/mL penicillin-streptomycin, 2 mM L-glutamate, 25 mM HEPES, and ITS Premix (5 mg insulin, 5 mg transferrin, and 5 [micro]g
selenous acid/L).
I added 6 mL of concentrated sulfuric acid, containing 4.2%
selenous acid, and 3 mL of 30% hydrogen peroxide and heated samples 1 h at 400[degrees]C with a block digestor (model 2040, Tecator, Herndon, VA).
The remaining dried soil was kept for analyses of total nitrogen (N) with the indophenol method and phosphorus (P) with the molybdenum blue method, after digesting 250 mg of soil in a sulfuric acid and
selenous acid mixture for 1 h (Kedrowski 1983).
Louis, MO, USA), and 50 mg/ml ITS+ Premix (Becton Dickinson; 6.25 [micro]g/ml insulin, 6.25 [micro]g/ml transferrin, 6.25 ng/ml
selenous acid, 1.25 mg/ml BSA, and 5.35 mg/ml linoleic acid).