for ContListBox:= 0 to listbox1.items.count - 1 do
begin
query1.Close;
query1.SQL.Clear;
query1.SQL.Add('Update tabla1');
query1.SQL.Add('set tipo_AT1 = tipo_AT1 & ' + ',' + Edit1.text );
query1.SQL.Add('where nombreT1 = ' + quotedstr(listbox1.items[ContListBox]) );
query1.ExecSQL;
end