sub show_news {
  my ($dbh, $article_id) = @_;
  my $sth = $dbh->prepare("...");
  $sth->execute($article_id);
}

##</code><code>##

$dbh->disconnect;

$sth    = $dbh->prepare(...) or die ...

##</code><code>##

UPDATE news_articles 
SET article_title = ? 
WHERE $article_id = ?