title: Using preg_replace with ASCII characters
body: <p>In my functions.php I added a function that replaces English with German quotation marks. I do this by simple str_replace calls, like this:</p>
  
  <pre><code> $content = str_replace (' &amp;#8220;', ' &amp;#8222;', $content);
  </code></pre>
  
  <p>Now I want to do this with preg_replace instead so I can handle special cases differently. However, this:</p>
  
  <pre><code> $haekchenunten = "&amp;#8220;";
   $regex = /^ . $haekchenunten . /;
   $content = preg_replace ($regex, '&amp;#8222;', $content);
  </code></pre>
  
  <p>Leads to a blank page (PHP Fatal, I'd presume).</p>
  
  <p>How can I use <code>&amp;#8220;</code> with preg_replace?</p>