First off, if you are being threatened with a legal action, you really need to consult with a lawyer. That said, I looked up RE43748 on the US Public Pair site. Select "Patent" and enter RE43748. It claims priority from PCT/JP99/04429 which has a filing date of 08-18-1999. There were no patent term adjustments so the patent should have expired by now.
If it has been granted it will say "Grant" in the "Publication type" heading.
Applications that are subsequently granted will link to the grant document. As an example:
Publication number: CA2128634 A1
Publication type: Application
Application number: CA 2128634
Publication date: Dec 23, 1995
Filing date: Jul 22, 1994
Priority date: ...
It does not appear so. The current status on PAIR indicates that it was abandoned whilst it was pending for failure to respond to an office action on 24th Feb 2011.
EDIT: link to the US PTO Public Patent Application Information Retrieval (PAIR) website is below:
I have attached a screenshot evidencing the current ...
In order to be allowed, the broader claims must be supported by the disclosure of the original application, and be novel and non-obvious in light of art prior to the original application's priority date. If that is not the case, and the inventor is relying on a new specification to support the new claims, it is possible that those new claims read on the ...
You need to calculate expiry from the US5662332 Re-issue is just publication of information. Here is another answer to calculate the same How do you determine a patent's expiration date?
MPEP 1405 Reissue and Patent Term [R-11.2013]
35 U.S.C. 251 prescribes
the effect of reissue on the patent term by stating that "the Director
There is a section of the Manual of Patent Examining Procedure (MPEP) that covers this.
1412.02 Recapture of Canceled Subject Matter
A reissue will not be granted to "recapture" claimed subject matter which was surrendered in an application to obtain the original patent.
It does go on to list a three-part test to see if this applies. It may be ...