Doctors and patients are excited about the dramatic effects the new combination drug therapies have made in combating HIV.

By Tom Corwin
Staff Writer

If there had been a button next to his bed that would kill him, Thomas would have pushed it.

To understand the optimism, it is necessary to understand how the new therapies prevent the spread of the virus:

1. When it attacks a human cell, the virus takes its single strand of genetic material, an RNA strand, and converts it to DNA using the human cell's genetic material and an enzyme called a reverse transcriptase enzyme. The virus DNA then invades the host DNA.

2. The virus also produces a large protein that it then cuts up into usable pieces using a special enzyme. Those smaller protein pieces then help it encapsulate reproduced virus copies and allow them to escape the host cell and spread to other cells.

3. The new drug therapies use two drugs, called nucleoside reverse transcriptase inhibitors (NRTIs) that attack the virus's RNA chain and give it a ``false building block,'' preventing it from replicating correctly. One of the most common of these drugs is AZT.

4. The Medical College of Georgia is now testing a fourth drug called a nonnucleoside reverse transcriptase inhibitor (NNRTI). Instead of giving the virus a false building block, the NNRTI actually gets the virus's RNA chain to fold in on itself and makes it unable to reproduce itself.

5. The school also is hoping to begin testing a new drug that targets the virus's enzymes more specifically and would cause fewer of the side effects patients suffer from the drug therapies.

Below are the number of AIDS cases and deaths in Richmond County for the past six years. The first figure is the number of new AIDS cases, followed by the number of AIDS deaths:

1990 43 33
1991 49 38
1992 108 67
1993 76 37
1994 93 44
1995 88 22
1996 62 13