|
|
| Home | Humor | Technology | About |
Choose YOUR language and Translate this page!
By PDQ Campbell
Society is almost always facing some kind of foe either from without or from within. If it isn't foreign political threats, then it is domestic unrest or something even closer to home. The popular culture is quick to pick up on people's concerns and turn them into books and movies. So if you've missed the threat of the day just check the bookstore or local theater. It should come as no surprise therefore that among the top concerns of people around the world currently is our age-old adversary "disease." And they are concerned for good cause. The bacteria of today are not the same the as germs we have all become accustomed to. Over time and exposure to various treatments, bacteria have either outright mutated, or simply become resistant to medications by natural selection.
Surprisingly, one of the diseases that have undergone such a transmutation is malaria, which has been a treatable condition for roughly a hundred years. The urgency for more new and effective antimalarials has escalated as human malaria parasite species (such as Plasmodium falciparum and others) have developed resistance to most of the commercially available antimalaria treatments.
While most
of the antimalarial drugs, for example chloroquine, are synthesized chemical
products, the discovery of artemisinin from the Chinese medical herb Artemisia
annua L. as a potent antimalarial has rekindled interest in screening natural
products for new antimalaria treatments. Generally, screening programs have
focused on natural products derived from land plants due to their abundance and
easy accessibility. However, there have been some recent efforts and limited
successes in discovery of novel antimalarial compounds from marine
organisms.
Those efforts have also finally come to fruition for a group of dedicated scientists. On November 7, 2000 inventors Anna Ursula Kara, Michael Holmes, Kean Hooi Ang, all of Singapore, along with their colleague Tatsuo Higa of Nishihara, Japan, received U.S. Patent no. 6,143,756 for their discovery of "Antimalarial Activity of ß-Carboline Alkaloids." The invention, now assigned to the National University of Singapore, has found malaria treatment compounds in probably the most unlikely place on earth: Sponges!
The group
of scientists examined a type of chemical called "manzamine." Manzamines are a
unique group of chemicals (specifically ß-carboline alkaloids) derived
from several sponge species found in Okinawan, Indonesian and the Philippine
waters. Manzamine A, the first of the series to be discovered, was initially
isolated from the sponge species Haliclona, and subsequently from other marine
sponges. (Pellina, Xestospongia, Ircinia, Pachypellina, and Amphimedon). In
addition, several structurally related compounds were characterized from these
sponges. The derivative manzamine F, for example, was isolated from the
Xestospongia sponge. Both manzamine A and manzamine F have previously
demonstrated anti-tumor activity inhibiting the growth of certain mouse
leukemia cells. As part of the scientists' screening programs for potential
antimalaria treatment compounds derived from marine natural products, these
manzamines were evaluated for antimalaria activity against the rodent malaria
parasite Plasmodium berghei.
Laboratory mice infected with the rodent malaria parasite were tested. The survival times of mice infected were compared after treatment with a single injection of either manzamine A, manzamine F, chloroquine or artemisinin. All control mice and the mice treated with manzamine F died within 4 days after treatment. However, a single administration of manzamine A prolonged the survival of the infected mice for more than 10 days with 40% of mice treated with larger quantities of manzamine A surviving more than 60 days and recovering with no detectable parasites in their systems.
In contrast to chloroquine and artemisinin treated mice, most infected mice treated with manzamine A were able to survive for a longer period of time still carrying the parasite, and two mice were able to clear the parasites completely. This remarkable fact concurred with a drastic increase in the white blood cell population noted in most manzamine A-treated mice. Such an immune response may have been responsible for the eventual recovery of the two mice treated.
As to whether the National University of Singapore has or will license this technology to any outside manufacturer remains to be seen given how recently the patent was even issued. It would be poor judgement to assume from these results that these sponge derivative chemicals are a panacea for treatment-resistant malaria. However, the results are significant, and according to the patent the compounds are useful not only as a treatment for malaria, but also as a preventative. Only time will tell if this new weapon against malaria will remain effect, or whether the search will continue for medications that remain effective in the face of ever changing germs.
Paul Campbell is a columnist and author in central Florida. His column Homeworld appears here every week. Feel free to write to Paul at techpubs@ix.netcom.com or visit him on the web at http://techpubs.home.netcom.com.
| Industrial and Engineering Books by Paul Campbell | |||
| Handbook of Mechanical Fasteners | Basic Fixture Design | Plastic Component Design | Introduction to Measuration and Calibration |
| Home | Humor | Technology | About |