Wednesday, March 07, 2007 Acid environ not enough By Zosimo T. Literatus, R.M.T. Breakthroughs
A woman’s body is equipped by nature, through the acidic environment in the vagina, to somehow protect itself from the wiles of the human immunodeficiency virus (HIV), the infamous virus that brings us the acquired immunodeficiency syndrome (Aids) trouble.
But apparently this acidic environment is not enough to do the job, resulting to HIV-1 infection among women.
In the absence of anti-HIV-1 vaccines, women need protection in other ways. The solution has been to develop topical microbicides (medicine that kills off microbes) to be applied vaginally to inactivate HIV-1 before it reaches susceptible cells. And only polymers (a kind of substance often used as synonym for plastic) can so far suit up for the job.
While previous studies on female rhesus macaques (short-tailed monkeys) showed that polymeric topical salves were effective against HIV-1 infection in vitro, scientists observed that these studies failed to consider the effect of seminal plasma, which may or may not undermine their effectiveness.
To check on this, researchers A. Robert Neurath, Nathan Strick, and Yun-Yao Li studied the interaction and found out that seminal plasma can lessen the effectiveness of the topical anti-HIV-1 polymers. Neurath, Strick and Li are researchers at the Biochemical Virology Laboratory of The Lindsley F. Kimbal Research Institute of the New York Blood Center (New York, USA).
The study utilized HIV-1 BaL virus (a representative of the more frequently sexually transmitted R5 virus) and HIV-1 IIIB to infect the cultured cells TZM-bl. Test polymers carrageenan, poly (naphthalene sulfonate), cellulose sulfate, cellulose acetate, CAP (1,2-benzenedicarboxylate), and polystyrene sulfonate were mixed with seminal plasma (33.3 percent final concentration) and incubated at 37 C for 90 minutes.
Results, published in BMC Infectious Diseases (Oct 16, 2006), showed that the efficacy of the polymeric microbicides are partly compromised by the seminal plasma. The reason appeared to be the difference in their acidity.
“Semen contains the polyamines spermine, spermidine, and putrescine, which are positively charged at neutral pH,” explained Neurath, “while the polymeric anti-HIV-1 inhibitors all have negative charges.” This explained the complex formation previously observed in previous studies between polyamines and sulfonic and carboxylic anions.
While synthetic technology had been associated with dangerous impacts on the human body, nature apparently needs critical help sometimes.
“Nature,” wrote John Milton in Paradise Lost (1667), “Hath done her part; do thou but thine.” (For comments and suggestions, email to ztliteratus6046@lycos.com or text to 0927-979-3519.)
