Editor's note: Science Scan is a roundup of recently published biotechnology-relevant research.

Sub-Saharan Africa is hostage to a lethal near-pandemic of HIV-1/AIDS infection and death. So what else is new?

A whistle-blowing paper is in The Lancet, dated June 22, 2002, titled: "HIV-1/AIDS and the control of other infectious diseases in Africa." Its authors are in the Department of Infectious and Tropical Diseases at the London School of Hygiene and Tropical Medicine.

The article opened by warning: "HIV-1 has become a major endemic infection in Africa, with an unusually high potential to interact with other disorders, both through the generation of many immunosuppressed individuals and because its own infectivity and clinical course is altered by other infections." It cites three co-conspiratorial enhancers of HIV/AIDS - namely malaria, STD (sexually transmitted disease) and tuberculosis.

"The high prevalence of untreated STD infections," the paper pointed out, "has been a major factor facilitating the spread of HIV-1 in Africa; with the synergistic interaction between HIV-1 transmission and genital herpes being of special concern for control of both diseases. Increased susceptibility to tuberculosis after infection with HIV-1," it added, "has led to a rising incidence and threat of increased transmission of tuberculosis."

And third among the gang-of-three co-infections: "Clinical malaria occurs with an increasing frequency and severity in HIV-1-infected individuals, especially during pregnancy."

The paper noted, "In sub-Saharan Africa, the HIV-1 epidemic has been superimposed on the long-standing malaria pandemic, which is consistently one of the top three causes of infant and child mortality. WHO [the World Health Organization] estimates that malaria contributes to more than 300 million infections and more than 1 million deaths of children every year, almost all in sub-Saharan Africa." It cited recent evidence that "there are indeed interactions between HIV-1 and malaria. In western Kenya, where between 25 percent and 33 percent of pregnant women are infected with HIV-1, the virus accounts for about a quarter of placental malaria cases, which could affect survival in HIV-1-infected and uninfected infants.

"Furthermore," the paper pointed out, "HIV-1 infection roughly doubles the risk of clinical malaria in non-pregnant adults. In Malawi, blood concentrations of HIV-1 were sevenfold higher in HIV-1-infected adults with acute uncomplicated malaria than in HIV-1-infected blood donors without malaria."

Heterosexual intercourse is the main transmission route of HIV-1 in sub-Saharan Africa. WHO estimates the yearly incidence of curable sexually transmitted diseases in the region to be the highest in the world, with 69 million new cases per year in a population of 269 million adults aged 15 to 49. Reported rates of active syphilis range from 2.5 percent in Burkina Faso to 17.4 percent in Cameroon - several orders of magnitude higher than in Western Europe.

In Africa, HIV-1 and herpes simplex virus type-2 have a synergistic relation. The genital infection rises to 70 percent to 80 percent prevalence by age 30 in some parts of eastern and southern Africa. One explanation: "Male circumcision may be protective against herpes genitalis as well as HIV-1 infection.

"The HIV-1 epidemic," the Lancet paper stated, "has greatly worsened tuberculosis control in Africa. It's the commonest cause of death in HIV-1-positive Africans. Communal settings - including mines, hospitals, prisons and bars - are important sites of tuberculosis transmission. Hopefully," the authors conclude, "antiretroviral drugs will soon be added to the package of care offered to HIV-1-positive individuals. Such treatment will contribute to reduced mortality and tuberculosis prevention by restoring and preserving immune function."

Vitamin E Succinate Lowers Prostate Cancer Risk By Bollixing PSA, Androgen Receptor

Prostate cancer is the most common noncutaneous malignancy, and second leading cause of cancer death in American men. Epidemiological evidence in the mid-1990s showed that a daily supplement of vitamin-E decreased the incidence of prostate cancer from 17.8 percent to 11.7 percent in male smokers.

Vitamin E (alpha-tocopherol) is contained in various edible oils, such as wheat germ, sunflower seed, cotton seed, palm and rice. It also is found in whole grain cereals, lettuce and organ meats - liver, pancreas and heart. It's known as "the fertility vitamin," because vitamin E deficiency causes sterility in men.

A paper in the Proceedings of the National Academy of Sciences (PNAS), dated May 28, 2002, carries the title: "Vitamin E succinate [VES] inhibits the function of androgen receptor and the expression of prostate-specific antigen in prostate cancer cells." Its authors are urologists, pathologists and oncologists at the University of Rochester in New York.

The androgen receptor (AR) is required for the development of both the normal prostate gland and prostate cancer. In the early stages of prostate cancer, almost all tumor cells are androgen-dependent, and respond therapeutically to anti-androgen drugs. But after a few years of such treatment, the cancer usually recurs, rendering anti-androgen therapy useless. Among vitamin E derivatives used to study the inhibition of cancer cell growth, vitamin E succinate effectively blocked the growth of several cancer cells. The co-authors report that VES decreased levels of prostate-specific antigen, a marker for the progression of prostate cancer.

Not So Useless After All, Junk DNA Uses LINE-1 To Plug Into Damaged Genome

Junk DNA is the Rodney Dangerfield of the genetics world. It constitutes nearly half of all human DNA, but many scientists dismiss it as useless genomic gibberish. A study published online in Nature Genetics, released May 13, 2002, suggests that segments of junk DNA called LINE-1 (long interspersed elements) deserve more respect.

The paper is titled: "DNA repair mediated by endonuclease-independent LINE-1 retrotransposition." Its authors are at the University of Michigan Medical School in Ann Arbor. They describe their findings as the first to show in mammalian cells that some human LINE-1 elements can jump to chromosomes with broken strands of DNA, slip into the break and fix the damage.