Health – Page 3 – GOLLYGEE!

02.25.2016

spermbots

Fortune magazine reports on some exciting research related to male infertility. As the headline says, “This Robot Is Like a Chauffeur for Slow Sperm”. Basically, researchers have developed tiny metal helices that wrap around the tail of a sperm cell. The helix effectively turns the sperm into a micromotor that can be directed a magnetic field. They are calling the invention a “spermbot”.

The video above lets you see how spermbots can propel once immobile sperm toward an egg. So far scientists haven’t been able to actually fertilize an egg using the spermbot, but they are optimistic that with further study and development, this might someday improve success of in vitro fertilizations.

Take a look at the original research paper here in Nano Letters. Caged Oligo explains some of the science behind the machine.

02.24.2016

a ring to prevent HIV

A monthly vaginal ring can prevent HIV transmission in women.

Bob Roehr at Scientific American reports on how the insertion of a vaginal ring can prevent HIV transmission in women. From the article:

Women use a silicone elastomer vaginal matrix ring that dispenses an anti-HIV drug—similar to ones used to dispense birth control hormones—and are protected from HIV infection for a month.

According to researchers who tested the ring on more than 4,500 African women between the ages of 18 and 45, the concept works. Women who used the ring were 27 percent less likely to become infected with the HIV virus, according to data presented last Monday at the annual Conference on Retroviruses and Opportunistic Infections in Boston.

The ring must remain inserted the entire month for the treatment to work most effectively. Researchers are currently working on ways of improving the ring to make it easier for women to adhere to the treatment.

“We need to figure out what women really want,” says Carl Dieffenbach, director of the Division of AIDS, National Institute of Allergy and Infectious Diseases who oversees more than a billion dollars of National Institutes of Health–funded AIDS research and was not involved with the study. “This is just a step along the way. Do we do better if we offer women protection from pregnancy as well as protection from HIV?” The next studies might have both birth control and antiviral properties or perhaps just contraception instead of a placebo.

10.28.2015

artemisinin

The Nobel Assembly at Karolinska Institutet awarded the 2015 Nobel Prize in Physology & Medicine earlier this month. The honors went to the scientists who discovered artemisinin and avermectin, which respectively treat malaria and parasitic infections. We’ll explore ivermectin in another post, but today let’s talk artemisinin!

Chemistry of artemisinin

Artemisinin is a sesquiterpene lactone compound that contains an endoperoxide bridge – a functionality biochemists are unaccustomed to seeing, but is believed to be essential for the drug’s anti-malarial activity. The drug is the fastest treatment available for malaria cause by the parasite Plasmodium falciparum.

The structure of artemisinin. Note the lactone in the lower portion of the molecule above, and the peroxide bridge -O-O- in the top left portion.

Artemisinin is biosynthesized by the plant Artemisia annua, or sweet wormwood. The plant is native to China and Vietnam, but is also grown in East Africa. When the plants reach full size after about 8 months of growth, the leaves are dried and then artemisinin is extracted by organic solvents, with hexane usually being the solvent of choice.

Leaves of Artemisia annua.

Semi-synthetic pathways to artemisia also exist. Genetically engineered yeasts can produce artemisinic acid, a precursor to artemisinin. Artemisinic acid can then be purified and further modified synthetically to yield artemisinin. Scientists have also engineered tobacco plants to produce artemisinic acid.

Mechanism

How artemisinin works is hotly debated. The likeliest mechanism involves radical formation by the endoperoxide bridge. In this mechanism, iron from the heme in blood reduces the peroxide bond in artemisinin, producing an iron-oxo species. This iron-oxo species leads to to a series of reactions that generate radical oxygen species that kill the parasites causing malaria. Experiments show that exposure to artemisinin leads to damage in parasites’ vacuolar membranes, and that the compound is present in the Golgi, endoplasmic reticulum, and mitochondria of P. falciparum after exposure.

Discovery

In 1967, Tu Youyou led a Chinese research program to find a treatment for malaria as mandated by Chairman Mao. After scouring the historic literature, for homeopathic and folk remedies to malaria symptoms, Tu Youyou stumbled across a recipe for extracting Artemisia annua in The Handbook of Prescriptions for Emergency Treatments written in 340 BC . After modernizing and improving the extraction prtocol, Tu Youyou discovered the extract was indeed anti-malarial. And upon purification artemisinin, which is named qinghaosu in Chinese, was the compound responsible for its activity. The results of his research were published in the Chinese Medical Journal in 1979.

So, that’s artemisinin in a nutshell. Artemisinin has saved countless lives world-wide. It is typically used in combination therapies these days. But even so, malaria still is estimated to kill over 1 million people each year.

GOLLYGEE!

Category: Health (page 3 of 27)

spermbots

a ring to prevent HIV

artemisinin