Here is the first man to be cured of HIV- AIDS

Timothy Ray Brown, 45, from San Francisco Bay Area, is in the news – as the first man cured of HIV- AIDS. “I think so,” he calmly tells his interviewers who ask if he actually is cured.

Brown has been facing cameras, gun mikes and diagnostic kits ever since the publication of a research paper on his unique case in the journal Blood in December 2010.

The researchers led by Kristina Allers and Gero Hutter at Charite University Medicine Berlin documented what can be dubbed as a miracle.

The successful reconstitution of a set of white blood cells that the HIV eats up in Brown’s body is a “very rare” occurrence, they noted.

Brown, who was tested HIV back in 1995 in Germany, was later diagnosed with another disease — leukaemia or blood cancer that involves an abnormal increase in white blood cell.

He was treated with bone marrow stem cell transplant — a cure for blood cancer. The stem cells came from a donor with a rare gene mutation that involves immunity to HIV — again a rare occurrence.

The mechanism involved special white blood cells called CD4+ helper T cells. When a dangerous material like a bacterium or a virus is detected in the body, immune cells immediately stimulate these special cells.

The helper T cells further activate and direct other immune cells to fight the disease. HIV specifically attacks helper T cells, making the body unable to launch a counter offensive against invaders.
Hence, AIDS patients suffer from other lethal infections. The researchers in Berlin showed that after stem cell therapy Brown’s body had reconstitution of CD4+ T cells at a systemic level and specifically in his gut mucosal immune system.

“While the patient remains without any sign of HIV infection,” they wrote. Brown has quit taking his HIV medication. The secret is that if the white cells could be manipulated to a state in which they are no longer infected or infectable by HIV that would mean a functional cure.

Researchers, however, have warned that though the study offers promise, it is not a surefire cure from the dreaded disease — transplants are risky, and this involved a very rare transplant. Brown is a rather lucky man. He said in a recent interview that appeared in the San Francisco media about his cure: “It makes me very happy — very, very happy.”

Read more »

Mystery unlocked in photosynthesis step

Tempe, Ariz. - An international team of scientists, including two from Arizona State University, have taken a significant step closer to unlocking the secrets of photosynthesis, and possibly to cleaner fuels.

Plants and algae, as well as cyanobacteria, use photosynthesis to produce oxygen
and "fuels," the latter being oxidizable substances like carbohydrates and hydrogen. There are two pigment-protein complexes that orchestrate the primary reactions of light in oxygenic photosynthesis: photosystem I (PSI) and photosystem II (PSII). Understanding how these photosystems work their magic is one of the long-sought goals of biochemistry.

The ASU scientists working with collaborators at the Max Planck Institute at Mülheim a.d. Ruhr in Germany have been investigating the PSI reaction center.

They have made an important observation that is nut-shelled in the title of a paper published in this week's online Early Edition of the Proceedings of the National Academy of Sciences (PNAS). The paper is titled "Independent initiation of primary electron transfer in the two branches of the photosystem I reaction center."

Kevin Redding, an associate professor in the department of chemistry and biochemistry in the College of Liberal Arts and Sciences, is leading the research at ASU. His lab created mutations in a single-celled green alga (Chlamydomonas reinhardtii or 'Chlamy' for short). Using these mutants, Redding and collaborators have shown that the primary light-triggered electron transfer event in the PSI reaction center can be initiated independently in each of its parallel branches. At the same time, they showed that PSI has two charge separation devices that effectively work in parallel to increase the overall efficiency of electron transfer.

"Although we knew that both branches were being used in PSI, and that our mutations had an effect upon the relative use of each pathway, what we did not know was how these mutations were having their effect," Redding explained. "Unraveling that has led to the discovery of how charge separation – the moment when electromagnetic energy is converted to chemical energy – actually occurs."

The team at the Max Planck Institute (MPI) was led by Alfred Holzwarth. His coworkers, Marc Müller and Chavdar Slavov, used lasers that sent out pulses of light lasting only 60 millionths of one billionth of a second to investigate the electron transfer processes in the two branches of PSI. This allowed them to look at extremely early events in the photosynthetic mechanism, events occurring in just a few picoseconds (a millionth of a millionth of a second), which is a time so short that a typical lattice atom could only execute a dozen oscillations on its lattice site.

This extremely sophisticated experiment and analysis required two years of laboratory effort from Rajiv Luthra, a graduate student in the Redding laboratory, to prepare a sample of sufficient purity to use. To interpret the observations, the researchers at the MPI had to develop a specific kinetic modeling approach that allowed them to estimate the individual electron transfer rates within the two branches. Comparison of mutants made in each branch with the non-mutant PSI was crucial to untangle these rates.

The current research is important for two separate reasons. Firstly, an understanding of how these complex processes work in Nature is crucial to future fundamental research in photosynthetic reaction centers, and this discovery may well be universal. Secondly, the use of two charge separation devices working cooperatively to maximize efficiency is a design theme that may well be applied in future efforts to create artificial photosynthetic devices.

Our society has urgent need of a renewable source of fuel that is widely distributed geographically, abundant, inexpensive, and environmentally clean. The use of solar energy to produce a clean fuel such as hydrogen is essentially the only process that can satisfy these criteria on a scale large enough to meet the world's energy demands. Redding is also a member of the DOE-funded Energy Frontier Research Center (led by Devens Gust, professor of chemistry and biochemistry at ASU). Its goal is to produce a clean, renewable fuel by mimicking the natural process of photosynthesis.

Read more »

Synthetic lethality: A new way to kill cancer cells

Ovarian and breast cancer treatments being developed that mix a protein inhibitor and traditional anticancer drugs are showing signs of success, according to a new review for Faculty of 1000 Biology Reports.

Susan Bates and Christina Annunziata looked at several recent papers on this form of treatment, which takes advantage of the synthetic lethality of BRCA (breast cancer susceptibility genes) and poly-ADP ribose polymerase (PARP) proteins to attack cancerous cells whilst sparing healthy ones.

BRCA and PARP are two key players in DNA repair and have different but complementary functions in the cell. Loss of the BRCA protein still allows the cell to survive but greatly increases its chances of becoming cancerous through the accumulation of mutations. The loss of both proteins, however, kills the cell in a process called synthetic lethality.

Researchers, by using drugs to block the activity of PARP in cells missing BRCA, such as those found in certain breast and ovarian cancers, can help spare healthy, non-cancerous cells because they have functional BRCA and are not affected by the loss of PARP. Thus, only cancer cells without functional BRCA protein are killed by drugs that inhibit PARP.

Recent clinical trials have shown that cancers caused by mutations that knock out BRCA activity can be controlled by blocking PARP activity with specific drugs. Patients were treated with traditional anticancer drugs alone or in combination with one of two new PARP inhibitors, olaparib or BSI-201.

Bates notes that patients on combination therapy had improved "[disease] progression-free survival, and overall survival" as compared to patients treated with traditional drugs alone.

Bates is optimistic about the promise of combining PARP inhibitors with existing cancer drugs. She says that the results of these clinical trials "have provided proof of principle in achieving synthetic lethality" with PARP-inhibiting drugs and that treatments combining novel PARP inhibitors with traditional chemotherapeutic drugs have the potential to vanquish BRCA-associated breast and ovarian cancers.

Source : Faculty of 1000: Biology and Medicine

Read more »