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Year: 2012 (page 17 of 55)

10.22.2012

hiv antibodies

Schematic diagram of an HIV virus and it’s coat glycoprotein bound to an antibody. Image from Corpus Christi College Oxford.

A South African study offers hope that an HIV vaccine can be developed. Certain changes in the virus’ coat proteins appear to trigger a more robust production of antibodies. From NPR news:

One of the women had neutralized 88 percent of 225 HIV virus subtypes after three years with the virus, while the other woman had neutralized 46 percent of 41 subtypes after two years of infection.

The researchers found that a specific change in the coating of the HIV virus appeared to be the trigger for the women to produce antibodies that could thwart its entry into cells.

One reason the HIV virus has proven so difficult to fight is that it is skilled at hiding from antibodies that can block the virus from attacking cells. But researchers believe that the more they understand how the antibodies develop, the better chance they have at developing an HIV vaccine.
 

The original research paper appears in Nature magazine.

10.22.2012

on the hunt for earth like planets

CHEOPS telescope illustration.

The hunt for Earth-like planets continues. A new telescope project is in development with the hopes to be launched sometime in 2017. From Popular Science.

The new telescope is called CHEOPS, for CHaracterising ExOPlanets Satellite, although it is not shaped like a pyramid. Its targets will be nearby stars that are known to harbor planets. Like Kepler, it will use the transit method of hunting planets, looking for blips in star brightness to tell if something is orbiting around them. This will allow more accurate measurements of a given planet’s radius.

Astronomers know the masses of several planets, partly through observations that measure how the planets affect the wobbling of their stars. Given a radius and a mass, you can figure out density, and this will give clues about the planet’s internal makeup. This will help astronomers learn how other planets form, especially the rocky super-Earths.

Measurements like this will help characterize Earth-scale planets like the one around the Alpha Centauri system, which astronomers announced last week. CHEOPS is just one in a handful of super-precise, powerful telescopes slated to start observing in the next few years, which astronomers believe could finally pinpoint whether life exists elsewhere in the cosmos. For instance: “I think it is realistic to expect to be able to infer within a few decades whether a planet like Earth has oxygen/ozone in its atmosphere, and if it is covered with vegetation,” Martin Rees, Britain’s Astronomer Royal, told Reuters.

10.12.2012

stem cell thyroid

Stem cells have been used to grow a hormone producing thyroid. This is the first report of that gland being regenerated from stem cells. From Scientific American by way of Nature:

Costagliola and her colleagues first genetically engineered embryonic stem cells to express two proteins — NKX2-1 and PAX8 — that are expressed together only in the thyroid. When these cells were grown in Petri dishes in the presence of thyroid-stimulating hormone, they turned into thyroid cells.

Thyroid cells, however, have to be organized into a particular three-dimensional shape before they can work. They need to form small, spherical follicles containing a cavity in which iodide — a component of some hormones produced in the thyroid gland — can be concentrated before being absorbed and used for hormone synthesis.

Remarkably, the stem-cell-derived thyroid cells spontaneously grouped into follicles similar to those in an intact thyroid gland. And Costagliola and her colleagues found that the follicles were able to trap iodide and synthesize thyroid hormones. “When started the project, our hope was to get some cells that could be used to study thyroid physiology,” says Costagliola. “We never expected to get thyroid follicles.”

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