Developments to Watch
FIGHTING FUNGUS WITH FAT
WHEN THE BODY'S IMMUNE system is weakened by AIDS or cancer chemotherapy, normally harmless fungi such as aspergillus (picture) can spread to the lungs and other organs, causing inflammation. Drugs based on a compound called amphotericin-B control fungal infections but cause side effects such as chills and kidney damage. So the Food & Drug Administration recommends their use only for diagnosed fungal infections.
Now, drug companies and research scientists are making important strides against fungal infections. NeXstar Pharmaceuticals Inc. in Boulder, Colo., is selling a drug called AmBisome, which encases amphotericin-B in tiny, synthetic bubbles of fat called liposomes. These keep the drug molecules sealed up until they have time to reach the fungus cells. So less goes a longer way. The FDA has cleared AmBisome for first-line use against suspected fungal infections.
Separately, biologist Gerald Fink, director of the Whitehead Institute for Biomedical Research in Cambridge, Mass., and his colleagues have shed light on the infectious mechanism of Candida albicans, another fungal scourge for AIDS and chemotherapy patients. The fungus' infectiousness depends on a genetic switch that lets it project protein filaments into host cells. In experiments with mice, Fink found a way to deactivate this switch and reduce the fungus' virulence.EDITED BY NEIL GROSSReturn to top
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EVERYTHING ON TV BECOMES 3-D
TECHNOLOGY CAN'T MAKE TV shows more interesting, but it can improve how they look. The latest leap is in 3-D special effects, which have evolved far beyond the red-and-blue plastic glasses of a few 1950s films. Chequemate International Inc. of Salt Lake City is demonstrating a $600 set-top box called C-3D that plugs into a TV or VCR and digitally doctors images. Viewed through special glasses connected to the box by wires, ordinary TV images take on a lifelike, 3-D veneer. And video images shot to C-3D specifications seem to jump from the screen.
Like IMAX Corp., the Canadian 3-D filmmaker, C-3D relies on liquid-crystal "shutter glasses." Lenses in front of both eyes switch from transparent to opaque about 60 times a second, and the switching is synchronized with images delivered separately to each eye.
Chequemate wants to enlist film and cable companies to develop special 3-D content. But it may face a tough sell with couch potatoes: Getting the system running requires substantial fiddling with TV and VCR wires and with set-up buttons on a special C-3D remote control.EDITED BY NEIL GROSSReturn to top
A FASTER TEST FOR DONOR MATCHES
CLOSELY MATCHING THE IMMUNE CELLS OF A PATIENT and donor greatly increases the patient's chance of surviving an organ or bone marrow transplant. But tissue-typing tests are time-consuming, costly, and give only a vague idea of a patient's immune-cell makeup.
Help is on the way from Visible Genetics Inc., a publicly traded DNA analysis company in Toronto. It has developed a benchtop DNA sequencer and tissue-typing kit that lets doctors examine a patient's DNA on a computer screen within hours of taking a blood sample. Doctors type the patient on the basis of genes that produce immune-system proteins called human leukocyte antigens, or HLAs. Individuals who produce similar HLA proteins are likely to be compatible.
Doctors first isolate white blood cells called leukocytes from the blood and extract DNA. Then they warm the sample, amplifying the stretch of DNA that corresponds to the HLA gene. The sample is run through the automated sequencer, which displays the specific chains of nucleotides as strands on a computer screen. By analyzing colored peaks and valleys of the DNA code, doctors can identify the specific HLA gene type. The kits, which have been tested for research applications at medical centers in Atlanta, Milwaukee, and Boston, may cost about $60 per patient.By Johanna Knapschaefer EDITED BY NEIL GROSSReturn to top