TechnologyBulletin

Coating technique may create universal blood type

Researchers at the Albany (NY) Medical College have developed a process for camouflaging the surface of red blood cells that, in essence, could create a universal blood type. The process involves coating the cell with a biocompatible polyethylene glycol (PEG). The PEG molecules form permanent covalent bonds on the cell's surface. This coating effectively hides the antigenic molecules on the surface of the red blood cells so that foreign cells are not recognized by the blood recipient's antibodies. For instance, a person who has type A blood will naturally have antibodies that attach to the antigens on the surface of type B blood cells and destroy the foreign blood. However, "the attachment of PEG to the surface of type B blood camouflages the surface of the cell so the antigens can no longer be recognized and thus prevents the destruction of the antigenically foreign red blood cells," explains Mark Scott, associate professor of pathology and laboratory medicine at the college. In addition to allowing blood transfusions between individuals with different blood groups, the technique may prove useful in tissue and organ transplants to prevent rejection, according to Scott. FAX Richard Puff at (518) 262-3880.

Terahertz sensing sees 'invisible' diseased tissue

A scientific breakthrough that could eventually become as important as X-ray and radar technologies may soon make it possible to see real-time images of diseased tissue. Called electro-optic terahertz sensing, the technology was invented under the leadership of Xi-Cheng Zhang, associate professor of physics at the Rensselaer Polytechnic Institute. With a frequency of more than a trillion cycles per second, terahertz signals occupy an extremely large portion of the electromagnetic spectrum between the infrared and microwave bands. Just as we can use visible light to create a photograph, inaudible radio waves to transmit music and speech, or invisible radiation to reveal broken bones, terahertz radiation can also be used to create images or communicate information. Until now, however, no technology existed that could use this radiation to rapidly create these images, according to Zhang. For instance, imaging work performed by Bell labs can create images in the terahertz range, but not in real time. The Rensselaer detector can produce an instantaneous image of 250,000 pixels. The detector features a zinc telluride crystal onto which the terahertz radiation is focused after flowing through the target material. At the same time, a laser "readout" beam is directed into the system and used to convert the spatial and temporal (spectral) distributions into visible images that can be captured by a video camera linked to a computer. Zhang also sees the technology being used to image electric fields, plastic explosives hidden in a suitcase, and "much more." E-mail [email protected].

Blood test rapidly pinpoints heart-attack risk

A new test developed at Washington University School of Medicine in St. Louis may help emergency-room doctors decide whether patients with chest pain are at risk of developing a potentially fatal heart attack. The test, used with 159 patients as part of a two-year study, detects soluble fibrin, the breakdown product of blood clots in blocked arteries. Because it produces results within an hour, the test could help doctors quickly decide which patients should receive aggressive, lifesaving surgical treatment and which should receive drug therapy. The latter is safer and much less expensive, so a way of distinguishing between the two types of patients would save money as well as lives, says Paul R. Risenberg, associate professor of medicine at the school, who headed the research team. In the test, the researchers used a novel assay test (ELISA, Agen, Brisbane, Australia) based on a specific antibody to measure the soluble fibrin. From the test results, the researchers found that high levels of fibrin products (3.6 micrograms per milliliter) in the blood indicated an increased risk of heart attack or unstable angina. E-mail [email protected].

Bacteria sensor detects toxic E. coli bug

Researchers at the Ernest Orlando Lawrence Berkeley National Laboratory have developed a sensor that, for the first time, can instantly detect the presence of toxic E. coli bacteria. The working part of the sensor consists of multiple copies of a single molecule, which is fabricated into a thin film. This molecule has a two-part composite structure. The surface of the molecule, developed by chemist Raymond Stevens and a post-doctorate student, binds the bacteria toxin. The backbone underlying this surface is the technology's color-changing signaling system. The backbone of the sensor molecule consists of a long diacetylene lipid, a molecule similar to phospholipids--the building blocks for cell membranes. Exposure to UV light links the molecules by activating a triple bond within the diacetylene lipids, creating a blue-tinted polydiacetylene (PDA) film. Changes on the film's surface are manifested by the wavelength of light it transmits. When the E. coli toxins bind to their synthetic membrane surface, the backbone chain of PDA reorganizes. The sensor that was blue turns red. The sensors can provide an extremely inexpensive, on-the-spot litmus test for the toxic bacteria, Stevens notes. E-mail [email protected].

Laser/drug therapy beams in on cancerous tumors

Scientists at the Thompson Cancer Survival Center in Knoxville, TN, have developed a cancer treatment that doesn't involve freezing, cutting, burning, or radiation. The treatment, known as photodynamic therapy, uses lasers and light-activated drugs to destroy malignant tumors. The most recent application of the procedure, previously used to treat cancer of the esophagus, involves clinical trails in the care of patients with squamous- and basal-cell carcinomas, the two most common skin cancers. During the procedure, patients are injected with a light-sensitive drug called Photofrin that quickly leaves healthy tissues, but mysteriously remains concentrated in tumor cells for days. Some 48 hours later a delicate optical fiber is placed a few inches away from the skin. The fiber delivers red laser light to the cancerous area, allowing doctors to reach the very base of the tumor. Typical treatments last about 24 minutes. FAX Julie Wood at (423) 541-1733.

Dental disease bows to laser treatment

Premier Laser Systems, Irvine, CA, has received the "first-ever" FDA clearance to market a laser system for a new dimension in dentistry--hard tissue procedure, including caries removal, cavity preparation, and related applications. Clinicians in five states developed data on more than 1,300 procedures using the Centauri^TM yttrium aluminum garnet (YAG) laser system for the final submittal to the FDA. The system resembles a high-speed drill and uses water or air to cool the tooth during cavity removal, while eliminating the piercing sound and vibrations emitted by a regular drill. Premier predicts it will sell as many as 10,000 to 15,000 YAG systems for dental applications within the next decade. The system will cost about $39,000. "Extensive pre-clinical and clinical studies, with a three-year follow up, have shown that Centauri's overall performance and safety offer patient comfort and other significant advantages when compared with the traditional high-speed drill, says Colette Cozean Premier CEO. FAX (714) 951-7218.

Robotic microsurgery makes difficult procedures easier

Anew robotic-assisted surgical system will enable doctors to perform delicate operations to the eye, ear, spine, heart, and brain with greater dexterity. NASA and Dr. Steve Charles of MicroDexterity Systems, Memphis, TN, co-developed Robotic-Assisted MicroSurgery (RAMS). Charles originated the concept of a telerobotic system to assist the microsurgeon, and engineers at the Jet Propulsion Laboratory developed RAMS based on surgical requirements provided by Charles. The primary control mode of RAMS is teleoperation where the operator's hand motions are transferred by a sophisticated joystick-like, hand-controlled device. It includes features that enhance a surgeon's manual positioning and tracking, helping the surgeon to overcome involuntary jerks and tremors. The first element of the RAMS workstation, now under test, is a six-degrees-of-freedom surgical robot made up of a torso-shoulder-elbow body with three-axis wrist. Clinical testing of the system will begin this year. Phone Dr. Charles at (901) 767-6662.

Software gives 'vision' back to the blind

"Unless you have lost your vision you can't realize how great I felt being able to read again," reports Marleen Stubson at the Saskatchewan Institute of Applied Science and Technology. Stubson's testimonial refers to the power of a new reading tool for computers. The Vortex 3.0 release, known as "orthotic" or human augmentation software, takes the computer user to the limits of the mind. Using a patent-pending display and intelligent agent technology, Vortex, developed by Tenax Software Engineering, Olympia, WA, separates legibility factors from the underlying document, giving the user complete control over the presentation of the document contents. It augments every readers' ability, including those who are legally blind, according to Cliff High, Tenax CEO. Vortex 3.0 features speeds to 2,000 words per minute, reactive text, font sizes to 3,000 points, custom color control, and reactive punctuation. E-mail: [email protected].

3-D modeling lets researchers visualize drug molecules

Historically, one of the most daunting challenges in biomedical research has been scientists' struggle to accurately visualize the molecules they were trying to manipulate. Past attempts included tinker-toy-type models and crude wireframe computer drawings. This is no longer the case at Parke-Davis Pharmaceuticals where the use of high-powered workstations, advanced modeling software, and the precision 3-D visualization of CrystalEyes (Sterographics Corp., San Rafael, CA) let the scientists see molecules as 3-D, porous objects with varied topography. CrystalEyes transmits separate left-eye/right-eye images to create the illusion that on-screen objects have depth and presence outside of the computer monitor. In addition, Parke-Davis has created a visualization room where the scientists can capitalize on CrystalEyes' capabilities to determine the exact reaction between a drug molecule and the bio-molecule. E-mail: [email protected].