Leading Clinical Edge

Biotechnology

Testicles Provide Better Stem Cells?

German scientists have successfully isolated a new type of stem cell from adult mice testes that can grow into a full range of tissue types, offering a possible alternative to embryonic stem cells for medical therapy. Although the study involved mice, the researchers believe it should be possible to produce similar results with samples taken from human testicles through a biopsy. The scientists created a transgenic breed of mice in which sperm-producing stem cells were labeled with a fluorescent marker. This allowed them to isolate the 0.3% of cells in mouse testes that are actual stem cells. These stem cells were then cultured and were found to resemble embryonic stem cells. The stem cells were able to transform into a number of different types of cell, including heart, brain and skin cells. The study also involved tagging the cells and injecting them into young mouse embryos to determine whether they could develop inside a living mouse. This proved to be successful in 90% of the cases. David Cyranoski, et al., Nature, 440(7084): 586–587. (March 30, 2006).
http://www.nature.com
(subscription required)

Cardiology & Cardiovascular Surgery

Study Reveals New Understanding of Valve Dysfunction

Microparticles, which are normally shed by endothelial cells, may damage heart valves when their concentrations increase, as they are known to do in certain diseases, report researchers from the Medical College of Wisconsin. The scientists subjected human cardiac-valve endothelial cells to high levels of endothelium-derived microparticles (EMPs), which then caused the valve cells to show signs of impaired proliferative and migratory function. Normal physiologic concentrations of EMPs, however, appeared to stimulate endothelial-cell growth. Research findings were presented by Tara Sander, MD, on April 4, 2006, at the Experimental Biology 2006 meeting in San Francisco.

Endocrinology

Mice Recover From Diabetes

Three separate studies have demonstrated that severely diabetic mice can recover if their faulty immune responses are repaired. Researchers from the University of Chicago, Washington University in St. Louis and Harvard injected diabetic mice with Freund’s complete adjuvant, a mixture of water, oil and a portion of dead bacteria. This mixture overstimulates the immune system cells, which then attacks the pancreas, making those white blood cells self-destruct. As a result, this prevents the white blood cells from attacking, allowing the pancreas to cure itself. The success rates in each of the studies were calculated differently, but in each case the researchers reported that a significant proportion of mice were cured. Anita Chong, et al., Science, 311(5768): 1774–1775 (March 24, 2006); Junko Nishio, et al., Science, 311(5768): 1775–1778 (March 24, 2006); Anish Suri, et al., Science, 311(5768): 1778–1780 (March 24, 2006).
http://www.sciencemag.org

Chong Abstract
Nishio Abstract
Suri Abstract

Gastroenterology

Gastric Electrical Stimulation Shows Promise

Gastric electrical stimulation (GES), which uses endoscopically placed electrodes to reduce patients’ food and water intake, could be a viable treatment for obesity, according to researchers from the University of Texas at Galveston. The small 12-patient study examined the effects of temporary GES during a three-day period on symptoms, gastric accommodation, food intake and gastric emptying. The researchers found that using GES decreases food and water intake and seemed to delay gastric emptying. Jun Liu, et al., The American Journal of Gastroenterology, 101(4): 798–803 (April 2006).
http://www.amjgastro.com

Imaging

Imaging Technique May Reduce Breast Cancer Surgeries

Medical terahertz imaging has the potential to eliminate the need for multiple breast cancer surgeries and tissue excisions to get clear surgical margins, report researchers from Cambridge, England.  A recent 22-patient study demonstrated that terahertz pulsed imaging could reliably distinguish between normal breast tissue, tumor and even early stage in situ cancers in excised tissue samples.  Essentially, this technology has the ability to assist surgeons in immediately identifying residual cancer after the main tumor has been removed, thus minimizing the need for additional surgeries.  Currently, it takes several days to receive results of histopathologic examinations of excised tissue. Therefore, surgeons do not always know if all of a tumor has been removed until well after the initial surgery, and in many cases repeat surgeries have to be scheduled. Anthony Fitzgerald, et al., Radiology, 239(2): 533–540 (May 2006).    
http://radiology.rsnajnls.org

Ophthalmology

Artificial Eye Imitates Insect Eyes

Bioengineers at the University of California, Berkeley, have developed a series of artificial eyes, using the eyes of insects such as dragonflies, bees and houseflies as models. These biologically inspired artificial eyes are the first hemispherical, three-dimensional optical systems to integrate microlens arrays with light-conducting channels that have been created by beams of light. The eyes consist of pinhead-sized polymer resin domes spiked with thousands of light-guiding channels, each topped with its own lens. Each is packed together in the same hexagonal, honeycomb pattern as in an insect’s compound eye and is also closely similar in size, design, shape and function to an ommatidium, the individual sensory unit of a compound eye. The researchers believe that these eyes could be used in endoscopies and image-guided surgeries that require cameras, as well as a number of clinical treatments that can be controlled by implanted light delivery devices. Ki-Hun Jeong, et al., Science, 312(5773): 557–561 (April 2006).
http://www.sciencemag.org

Orthopedics

Bio-Gel Helps Culture Cartilage Cells

A new type of “bio-gel” developed by researchers from the United Kingdom, provides a pH neutral environment for culturing cells in 3-D. The bio-gel is the first pH neutral material made from combinations of di-peptides to provide an environment in which cells can be cultured. Since the gel mimics the properties of cell scaffolds that naturally occur in the body, it could potentially be applied to wound healing and tissue engineering. The researchers have already been successful in culturing cartilage cells using the gel. They discovered that both the properties of the gels and the cell response to the gels could be controlled using different combinations of di-peptides. Rein Ulijn, et al., Advanced Materials, 18(5): 655–659 (March 2006).
http://www3.interscience.wiley.com/cgi-bin/jhome/10008336

Pediatrics

Newborn Screening Test Detects Enzyme Deficiencies

Researchers from the University of Washington have developed a relatively simple test to detect enzyme deficiencies, which can result in rare metabolic diseases such as Tay-Sachs, Fabry and Gaucher syndromes. The test involves drawing blood from a baby’s heel and drying it on a paper card. A two-millimeter section is punched out of the spot, is then rehydrated, and the target enzymes are incubated and measured using tandem mass spectrometry. A sample can be screened for possibly 15 enzyme deficiencies at the same time and the entire process takes less than two days. To date, the test has been able to detect seven diseases. Research findings were presented at the American Chemical Society national meeting on March 28, 2006, in Atlanta. For more information, contact Frank Turecek at turecek@chem.washington.edu.

Vascular Surgery

Minimally Invasive Treatment for Thoracic Aortic Trauma

A new, minimally invasive procedure for repairing blunt thoracic aortic trauma has been developed by surgeons at the University of Cincinnati. The procedure is conducted by placing a standard surgical stent in the aorta and lining it with a series of small endografts, which protect the damaged area without stopping blood flow to the rest of the body. Once in place, the dual lining supports the weakened vessel walls and allows blood to continue flowing through the aorta without applying pressure to the damaged area. The FDA has yet to approve a device for treatment of blunt thoracic aortic trauma and custom-made devices are usually large and difficult to use in emergency situations. Research findings were presented on May 6, 2006, by Joseph Giglia, MD, at the annual meeting of the Association of Vascular Surgeons in Cincinnati, Ohio. For more information, contact Joseph Giglia, MD, at joseph.giglia@uc.edu.