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Frontlines Image: Erica P. Johnson But will the tooth fairy expand operations? Pamela Yelick is not an evil scientist; she is not creating rats that eat themselves alive. Rather, she and her group at Boston's Forsyth Institute have grown tooth crowns in rodents' abdomens to demonstrate the feasibility of bioengineering mammalian teeth from dissociated cells (C.S. Young et. al; "Tissue engineering of complex tooth structures on biodegradable polymer scaffolds," Journal of Dental Research, 81:695-700, September 2002). Cells were harvested from pig tooth buds and placed on tooth-shaped biodegradable polymer scaffolds; these were then implanted in the rats' omenta, located in the abdomen. After 20 to 30 weeks, small, mineralized tissues containing both dentin and enamel had formed. The group had adopted the technique of coauthor Joseph Vacanti, who had bioengineered neonatal intestines. Both teeth and intestine are derived from epithelial and mesenchymal components, Yelick remarks, and the omentum can supply enough blood to grow larger-sized tissues. "The goal," she says, "is to take someone's own cells and start a tooth growing in someone's own jaw," perhaps even from circulating precursors. They have begun trying to isolate and characterize the putative "dental stem cells" responsible for the structures. Paul Sharpe, professor of craniofacial biology at Kings College, London, was not convinced that the researchers had found stem cells, postulating that perhaps they may have recreated the epithelium-mesenchymal recombination that exists in the early tooth bud. Irma Thesleff's remarks were less biting: The University of Helsinki Academy professor commended the group on its novel use of a biodegradable scaffold. --Josh P. Roberts Photo: Courtesy of Stazione Zoologica Stazione Zoologica escapes merger Naples' renowned marine research institute, the Stazione Zoologica Anton Dohrn, will not be merged with institutes run by Italy's National Research Council (CNR). "We keep the statutes, we remain independent," said Giorgio Bernardi, the Stazione's president, after meeting with vice minister Guido Possa and other officials of the Ministry of Education, Universities and Research. Fears for the CNR's inclusion ensued after an incomplete reform plan, prepared by the ministry, was leaked to a newspaper. The draft listed eight publicly funded but independent institutes that would become part of the CNR, including the Stazione Zoologica (A. Hellemans, "Scientists, government clash over reforms in Italy," The Scientist, 16[20]:30-1, Oct. 14, 2002). Fearing that a merger would negatively affect the institute's research, Bernardi asked local politicians as well as life scientists worldwide for support; 150 scientists from Italy and 300 from abroad responded with letters, he says. The international outcry appears to have worked. --Alexander Hellemans Image: Erica P. Johnson SV40 linked to cancer? Not enough evidence exists to link a polio vaccine contaminated with the simian virus, SV40, to elevated risk for four rare cancers associated with the virus, says an Institute of Medicine report issued Oct. 22 (K. Stratton et al., "Immunization safety review: SV40 contamination of polio vaccine and cancer," Washington, DC: National Academies Press, 2002). An estimated 10 million to 30 million Americans were given the contaminated vaccine between 1955 and 1963. It is unknown who the recipients were, says report coeditor Marie McCormick, professor and chair of the Department of Maternal and Child Health at the Harvard School of Public Health. Further, the epidemiological studies examining a possible link between SV40 exposure and the cancers are flawed, says McCormick. "It would not be possible with the current methodological tools available to know if you had been exposed to SV40 or not." McCormick says those vaccinated have little cause for concern. "Having been one of those people who were potentially exposed, because I was vaccinated at that time, there are a lot of other things I would worry about first." The report was undertaken, says McCormick, "to look at this as a case study and say, 'What are the take-home lessons for thinking about future contamination?'" Among the committee recommendations is a response plan in the event of contamination, and improved procedures to safeguard vaccine manufacturing and storage. --Harvey Black Image: Courtesy of Molly Lenore, Barrett Klein, and the American Museum of Natural History Strep and obsessive-compulsive disorder Is there a tie between strep throat and the development of tic disorders and obsessive-compulsive disorder? (H. Black, "Strep and obsessive-compulsive disorder: what's the link?" The Scientist, 13[18]:4, 1999.) Researchers at the University of Florida and the National Institutes of Mental Health want to find out. Over a 30-month period, these investigators will compare variation in levels of streptococcal antibodies in children with OCD and tic disorders to those disorders' intensities. "The goal is to see if there is a time correlation between strep [antibody] titer fluctuations and their neuropsychiatric exacerbations," says Florida's Tanya Murphy, associate professor of psychiatry. The research, notes Murphy, is not designed to discover if strep throat can cause these disorders, as some researchers have hypothesized. Rather, the prospective study focuses on another question: "It will give us a stronger link that when these kids have exposure to strep and therefore their antibodies are increasing to strep ... is [strep] triggering or worsening their symptoms," she says. Murphy and her colleagues will also examine whether using antibiotics reduces the severity of the psychiatric disorders. "The idea is that the ones who get on antibiotics may have an improved course compared to the ones whose strep remains asymptomatic and are not on antibiotics," she says. --Harvey Black Image: Erica P. Johnson Array on an old CD Researchers are finding uses for compact discs beyond holding your drink. Hua-Zhong "Hogan" Yu, Simon Fraser University, British Columbia, developed a way to create a regular pattern of molecular materials on the surface of a recordable compact disc (CD-R). His team strips off the disc's protective plastic layer with nitric acid. This exposes the regular "mountain-valley" arrangement of a CD-R's thin gold film (H.-Z. Yu et al., "Templated electrochemical deposition of zirconia thin films on 'recordable CDs'," Analytical Chemistry, advance online publication, DOI:10.1021/ ac025686n). "This is an easy, inexpensive, and reproducible method for preparing thin layers of material with an ordered pattern at the microscale," says Yu. They can then attach organic molecules containing gold-loving sulfur. The sulfur-organic layer, once attached, creates a sticky surface to create peptide, DNA, or protein arrays. Yu says he's been using the gold substrates from CD-Rs to assemble molecular layers of DNA. On an array of single-stranded DNA, complementary strands would change the electrical characteristics of the gold film. "The writing-reading mechanism of a CD drive might be adapted to detect these changes on the CD-R surface," Yu says. "This could allow DNA testing to be done on tiny amounts of DNA." Lúcio Angnes, who also investigates such techniques at São Paulo University in Brazil, says that CD surfaces seem more favorable for these processes than ordinary gold surfaces. There could be a stumbling block, however, he adds. "Some manufacturers are substituting gold with silver or aluminum, which won't work as well." --David Bradley Image: Erica P. Johnson Redheads and pain Redheads often turn the heads of passers-by with their distinctive hair color, and now they're drawing particular notice from anesthesiologists. A study released last month at the annual meeting of the American Society of Anesthesiologists linked red hair to an increased need for anesthetics. Edward Liem, University of Louisville, Ky., says the study was conducted based on anecdotal, clinical observations from several anesthesiologists. It is the first example of a phenotype associated with anesthetic dosage. "We've seen differences due to age, but no one before has shown any difference between hair color," he says. Redheads have a dysfunction in the melanocortin 1 receptor that is responsible for their freckles and their hair color. Liem hypothesizes that the defect causes an increase of a-melanocyte stimulating hormone and is responsible for lowering the pain perception threshold. The study indicates that redheads need about 20% more anesthesia than brunettes and blondes. Other physiological observations, such as a tendency toward bleeding and hypertension while under anesthesia, have previously been observed in redheads. But, Liem says, it's questionable whether those are due to receptor dysfunction. --Hal Cohen

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