Science News and Resources

INFECTIOUS DISEASE UPDATES

Rapid Genetic Evolution of SARS Increases Transmission Efficiency
A recent issue of Science showcases the work of Chinese scientists who analyzed the genome of the SARS virus, documenting the immense rapidity with which it evolved from an animal pathogen into one capable of affecting human cells. As the virus mutated, its potency soared from being able to infect only 3 percent of the people who came in contact with a patient to an infectivity rate of 70 percent just a few months later.

SOURCE: The Chinese SARS Molecular Epidemiology Consortium, Molecular evolution of the SARS coronavirus during the course of the SARS epidemic in China. Science published online 29 Jan, 2004; 0:10920021-0.

Avian Bird Flu in Asia
Although most of the human cases of avian flu have been traced to direct contact with sick birds, experts fear that the longer it takes to contain the virus, the greater the chances it might link with the human flu virus and become easily transmittable from person to person, sparking a new flu pandemic. Cases have been reported in Cambodia, Indonesia, Laos, Japan, South Korea, Pakistan, and Taiwan. New tests have turned up a disturbing problem with the avian influenza virus that is spreading in Asia: The strain appears resistant to one of the two main classes of drugs used to fight influenza viruses. For the latest information, go to the World Health Organization Web site at www.who.org.

Chiron Begins Human Trials of Combination HIV Vaccines
Chiron, a biotechnology company, announced in January that it will begin human clinical trials of a two-part experimental HIV vaccine. Phase I safety trials on 168 HIV-negative U.S. participants will be conducted in St. Louis, Seattle, and Nashville, Tenn. The first vaccine will contain altered DNA proteins, followed by a second vaccine of protein alone. Following successful completion of Phase I safety trials, Phase II and Phase III efficacy trials will be considered.

WOMEN'S NEWS

Antibiotic Use Linked to Increased Breast Cancer Risk
Two articles in a recent issue of the Journal of the American Medical Association (JAMA) link breast cancer and antibiotic use. Women who used increased amounts of antibiotics appear to have a one-and-a-half times greater risk of breast cancer, according to a new study in the Feb. 18 issue of JAMA. However, the researchers point out that more studies are needed to determine if the association between breast cancer and antibiotics is causal or if there are other underlying factors to be considered.

With breast cancer as the "most frequently diagnosed nonskin malignancy and the second leading cause of cancer mortality in U.S. women," the researchers examined medical data from 10,219 women enrolled at Group Health Cooperative (GHC), a large, nonprofit health plan in western Washington. The study compared 2,266 female health plan members over age 19 with primary, invasive breast cancer to 7,953 randomly selected female health plan members who did not have breast cancer. Their pharmacy database provided data on antibiotic use. Researchers looked at the cumulative number of days of antibiotic use and the total number of antibiotic prescriptions for each study participant. "Increasing cumulative days of antibiotic use and increasing cumulative number of antibiotic prescriptions were associated with increased risk of incident breast cancer, after controlling for age and length of enrollment," the researchers stated. Drs. Ness and Cauley write, "This study provides many (or more) questions than answers. While more research is needed, this study raises the possibility that long-term use of antibiotics may have harmful consequences, especially for patients for whom other therapeutic options are available."

SOURCE:Velicer C, et al. Antibiotic use in relation to the risk of breast cancer. JAMA 2004; 291:827-835. Ness R, Cauley J. (Accompanying editorial) Antibiotics and breast cancer — what is the meaning of this? JAMA 2004; 291:880-881.

Women's Chamber of Commerce
For support in finding capital for your practice acquisition or expansion and networking with other women business leaders, go to www.thewomensnews.com/html/live-connect.asp#money, the Women's Chamber of Commerce Web site. The site offers helpful tips on business, health, and even live teleconferences designed just for women.

ORAL HEALTH MATTERS

Initial Results of Phase III Clinical Trial Shows Promise for Treating Gingival Defects
In March, Isolagen, Inc., a biopharmaceutical company specializing in utilizing a patient's own (autologous) cells for hard- and soft-tissue regeneration announced the results of a Phase III trial. Utilizing 158 patients with intent to treat, 77 percent of 146 patients evaluated responded to treatment over four months, as opposed to 36 percent of the placebo group (Fisher's Exact Test, p<.0001). Earlier this year, Isolagen reported results of a Phase I trial of 21 subjects. With 176 intraoral sites treated with cellular therapy, gingival recession was reversed, with improved deep periodontal pocketing an average of 1.1 mm (p=0.0005). Eighty-one percent of the 21 subjects showed an improvement in pocket depth in treated areas, compared to 33 percent of the subjects showing improvement in pocket depth in placebo-treated areas. (Fisher's exact test p=0.0113)

The patented process requires that patient tissue samples be utilized to reproduce cells for injection into the same patient in areas with gingival defects. Dr. Rena Souza, professor and director of research at the University of Texas Health Science Center Dental Branch, was the co-principal investigator of the study. For further information on the status of additional studies, go to www.isolagen.com.

SOURCE:Esposito M, Coulthard P, Oliver R, Thomsen P, Worthington HV. Antibiotics to prevent complications following dental implant treatment (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd.

Background: Some dental implant failures may be due to bacterial contamination at implant insertion. Infections around biomaterials are difficult to treat and almost all infected implants have to be removed. In general, antibiotic prophylaxis in surgery is only indicated for patients at risk of infectious endocarditis, for patients with reduced host-response, when surgery is performed in infected sites, in cases of extensive and prolonged surgical interventions, and when large foreign materials are implanted. To minimize infections after dental implant placement, various prophylactic systemic antibiotic regimens have been suggested. More recent protocols recommended short-term prophylaxis, if antibiotics have to be used. With the administration of antibiotics, adverse events may occur, ranging from diarrhea to life-threatening allergic reactions. Another major concern associated with the widespread use of antibiotics is the selection of antibiotic-resistant bacteria. The use of antibiotics in implant dentistry is controversial. It would be useful to know whether prophylactic antibiotics are effective in reducing failures of dental implants.

Objectives: To assess the beneficial or harmful effects of the administration of prophylactic antibiotics for dental implant placement vs. no antibiotic/placebo administration, and if antibiotics are of benefit, to find which type, dosage, and duration is the most effective.

Search strategy: We searched the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE. We handsearched several dental journals. No language restrictions were applied. Personal contacts and manufacturers of dental implants were contacted to identify unpublished trials. Most recent search: March 2003.

Selection criteria: Randomized controlled clinical trials (RCTs) with a follow-up of at least three months comparing the administration of various prophylactic antibiotics regimens and no antibiotics/placebo to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections, and adverse events (gastrointestinal, hypersensitivity).

Data collection and analysis: Screening of eligible studies, assessment of the methodological quality of the trials, and data extraction were to be conducted in duplicate and independently by two reviewers. Results were to be expressed as random effects models using weighted mean differences for continuous outcomes and relative risk for dichotomous outcomes with 95 percent confidence interval. Heterogeneity was to be investigated including both clinical and methodological factors.

Main results: No RCTs were identified.

Reviewers' conclusions: There is not appropriate scientific evidence to recommend or discourage the use of prophylactic systemic antibiotics to prevent complications and failures of dental implants. Even though the present review did not assess the effectiveness of prophylactic antibiotics for patients at risk for endocarditis, it seems sensible to recommend the use of prophylactic antibiotics for patients at high and moderate risk for endocarditis, with immunodeficiencies and metabolic diseases, irradiated in the head and neck area and when an extensive or prolonged surgery is anticipated.

UPCOMING CONFERENCES

AACD (American Academy of Cosmetic Dentistry) — April 27-May 1, 2004; The Fairmont Waterfront; Vancouver, British Columbia; www.aacd.com; (608) 222-8583

AAPD (American Academy of Pediatric Dentistry) — May 27-31, 2004; San Francisco Marriott; San Francisco, Calif.; www.aapd.org; (312) 337-2169

AAWD (American Association of Women Dentists) — July 8-11, 2004; Anaheim Marriott; Anaheim, Calif.; www.aawd.org; (800) 920-2293

AGD (Academy of General Dentistry) — July 8-11, 2004; Anaheim Convention Center; Anaheim, Calif.; www.agd.org; (888) 243-3368

NDA (National Dental Association) — July 30-Aug. 4, 2004; Century Plaza; Los Angeles, Calif.; www.ndaonline.org; (202) 588-1697

ADA (American Dental Association) — Sept. 30-Oct. 3, 2004; Orlando, Fla.; www.ada.org; (312) 440-2500

AOS (American Orthodontic Society) — Oct. 21-24, 2004; Westin Riverwalk; San Antonio, Texas; www.orthodontics.com; (813) 264-6677

GNY (Greater New York Dental Meeting) — Nov. 26-Dec. 1, 2004; Jacob K. Javitz Center; New York, N.Y.; www.gnydm.com; (212) 398-6922

KUDOS!

  • to Dr. Cherilyn Sheets, founder of the Children's Dental Center, a comprehensive, state-of-the-art children's oral health center for underprivileged children and their families. Dr. Sheets received the second annual 1-800- DENTIST Cares Award.
  • to Marsha Butler of Colgate Palmolive for receiving the Ed Shils Entrepreneurial Award for her work on "Bright Smiles, Bright Futures," bringing the oral health message to millions of children worldwide.

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