Decades of research on lab animals have shown that restricting caloric intake can extend lifespan and protect against some cancers and neurodegenerative disorders. Now P&S researchers have evidence that a low-calorie diet retards age-related damage in the retinas of rats, according to their study in the Sept. 19 issue of Biochemical and Biophysical Research Communications.
The new study, led by Dr. Keyang Wang, associate research scientist in ophthalmology at P&S, compared rats on a limited diet with those allowed to eat as much as they like.
Dr. Wang and colleagues found that the rats on restricted diets had significantly higher levels of some protective factors including amino acids and antioxidant levels in the neural retina, which includes all neurons of the retina and the protecting cells around those neurons. They also retained more retinal cells as they aged, keeping a higher density of such cells.
The low-calorie regimen appears to limit harm caused by free radicals, possibly by maintaining the protective factor levels, Dr. Wang says.
"The findings give us an idea of what may be happening in humans, because there are similar biochemical processes at work in both types of retina. But the human retina is more complex than the rat's," Dr. Wang says.
He cautioned that restricted diets are not a "magic bullet" to prevent age-related disease because it would probably be very difficult to follow such a diet. "We need to find out more about the mechanisms behind these benefits to see if there are easier ways to achieve them," Dr. Wang says.
Next, he hopes to investigate further the changes in the retina's protein profiles as the animal ages on both restricted and unrestricted diets. He would also like to examine how the retina gets signals that the body is under calorie restriction.
In a pilot study of northern Manhattan seniors, Columbia School of Dental and Oral Surgery researchers were surprised to find that African-Americans have a higher oral disease burden than Latinos. Even though both groups had similarly high levels of overall dental disease, African-Americans had more missing teeth, while Latinos had more teeth with fillings.
The Hispanics' better oral health may be due to dental care they received earlier in life, says Dr. Kavita P. Ahluwalia, assistant professor of clinical dentistry in the section of social and behavioral sciences, who led the research.
The study consisted of oral exams and interviews of 80 adults age 55 and older who live in two senior centers in Washington Heights and Harlem. The results showed high rates of oral disease, as 34 percent of the study participants had no teeth, along with few trips to the dentist. The average time since the seniors' last dental visit was almost three-and-a-half years.
"Dental and public health professionals must develop interventions to improve access to dental services and the oral health of young adults in both of these populations to prevent the loss of teeth, in order to maintain oral health and function in later life," Dr. Ahluwalia says.
Quality of life issues, such as how many teeth a person needs, are receiving more attention in dentistry, she says. The number of teeth a person has affects his or her ability to chew, smile, talk, socialize, and sometimes maintain a nutritious diet. Besides the loss of teeth, few trips to the dentist also mean that the elderly are not being screened for oral cancer, which is more prevalent in older populations.
Dr. Ahluwalia and her colleagues have received funding to expand the study to examine a larger number of people, including homebound elderly. The study was published in the August issue of the Journal of Community Health.
Columbia University researchers have found that northern Manhattan homemakers carry more antibiotic-resistant strains of some types of bacteria on their hands than hospital neonatal intensive care nurses.
The findings, published in the August issue of the Journal of Hospital Infection, indicate that antibiotic-resistant bacteria are spreading in the community, not just in hospital wards, says Dr. Elaine Larson, professor of pharmaceutical and therapeutic research at the School of Nursing and of epidemiology at the Mailman School of Public Health.
The study compared hand bacteria cultures from 204 homemakers in Washington Heights with those of 119 nurses at NewYork-Presbyterian Hospital. The researchers defined homemaker as the person, usually the mother, with primary responsibility for arranging childcare, cooking, and cleaning. Overall, the nurses had fewer bacteria on their hands than the homemakers. However, both groups had high levels of antibiotic resistance.
Another study of the same homes by Dr. Larson and School of Nursing colleagues, published in the September issue of Emerging Infectious Diseases, suggests that some household members may use antibiotics incorrectly, which helps bacteria develop drug resistance. For example, some people take antibiotics to fight viruses, such as a common cold, because they are unaware that antibiotics have no effect on viruses.
Part of the problem is that some New York City bodegas sell antibiotics without requiring a prescription a common practice in other countries, including the Dominican Republic. Many immigrants who come to New York are used to taking antibiotics without a healthcare provider's supervision.
"We need to work with the community to improve appropriate use of antibiotics to slow the spread of antibiotic resistance," Dr. Larson says. She hopes to involve community leaders and local healthcare providers to collaborate on strategies to reduce the problem.