Several epidemiological studies have shown that green tea may have protective effects against some types of cancer. Green tea extracts also inhibit tumor growth in animals. Research has shown that epigallocatechin-3-gallate (EGCG), a compound present in these extracts, provides the chemoprotective benefit by working through the epidermal growth factor receptor (EGFR).
Over-expression of EGFR frequently occurs in human head and neck squamous cell cancers and is an indicator of a poor prognosis. So Dr. Muneyuki Masuda, an oncologist who specializes in otolaryngology at Kyushu University in Japan and who has been working in the laboratory of Dr. I. Bernard Weinstein, director emeritus of the Irving Comprehensive Cancer Center and the Frode Jensen Professor of Medicine, studied the effects EGCG might have on head and neck cancer cell lines via the EGFR signaling pathways.
Drs. Masuda and Weinstein found that a dose of 10 micrograms per milliliter of EGCG could kill 70 percent of the cells growing in vitro. The compound works by stopping the cells in the G1 phase of the cell cycle and by inducing apoptosis. EGCG decreases cyclin D1 expression, which explains the arrest in G1; inhibits the activity of antiapoptic genes Bcl-2 and Bcl-Xl; and increases pro-apoptotic Bax and caspase 9 activity. ECGC also inhibits the synthesis of the angiogenesis factor VEGF.
In addition to promoting apoptosis and cell cycle arrest and inhibiting angiogenesis, EGCG also markedly enhanced the killing effect in cell culture of the chemotherapeutic drug 5-fluorouracil. A tenth of a microgram per milliliter of EGCG promoted the killing effect of 5-FU by approximately 50 fold.
The researchers suggest that green tea extracts, which are relatively non-toxic, may be beneficial in the treatment of patients with head and neck cancers. Further studies are necessary to determine the proper dosage of the extract. Dr. Masuda presented these findings at the International Society of Preventive Oncology meeting in February. The research was published in December 2001 in Clinical Cancer Research.
EGCG may also inhibit other types of cancers via other growth factor receptors. Recent evidence from Drs. Masuda and Weinstein indicates that EGCG inhibits HER2-neu activity in breast cancer cell lines; this natural product, therefore, may also be useful in treating patients with breast cancer.
The National Foundation for Cancer Research, the T.J. Martell Foundation, and the Richard and Hinda Rosenthal Center for Complementary and Alternative Medicine sponsored this research.
In the past decade, researchers have increasingly found that many heart bypass patients suffer from a loss in cognitive function after surgery. Much of the blame has been placed on the heart-lung machine that pumps and oxygenates the patients blood during the procedure.
Now P&S researchers, led by Dr. Eric Heyer, associate professor of clinical anesthesiology and clinical neurology, have found that bonding heparin to the tubing and reservoirs of a heart-lung machine may reduce cognitive loss.
The randomized study found that 26 patients undergoing cardiac surgery with heparin-coated circuits in the heart-lung machine suffered less cognitive loss after surgery than 35 patients undergoing surgery with the standard circuits. Cognitive function was measured before surgery, five days after surgery, and six weeks after surgery with neuropsychometric tests that measured the patients memory, attention, and motor skills.
The heparin group also had fewer inflammatory molecules and more clotting inhibitors than the control group.
The researchers believe the heparin-coated circuits may reduce a systemic inflammatory response by shielding the white blood cells from the plastic surfaces of the tubes. Without heparin, white blood cells recognize the plastic surfaces as foreign and release molecules that promote inflammation. In the brain, the inflammatory molecules augment the possible injury caused by particles freed from the surgical site. Heparins role as an anti-coagulant may also reduce the formation of small clots in the machine that later lodge in the brain and block oxygen delivery.
The results agree with another study of heparin-coated circuits, but the other research did not include a control group. The P&S study, funded by the anesthesiology department, the Charles A. Dana Foundation, and the NIH, appeared in the February Journal of Cardiothoracic and Vascular Anesthesia. Dr. Craig Smith, professor of surgery; Linda Mongero, director of clinical perfusion at New York-Presbyterian Hospital; and Dr. Barry Esrig, assistant clinical professor of surgery, also contributed to the study.
Dr. Heyer says the cognitive side effects of bypass surgery are prompting surgeons to ask if they can avoid using the heart-lung machine. But in cases when we do use it, Dr. Heyer says, it behooves us to find a better circuit.
Nutrition education and a heart-healthy diet at school and at home can reduce the amount of artery-clogging saturated fat children eat, according to new research findings by Columbia Health Sciences researchers and colleagues.
The study analyzed the effectiveness of a nutrition education and food service modification program called Healthy Start in nine Head Start schools in upstate New York between Fall 1995 and Spring 1997. Head Start is a national initiative that provides education, health, and social services for low-income preschool children.
In the study, two-thirds of the schools followed the Healthy Start program, the other three schools served as a control. The Healthy Start preschool curriculum taught the 2- to 5-year-old students about more nutritious foods and taught their mothers and preschool cooks how to prepare meals with less saturated fat. Dieticians documented what the children ate in school and the childrens mothers wrote down what the kids had at home. For each of the 1,296 children in the study, the investigators also used finger-stick blood tests to measure lipid content twice a year.
The researchers found that over the two-year study period, preschoolers in the Healthy Start program ate less than 10 percent of their daily calories as saturated fata level nutrition experts deem is heart healthy. Blood tests also showed that the children eating the lower fat diet had lower cholesterol levels. Children in the control group continued to consume a diet that was too high in saturated fat.
Their study results appeared in the February issue of the Journal of the American College of Nutrition.
Dietary saturated fat can promote high blood cholesterol levels and eventually lead to hardening of the arteries, even as early as adolescence. If children reduce saturated fat intake, we might expect a small decrease in average blood cholesterol levels in children and adults, which could translate into far fewer heart attacks and coronary artery disease deaths later in life, says Dr. Christine L. Williams, professor of clinical pediatrics (in the Institute of Human Nutrition) and lead author of the paper.
Other Columbia Health Sciences researchers who participated in the study were Marguerite C. Bollella, nutrition coordinator, and Dr. Barbara A. Strobino, associate research fellow. Contact Dr. Williams at firstname.lastname@example.org for more information about the Healthy Start Preschool program.