Ken Southward graduated from the University of Toronto Dental School in 1971. Dr. Southward achieved the Fellowship level in the Academy of General Dentistry. He maintained a preventively oriented dental practice in Ontario, Canada for 43 years. He has published articles on nutrition, periodontal disease and the systemic process of dental caries.
The links of oral and systemic diseases are continuing to emerge. While periodontal disease has been linked to many systemic diseases through the process of uncontrolled inflammation, the same paradigm has only recently been applied to dental caries. Southward’s systemic theory shows the caries process starting in the hypothalamus part of the brain. Through the endocrine system, signals are sent to the parotid glands. Like the pancreas, the parotid glands have both an endocrine and exocrine function. The endocrine part of the parotid gland secretes parotid hormone, which stimulates a centrifugal fluid flow through the tooth. This dentinal fluid flow both cleanses and nourishes the tooth from the inside. A high sugar diet elevates blood glucose levels. This causes the brain to signal for a halt or reverse of the dentinal flow. This allows oral acids to be absorbed by the tooth. Figuratively, a healthy tooth sweats and an unhealthy tooth acts more like a sponge. These acids irritate the dentin and pulp of the tooth, which responds with an inflammatory response. When inflammation can no longer be controlled, tissue breakdown occurs in a process similar periodontal disease. It is the body’s own enzymes rather than acid that causes caries in the dentin. Antioxidants have been shown to preserve the dentinal fluid flow, even in elevated sugar diets. Vitamin K2 may preserve the centrifugal fluid flow moderated by the endocrine system. It may also influence salivary ph in the exocrine function of all salivary glands.
Masakatsu Fukuda had completed his Ph.D at the age of 31 years from Nihon University and postdoctoral studies from International Agency for Research on Cancer (IARC; Lyon, France). He is a junior associate professor of Division of Oral and Maxillofacial Surgery, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry. He has published more than 40 papers in reputed journals.
Mangosteen, scientific name Garcinia mangostana, is a tree found in South East Asia, and pericarps of the fruit have been used in folk medicine for the treatment of many human illnesses such as skin and wound infections, and inflammatory diseases. Mangosteen fruit rinds contain high concentration of xanthones. -Mangostin, and -mangostin are the main xanthones isolated from G. mangostana. Xanthone extracts from G. mangostana have been reported with chemoprevention effects against the chemically induced colon cancer via the reduction of c-myc expression, suppression of tumor growth and metastasis in a mouse model of mammary cancer, and a recent report showed the inhibition of prostate cancer growth by -mangostin, the main constituent of the G. mangostana xanthones. However, it is unclear whether -mangostin induces cell death to oral cancer. Then, this study examined the impact of -mangostin against oral squamous cell carcinoma. At first, we analyzed the expression of c-myc in 5 human oral suquamous cell carcinoma (HOSCC) cells. The expression level of c-myc mRNA was maximum in SAS cells, while on the other hand, it was minimum in HSC-4 cells. Hence, SAS cells were treated with -mangostin. The-mangostin slightly induced cell death to SAS cells, but not strongly. Synergistic effects by the combined treatment of -mangostin and anti-cancer drugs were reported. Then, we attempted to evaluate the synergistic effect on cell growth when cytokine, TNF related apoptosis inducing Ligand (TRAIL), was used with -mangostin (total 10 ng/ml and 30 μM). As the result, cell death was clearly induced to SAS cells. It was demonstrated that the combined treatment of -mangostin and TRAIL in SAS cells led to apoptosis via the activation of caspases-9, -3/7. Furthermore, this apoptosis was induced by G1 cell cycle arrest in SAS cells. These data suggested that the combination therapy by -mangostin and TRAIL might be a great useful with a tremendous amount of potential as an anti-oral cancer drug.