Osamu Shinozuka

Effects of salivary protein flow and indigenous microorganisms on initial colonization of Candida albicans in an in vivo model.

BackgroundCandida albican s is a dimorphic fungus that is part of the commensal microbial flora of the oral cavity. When the host immune defenses are impaired or when the normal microbial flora is disturbed, C. albicans triggers recurrent infections of the oral mucosa and tongue. Recently, we produced NOD/SCID.e2f1-/- mice that show hyposalivation, decrease of salivary protein flow, lack IgA and IgG in saliva, and have decreased NK cells. Our objective was to characterize C. albicans infection and biofilm formation in mice.MethodsNOD/SCID.e2f1-/- mice were used as an animal model for C. albicans infection. C. albicans yeast and hyphal forms solutions were introduced in the oral cavity after disinfection by Chlorhexidine.ResultsThe numbers of C. albicans colonized and decreased in a time-dependent manner in NOD/SCID.e2f1+/+ after inoculation. However, the colonization levels were higher in NOD/SCID.e2f1+/+ than NOD/SCID.e2f1-/- mice. In the mice fed 1% sucrose water before inoculation, C. albicans sample was highly contaminated by indigenous microorganisms in the oral cavity; and was not in the mice fed no sucrose water. The colonization of C. albicans was not influenced by the contamination of indigenous microorganisms. The hyphal form of C. albicans restricted the restoration of indigenous microorganisms. The decreased saliva in NOD/SCID.e2f1-/- did not increase the colonization of C. albicans in comparison to NOD/SCID.e2f1+/+ mice. We suggest that the receptor in saliva to C. albicans may not be sufficiently provided in the oral cavity of NOD/SCID.e2f1-/- mice.ConclusionThe saliva protein flow may be very important for C. albicans initial colonization, where the indigenous microorganisms do not affect colonization in the oral cavity.

Study of the oral microbial flora in patients with renal disease

Aim:  The aim of this study is to bacteriologically investigate the oral environment in patients with renal disease and thereby reveal their influence on both caries and periodontal diseases.

Hinokitiol Inhibits Candida albicans Adherence to Oral Epithelial Cells

Abstract Candida spp. are an opportunistic pathogen causing serious local and systemic infections, especially in immuno-compromised hosts such as the elderly and HIV-positive patients. Hinokitiol C 10 H 12 O 2 (β-thujaplicin) is a component of the essential oils isolated from Cupressaceae and shows antibacterial activities for various bacteria. The aim of this study was to demonstrate the preventive effects of hinokitiol on the adherence of seven species of Candida to oral epithelial cells and to establish a safe and useful method for oral hygiene. A short-time treatment (30 min) with 0.25 mM hinokitiol showed 30–70% inhibition of adherence of Candida spp. to oral epithelial cells, inhibited about 11% biofilm formation, and did not inhibit the cell growth of Candida spp. Furthermore, short treatment with 0.25 mM hinokitiol was a safe method for oral hygiene against Candida infection because it did not inhibit the cell growth of commensal bacteria, such as oral streptococci existing in normal flora, or damage the epithelial cells. However, long-time treatment and a high concentration of hinokitiol demonstrated both the adherence inhibition of Candida and damage to commensal bacteria and epithelial cells. Our data suggest an appropriate procedure to apply hinokitiol that may be beneficial for the prevention of opportunistic pathogens such as Candida spp. in the oral cavity. The clinical and daily use of hinokitiol under an appropriate procedure may be a preventive and realistic therapy for Candida infection in immune-compromised hosts.

Oral findings and dental treatment in a patient with Dandy–Walker syndrome: a case report

Dandy-Walker syndrome (DWS) is congenital disease characterized by hypoplasia of the cerebellum, the formation of cysts that communicate with the fourth ventricle of the posterior cranial fossa, and hydrocephalus. In addition to various other complications, cleft lip/palate, facial retrognathia, a high-arched palate, and maldentition occur at an increased frequency in patients with DWS. However, few studies have reported the dental manifestations of DWS. Herein, we report the clinical manifestations, oral findings, and dental management of a DWS patient who was treated under general anesthesia. Poor oral hygiene, gingivitis, and several congenital dental abnormalities (e.g., generalized microdontia, conical tooth, transposition, and congenitally missing teeth) were observed. This report is the first to describe the oral findings and dental treatment of DWS. Our findings emphasize the importance of a multidisciplinary approach in the diagnosis and treatment of DWS.