Li-Min Lin

Isolation and characterization of human dental pulp stem/stromal cells from nonextracted crown-fractured teeth requiring root canal therapy.

INTRODUCTION Human dental pulp stem/stromal cells (hDPSCs) in adults are primarily derived from the pulp tissues of permanent third molar teeth in existing literatures, whereas no reports exist, to our knowledge, on deriving hDPSCs from a tooth without the need for surgical procedure. The aim of this study was to raise a novel idea to source hDPSCs from complicated crown-fractured teeth requiring root canal therapy. METHODS hDPSCs were harvested from the pulp tissues for two complicated crown-fractured teeth requiring root canal therapy, retaining the teeth for subsequent prosthodontic rehabilitation, in a 41-year-old woman who had suffered a motorcycle accident. Pulp tissue from the left lower deciduous canine of a healthy 10-year-old boy (the positive control) was also removed because of high mobility and cultured for hDPSCs. RESULTS The hDPSCs derived from the two complicated crown-fractured teeth and the deciduous tooth were able to differentiate into adipogenic, chondrogenic, and osteogenic lineages and also expressed stem cells markers and differentiation markers, which indicated their stem cell origin and differentiation capability. In addition, hDPSCs from both the complicated crown-fractured teeth and the deciduous tooth showed high expression for bone marrow stem cell markers including CD29, CD90, and CD105 and exhibited very low expression of markers specific for hematopoietic cells such as CD14, CD34, and CD45. CONCLUSIONS This report describes the successful isolation and characterization of hDPSCs from the pulp tissue of complicated crown-fractured teeth without tooth extraction. Therefore, pulp exposed in complicated crown-fractured teeth might represent a valuable source of personal hDPSCs.

Tuberculosis of the head and neck: a review of 20 cases

OBJECTIVE Tuberculosis (TB) of the head and neck is currently a reemerging infectious disease and may be a diagnostic challenge for dental care providers. The aim of the present study was to retrospectively review the clinical features of patients diagnosed with TB of the head and neck during the past 16 years. MATERIALS AND METHODS Thirteen male and 7 female patients with TB of the head and neck were histologically identified following surgical biopsy in our department between 1991 and 2007. The medical charts were reviewed. RESULTS The age distribution was broad, with 11 patients (55%) older than 50 years and 4 (20%) younger than 10 years old. Thirteen patients had oral lesions and 2 had multiple lesions. The most common oral location was the buccal mucosa and/or vestibule (5 cases), followed by the alveolar mucosa (4 cases), palate (2 cases), lip (2 cases), and tongue (1 case). Seven patients had cervical TB. The predominant clinical manifestation was ulceration. Two patients were found to have coexistent metastatic squamous cell carcinoma. Four patients were identified with active pulmonary lesions and 1 patient with evidence of old pulmonary TB on the 14 chest radiographs available. CONCLUSION Tuberculosis of the head and neck may not be as rare as once thought. We emphasize the importance of early diagnosis in such lesions, especially in slow-to-heal wounds and undiagnosed neck lumps.

Sialolipoma of the Floor of the Mouth: A Case Report

Intra‐oral lipoma is a well‐known entity, but lipomatous tumors including salivary gland tissue containing clustered or peripherally located ducts and acinar cells are uncommon. They are a newly recognized entity of salivary gland lipoma, designated sialolipoma. We describe a case of sialolipoma arising in the floor of the mouth presenting with apparently normal salivary gland tissue, as demonstrated by both histologic and immunohistochemical findings, in a 67‐year‐old female. Complete surgical removal of the tumor with preservation of the sublingual gland was implemented after a careful examination confirming that the lesion did not originate from the sublingual gland.

Human dental pulp stem cells derived from different cryopreservation methods of human dental pulp tissues of diseased teeth

BACKGROUND Successful isolation of human dental pulp stem cells (hDPSCs) has been documented at least 120h after tooth extraction. Viable hDPSCs have been isolated chiefly from cryopreserved healthy molar teeth and their undigested dental pulp tissue. Isolation of hDPSCs from diseased but vital teeth after cryopreservation has not been reported. This study aimed to isolate hDPSCs from cryopreserved diseased but vital teeth of various tooth types. MATERIALS Fifty tooth samples were divided into group A (n = 20) - freshly derived dental pulp tissues, group B (n = 20) - liquid nitrogen (liq N(2) )-stored dental pulp tissues and group C (n = 10) - liq N(2) -stored intact teeth. METHODS AND RESULTS The success rate for hDPSCs isolation was 100% for groups A and B and only 20% for group C. hDPSCs from all groups demonstrated self-renewal properties and similar multipotent potential characteristics of adipogenic, chondrogenic and osteogenic differentiation. In addition, hDPSCs showed high expression of bone-marrow mesenchymal stem-cell markers (CD29, CD90 and CD105) and very low expression of specific hematopoietic cells markers (CD14, CD34 and CD45). CONCLUSION Our results indicate that hDPSCs isolated from diseased but vital teeth of various tooth types can be stored in liq N(2) for future usage.

DMBA-induced hamster buccal pouch carcinoma and VX2-induced rabbit cancer as a model for human oral carcinogenesis

In this article, we have described and compared the advantages and disadvantages of two potential animal cancer models (the hamster buccal pouch cancer model and the VX2-induced rabbit cancer model) for human squamous cell carcinomas of the oral mucosa. Currently, no animal cancer model is perfectly applicable to human oral squamous cell carcinomas. This is because the hamster buccal pouch cancer model has a different etiology and genetic constitution compared with human oral carcinomas. In addition, the VX2-induced rabbit cancer model is not produced in situ and, consequently, its natural behavior is totally reliant on the location of transplantation. Nonetheless, with the use of these two animal cancer models together, researchers could evaluate different aspects of the cellular and molecular biological characteristics or assess potential novel treatment regimens for squamous cell carcinomas of the human oral mucosa.

Increased expression of inducible nitric oxide synthase for human buccal squamous-cell carcinomas: Immunohistochemical, reverse transcription-polymerase chain reaction (RT-PCR) and in situ RT-PCR studies

The inducible nitric oxide synthase (iNOS) is involved primarily in inflammatory and carcinogenesis processes. An enhanced expression of iNOS at the protein level has been reported previously for human oral squamous cell carcinoma; however, the expression of iNOS at the mRNA level has not yet been demonstrated. Furthermore, no studies have addressed whether iNOS expression at mRNA level correlates with cervical lymph node metastasis.

Osseous choristoma of oral cavity--report of two cases and review of the literature.

Osseous choristoma of the oral cavity is an extremely rare lesion. Two cases of osseous choristomas of oral cavity, representing two different natures of such lesions are reported. One was situated on the dorsal surface of posterior tongue just anterior to the circumvallate papillae and the other on the right buccal mucosa just below the orifice of the Stensens duct. To date, about 73 cases of oral osseous choristoma have been reported in the literature including the two present cases, of which, 61 and 8 cases occurred in the tongue and buccal mucosa, respectively. The clinical and microscopic characteristics, and their common sites of these peculiar lesions are presented. The origin and pathogenesis of the lesion are discussed and the literature on the subject is reviewed.

Expression of inducible nitric oxide synthase in human oral premalignant epithelial lesions

Increased expression of inducible nitric oxide synthase (iNOS) has been found at the protein level in human oral epithelial dysplasias, but, a corresponding expression at the mRNA level has not been demonstrated. The purpose here was to assess the expression of iNOS mRNA and its correlation with the expression of the enzyme protein in human buccal premalignant epithelial lesions. Activities for iNOS protein (57/80, 64%) and mRNA (53/80, 53%) were detected in the specimens examined. Cytoplasmic and/or nuclear staining for iNOS protein was detected immunohistochemically in a number of mild oral epithelial dysplasias (16/20, 80%), moderate to severe oral epithelial dysplasias (14/20, 70%), submucous fibrosis (14/20, 70%) and verrucous hyperplasia (13/20, 65%). Upon in situ reverse transcription-polymerase chain reaction (RT-PCR), the cellular location of iNOS mRNA was compatible with the immunohistochemical findings. Furthermore, iNOS mRNA was found in 15 specimens of mild oral epithelial dysplasia (15/20, 75%), 13 specimens of moderate to severe oral epithelial dysplasia (13/20, 65%), 13 specimens of submucous fibrosis (13/20, 65%) and 12 specimens of verrucous hyperplasia (12/20, 60%). No iNOS protein or mRNA was found in samples of normal buccal mucosa, or in negative controls. Further studies on the characteristics of iNOS-positive cells and more long-term clinical follow-up data are needed.

Differential expression of p53, p63 and p73 protein and mRNA for DMBA-induced hamster buccal-pouch squamous-cell carcinomas

Abnormalities in the p53 gene are regarded as the most consistent of the genetic abnormalities associated with oral squamous‐cell carcinoma. Two related members of the p53 gene family, p73 and p63, have shown remarkable structural similarity to p53, suggesting possible functional and biological interactions. The purpose of this study was to investigate the differential expression of p73, p63 and p53 genes for DMBA‐induced hamster buccal‐pouch squamous‐cell carcinoma. Immunohistochemical analysis for protein expression and reverse transcriptase‐polymerase chain reaction (RT‐PCR) for mRNA expression were performed for 40 samples of hamster buccal pouches, the total being separated into one experimental group (15‐week DMBA‐treated; 20 animals) and two control groups (untreated and mineral oil‐treated; 10 animals each). Using immunohistochemical techniques, nuclear staining of p53 and p73 proteins was detected in a subset of hamster buccal‐pouch tissue specimens treated with DMBA for a period of 15 weeks, whereas p63 proteins were noted for all of the 20 hamster buccal‐pouch tissue specimens treated with DMBA for 15 weeks as well as for all of the untreated and mineral oil‐treated hamster buccal‐pouch tissue specimens. Differential expression of p63, p73 and p53 protein for the experimental group was as follows: p63+/p73+/p53+ (n = 14; 70%); p63+/p73+/p53– (n = 2; 10%); p63+/p73–/p53– (n = 4; 20%) and p63+/p73–/p53– (untreated [n = 10] and mineral oil‐treated mucosa [n = 10]; 100% each). Upon RT‐PCR, ΔNp63mRNA was detected within all of the 20 hamster buccal‐pouch tissue specimens treated with DMBA for 15 weeks, whereas expression of TAp63 was not detected. Furthermore, p73 mRNA was identified for 16 of the hamster buccal‐pouch tissue specimens treated with DMBA for 15 weeks, whereas p53 mRNA was noted for 14 15‐week DMBA‐treated pouches. The proportional (percentage) expression of ΔNp63, p73 and p53 mRNA for the hamster buccal‐pouch tissue specimens treated with DMBA for 15 weeks was noted to be consistent with the findings using immunohistochemical techniques. A significant correlation between p53, p63 and p73 expression (protein and mRNA) was demonstrated for the hamster buccal‐pouch carcinoma samples. Our results indicate that both p73 and p63 may be involved in the development of chemically induced hamster buccal‐pouch carcinomas, perhaps in concert with p53.

p73 expression for human buccal epithelial dysplasia and squamous cell carcinoma: Does it correlate with nodal status of carcinoma and is there a relationship with malignant change of epithelial dysplasia?

TP73, a p53 homologue gene, shares similar structural sequences with p53. The aim of this study was to investigate the p73 expression for human buccal epithelial dysplasia (ED) and squamous cell carcinoma (SCC).