Concurrence of replicative senescence and elevated expression of p16(INK4A) with subculture-induced but not calcium-induced differentiation in normal human oral keratinocytes

Primary normal human oral keratinocytes (NHOKs) undergo differentiation in the presence of calcium concentrations higher than 0.15 mM in vitro, which is useful in investigating the mechanisms involved in the differentiation of epithelial cells. Serial subculture of NHOKs to the postmitotic stage also induces terminal differentiation. However, the detailed mechanisms of both differentiation processes remain substantially unknown. To investigate the molecular differences in these processes, NHOKs were induced to differentiate by exposure to 1.2 mM of calcium and by serial subculture to the postmitotic stage. To study whether the cells were induced to differentiate and to undergo replicative senescence, the amount of cellular involucrin and the expression of senescence-associated beta-galactosidase (SA-beta-gal) were measured respectively. The expression of replicative senescence-associated genes and the activity of telomerase from the differentiated cells were also determined. Both calcium treatment and serial subculture to the postmitotic stage notably elevated the cellular involucrin. The percentage of SA-beta-gal-positive cells was significantly elevated by the continued subculture, but such changes were not observed in keratinocytes exposed to calcium. The concentration of cellular p16(INK4A) protein was progressively increased by the continued subculture but was not changed by calcium treatment. On the other hand, the concentrations of cellular p53 were similar in both differentiation processes. However, telomerase activity was lost in NHOKs that had undergone differentiation by both calcium treatment and serial subculture. The results indicate that calcium-induced differentiation of NHOKs has similar characteristics to their serial subculture-induced differentiation, but that the differentiation processes are not identical, because calcium-induced differentiation does not concur with either replicative senescence or the gradually increased concentration of p16(INK4A).     

Antibody responses against Porphyromonas gingivalis infection in patients with early-onset periodontitis

BACKGROUND, AIMS: The aim of this study was to evaluate antibody responses against Porphyromonas gingivalis (P. gingivalis) infection in early-onset periodontitis (EOP) patients to elucidate further the host-parasite interactions in the pathogenesis of EOP. METHOD: 16 P. gingivalis-infected EOP and 20 adult periodontitis (AP) patients, and 18 periodontally healthy subjects (HS) participated in this study. Serum immunoglobulin G (IgG) antibody levels and avidities against extracted P. gingivalis whole cells were measured. The components of P. gingivalis outer membrane antigens (OMA) reacting to patients' sera were analysed from the molecular weights by Western blotting. Serum antibody levels against P. gingivalis lipopolysaccharide (LPS) were also measured. The ability of the patients' sera to block interleukin-1beta (IL-1beta) production by human mononuclear cells in response to P. gingivalis LPS was examined. RESULTS: Antibody levels were positively correlated with antibody avidities in both EOP and AP patients (r=0.91, r=0.72, p<0.0005, respectively), while not significantly so in HS (r=0.09). There was variability in the antigen recognition of P. gingivalis OMA in EOP and AP patients. Smear and 53-kDa protein were more frequently recognized by sera of EOP and AP patients rather than that of HS (p<0.05). The smear was partly diminished by absorption with P. gingivalis LPS, indicating the smear antigen was partly composed of LPS. There was high correlation between antibody levels against P. gingivalis whole-cell extracts and LPS in EOP and AP patients (r=0.81, p=0.0002, r=0.87, p<0.0001, respectively), while not significant in HS (r=0.22). The sera of EOP and AP patients with high IgG titre to P. gingivalis LPS blocked IL-1beta production more effectively than that of the patients with low IgG titre to P. gingivalis LPS. CONCLUSIONS: These results indicate that EOP patients' antibody response against P. gingivalis infection does not differ significantly from that of AP patients. The person-to-person heterogeneous antibody production against P. gingivalis LPS could contribute to our understanding of the relationship between the defensive ability of EOP patients and their chronic infection with this pathogen.     

Crown dilaceration of a first premolar caused by extraction of its deciduous predecessor: a case report

This report describes a rare case of crown dilaceration of the mandibular first premolar caused by trauma during extraction of the precedent primary first molar. The mandibular first primary molar had been extracted at the age of 4 years 7 months. Compared to the pre-operative radiograph, the post-operative film showed that the direction of the first premolar tooth germ had changed, suggesting that crown dilaceration had been induced by the surgical procedures during tooth extraction. From radiographic examinations, the premolar was considered to have erupted spontaneously.     

Collagen fibers and inflammatory cells in healthy and diseased human gingival tissues: a comparative and quantitative study by immunohistochemistry and automated image analysis

BACKGROUND: Periodontal disease is histologically characterized by the degradation of extracellular matrix components associated with a gingival infiltration of inflammatory cell populations. The purpose of this in situ study was to quantify inflammatory cell subsets and the area fraction (AA%) occupied by collagen fibers in healthy and diseased upper gingival connective tissue in order to investigate the association, if any, between collagen loss and inflammatory cell infiltrate. METHODS: Paraffin gingival tissue sections from 10 healthy controls (C), 9 patients with gingivitis (G), and 10 patients with severe chronic periodontitis (P) were immunohistochemically stained by antibodies against CD45, CD3, CD8, CD20, CD68, TIA-1, and GrB molecules, and the collagen fibers were stained using sirius red F3Ba. The quantitative evaluations of inflammatory cell numbers and the AA% occupied by collagen fibers were performed by morphometric and automated image analysis. RESULTS: In group P, CD45+, CD20+, CD68+, TIA-1+, and GrB+ cell numbers were significantly increased (P<0.05) when compared to both C and G groups. The present study revealed significant differences (P <0.01) between means of AA% observed in group C (63%), group G (46%), and group P (26%), and AA% of group G and group P was inversely correlated with the numbers of TIA-1+ cells (P<0.01) and GrB+ cells (P<0.01 and P<0.05, respectively). CONCLUSIONS: This study showed great differences in the number of the distinct inflammatory cell subsets according to the severity of the periodontal disease and suggested that activated cytotoxic cells could play a pivotal role in the loss of collagen fibers observed during these pathological states. During periodontitis, collagen loss was significantly correlated with all inflammatory cell subset numbers. Finally, the quantitative evaluation of the area fraction occupied by gingival collagen fibers may reflect the clinical severity of the periodontal disease.     

Dental panoramic radiographic evaluation in bisphosphonate-associated osteonecrosis of the jaws

Objectives:  To determine the extent to which clinical and radiographic features of bisphosphonate-associated osteonecrosis of the jaw (BONJ) are correlated.
Design:  Retrospective case review.
Methods:  The records of 39 patients diagnosed with BONJ and examined by panoramic radiography were retrospectively evaluated. The arches were divided into sextants ( n  = 234) and evaluated for the following signs: sclerosis, surface irregularity, sockets, fragmentation and lysis.
Main outcome measures:  The McNemar, Kruskall–Wallis and equivalency tests were performed to analyze the association between clinical and radiographic signs and BONJ severity.
Results:  Sixty-two out of 234 sextants were abnormal by clinical criteria and 61 out of 234 sextants demonstrated at least one radiographic abnormality. There was agreement between clinical and radiographic detection in 41 sextants. The data showed equivalency between BONJ diagnosis and both sclerosis and surface irregularity. The correlation between number of clinical sites and any radiographic finding was significant in the maxilla ( P  < 0.001) but not in the mandible ( P  = 0.178). The total number of radiographic signs per patient increased with BONJ stage.
Conclusion:  Focal panoramic radiographic findings of sclerosis and surface irregularity correlate with clinical sites of BONJ. This may be a useful and reliable tool to detect early changes of BONJ or to confirm a clinical diagnosis.     

Hemifacial microsomia: a case report

Hemifacial microsomia is a congenital malformation in which there is a deficiency in the amount of hard and soft tissue on one side of the face. It is primarily a syndrome of the first branchial arch, involving underdevelopment of the temporomandibular joint, mandibular ramus, masticatory muscles and the ear. The affected ear may have an external soft-tissue malformation in addition to being lower set than on the contra lateral side. Hearing loss may result from underdevelopment of the osseous components of the auditory system and a diminished or absent external auditory meatus. Occasionally, second branchial arch defects involving the facial nerve and facial muscles coexist with Hemifacial microsomia. Radiographic examination in case of Hemifacial microsomia is of limited value because of superimposition of normal and abnormal bony structures. The skeletal and soft-tissue findings of a patient with Hemifacial microsomia who underwent three-dimensional computerized tomography is presented here to improve our knowledge and diagnostic skill of this uncommon entity.     

Recurrent multinodular neurilemmoma of the female upper lip

Neurilemmoma is the most commonly encountered nerve sheath tumour of the oral cavity. It generally appears as a single encapsulated nodule. The tongue is involved most frequently and the lip rarely. The tumour is usually uninodular. Multinodular neurilemmoma of the upper lip is very rare and has been reported in only one patient. This is the first reported case of multinodular neurilemmoma in the upper lip of a female.     

Effect of anesthetics containing lidocaine and epinephrine on cardiovascular changes during dental implant surgery

The purpose of this study was to evaluate cardiovascular changes during dental implant surgery using 2% lidocaine with 1:80 000 epinephrine. Eleven normotensive subjects, ranging from 18 to 56 years, were selected to undergo dental implant surgery in the jaw. They were monitored in the pre-, intra-, and postsurgical periods by continuous noninvasive automatic arterial pressure and cardiac frequency measurements taken every 2 minutes. Parameter scores were obtained for the following phases: P1, 15 minutes during preparation of the patient (control period); P2, before anesthesia; P3, immediately after anesthesia; P4, 2 minutes into anesthesia; P5, during incision and detachment; P6, during perforation; P7, during implant placement; P8, during suturing; P9, on completion; and P10, 10 minutes after termination. Individualized statistical analysis for each group during the pre-, intra-, and postoperative periods were performed by analysis of variance. The greatest variations in systolic pressure were increases of 2.29% during phase P2 and 2.59% in phase P5. Diastolic pressure decreased during phase P6 (-2.58%) and increased in P10 (3.27%). The greatest changes in heart rate occurred in phase P10 (-3.24%). There were no statistically significant changes among the evaluated phases (P > .05). In conclusion, there were no changes in the analyzed cardiocirculatory parameters during dental implant surgery (systolic, diastolic, and mean arterial blood pressures and heart rate) in normotensive subjects anesthetized with 2% lidocaine with epinephrine 1:80000.     

Rapid detection of Actinobacillus actinomycetemcomitans using a loop-mediated isothermal amplification method

INTRODUCTION: Actinobacillus actinomycetemcomitans has been implicated in the etiology of aggressive periodontitis. In this study, we applied a novel nucleic acid amplification method, called loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions, allowing the rapid detection of A. actinomycetemcomitans. METHODS: We designed the primers for detecting A. actinomycetemcomitans and evaluated the specificity and sensitivity of the assay. RESULTS: The LAMP primers used in this study successfully amplified serotypes a-e of A. actinomycetemcomitans, while other oral bacteria were not amplified. By measuring the precipitation of magnesium pyrophosphate, we could quantify the chromosomal DNA of A. actinomycetemcomitans. The detection limits using the real-time turbidimetry analysis were 5.8 x 10(2)-5.8 x 10(7) copies of A. actinomycetemcomitans template DNA per reaction tube. In addition, the LAMP assay was used for the rapid detection of A. actinomycetemcomitans in clinical specimens from eight individuals. The results with the LAMP method were similar to those using conventional polymerase chain reaction. CONCLUSION: Our results suggest that the LAMP-based assay is very useful for the rapid detection of A. actinomycetemcomitans.