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Biomedical subjects

H X Meng

Publications and source records attributed to H X Meng.

15 recordsLinked to original sources
PubMed2002

Relationship between vitamin D receptor gene polymorphism and periodontitis.

UNLABELLED: Recent studies have shown that vitamin D receptor (VDR) gene polymorphism had regulatory effects on bone mineral density (BMD) and bone turnover. The VDR gene has also been indicated as a candidate gene for the susceptibility of osteoporosis. However, it is unclear whether VDR genotypes could be associated with alveolar bone loss of patients with periodontitis, or whether vitamin D receptor gene could be a candidate gene for susceptibility to periodontitis. The purpose of this study was to answer these two questions. METHODS: Twenty-four cases of adult periodontitis (AP), 37 cases of early onset periodontitis (EOP) and 39 healthy controls were recruited for the study. Individual samples of venous blood and DNA were obtained from each subject. Genotypes of the TaqI VDR gene were determined by PCR and TaqI restriction endonuclease digestion. RESULTS: One out of 24 AP patients, nine out of 37 EOP patients and two out of 39 healthy controls were detected with Tt genotype, while the rest had the TT genotype. The detected frequency of Tt genotype was significantly higher in EOP patients (24.3%) than in AP patients (4.2%) and healthy controls (5.1%). The frequency of t allele was also significantly higher in EOP patients. There was no statistical difference in the distribution of TaqI VDR genotypes between AP patients and healthy controls. The study suggests that Tt genotype might be a risk indicator for the susceptibility to EOP. Carriage of the allele (t) of the TaqI VDR gene may increase the risk of developing EOP.

Adolescent↗
PubMed2001

Comparison of the clinical effects and gingival abrasion aspects of manual and electric toothbrushes.

AIMS: The clinical effects and gingival abrasion aspects of 2 electrical tooth-brushes (Braun Oral-B Plak Control Ultra and the novel development Braun Oral-B Plak Control 3D) were to be compared with conventional manual tooth-brushing. MATERIAL AND METHODS: In a cross-over study, 26 dental student volunteers participated and were assigned to 1 of 3 groups. Following instruction in the use of the electric as well as manual toothbrushes, the volunteers were timed for 2 min each day to apply one electric or the manual toothbrush, respectively, during 3 experimental phases of 2 weeks. No other methods of tooth cleaning were to be performed except the one specified for the respective test period. When brushing manually, the Bass toothbrushing technique was applied. Between each test period, a recovery period of 1 week was allowed during which no oral hygiene was performed at all. At the start and the end of each of the experimental periods, the extension of plaque deposits from the gingival margin in coronal direction was assessed using the Turesky et al. modification of the Quigley and Hein plaque index. Presence or absence of gingival inflammation was evaluated by bleeding and probing (BOP). The extent and severity of gingival abrasions were assessed by use of a modified method of Breitenmoser et al. and adapted by Danser et al. RESULTS: The plaque-reducing effect was similar in all groups with the same cleaning regime. For that reason, the result of the different experimental phases with the respective cleaning modalities were collapsed. Cleaning with the Braun Oral-B Plak Control Ultra electric toothbrush resulted consistently in the lowest plaque scores when compared to both the Braun Oral-B Plak Control 3D and the manual toothbrush. Although the differences in plaque reduction were statistically significant between cleaning with Braun Oral-B Plak Control Ultra and 3D, they were small and of questionable clinical relevance. No significant differences in plaque reductions were found between manual brushing and any of the 2 electric brushes. Gingival abrasions were least pronounced following brushing with the Braun Oral-B Plak Control 3D electric toothbrush. However, no significant differences in gingival abrasion were encountered following brushing with the Braun Oral-B Plak Control Ultra electric in comparison with the manual toothbrush. CONCLUSIONS: The results of the present study have shown that in a group of dental students trained in manual brushing technique, where efficacy was similar with the 3 toothbrushes tested, there is no evidence of greater gingival abrasion with either Braun Oral-B Plak Control Ultra or 3D when compared with a manual brush.

Adult↗
PubMed2001

Polymorphonuclear neutrophils and their mediators in gingival tissues from generalized aggressive periodontitis.

BACKGROUND: Impaired polymorphonuclear neutrophil (PMN) functions were generally considered to be related to the onset of generalized aggressive periodontitis (GAgP). However, some research has indicated that the hyperreactivity of PMN seems to be involved in the inflammatory response of GAgP. The present study's main purpose was to provide more evidence about the role of PMN in the pathogenesis of GAgP by surveying PMN infiltration in gingiva and its relationship with the expression of their mediators including intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The inflammatory response in GAgP was also compared with that in adult periodontitis (AP) and periodontally healthy subjects. Since these PMN mediators were reported to be produced mainly by macrophages, the association between the expression of these PMN mediators and the distribution of macrophages was also investigated. METHODS: A total of 25 gingival specimens were obtained from 10 GAgP patients, 10 AP patients, and 5 periodontally healthy subjects. Serial sections were obtained from each specimen, and the following techniques were adopted to investigate the distribution and interrelation of different cells and cytokines. Infiltration of PMN was observed by using hematoxylin and eosin staining. Distribution of the macrophages, identified as CD68+, was shown by using immunohistochemistry. Immunohistochemistry and in situ hybridization were used to detect the expression of ICAM-1, IL-8, IL-1beta, and TNF-alpha in gingival tissues. These techniques were performed in serial sections from each individual specimen. RESULTS: Large numbers of infiltrating PMNs were observed in gingiva from GAgP. In gingiva from both GAgP and AP, the strongest protein and mRNA expression of IL-8, ICAM-1, IL-1beta, and TNF-alpha were located in pocket epithelium and adjacent connective tissue with large numbers of infiltrating PMNs. In tissues without abundant PMN infiltration, the appearance of positive cells expressing IL-8, ICAM-1, IL-1beta, and TNF-alpha was scattered. CD68+ was distributed sparsely in connective tissue and was hardly seen in pocket epithelium with large numbers of PMN infiltration. The degree of leukocyte infiltration and connective tissue destruction in gingiva from GAgP patients was not distinctly different from that in gingiva from AP. The gingival specimens with heavy PMN infiltration from both GAgP and AP patients presented strong expressions of IL-1beta and TNF-alpha; showed more extensive inflammatory cell infiltration; had severe connective tissue destruction; and presented severe elongation and ulceration of pocket epithelium. In gingiva from healthy subjects, inflammation was minor with visually no PMN, CD68+, or the positive cells of IL-8, ICAM-1, IL-1beta and TNF-alpha expression. CONCLUSIONS: Enhanced accumulation of PMN, which is associated with the upregulation of IL-8, ICAM-1, IL-1beta, and TNF-alpha expression, relates to the severity and activity of GAgP. In addition to macrophages, PMN and/or epithelial cells might also be important sources of IL-8, IL-1beta, and TNF-alpha production in gingiva.

Adult↗
PubMed1999

Periodontal abscess.

This review focuses on the classification of periodontal abscesses, which are localized purulent infections of periodontal tissues, and discusses their etiology and clinical characteristics.

Humans↗
PubMed1999

Periodontic-endodontic lesions.

Lesions of the periodontal ligament and adjacent alveolar bone may originate from infections of the periodontium or tissues of the dental pulp. This review focuses on the relationship of lesions of endodontic origin with lesions of periodontal origin and their classification.

Dental Pulp Diseases↗
PubMed1998

Existence of IL-8 degrading protease and anti-IL-8 immunoglobulin G in gingival crevicular fluid.

OBJECTIVE: The aim of this study is to identify the nature of the IL-8 inhibitor(s) in gingival crevicular fluid (GCF). METHODS: Part 1: Fourteen GCF samples were collected from 13 adult periodontitis (AP) patients, and 9 samples were taken from 8 healthy subjects. Each GCF sample was divided into two aliquots. A serine protease-specific inhibitor, PMSF, was added to one aliquot, and PBS was added to the other aliquot as control. ELISA was used to measure IL-8 level in the samples. Part 2: Forty-one GCF samples were collected from 15 AP patients and indirect ELISA was performed to detect the anti-IL-8 IgG antibody. RESULTS: Part 1: IL-8 level in the PMSF samples was significantly greater than that in the control group (3.01 +/- 5.79 mg/L vs 0.05 +/- 0.15 mg/L, respectively P < .001). Part 2: The mean value of anti-IL-8 IgG in GCF was greater than that of negative control + 3 x SD. CONCLUSIONS: A serine protease that can "cleave" IL-8 exists in GCF. Gingival crevicular fluid from AP sites contains an autoantibody against IL-8.

Adult↗
PubMed1994

[Neutrophils and monocytes in gingival epithelium]

Neutrophils and monocytes of gingival epithellium in health gingiva(H),marginal gingivitis(MG),juvenile periodontitis(JP),adult periodontitis(AP) and subgingival bacteria were quantitated and analyzed,The results showed that the numbers of PMN within either pocket epithelium or oral gingival epithelium in JP were significantly lower than in AP and G.The amounts of PMN in AP were much larger than other three groups.Positive correlation between the number of PMN in sulcular pocket epitelium and the motile bacteri of subgingival plaque was demonstrated by correlation analysis.Monocytes mainly presented in deep pocket and junctional epithelum which were stained by NAE method,however very few Langhans cells were seen in these areas.

Journal Article↗
PubMed1994

[Immunoglobulin bearing cells and complement 3 in periodontal diseases].

Frozen gingival tissue sections from marginal gingivitis (MG), juvenile periodontitis (JP), adult periodontitis (AP) patients and clinical healthy subjects (H) were immunohistochemically stained with specific antibodies to aid in identification and quantification of different Ig bearing cells in inflammatory infiltrates. IgG, IgA, IgM, K and lambda were present in all specimens studied. The numbers of Ig cells in disease groups were much greater than in H group, especially the IgG cells. The numbers of IgG cells in AP and JP were most abundant, followed by MG and H. The correlation between the number of IgG cells and the percentage of infiltrated connective tissue was obtained by linear correlation analyses (r = 0.534, P < 0.001). This means that the inflammatory infiltration became heavier as the number of IgG cells increased. It is the new finding that the number of IgA cells was smaller than the IgM cells in JP, the IgA/total heavy chains ratio was much lower than other groups. The C3 deposition was found in all of the gingival specimens. In healthy gingival tissue, C3 mainly deposited in both of the surface of inflammatory cells and vessels. In diseased status C3 located not only in these two, but also in sulcular (pocket) epithelium and oral epithelium, Igs were also observed in these areas. It is suggested that immunocomplex may deposit in gingival tissue.

Adolescent↗
PubMed1994

[Clinical and histopathological analysis of 2485 gingival biopsy specimens].

This study was based on a clinical and histopathological analysis of 2485 gingival biopsy specimens. sixty-nine types of gingival lesions were, identified they were 14 types of gingival inherent diseases, 29 types of tumor and tumorous lesions, 5 types of dermal and mucosal diseases, 2 types of periodontal diseases, 29 types of other diseases. Among them, eighteen have not been published by others.

Adolescent↗
PubMed1990

[Langerhans cells in the gingival epithelium].

Langerhans cells (LCs) were specifically demonstrated by monoclonal antibody OKT 6. In healthy gingival tissue LCs were mainly seen in stratum spinosum of the surface epithelium. They had small nuclei and with long cell processes. The LCs of oral epithelium in marginal gingivitis and adult periodontitis tissue were more in numbers than in healthy tissue. In juvenile periodontitis tissue LCs numbers seemed to be increased obviously in comparison to the healthy tissue. The LCs were round and often located in both deep spinous and basal layers. These results demonstrate that LCs play an important role in the local immune response of the periodontal tissues.

Adult↗
PubMed1989

T cells and T-cell subsets in periodontal diseases.

Acetone-fixed cryostat gingival tissue sections from marginal gingivitis (MG), juvenile periodontitis (JP), adult periodontitis (AP) patients and clinically healthy subjects (H) were immunohistochemically stained with monoclonal antibodies to aid in identification and quantification of T cells and T-cell subsets in the inflammatory infiltrates. T cells were present in all specimens studied. The number of T cells in the connective tissue (CT) zone of AP was much greater than in any other groups. The amounts of T cells in oral epithelium and sulcular (pocket) epithelium zones of diseased groups were larger than in the healthy group. There was a significant positive correlation between the number of T cells and the percentage of infiltrated connective tissue. While there were no significant differences between the mean ratios of T-helper/T-suppressor cells from diseased and healthy tissues, large individual variance existed in the three diseased groups. The existence of a high or low T4/T8 ratio in inflamed gingiva might be related to an abnormal immunoregulation.

Adolescent↗
PubMed1989

[An ultrastructural study of proliferative gingivitis].

Proliferative gingivitis was studied by electron microscopy. The crevicular epithelium adjacent to inflamed gingival connective tissue was primarily characterized by its relatively larger intercellular spaces which contained a variety of emigrating cells and granular precipitates resembling plasmic substances. Neutrophils and lymphocytes migrated between epithelial cells so that the intercellular spaces enlarged. The interruption of basement membrane was associated with inflammatory cells. Among the inflammatory cells plasma cells were predominant and displayed a variety of morphological characteristics. They consisted primarily of tightly packed, flattened cisternae of rough endoplasmic reticulum (rER) and a prominent paranuclear golgi zone. Fragments of cytoplasm apparently originating from the plasma cells were lying free in the surrounding intercellular space, in which collagen fibrils were impaired, disrupted and dissolved. All of these changes in plasma cells may relate to the synthesis and release of antibody. It is suggested that the inflammatory destructive features in connective tissue were mainly contributed to plasma cells.

Epithelium↗