HLA-DR4 and salivary immunoglobulin A reactions to oral streptococci

The aim of this study was to describe and compare salivary immunoglobulin A (IgA) antibody reactions to extracts of strains of three oral streptococci in human leukocyte antigen (HLA)-DR4-positive and -DR4-negative subjects. Whole paraffin-stimulated saliva samples were collected from 27 apparently healthy subjects. Previous HLA typing showed that 20 subjects were DR4 positive and 7 were DR4 negative. HLA-DRB1*04 subtyping was performed among the DR4-positive subjects. Whole-cell antigen extracts from Streptococcus mutans (KPSK 2), Streptococcus sobrinus (OMZ 65) and Streptococcus parasanguis (Nt 62) were separated in SDS-PAGE. The antigens were immunoblotted with diluted saliva (Western blot), scanned and analyzed in a computer system. All immunoblot bands were recorded in DR4-positive and DR4-negative saliva pools, and bands with an optical density >or=0.1 were selected for analysis in individual salivas. The DR4-negative subjects in general had more immunoblot bands and more distinct bands than did the DR4-positive subjects. A higher concentration of total IgA in saliva was correlated with more bands, especially to antigens separated from S. mutans. When the number of bands was calculated per IgA unit, significant differences were observed between DR4-positive and DR4-negative salivas. This was particularly seen for S. mutans and S. parasanguis. As the number of bands was analyzed in relation to DR4 subgroups, DRB1*04, there was a lower salivary IgA activity to S. mutans in the DRB1*0401 and *0404. The variable level of correlation previously demonstrated for S. mutans colonisation and serologically defined DR4 positive subjects might be explained by the heterogeneity in this group, and the relation should be sought on a subgroup level.     

Functional variants of IL4 and IL6 genes and risk of tobacco-related oral carcinoma in high-risk Asian Indians

Oral Diseases (2011) 17 , 720–726 Background: Tobacco‐related oral squamous cell carcinoma (OSCC) is one of the most common cancers involving Indian males. We assessed the association of IL4 promoter –589 T>C, –33 T>C, and IL6–174 G>C functional genetic polymorphisms with tobacco‐related OSCC in Asian Indians. Patients and Methods: The IL4 and IL6 promoter polymorphisms were assessed in 140 patients with OSCC and 120 normal subjects by PCR–RFLP technique, and significance of the data was determined using chi‐square test. Results: The frequency of TC, CC genotype, and C allele at IL4 promoter sites –589 and –33 were higher in patients when compared with controls. Consequently, TC/CC genotypes and C allele at both sites appeared as susceptible. However, IL6–174 G>C single‐nucleotide polymorphisms (SNP) appeared to be protective in patients with OSCC. Of eight haplotypes, five were associated with two‐ to seven‐fold increased risk of tobacco‐related OSCC. These SNPs further showed heterogeneity among different ethnic population, but their distribution in Asian Indians stand closer to other Asian populations. Conclusions: In this study, IL4–589 CC, –33 CC genotype, and *C allele at both sites appeared to be susceptible, while IL6–174 CC genotype and *C allele appeared to be protective in patients with OSCC; hence, these SNPs may be a potential prognostic markers for tobacco‐related OSCC in Asian Indians.     

Oral manifestations as predictors of immune suppression in a HIV-/AIDS-infected population in south India

The objectives of the study are to evaluate the relationship between common HIV-related oral lesions and absolute CD4+ count, age, gender, and medication used and to assess the sensitivity, specificity, positive and negative predictive value of oral manifestations for low absolute CD4+ counts. HIV-positive patients, 200, from south India were selected, whose absolute CD4+ counts were determined within 2 weeks of oral examination. Sociodemographic data was obtained using a structured questionnaire. Oral manifestations were diagnosed according to presumptive criteria of EEC-clearinghouse classification (1993). Four or more concurrent oral lesions were statistically significant with low CD4+ counts <200 cells/mm3 (P = 0.005). The highest and lowest mean CD4+ cell counts were seen in individuals with linear gingival erythema (LGE; 172.5 cells/mm³) and pseudomembranous candidiasis (PC; 87 cells/mm³), respectively. Smoking, age (<35 years), and males had a positive association with oral hairy leukoplakia (OHL; P < 0.05). Patients with CD4+ counts < 200 cells/mm³ were associated with 15 times greater risk of PC and four times at greater risk for occurrence of any oral manifestation. Concurrent oral manifestations (≥4) were good predictors (80–100%) of severe immune suppression. In most resource poor countries where facilities for undertaking CD4+ counts are not available, the presence of concurrent oral manifestations may be used as an indicator of deteriorating immune status.     

窝洞内内毒素对牙髓组织LPS结合受体TLR4表达的影响研究

目的 动物实验观察窝洞内内毒素对牙髓组织LPS结合受体TLR4表达的影响,探讨牙髓组织在LPS刺激后的信号转导途径.方法 在8头小型猪磨牙和前磨牙上制备不同深度窝洞,窝洞分为牙釉质深层组、牙本质浅层组、牙本质深层组.封入一定量的内毒素,分另q于术后3天、7天、14天、28天处死动物取牙.采用免疫组织化学染色的方法,观察小型猪磨牙和前磨牙窝洞内封入内毒素后牙髓组织中TLR4的表达和分布.结果 小型猪正常牙髓中未见TLR4阳性细胞.内毒素实验组随着窝洞深度增加,TLR4阳性细胞数增加.在深窝洞组3a窝洞下方牙髓组织中TLR4阳性细胞多为中性粒细胞表达,其他实验组多为单核细胞表达.结论 牙髓组织中TLR4的表达提示内毒素通过牙本质渗透至牙髓,通过LPS信号受体TLR4在牙髓组织的炎症发展过程中发挥作用.     

两种浓度4NQO饮水法诱发小鼠舌癌及癌前病变动物模型的比较

目的:快速、准确的建立与人舌癌及癌前病变发生相似的动物模型。方法:0.001%和0.002%四硝基喹啉-1-氧化物(4-nitroquinoline 1-oxide,4NQO)饮水喂养Balb/c小鼠16~28周,肉眼及组织学观察癌变全过程。结果:随4NQO作用时间和观察时间的延长,小鼠舌黏膜相继出现白色斑块、红白相间斑块、乳头状新生物、溃疡等改变。饮用0.001% 4NQO 16周后的小鼠50.0%小鼠舌背黏膜表现为轻度异常增生,45.0%为中度异常增生,5.0%为重度异常增生;20周后5.0%为轻度异常增生,60.0%为中度异常增生,30.0%为重度异常增生,5.0%为原位癌;24周后50.0%为中度异常增生,40.0%为重度异常增生,10.0%为原位癌;饮用0.002%4NQO16、20、24、28周停药观察至40周的小鼠,舌癌的发生率分别为10%、25%、37.5%、45.5%,未见远处转移。结论:4NQO饮水法诱发小鼠舌癌及癌前病变生长缓慢、潜伏期长,致癌过程和组织病理学特征与人相似,方法简便;0.001%是诱发小鼠舌癌前病变的理想浓度,0.002%是诱发小鼠舌癌的理想浓度。     

氟钼酸铵对牙本质胶原分解的抑制作用

目的：评价氟钼酸铵对牙本质龋损中胶原分解的抑制作用。方法：用１０％、２．８％氟钼酸铵、２％氟化钠、去离子水分别处理４组牙本质人工龋损，然后用胰蛋白酶、胶原酶分解其胶原，通过羟脯氨酸含量测定，计算并比较各组牙本质标本胶原分解量。结果：１０％、２．８％氟钼酸铵比２％氟化钠抑制两酶分解胶原的作用强（Ｐ＜０．０１），对胶原酶的作用尤为显著（Ｐ＜０．０１）。结论：氟钼酸铵抑制蛋白分解酶（尤其胶原酶）对胶原的分解作用是它抑制牙本质龋发展的重要机制之一。     

Electrochemical behaviour of 2-(4′-hydroxybenzeneazo)benzoic-acid at pyrolytic graphite electrodes

The electrochemical reduction of 2-(4′-hydroxybenzeneazo)benzoic acid (I) has been studied at pyrolytic graphite electrodes in the pH range 2.0–10.4. The cyclic voltammetric behaviour clearly indicated an ECE mechanism in acidic medium in which the two-electron two-proton reduction of I gives the hydrazo derivative. The acid catalysed disproportionation of the hydrazo intermediate was also studied in the pH range 2.0–6.0 and the value of k′/[H⁺] was found to be 1.4 × 10^?2 1 mol^?1 s^?1 The products of the reduction have been isolated and characterized using IR, melting point, mass and related techniques.     

Thymosin beta4 is cytoprotective in human gingival fibroblasts

Thymosin beta4 (Tbeta(4)) is a naturally occurring, ubiquitous, non-toxic protein with documented wound-healing, anti-inflammatory, anti-apoptotic, and tissue-repair properties in skin, the ocular surface, and the heart. The ability of Tbeta(4) to demonstrate similar protective properties in cells of the oral cavity was analyzed using an in vitro model of cultured human gingival fibroblasts. Thymosin beta 4 significantly suppressed the secretion of interleukin-8 (IL-8) following stimulation with tumor necrosis factoralpha (TNF-alpha), suggesting that it may suppress the inflammatory response initiated by pro-inflammatory cytokines. By contrast, Tbeta(4) was not effective in protecting fibroblasts from challenge with lipopolysaccharide purified from Porphyromonas gingivalis or Escherichia coli. Thymosin beta 4 was able to protect gingival fibroblasts against the known cytotoxic effects of chlorhexidine digluconate, a mouthrinse containing chlorhexidine digluconate, and carbamide peroxide. Additionally, Tbeta(4) was able to protect gingival fibroblasts from the apoptosis that is induced by stimulation with TNF-alpha or by exposure to chlorhexidine. Because of its multifunctional roles in protecting cells against damage, Tbeta(4) may have significant potential for use as an oral heathcare aid with combined antimicrobial, anti-inflammatory, anti-apoptotic, and cytoprotective properties.     

Metabolic syndrome: pathogenesis, medical care and dental implications

BACKGROUND: The dental literature contains little information about metabolic syndrome (MetS) and its dental implications. TYPES OF STUDIES REVIEWED: The authors conducted a MEDLINE search for the period 2000 through 2005, using the term "metabolic syndrome" to define its pathophysiology, medical treatment and dental implications. RESULTS: MetS is the co-occurrence of abdominal obesity, hyper-triglyceridemia, reduced high-density lipoprotein cholesterol levels, hypertension and impaired fasting glucose, which results from consumption of a high-calorie diet and decreased levels of physical activity superimposed on the appropriate genetic setting. Components of MetS synergistically promote the development of atherosclerosis, resulting in myocardial infarction and stroke. CLINICAL IMPLICATIONS: Deteriorating oral health status is associated with worsening of the atherogenic profile. Tooth loss often results in chewing difficulties because of inadequate occlusive surfaces and may lead to alterations in food selection and dietary quality. This, in turn, adversely affects body composition and nutritional status, both of which are related to vascular health. Dentists should develop treatment plans that preserve and restore the dentition, thus ensuring maximum masticatory efficiency and affording patients the optimum opportunity to consume food that will not foster atherogenesis.