Capsaicin receptor expression in the rat temporomandibular joint

Experimentally, temporomandibular joint (TMJ) nerve units respond to capsaicin, which is used clinically to treat TMJ pain. However, the existence of capsaicin receptors in the TMJ has not previously been clearly demonstrated. Immunohistochemical analysis has revealed the presence of transient receptor potential vanilloid subtype 1 (TRPV1) expression in the nerves and synovial lining cells of the TMJ. TRPV1-immunoreactive nerves are distributed in the synovial membrane of the joint capsule and provide branches to the joint compartment. The disc periphery is supplied by TRPV1 nerves that are mostly associated with small arterioles, and occasional nerves penetrate to the synovial lining layer. Double immunofluorescence has shown that many TRPV1-immunoreactive nerves are labeled with neuropeptide calcitonin gene-related peptide, whereas few are labeled with IB4-lectin. The results provide evidence for the presence of TRPV1 in both nerves and synovial lining cells, which might thus be involved in the mechanism of nociception and inflammation in the TMJ. This study was supported by a grant-in-aid for Scientific Research (C), no. 15591938, from the Japanese Ministry of Education, Science, Sports, Culture, and Technology (to M.A.K.).     

mu-Opioid receptor mRNA expression and immunohistochemical localization in the rat temporomandibular joint

This study was undertaken to examine the presence and distribution of the mu-opioid receptor (MOR) in the non-inflamed rat temporomandibular joint (TMJ) using non-radiographic in situ hybridization at the mRNA level and immunohistochemistry at the protein level. MOR mRNA and MOR-like immunoreactivity (MOR-LI) were found around the small blood vessels in the anterior part of the synovial membrane. The number of MOR mRNA signals in the anterior synovial membrane was significantly higher than that in the posterior part. Morphologically, MOR mRNA and MOR-LI were localized in amorphous materials considered to be nervous tissue, as well as some cell types considered to be macrophages, mast cells and endothelial cells. The present study showed the distribution of MOR in the rat TMJ synovial membrane and suggests that the opiate system plays an important role in endogenous analgesia in the TMJ.     

Evidence for the expression of the EGF receptor on human monocytic cells

Several malignancies over-express the epidermal growth factor receptor, ligation of which results in cellular differentiation and multiplication. Mononuclear phagocytes secrete this cytokine and its receptor has been detected on microglial cells. This communication describes the expression (and its regulation) of epidermal growth factor receptor (EGFR) on U937 cells. We have shown that a few are EGFR-positive, with expression being up regulated by interleukin 6 (IL-6). Also, when cultured in the presence of serum with the monoclonal anti-EGFR, ICR62, U937s showed a reduced growth rate. By contrast, ICR9 caused a significant increase in cellular proliferation. Both antibodies induced cycle arrest in late G(1)/S phase. When the cells were cultured in the absence of serum, low antibody concentration (10 microg/ml) showed an early inhibitory effect on cell proliferation. By contrast, at high antibody concentrations (50 micro/ml), ICR62 significantly increased the proliferation of U937 cells. We suggest that these results provide indirect evidence for an autocrine action of EGF on U937 cells.     

Differential expression of the angiogenic Tie receptor family in arthritic and normal synovial tissue

Angiopoietins (Ang) are vascular endothelial cell-specific growth factors that play important roles principally during the later stages of angiogenesis. We have compared the distribution of the receptor tyrosine kinase (Tie) and the Ang ligands in synovial tissues from normal subjects and those with rheumatoid arthritis (RA) and osteoarthritis (OA).     

Influence of serotonin on the analgesic effect of granisetron on temporomandibular joint arthritis

The influence of circulating serotonin (5-HT) on the effects of intra-articular administration of granisetron on temporomandibular joint (TMJ) pain was investigated in 11 patients with chronic polyarthritides. An analgesic effect superior to placebo has been shown previously. The change in TMJ movement pain intensity was negatively correlated to circulating 5-HT; that is, the higher the 5-HT before injection, the greater the reduction of pain intensity. The resting pain intensity reduction was not related to 5-HT. In conclusion, this study indicates a stronger short-term analgesic effect on TMJ movement pain by intra-articular administration of the 5-HT3 receptor antagonist granisetron in patients with high levels of circulating 5-HT.     

The effect of occlusal relationships on the occurrence of sounds in the temporomandibular joint

The aim of this investigation was to determine the influence of occlusal relationships on the occurrence of sounds in the temporomandibular joint. A group of 100 male subjects aged 24-52 years (X = 35.03+/-6.92) was examined. Analysis of occlusion included determination of the number of existing teeth, number of teeth in occlusion, overbite and overjet, type of occlusion, mediotrusion interferences, relationship of the retruded contact position (RCP) to intercuspal position (ICP), and the amount and direction of sliding from RCP to ICP. Sound was registered by means of a stethoscope and classified according to its character in click or crepitation. Sound was present in 29% of subjects. In 28% of cases it was registered as click and in 2% of cases as crepitation. One subject had simultaneous click and crepitation. The results of the statistical analysis indicate that overbite, type of occlusion, existence of mediotrusion interferences, the relationship of RCP to ICP, and the amount and direction of sliding from RCP to ICP do not have an influence on the occurrence of sounds. The risk of the occurrence of crepitation is significantly increased in the case of the loss of more than 5 teeth, and in the case of horizontal overbite larger than 7.5 mm (p<0.05).     

A model of temporomandibular joint function in anthropoid primates based on condylar movements during mastication

The hypothesis that the shape of the bony temporomandibular joint (TMJ) is functionally related to sagittal sliding of the condyle during mastication is tested, and a model of the relation of sagittal sliding to mandibular size, TMJ shape, and diet is developed. Sagittal sliding is defined as fore-aft motion of the condyle during mandibular translation and/or angular rotation. Ascending ramus height is used as a structural correlate of the distance between the condyle and the mandibular axis of rotation (CR). Cineradiographic data on sagittal sliding and gape during mastication in Ateles spp., Macaca fascicularis, Papio anubis, and Pan troglodytes in conjunction with comparative data on mandibular size and TMJ shape are used to evaluate the hypothesis. The results show that 1) linear and angular gape are highly positively correlated with sagittal sliding, 2) pure mandibular translation is rare during mastication, 3) the CR is rarely if ever located at the condyle during mastication, 4) angular gape should be standardized in interindividual comparisons of sagittal sliding, and 5) the height of the ascending ramus (and by inference the CR-to-condyle distance) is highly positively correlated with absolute sagittal sliding. Sagittal sliding relative to the length of the articular eminence was the variable used to explore the relation between TMJ shape and sliding. This variable standardized absolute sagittal sliding relative to joint size. The relative depth and orientation of the articular eminence were not correlated with relative sagittal sliding. The anteroposterior curvature of the condyle was highly negatively correlated with relative sagittal sliding. Flat condyles are associated with large amounts of relative sagittal sliding. A flat condyle increases joint contact area, which reduces joint stress. A flat condyle also increases joint congruence, and this may facilitate the combined sliding and rolling motion of the condyle when the sliding motion is relatively large. The shape of the entoglenoid process was also positively correlated with relative sagittal sliding. A relatively large entoglenoid process may help to guide sagittal sliding and prevent excessive mediolateral sliding of the condyle. The functional model makes a number of predictions about the correlations between food consistency and food object size, mandibular size, TMJ shape, and sagittal sliding of the condyle during mastication and incision. Am J Phys Anthropol 109:67–88, 1999. © 1999 Wiley-Liss, Inc.     

Biofeedback in the treatment of long-term temporomandibular joint pain an outcome study

Eleven patients with long-term pain related to the temporomandibular joint (TMJ) were trained in tension awareness and relaxation using feedback of muscle tension level in the masseter through a digital display. At a follow-up examination 4–15 months after the termination of treatment, 8 of the 11 patients were totally symptom-free or significantly better; 1 patient was slightly better, and there was no effect for 2 patients. Possible reasons for failure and sex differences are discussed.     

Activation of human monocytes occurs on cross-linking monocytic antigens to an Fc receptor

Murine mAb to CD13, CD14, and class II MHC, are able to mobilize calcium in normal human monocytes and enhance superoxide production in primed cells. Antibodies to CD35 (CR1) also cause a minor calcium response in some individuals. Antibodies to CD11a, CD11b, CD11c, CD15, CD17, CD18, and CD45 do not activate monocytes. The ability of mAb to cause monocyte activation is not only dependent on the Ag with which they react but also on the isotype of the antibodies and the individual from whom the monocytes were obtained. It is shown that this is because the mAb that activate monocytes do so by formation of Ag-antibody-FcR complexes. F(ab')2 fragments of mAb to CD13 and CD14 do not therefore activate monocytes even when cross-linked with F(ab')2 anti-mouse Ig but do so when cross-linked with intact anti-mouse Ig. These data indicate that activation via the FcR requires perturbation of this receptor but does not necessarily require cross-linking of one FcR to another. Antibody-coated particles or cells able to bind to cell surface receptors on monocytes other than the FcR would thus augment FcR-mediated activation.     

肺炎克雷伯菌生物膜对单核细胞株THP-1 TLR2受体表达的影响

目的研究肺炎克雷伯菌生物膜对单核细胞株THP-1TLR2受体表达的影响,探索细菌生物膜逃脱宿主免疫防御的机制。方法以体外建立肺炎克雷伯菌生物膜的合成分泌物处理单核细胞株THP－1作为实验组,以等量浮游细菌的合成分泌物处理单核细胞株THP-1作为对照组。RT—PER半定量分析THP－1 TLR2mRNA的表达,流式细胞仪检测分析THP－1 TLR2蛋白的表达。结果实验组THP－1 TLR2 mRNA表达（0．453±0．06）明显低于对照组（4．872±0．36）（P〈0．05）;实验组TLR2蛋白表达率（8．42％±3．74％）明显低于对照组（12．35％±7．36％）（P〈0．05）。结论细菌生物膜与浮游细菌不同的代谢产物能显著下调THP－1 TLR2的表达水平,影响固有免疫进而影响适应性免疫,可能是生物膜细菌逃脱机体免疫防御系统的又一机制。     

The effect of collagen reinforcement in the behaviour of the temporomandibular joint disc

In this paper, the influence of collagen fibres in the behaviour of the temporomandibular joint disc is studied. A three-dimensional finite element model of the joint is developed from a set of medical images. The model comprises the mandible, part of the cranium and both temporomandibular joints. Joints have been considered to be composed of the articular discs and the temporomandibular ligaments. A fibre-reinforced porohyperelastic model was used to study the response under clenching of the fibrocartilage that composes the articular disc. This was divided in an intermediate zone, and two bands, an anterior and other posterior, in order to define the orientation of collagen fibres. The study demonstrates that the introduction of collagen fibres in the biphasic behaviour of the articular disc implies for a prescribed displacement not only an increase of the pressurization in the tissue, but also higher stresses in the anterior and posterior bands, as well as in the lateral zone of the disc. Thus, modelling the disc as an isotropic solid matrix leads in this case to an overestimation of the stresses in the intermediate zone, an underestimation of the pore pressure in this area, and an underestimation of the stresses in the rest of the disc.     

Estrogenic effect of a series of bisphenol analogues on gene and protein expression in MCF-7 breast cancer cells

Bisphenols constitute a family of compounds, which includes many substances that have as a common chemical structure two phenolic rings joined together through a bridging carbon. In the present study, we aimed to determine whether several events triggered by 17 beta-estradiol (E(2)) in MCF-7 breast cancer cells were also observed in response to various bisphenol-A (BPA) analogues. We studied the expression of estrogen controlled genes by measuring the induction of pS2 (mRNA and protein) and progesterone receptor (PgR) as well as the expression of a luciferase reporter gene transfected into MVLN cells. These data were compared to the cell proliferation potency and effectiveness as the latest expression of estrogen controlled functions. Bisphenols showed an agonistic effect in all our assays, suggesting that these compounds may act through all the response pathways triggered by the natural hormone. We found differences between the assays in the potency of bisphenols, defined as the minimum concentration required to produce a maximal effect. In the cell proliferation assay, all tested compounds needed a lower concentration than in the other assays to give maximal response. Our results suggest that the polarity and nature of the substituent in the central carbon determines the estrogenic potency. Presence of two propyl chains at the central carbon appears to confer the greatest potency in both gene and protein expression assays.     

Mandibular biomechanics and temporomandibular joint function in primates.

There is disagreement as to whether the mandibular condyles are stress-bearing or stress-free during mastication. In support of alternative models, analogies have been drawn with Class III levers, links, and couple systems. Physiological data are reviewed which indicate that maximum masticatory forces are generated when maxillary and mandibular teeth are in contact, and that this phase lasts for over 100 msec during many chewing strokes. During this period, the mandible can be modeled as a beam with multiple supports. Equations of simple beam theory suggest that large condylar reaction forces are present during mastication. With unilateral molar biting in man, the total condylar reaction force may be over 75% of the bite force. Analysis of a frontal projection demonstrates that up to 80% of the total condylar reaction force is borne by the contralateral (balancing side) condyle during unilateral molar biting. A comparison of human, chimpanzee (P. troglodytes), spider monkey (A. belzebuth), and macaque (Macaca sp.) morphology indicates that the frugivorous chimpanzee and spider monkey have a relatively lower condylar reaction force than the omnivorous macaque or man during molar biting. The percentage reaction force during incisal biting is lower in man than in the other primates, and lower in the frugivorous primates than in the macaque.