The value of arthrography in the decision-making process regarding surgery for internal derangement of the temporomandibular joint.

In this study, the clinical and arthrographic findings from 43 internally deranged temporomandibular joints (TMJs) were compared with the intra-surgical observations. In 40 of 43 joints, arthrography did not provide any additional information useful for diagnosis or treatment. In six joints, the problem was misdiagnosed. Only in three joints did arthrography demonstrate the existence of perforation in the posterior attachment that had not been suspected during the clinical examination. Because of the doubtful importance of arthrographic information for the decision-making process, it is suggested that the method be applied only in cases in which clinical examination and plain radiographs have failed to uncover the signs and symptoms indicative of a TMJ disorder.     

Suppression of chemotactic activity of human polymorphonuclears by monoclonal IgMs with and without biological activity

The influence of monoclonal IgMs on migration of human polymorphonuclears was studied at various temperatures by the use of 19 sera with monoclonal IgMs from patients with macroglobulinemia of Waldenstrom (MW) without obvious biological activity, 29 sera with monoclonal IgM cold agglutinins (18 with anti-I and 11 with anti-i IgMs) and 3 sera with monoclonal IgM rheumatoid factor (RF). Under-agarose migration method and modified Boyden chamber method with double filters and 51Cr-PMNs were used. In under-agarose method, chemotactic differentials for controls, MW, anti-I, and anti-i groups were, respectively, 57 +/- 8 mm, 39 +/- 9 mm, 44 +/- 14 mm, and 32 +/- 16 mm at 37 degrees C and 47 +/- 18 mm, 22 +/- 11 mm, 17 +/- 9 mm, and 15 +/- 12 mm at 24 degrees C. All three sera with IgM RF inhibited chemotaxis. The differences between all groups and controls were significant at p less than 0.01. Random migration was inhibited at 24 degrees C (p less than 0.01) but not at 37 degrees C. Inhibitory concentrations of IgM in the sera tested were equal or less than 0.5 mg/ml. Thirteen sera were tested by the modified Boyden chamber method. At 37 degrees C 8 of 13 sera and at 24 degrees C 11 of 13 sera inhibited significantly chemotaxis at a concentration of IgM of 1 mg/ml. The lowest inhibitory concentration of IgM was 25 micrograms/ml. Eleven chromatographically pure IgMs were tested in the under-agarose assay. At concentrations of 0.4-3.7 mg/ml, eight IgMs inhibited chemotactic differential at 37 degrees C and nine inhibited it at 24 degrees C. At concentrations of 0.6-2.0 mg/ml, all seven pure IgMs tested by the Boyden chamber method significantly inhibited chemotaxis at 24 degrees C and 37 degrees C. Some IgMs inhibited chemotaxis at concentrations as low as 25 micrograms/ml. Ten IgM CA were eluted from the red blood cells. Eluates inhibited strongly chemotaxis at 24 degrees C and 37 degrees C. Heat inactivation did not alter inhibitory activity of IgM, however pepsin digestion or reduction and alkylation of purified IgMs did abolish their inhibitory activity. Inhibition of chemotaxis was not related to the light chain type, the titre, or the thermoamplitude of cold agglutination. However, monoclonal IgMs with anti-i cold agglutinin activity were stronger inhibitors than anti-I. Since 75% of IgMs tested inhibited chemotaxis at 37 degrees C, it is possible that monoclonal IgMs, especially those with anti-i cold agglutinin activity, inhibit PMN migration in vivo.     

Diagnosis of a sublingual epidermoid cyst using contrast medium radiography: a case report

A case of a sublingual epidermoid cyst is presented. The advantages of contrast medium radiography in diagnosis, localization and surgical treatment planning are exemplified.     

2-Butoxyethanol model of haemolysis and disseminated thrombosis in female rats: a preliminary study of the vascular mechanism of osteoarthritis in the temporomandibular joint

Female rats develop haemolytic anaemia and disseminated thrombosis and infarction in multiple organs, including bone, when exposed to 2-butoxyethanol (BE). There is growing evidence that vascular occlusion of the subchondral bone may play a part in some cases of osteoarthritis. The subchondral bone is the main weight bearer as well as the source of the blood supply to the mandibular articular cartilage. Vascular occlusion is thought to be linked to sclerosis of the subchondral bone associated with disintegration of the articular cartilage. The aim of this study was to find out whether this model of haemolysis and disseminated thrombosis supports the vascular hypothesis of osteoarthritis. Six female rats were given BE orally for 4 consecutive days and the two control rats were given tap water alone. The rats were killed 26 days after the final dose. The mandibular condyles showed histological and radiological features consistent with osteoarthritis in three of the four experimental rats and in neither of the control rats. These results may support the need to explore the vascular mechanism of osteoarthritis further.     

The process of lubrication impairment and its involvement in temporomandibular joint disc displacement: a theoretical concept.

PURPOSE: This article re-evaluates the chain of events leading to temporomandibular joint (TMJ) disc displacement. The joint lubrication system and the process of its breakdown are clarified and an attempt is made to evaluate the possible effect of increased friction between the disc and fossa on the anterior displacement of the disc. MATERIALS AND METHODS: The study is based on the author's accumulated clinical data and results obtained from laboratory investigations regarding TMJ lubrication and its possible breakdown, coupled with pertinent information culled from the literature. RESULTS: Translation of the disc in the TMJ is enabled due to the presence of phospholipids and hyaluronic acid, which constitute an efficient lubrication system. This system may break down in the presence of uncontrolled free radicals. In the absence of lubricants, the articular surfaces are smooth, elastic in texture, and possess strong surface energy. Such opposing planes, especially in the presence of a thin fluid film (sub-boundary lubrication) tend to generate high friction while the disc is sliding against the fossa. Such friction is probably the prime mover in loosening the disc attachments to the condyle, with subsequent disc displacement. CONCLUSIONS: Increased friction of the contiguous parts may well be a major causative factor in displacement of the articular disc. This should be taken into account in considering the appropriate treatment approach. It also raises some doubts regarding the validity of using repositioning techniques.     

Electron microscope and biochemical observations of the surface active phospholipids on the articular surfaces and in the synovial fluid of the temporomandibular joint: a preliminary investigation.

PURPOSE: The goal of this article is to investigate the surface-active phospholipids located on the articular surfaces and in the temporomandibular joint (TMJ) synovial fluid (SF) by means of electron microscopy and biochemical analysis. MATERIALS AND METHODS: Synovial fluids and articular cartilage samples taken from 6 normally functioning TMJs were studied. The osmiophilic lining of human TMJ articular surfaces has been studied by using special nondestructive fixation procedures. To study the SF, negative staining technique has been used. In addition, thin-layer chromatography has been used to identify the phospholipids extracted from synovial fluid of human TMJs. RESULTS: In the SF, granular bodies were identified with diameter of between 170 and 280 nm. Their diameter decreased dramatically when exposed to phospholipase-A(2). The amorphous and highly osmophilic material on the articular surface include membrane-bound vesicles (270 nm in diameter) with lamellated pattern surrounding the amorphous-dense core. Biochemical extraction revealed phosphatidylcholine as the major component of the polar lipids. CONCLUSIONS: This preliminary study presents findings that suggest that phospholipids present in the TMJ may provide an efficient boundary lubrication that enables the disc to slide down the slope of the eminence on joint function.     

Modulation of locomotor activity of polymorphonuclear cells by cationic substances and cationic lysosomal fractions from human neutrophils

Seven cationic substances — human and egg-white lysozyme, RNase, protamine, histone, poly-l-lysine and poly-l-arginine; five cationic lysosomal fractions from human polymorphonuclears (PMNs); RNA; poly-l-glutamic acid; DNA; heparin; endotoxin; mastocytotropic agent compound 48/80; and cytochalasin B were tested for the influence on chemotaxis and random migration of human PMNs using under-agarose migration and Boyden chambers with two filters and [⁵¹Cr]PMNs. The above substances were either preincubated with PMNs, added to chemoattractants, or used instead of chemoattractants. In under-agarose migration method chemotaxis was inhibited by 11–35% when egg-white lysozyme, protamine, heparin, endotoxin, or compound 48/80 was added to the cells. High concentration of cytochalasin B inhibited chemotaxis by 73 %. Cationic fractions I and V and low concentration of cytochalasin B enhanced chemotaxis by 11%, 41%, and 30%, respectively. When human and egg-white lysozyme, DNA, or cytochalasin B was added to the chemoattractants, motility of PMNs was inhibited. Cationic fractions II and V from human PMNs, when used as chemoattractants, enhanced cellular motility by 143–167%. Random migration was enhanced by heparin and inhibited by cytochalasin B and by cationic fractions from human PMNs. These findings suggest that various cationic and anionic substances and cationic fractions from human PMNs have heterogeneous influence on random migration and chemotactic activity of human PMN. Analysis relating chemotaxis to phagocytosis and to intracellular bactericidal activity (ICBA) has shown several patterns. Protamine, poly-l-lysine, poly-l-arginine, and agent compound 40/80 all inhibit chemotaxis and enhance phagocytosis and ICBA; cationic fractions II and V enhanced all three functions, whereas cytochalasin B suppressed phagocytosis and ICBA and had concentration-dependent modulatory influence on chemotaxis. It implies diverse mechanisms of action and possible impact on inflammatory reactions.Supported by agrant-in-aid from the Medical Research Council of Canada.     

The ovarian endothelin network: an evolving story

The endothelin (ET) system consists of three ET isopeptides, several converting enzyme isoforms and two G-protein-coupled receptors, ETA and ETB, which are linked to multiple signaling pathways. Less than 20 years after the initial detection of ET-1 in granulosa cells, the ovarian ET network continues to expand with the discovery of new members and functions. ETs influence a broad range of essential reproductive processes, such as ovulation, steroidogenesis and luteolysis. Therefore, a more comprehensive understanding of the ovarian ET network might provide new strategies for controlling reproduction. This review presents up-to-date findings on the ET network in the ovary.