[Morphometric analysis of the temporomandibular joint with MRI in 320 joints]. / Morphometrische Analyse des Kiefergelenkes anhand von 320 Gelenken mit der MRT.

PURPOSE: To compare several morphometric parameters in MRI with the functional status of the articular disc in a large patient group suffering from internal derangement (ID) of the temporomandibular joint (TMJ). MATERIALS AND METHODS: In a retrospective study, 320 analyzable high resolution MRI examinations of the TMJs obtained in a 1.5 T unit were evaluated in 184 patients with clinically suspected ID. The analysis included the anatomical structures and a number of morphometric parameters previously described in the literature. The parameters were compared with the position of the articular disc. RESULTS: The disc position was categorized as "normal" (NDP, 21.9 %, n = 70), "anterior displacement with reduction on opening" (AMR, 51.6 %, n = 165) and "anterior displacement without reduction on opening" (AOR, 26.6 %, n = 85). With increasing disc displacement, significant configurational changes of the disc were observed. Disc displacement was associated with changes of the condyle consisting of increasing deformity and other degenerative changes. A large tuberculum and marked inclination of the eminence can be seen as predisposition for the development of ID. With increasing severity of the ID, the position of the condyle moved from a centric position of the condylar center to an excentric (dorsal and cranial) position. CONCLUSION: MRI demonstrated that increasing disc displacement is associated with changes of the disc, condyles and condylar position in the fossa.

Sustained suppression of voluntary sodium intake of spontaneously hypertensive rats (SHR) in hypobaric hypoxia.

Spontaneously hypertensive rats (SHR) of the Okamoto-Aoki-strain (n = 20) and normotensive rats (NCR) of a random-bred Wistar strain (n = 20) were kept in low-pressure chambers for 13 days at sea-level atmospheric pressure, then for 20 days at a simulated altitude of 4000 m, and subsequently again for 10 days at sea-level. The unrestrained animals were placed singly in metabolic cages and had free access to food, water, and a 2.5% NaC1-solution. Exposure to hypobaric hypoxia led to a transient decrease of daily food and water intake in both strains of animals and a slight reduction of saline consumption in the NCR. In contrast, the SHR showed a massive and sustained suppression of their voluntary intake of hypertonic saline throughout high-altitude exposure. Renal electrolyte and water excretion followed the reactions of salt and water intake. - In an additional series of experiments it was found that SH-rats react with a decrease of their systemic arterial blood pressures in hypobaric hypoxia only on condition that food and water but no additional salt is available to the animals. The data suggest that the antihypertensive effects of chronic high-altitude hypoxia depend both on the availability of salt and a reduction of salt appetite.