Influence of the thyroid upon the glycosaminoglycans in the salivary glands in the rat

The glycosaminoglycans of the salivary glands were studied in male rats 2 months after radiothyroidectomy, and after the daily administration of 0.1 and 1.0 μg of sodium-1-triiodothyronine to radiothyroidectomized rats for 1 month. Total uronic acid concentration was determined in the salivary glands. Chromatographie separation of the uronic acid fractions was performed on cellulose microcolumns. Radiothyroidectomy increased and the administration of triiodothyronine decreased the uronic acid concentration in the submandibular glands. These changes occurred only in the hyaluronic acid and glycoprotein fractions. No changes in uronic acid concentration were detected in the retrolingual and parotid glands.     

Changes in the mandibular angle in the edentulous state

Several textbooks of anatomy and at least one prosthodontic text make unsupported statements that the mandibular angle widens in the edentulous state. A search of the literature for support of those statements shows a disparity in conclusions on the subject. Several reports merely make statements that the angle does widen in the edentulous mandible. These articles present no original research. There are reports in the literature that lend some verification of the widening of the mandibular angle. However, an approximately equal number report nonwidening of the angle in the edentulous state. From these conflicting reports it would seem that if indeed there is a widening of the mandibular angle in the edentulous state, it is slight. This is verified by the results of this study which shows a mean increase of 2.4 degrees in the edentulous state (p = .001). The mean edentulous angle in this study was 126.3 degrees. This does not come close to the 140 degrees mentioned in two anatomy texts. If statements are to be made in the literature concerning this widening of the edentulous mandibular angle, they should be qualified with the words "slight widening." Several articles have stated that dentures prevent widening of the mandibular angle. This conclusion is refuted by a preliminary study in which we measured the mandibular angles of edentulous men patients who have never worn dentures. Sixty-eight angles were measured on 34 Panelipse radiographs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Experimental study in the dog of the non-active role of the tooth in the eruptive process

The role of the tooth in eruption was studied radiographically and histologically after experimental manipulations of the crowns of permanent mandibular premolars in dogs. Crowns were removed and dead crown shells or metal or silicone replicas were substituted into dental follicles just prior to scheduled eruption. These replacements erupted on schedule after formation of the usual eruption pathways and formation of trabecular bone from the base of the bony crypt. Removal of crowns, but without adding replacements, also exhibited these same hallmarks of eruption. We conclude that tooth eruption is a series of metabolic events in alveolar bone characterized by bone resorption and formation on opposite sides of the dental follicle and the tooth does not contribute to this process.     

Valves in the subsidiary lymph trunks in the neck.

INTRODUCTION: The thoracic duct drains both lymph and chyle into the confluence of the great veins in the root of the neck. The venous termination of the duct is protected from retrograde flow of blood by valves. However, little attention has been focused on the presence or absence of valves in the subsidiary lymph trunks in the neck. AIMS: The aim of this study was to determine whether there are valves in the subsidiary lymphatic system in the neck. Material and methods: The left side of the neck was explored in ten formalin-fixed cadavers. Subsidiary lymphatic trunks were carefully preserved for stereomicroscopic examination. RESULTS: Eight subsidiary trunks were identified comprising four jugular, two subclavian and two bronchomediastinal trunks. Both subclavian lymph trunks drained directly into a vein. A bicuspid ostial valve was present at the termination of the trunks. The bronchomediastinal and jugular trunks drained into the thoracic duct prior to its venous termination. Valvular structures were identified along the bronchomediastinal trunks and at their termination with the thoracic duct. No valves were identified in the jugular trunks. CONCLUSION: The absence of valves in the jugular lymph trunks is proposed as a possible contributory factor in the creation of chyle leaks following neck dissections.