S. Sigmund Stahl

Functional Demands on the Cell Proliferative Activity of the Rat Periodontium Studied Autoradiographically

Functional demands on the cell proliferative activity of the rat periodontium were studied autoradiographically with tritiated thymidine. Labeling indexes were assessed for fibroblasts, osteoblasts, and cementoblasts in the regions of the first molars of the maxilla and the mandible. Fibroblasts had the highest labeling index.

A [3H]-thymidine autoradiographic study of cell proliferative activity of injured parodontal tissues of 5-week-old mice

Abstract Evaluation of the cell proliferative changes which occur in response to trauma in young mice was investigated autoradiographically. Forty-four 5 week-old female mice of the short-lived Brookhaven National Laboratory (BNL) strain were gingivectomized surgically, removing the papilla mesial to the maxillary first molar. One hour prior to death, each animal received 1.0 μCi of tritiated thymidine per g of body weight by subcutaneous injection. Following death, the maxillae were removed, and the appropriate tissues were prepared for histologic and autoradiographic studies. Labelling indices were determined of various parodontal tissue cell compartments. The results were compared with previously published control values and rat data. Response of the mouse parodontal tissues to injury was, by and large, similar to that of the rat, with the exception that the proliferative activity of mouse tissues was significantly lower and occurred sooner following injury. The differences do not appear to be biologically significant in young animals. On the basis of the present findings, it was concluded that the size of the normal proliferative activity cannot be taken as (1) an index of the rate of repair, (2) an indication of the required length of repair, or (3) a measure of the proliferative capacity of the tissue. Normal labelling indices reflect only the level of cell turnover occurring in a given cell compartment, at a given anatomical site, in response to current physiological demands of the organism.

Comparative Assessment of the Cell Proliferative Activities of Injured Parodontal Tissues in Aging Mice

Little effect was noted on the labeling indexes of the gingival epithelium in aging mice after gingival excision. However, significantly diminished labeling indexes, shifted peak activities to later time periods, and delayed tissue regeneration were observed in associated connective tissues. The effects of aging were most pronounced on the connective tissue compartments that retained their cell proliferative potential despite aging.

Collagen Restoration in Healing Human Gingiva

Wound healing in human gingiva was stud. ied on 15 gingivectomy and 85 second biopsy sections taken at 6, 7, 14, 21, or 28 days after gingivectomy. Hydroxyproline concentration did not indicate completion of healing by 28 days. Projected time for completion of connective tissue repair was 49 days.

Autoradiographic Evaluation of Gingival Response to Injury: IV. Surgical Trauma in Low-Protein-Fed Young Adult Rats

Low-protein-fed rats demonstrated lower levels of proliferative activity in non-injured periodontal tissues than was noted in ad-libitum-fed or pair-fed rats. Gingival wounding resulted in tissue compensation, at the site of injury, for the reduction in proliferative activity present in low-protein-fed young adult rats.

The effects of desalivation on periodontal tissues of the Syrian hamster

Abstract Sixty hamsters were used to study the effects of desalivation on the incidence of periodontal lesions under three different dietary regimens. The desalivated animals consistently showed a greater number and extent of periodontal lesions in the soft and calcified tissues than their controls. Highly statistically significant differences were observed between the lesions of the control animals and those of the desalivated animals. The consistency and composition of diet seemed to play a role in the production of periodontal lesions in the hamster. High-carbohydrate, finely powdered, cariogenic ration 4 produced a greater number and extent of soft-and calcified-tissue lesions than either the laboratory chow or the ground laboratory chow. Ground laboratory chow produced a greater number and extent of lesions than laboratory chow in pellet form. The effects of the diets on the soft tissues appeared to be more severe than on the calicified tissues. The microscopic findings substantiated the gross observations. The desalivated animals showed histologic changes of greater severity than the intact controls. The pronounced changes in the desalivated animals were apical migration of the epithelial attachment and the presence of epithelium at the interradicular area. The control and desalivated animals fed ration 4 showed severe osteoporosis, possibly due to the nutritional inadequacy of the diet.

Autoradiographic Evaluation of Gingival Response to Injury: V. Surgical Trauma in Low-Protein-Fed Mature Rats

Mature low-protein-fed and control rats received a gingival injury. Healing responses were studied by autoradiographic analysis. Thirty days after injury, malnourished rats showed lower mean labeling indexes than rats fed ad libitum, which suggests that aging and malnutrition may reduce the compensatory response to injury after initial peaks of repair activity are completed.

Biochemical and Histochemical Studies of Aerobic Oxidative Metabolism of Oral Tissues. II. Enzymatic Dissection of Gingival and Tongue Epithelia from Connective Tissues

The interpretation of biochemical and metabolic studies of intact tissues, tissue slices, and tissue homogenates may be extremely difficult when different cell types are present, because one cannot ordinarily assess the relative contribution of each cell type to the over-all activity exhibited by the tissue preparation. Histochemical techniques may provide qualitative and, less frequently, semiquantitative or quantitative information concerning relative activities of the different tissue components. Previous studies from this laboratory dealing with aerobic metabolism of gingiva1 and of salivary glands2 have demonstrated an urgent need for separating the epithelial components of oral tissues from their associated connective tissues to permit quantitative biochemical estimations of the metabolic activities of the separated cell types. For salivary glands, this problem was solved in our laboratory by the development of a combined mechanical crushing and differential centrifugation procedure, permitting isolation of relatively pure, separate acinar and duct fractions, whose respective biochemical and metabolic properties could be determined.3 4 The present paper will deal with the problem of the separation of gingival and tongue epithelia from their underlying connective tissues, with retention of the activities of their labile terminal respiratory metabolic systems. A preliminary oral report on aspects of this work was made at the Second International Conference on Oral Biology in Bonn, Germany, July, 1962. At the same time there appeared an abstract by Araya, Imagawa, and Shizuya,5 in which they reported

Influence of Prolonged Low -Protein Feeding on Epithelized Gingival Wounds in Adult Rats

SYNOPSIS IN INTERLINGUA INFLUENTIA DEL PROLONGATE USO DE UN DIETA A BASSE CONTENTO DE PROTEINA SUPER EPITHELISATE VULNERES GINGIVAL IN RATTOS ADULTE.—Un mense post le infliction de lesionage gingival, gruppos de rattos esseva alimentate (1) con un dieta a un contento de 8 pro cento de caseina, accessibile ad libitum, (2) in pares con un dieta a un contento de 27 pro cento de caseina, e (3) con un varietates de dietas de controlo, accessibile ad libitum. Le animales esseva sacrificate in le curso de un periodo de 7 menses. Le examines histologic monstrava que le sitos del vulneres in le rattos del prime duo gruppos manifestava un plus alte incidentia de inflammation e de sequestration que illos del gruppos de controlo. Iste constation pare significar le occurrentia de un persistente influentia adverse de privation nutritional e spicificamente de alimentation a basse contento de proteina super epithelisate vulneres gingival.

Trauma affects cyclic AMP and DNA levels at injured and non-injured distal oral mucosal sites

SummaryExperiments in rats were conducted to test the hypothesis that gingival trauma affects cyclic AMP and DNA levels at the gingival wound, and non-injured distal (gingival, palatal) sites. Cyclic AMP and DNA levels rose and fell in a cyclic fashion during the time (0.5–24 h) periods analyzed. Significant increases in cAMP levels occurred at 8 and 20 h and at 8 and 16 h, respectively, at the wound and non-injured palatal site, peripheral to the wound. Similar increases (not significant) in cAMP levels were also noted at the non-injured gingival contralateral site at the same time intervals. DNA distributions were found to be significantly greater 10 and 16 h after injury at the gingival wound, and distal non-injured gingival and palatal sites.ZusammenfassungExperimente zur Unterstützung der Hypothese, daß die operative Zahnfleischwunde (Entfernung von einem 1×4 mm Stück Zahnfleisch) die Konzentrationen von cyclischem AMP (cAMP) und DNA an der Seite der Zahnfleischwunde und der nichtoperierten distalen Seiten (Zahnfleisch, Gaumen) beeinflußt, wurden ausgeführt. Die Konzentrationen von cAMP und DNA stiegen und fielen in einem cyclischen Modus während der Zeitspanne der Analyse (0.5–24 h). Eine signifikante Zunahme der cAMP-Konzentrationen wurde zwischen 8–20 h erhalten; nach 8 h an der Zahnfleischwunde und nach 16 h an dem nichtoperierten Gaumen, in der Peripherie der Zahnfleischwunde. Ähnliche Zunahmen (nicht signifikant) der cAMP-Konzentrationen wurden an der nichtoperierten kontralateralen Seite des Gaumens in den gleichen Zeitintervallen beobachtet. Die Konzentration der DNA an der operierten Zahnfleischwunde, der nichtoperierten distalen Seite des Zahnfleisches und des Gaumens war ebenfalls nach 10–16 h signifikant erhöht.