Spontaneous regeneration after juvenile ossifying fibroma resection: a case report

A case of unusual bone regeneration after resection of a juvenile ossifying fibroma (JOF) is presented. Secondary mandibular reconstruction with autogenous grafts was delayed due to the rapid bone formation. To the best of our knowledge there are no reports of this unusual response following JOF resection.     

Time-dependent effects of discrete spatial cues on the planning of directed movements

The degree of preparation of a motor response varies with the information available regarding the response that will need to be executed and with the time provided to process that information. In experiment 1 we investigated the time-course of processing the information specified by discrete spatial cues regarding the upcoming target of directed movements. For this purpose we varied the number of cues that indicated the possible locations of the target and the duration of the cue period preceding the target. The results showed that the effects of processing the information provided by the cues developed progressively and stabilized after 0.2 s. In addition, the level of motor preparation reached was a function of number of cues. However, the effect of number of cues occurred even in the no cue period condition, i.e. when subjects could not have benefited from the information provided by the cues to prepare the response. Further analyses suggested the hypothesis that, in the no cue period condition, the effect of number of cues resulted from the cues acting as distractors (i.e., interference) whereas, with longer cue periods, the effect resulted from the motor preparatory process (i.e., facilitation). This hypothesis was tested in experiment 2 where the number of cues and the number of distractors were varied inversely. Cues and distractors were the same type of stimuli and differed only in their relation to the time of presentation of the target. Subjects performed in a directed response task and in a control detection task. It was predicted that the facilitatory effect of the cues and the interference effect of the distractors on the planning of the directed response would oppose each other and produce a non-monotonic change of RT across conditions. The results conformed to the prediction and, therefore, supported the hypothesis of independent effects of facilitation and interference. In addition, we found that the pattern of RT across conditions in the detection task differed radically with that in the directed response task. This result indicates that the time-dependent effects of cues and distractors are contingent on the type of motor response required in the task, and, in particular on the spatial requirement on the motor response.     

Role of epithelium in agonist-induced contractile responses of guinea-pig trachealis: influence of the surface through which drug enters the tissue.

1. A method has been used in guinea-pig isolated tracheal rings to achieve selective drug entry from the adventitial or mucosal surface. A study has been made of the effects of epithelium removal on responses to spasmogens entering the tissue solely from the adventitial or the mucosal surface. 2. Cumulative concentration-response curves for KCl (1 to 100 mM), acetylcholine (0.1 microM to 10 mM) and histamine (1 microM to 1 mM) were constructed in intact and epithelium-denuded tracheal rings in circumstances where drug entry was unrestricted or restricted to the adventitial or mucosal surface. 3. Epithelium removal did not alter the responsiveness or sensitivity of tracheal rings to KCl either when drug entry was unrestricted or when drug entry was restricted to the adventitial or mucosal surface. 4. When acetylcholine entered from the mucosal or adventitial surfaces of intact tracheal rings its concentration-response curve was displaced to the right with respect to that obtained for unrestricted drug entry. A greater rightward shift was observed for mucosal drug entry than for adventitial drug entry. Epithelium removal potentiated acetylcholine entering from the mucosal surface to a greater extent (27.5 fold) than it potentiated acetylcholine entering from both surfaces (4 fold). Epithelium removal did not potentiate effects of acetylcholine entering from the adventitial surface alone. 5. In intact tracheal segments, concentration-response curves for histamine entering from the mucosal surface were displaced to the right compared with those for histamine entering in an unrestricted fashion or from the adventitial surface alone. This displacement was absent in epithelium-denuded preparations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of plasma on composition of human enamel and cementum pellicle

Abstract – Slabs of human enamel and cementum were incubated with plasma alone or with various mixtures of plasma and saliva. Proteins and glycoproteins that adsorbed to the surface of the slabs in 0 to 60 min were labeled by lactoperoxidase-catalyzed ¹²⁵I-iodination and by mild periodate oxidation followed by NaB³H₄ reduction. The labeled components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by autoradiography or fluorography. From plasma alone, a 58 and a 66 kDa protein (probably albumin) were adsorbed to the enamel surface in relatively equal amounts, but no ¹²⁵I-labeled components were detected on the cementum surface in the absence of saliva. Adding 10% saliva to the incubation mixture promoted the adsorption of the 58 and 66 kDa components to cementum. In addition, another set of proteins, including components of 44, 47, 29, and 25 kDa, was adsorbed to both cementum and enamel in the presence of saliva. These six proteins were the major ¹²⁵I-labeled species in all of the pellicles formed from mixtures of plasma and saliva. The electrophoretic mobility of the major 120 and 140 kDa ³H-labeled sialoglycoproteins adsorbed to both cementum and enamel was similar to that of the low-molecular-weight mucin of submandibular/sublingual saliva.     

A Review of Methods Used to Reinforce Polymethyl Methacrylate Resin

Various methods to reinforce acrylic denture base material have been used to repair fractures in complete dentures. Metal wires and plates have been tested as reinforcement of polymethyl methacrylate (PMMA) resin. The contributions of the studies conducted on this biphase composite system are discussed in this review article. The literature has reported that even thin metal wires incorporated into the PMMA matrix increased the transverse strength of the PMMA construction. Metal mesh inserted into PMMA resin had negligible effects on the transverse strength of the restoration. Macroscopic retention of the metal strengtheners to the PMMA had only a minor effect on the strength in contrast to microscopic retention, which showed a more marked effect. Chemical bonding between the PMMA and metal reinforcer enhanced the strength of the prosthesis with some exceptions.     

Immunotoxicity of Cocaethylene

This report describes the response of normal human T cells to stimulation in vitro in the presence of nano-micromolar concentrations of cocaethylene. Thymidine incorporation by concanavalin A-stimulated peripheral blood mononuclear cells was generally blunted by cocaethylene, albeit to different degrees depending upon the donor tested. the formation of concanavalin A-induced blast cells was decreased by increasing concentrations of cocaethylene. the production of interleukin-2 was also blunted in a dose-dependent fashion by cocaethylene, and this outcome was more consistently observed in stimulated peripheral blood mononuclear cells, compared to unseparated whole blood preparations. An inverse dose dependence was obtained in relation to the response of blast cells to recombinant human interleukin-2 in the presence of cocaethylene. These lines of evidence, taken together with our preliminary studies aimed at testing the effect of cocaethylene on the expression of certain membrane markers of activation (i.e., interleukin-2 receptor, transferrin receptor, serine aminopeptidase IV) and the expression of the proliferating cell nuclear antigen (cyclin PCNA), suggest that cocaethylene modulates relatively early events following T cell stimulation probably related to the interleukin-2 system.