Tetsuya Habu

Changes in Protein Secretion by Rat Submandibular Glands in Response to Isoproterenol, a-Methylnoradrenaline, and Clonidine during Post-natal Development

We studied developmental changes in salivary volumes and proteins secreted by the submandibular glands of male rats at weekly intervals from two to ten weeks of age in response to the β1-, α1-, and α2- adrenoceptor agonists, isoproterenol (IPR), a-methylnoradrenaline (a-mNA), and clonidine (Clonid). The types of proteins in saliva samples were determined and compared by isoelectric-focusing electrophoresis with the Phast system in both the gradient pH -3.5-to-5 and pH-3.5-to-9 gels by means of silver staining. Salivary volume and protein concentration in saliva samples elicited by IPR and a-mNA were positively related to the weight of the submandibular glands up to six or seven weeks of age, whereas in saliva elicited by Clonid, no relation was found. The isoelectric-focusing electrophoretic patterns of proteins secreted by the glands in response to three stimuli were different from each other during post-natal development. Within one stimulation, differences were also observed at two and three weeks of age for Clonid, and from seven weeks of age for the three stimuli, respectively. The a-type proteins, but not the β-type proteins, were very similar to those in extracts from glands of rats at seven weeks of age. Almost all of the a-type proteins, but not the β-type proteins, reacted with antibodies to two proteases. We conclude that functional maturation precedes morphological maturation in the submandibular glands of rats.

Effect of light-exposure duration on the amount of leachable monomers from light-activated reline material

Leaching of monomers from light-activated direct intraoral reline material (Lebaron LC) was determined by means of high-pressure liquid chromatography analysis. This study evaluated the effects of exposure duration and thickness to determine appropriate curing conditions that reduce the levels of unreacted monomeric components. Prolonged duration of exposure (30 minutes) reduced the amount of leached monomer. However, the results of this study indicated that the amount of leached monomeric components increased with an increasing reline material thickness. The results suggest that the light-activated reline material should be cured for sufficient prolonged exposure duration.

Age Changes in Secretory Function of Male and Female Rat Parotid Glands in Response to Methoxamine and Pilocarpine

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of both parotid glands of male and female rats at weekly age intervals from three to 10 weeks, and at 3.5, 8, and 15 months of age. It was analyzed for the concentrations of protein, potassium, calcium, inorganic phosphate, and for amylase activity. The types of protein were determined electrophoretically, and an amino acid analysis of the total protein was also carried out. The wet weights of the glands increased substantially up to eight weeks of age, then reached almost plateau values, and finally tended to decrease at 15 months of age in both sexes. The salivary volumes secreted in response to methoxamine and pilocarpine were positively correlated with the parotid gland weights in both sexes. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the salivary flow rates only at relatively low rates of flow. The amylase activity was positively correlated with the concentration of protein, independent of the nature of the stimulus, age, and sex. With methoxamine as a stimulus, the amylase activity was positively correlated with the concentration of calcium, independent of age and sex. The types of protein and amino acid concentrations were independent of the nature of the stimulus, age, and sex up to 15 months of age. However, in parotid saliva of several rats at 8 and 15 months of age, unusual proteins were observed electrophoretically, independent of the nature of the stimulus and sex.

Protein secretion by rat submandibular glands in response to isoproterenol, α-methylnoradrenaline and clonidine during aging

Changes in salivary volumes and the three types of proteins secreted by the submandibular salivary gland (SMG) of male rats at 3.5, 5.5, 8, 12, 13, 14, 15, 19, 21 and 24 months of age in response to the beta 1-, alpha 1- and alpha 2-adrenoceptor agonists, isoproterenol (IPR), alpha-methylnoradrenaline (alpha-mNA) and clonidine (Clonid), were studied and compared by measuring the weight and by isoelectric focusing electrophoresis with the Phast System on both the gradient pH 3.5-5 and 3.5-9 gels with silver staining. A protein (protein A, tentatively termed in this study) purified by FPLC from saliva elicited by IPR was also analyzed by SDS-polyacrylamide gel electrophoresis, the immuno-thermoblotting method, carbohydrate determination and neuraminidase treatment. Unexpected findings were observed that salivary volumes, but not the protein concentration, were substantially increased by Clonid-, but not IPR-, stimulation with ages up to 24 months of age and that the three types of proteins elicited by each agonist were different during aging. The gamma-type of proteins elicited by Clonid was not greatly changed during aging, whereas several proteins at about neutral pI in the alpha-type, elicited by alpha-mNA, at 5.5 to 21 months of age and a protein A in the beta-type, elicited by IPR, at 13 to 24 months of age were greatly increased. This protein A without any carbohydrate and sialic acid, located only in the acinar cells, but not in any duct system, had a molecular weight of 16,000 and a pI of 4.05. We conclude that the secretory function of the SMG in the aged animals is in general little changed.

Bond Strength of Self-curing Acrylic Resin Bonded to Occlusal Surfaces of Abrasion-resistant Plastic Denture Teeth.

The effect of the four types of surface treatment methods was evaluated to improve the bond strength between the self-curing acrylic resin and the abrasion-resistant plasticdenture teeth. All of the surface treatment methods significantly increased the bond strength. Specimens without surface treatment showed surface fractures after the bond test. As for the surface treatments using the silane coupling agent and 5% hydrofluoric acid-UDMA, most specimens showed surface fractures. The mechanically-roughened specimens (polished with # 100-SiC paper, sandblasted) showed cohesive fractures in self-curing acrylic resin. Although the bond strengths of specimens with or without surface treatment were significantly reduced after the thermocycle test (5, 000 cycles), most specimens that underwent the mechanical-roughening treatment showed cohesive fractures. The results of this study suggested that surface treatments of mechanicalroughening were effective methods to improve the bond strength and the bond durability of self-curing acrylic resin to occlusal surfaces of cross-linked abrasion-resistant plastic denture teeth.

Surface Treatment Agents for Denture Base Resin. Part 1. The Effect of Organic Solvents.

The ultimate purpose of these series is to manufacture the most effective surface treatment agent for repairing or relining denture base resins. As the preliminary step, the effects of chemical etching of the base resin by surface treatments with sixteen organic solvents on the bond strength between base resin and repair resin are presented in this report.The results of the investigation are as follows:1. Treating the surface of the denture base resin with chloroform, 1-butanol and ethyleneglycolmonobuthylether for 30 seconds before bonding of repair materials significantly improved the bond strengths between base resin and repair resin.2. The bond strength was significantly decreased by treatment with ethyl acetate and xylene for 30 seconds.

Bond Strength of Highly Cross linked Layers of Abrasion resistant Plastic Denture Teeth Bonded to Pour type Denture Base Resin.

Bond strength between abrasion-resistant plastic denture teeth bonded to pour-type denture base resin was measured to evaluate the effect of five kinds of surface treatment. Bond strength to the enamel layer of teeth was significantly improved by applying of silane coupling agent. Etching of the enamel layer by 5% of hydrofluoric acid (HF) also improved the bond strength. The maximum bond strength was obtained from the surface which was etched by HF and then applied urethane dimethacrylate-based light-activated monomers (HF+UDMA treatment). Bond strength to the dentin layer of teeth was also significantly improved by HF+UDMA treatment. There was no significant reduction of the bond strength to the dentin layer after the thermo-cycling test (10, 000 cycles), but statistically significant reduction was observed in the enamel layer. The results of this study suggested that the HF + UDMA treatment would be a useful method to improve the bond strength between highly cross-linked enamel and dentin layers of abrasion-resistant plastic denture teeth and pour-type denture base resin.

Bond Strengths of Abrasion-resistant Plastic Denture Teeth Bonded to Pour-type Denture Base Resin.

The purpose of this study was to evaluate the bond strengths of two abrasion-resistant plastic denture teeth (Endura, Duradent) bonded to pour-type denture base resin. The bond strengths of abrasion-resistant plastic denture teeth were compared with plastic tooth and porcelain tooth. The effects on bond strength produced by treatment of ridge-laps were also studied. Specimens were prepared and tested in accordance with JIS specification. The bond strengths of Endura, Duradent and the plastic tooth were not statistically different, and those were significantly lower than that of the porcelain tooth. The bond strengths of Endura and the plastic tooth were increased by treatment of ridge-laps surface with Dichloromethane and Duradent were increased by the same treatment and grinding ridge-laps.