A new method to evaluate the affinity for hydroxyapatite (HAP) was devised by the application of column chromatography. When oral Streptococcus mutans MT8148 was chromatographed, bacteria eluted into three groups with different degrees of aggregation. This system also demonstrated that prior treatment of HAP with parotid or whole saliva dramatically enhanced the affinity of Streptococcus mutans MT8148 (serotype c) to the column, such that bacteria could only be eluted by 4 M guanidine HCl.

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Five different types of carriers combined with bone morphogenetic protein (BMP) were implanted into the dorsal subcutaneous tissue in the rat in order to study and compare the osteoinductive capacity and histological patterns. The carriers were: insoluble bone matrix (IBM), porous particles of hydroxyapatite (PPHAP), wet and dry collagen beads (CBw, CBd), fibrous collagen membrane (FCM), and fibrous glass membrane (FGM). The carriers alone were implanted for control studies. Each composite and its surrounding tissues were removed after 1, 2 and 3 weeks, and were studied by routine histology. Our results demonstrated that BMP-IBM, BMP-CBd, BMP-FCM and BMP-FGM induced bone tissue in a process that resembled an endochondral ossification mode; in BMP-IBM and BMP-CBd there was an early initiation of the process, in contrast with BMP-FCM and BMP-FGM where a delayed endochondral ossification was observed. These systems, with the exception of BMP-FGM, also induced bone formation through a direct ossification mode. On the other hand, BMP-PPHAP and BMP-CBw induced bone formation in a process that resembled an intramembranous ossification. BMP-carrier composites induce immature mesenchymal cells to become either osteogenetic or chondrogenetic cells, or both, depending on the physicochemical nature of the carrier that affected the microenvironment for cell differentiation. The presen study suggests that BMP-FCM, BNIP-PPHAP and BMP-CBd could be applicable carriers to explore the osteoinductive function of BMP, since no side-effects caused by the carrier were observed.

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The concentrations of rat salivary cystatin in serum, submandibular saliva and various tissue extracts in control and isoproterenol (IPR)-treated rats were determined by a sensitive enzyme immunoassay (EIA). In control rats, the cystatin was detected in submandibular saliva and in the submandibular gland extract but could not be detected in the other samples tested. A single injection of IPR induced the presence of salivary cystatin in submandibular, parotid and sublingual glands, with the highest levels in the submandibular glands. Treatment for two days with IPR resulted in the induction of salivary cystatin in the serum, esophagus, stomach, small intestine and kidney. The distributions of three salivary cystatins (designated as RSC-1, RSC-2 and RSC-3) in saliva and tissue extracts from rats that were chronically treated with IPRwere found to differ and a new form was induced in the kidney.

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Human oral spirochetes found in large numbers in periodontal pockets seem to be a potent immunogen. In order to determine the antibody-producing proteins of spirochetes, sera were collected from 25 subjects between 12 and 45 years of age, including 6 periodontally healthy subjects and 19 periodontal patients, and the serum was reacted with polypeptides from Treponema denticola, T. socranskii, T.phagedenis, T. pallidum and a human oral intermediate-sized isolate strain G7201. Immunoblot analyses demonstrated that the 34 kDa, 38 kDa, 52 kDa, 66 kDa and 72 kDa polypeptides from T. denticola ATCC 33520 and ATCC 35404, the 34 kDa, 45 kDa, 66 kDa, 78 kDa and 83 kDa polypeptides from T. socranskii subsp. buccale ATCC 35534, the 34 kDa and 66 kDa polypeptides from the G7201 strain, the 18 kDa, 32 kDa, 34 kDa, 50 kDa, 62 kDa, and the 66 kDa and 84 kDa polypeptides from T. pallidum ATCC 27087 and the T. phagedenis biotype Kazan 8 reacted with the sera of some periodontal patients. Of the six sera from healthy subjects one reacted with the 18 kDa polypeptide from the T. pallidum and T. phagedenis biotype Kazan. While the antibody-producing polypeptides with molecular sizes of 41 kDa, 45 kDa, 52 kDa, 62 kDa, 66 kDa, 72 kDa, 83 kDa and 84 kDa were from the outer envelopes or the wall-membrane complexes, the 34 kDa and 38 kDa polypeptides were from the axial flagella. The antibodies against the major polypeptides from the outer envelopes, wall-membrane complexes and axial flagella of oral spirochetes may contribute to progressive inflammation and destruction of periodontal tissues in humans.

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Morphological changes of epithelial cells in the main excretory ducts of rat submandibular glands were observed by transmission and scanning electron microscopies at 1, 3, 7 and 14 days after ductal ligation. At 3 rd day after ductal ligation, many inflammatory cells were seen in the intercellular spaces, and epithelial cells had many vacuoles with low density. At 7 th day after ductal ligation, a few cell had become to be lucent, therefore, it seemed that its cells were undergone death. Other cells had well-developed Golgi apparatus locating near nucleus, many lysosomes present beneath luminal surface. Microvilli still persisted but were decreased in number. But no obvious differences on structures of basal cells were detected between control group and ligated group. At 14 th day from ductal ligation, epithelial cells became cube-like in shape, but no differences of structures between the control group and ligated group, except to presence of the primary cilium projecting toward lumen, were observed. Although lumen of main duct was still enlarged, many inflammatory cells and lysosomes had disappeared in the epithelia.
The above observation may serve to help understanding of physiological function of the main excretory duct.

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Pharmacological properties of phenolic dental medicaments such as eugenol (EUG), guaiacol (GUA) and thymol (THY) on analgesic action, blood flow and substance P (SP) release were studied in comparison with that of capsaicin (CAP), a potent SP depletor, because these phenolic compounds are partly similar to CAP in chemical structure. While EUG, GUA and CAP had long lasting analgesic actions on hotplate and formalin tests after intrathecal and intraplantar (i. pl.) injections in mice, THY had no apparent effect. CAP (i. pl.) elicited a transitory pain which was reduced by spantide, and EUG and GUA produced similar effects. EUG and GUA caused a significant increase of cutaneous blood flow in the rat hindpaw, which spantide antagonized in the same manner as CAP. EUA and GUA significantly increased SP release from dental pulp and spinal cord slices in vitro, but were less potent than CAP. These results suggest that the analgesic effect of these phenolic compounds may be due in part to the ability to release SP.

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In order to determine the facial regions responsible for evoking the trigemino-neck reflex, the activity of the second cervical nerve innervating the dorsal neck muscles was investigated by electrically stimulating different facial afferent nerves of cats anesthetized with pentobarbital sodium. The infraorbital nerve trunk arising from the frontal part of facial skin was composed of several nerve fascicles with different receptive fields. An electrical stimulation of each fascicle elicited certain reflex discharges in the bilateral cervical nerves. All of these reflex responses had a low threshold and showed no differences in magnitude. With increasing stimulus intensity, the latency of these reflexes decreased, while both their amplitude and duration increased. Comparing the latencies under identical response magnitudes, the responses could be divided into two groups; one with a short latency elicited by the stimulation of the fascicles arising from the skin from the nose and another with a longer latency by those from the skin from the upper lip. These findings suggest that there are two groups of reflex responses, each corresponding to sensory inputs from different areas of the facial skin in the trigemino-neck reflex of cats.

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