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阿蘇火山直下のマグマ溜りの化学的進化を明らかにするため，先阿蘇火山岩類の岩石記載と全岩化学組成分析を行った．それら溶岩は，斑晶鉱物組合せと全岩化学組成の異なる8タイプに区分できる．液相濃集元素のモデル計算結果は，先阿蘇火山岩類が示す組成多様性が単純な分別結晶作用では導かれないことを示した．さらに，先阿蘇火山岩類とカルデラ形成期以降噴出物を比較した結果，特に安山岩～流紋岩の斑晶鉱物組合せ，量比に顕著な違いがみられること，前者が後者に比べてSiO2含有量に対する液相濃集元素含有量が乏しい特徴があることが明らかになった．これらの結果は，先カルデラ火山活動期からカルデラ形成期の間に，安山岩～流紋岩マグマの起源物質化学組成や生成時の物理条件などに変化が生じたということを示唆している．

Neutron induced prompt gamma-ray activation analysis (PGAA) is applied for determining boron contents in volcanic rocks, which is an important element in the discussion of material circulation in volcanic arc systems. To evaluate the recycling of oceanic crust in Kyushu, we analyzed boron and other trace element contents in basaltic rocks from the area. The basalts from volcanic front have high B/Nb (2.9–3.7), B/Zr (0.1–0.2) and B/Sm (2.8–6.0) ratios, whereas those ratios in the basalts from backarc are extremely low (

Although heat stress can cause irritation in the dentin/pulp complex, little is known about the thermotolerance of pulp cells and their response to heat stress. We investigated cultured rat pulp cell responses to heat stress. Cells were subjected to a temperature of 42°C for 30 minutes, and HSPs, alkaline phosphatase activity, and gap-junctional communication were determined at various time points. Although only low levels of HSP70 expression were detected before heat treatment, heat shock markedly induced HSP70 expression, with it gradually increasing at 1 hour after being heated. HSP25, however, showed no dramatic change. Gap junction protein connexin43 rapidly degraded after heat treatment, recovering to normal levels within the following 6 hours. Alkaline phosphatase activity decreased immediately after heat stress, recovering after 1 hour. These results indicate that dental pulp possesses protective factors, including HSPs, and that it can recover viability of intercellular communication and alkaline phosphatase activity after heat stress.

We analysed the N1 latency and amplitude for non-target event-related potential (ERP) and the N1 and P3 latencies and amplitudes for the target ERP in a continuous 40-min auditory oddball task. The N1 amplitude at Fz of non-target ERP was significantly less in the 3rd session than in the 1st session. The N1 amplitude to the target ERP was not different among the three sessions. The P3 amplitudes at Fz and Cz of target ERP was significantly less in the 3rd session than in the 1st session. These results suggest that a number of intracranial neural generators of P3 might change in prolonged extension of an auditory oddball task.

Molecular dynamics study of martensitic transformation based on a simple model for binary alloys, where interaction between atoms is represented by Lennard-Jones type potential with two parameters. One represents atomic size or molar volume and the other bond strength. This simple model allows us to study such common features of matensitic transformation as successive appearance of different modifications of close-packed structures, dependence of transformation temperature on the size of nanocrystals and also positive temperature coefficients of shear elastic moduli above Ms.

In this paper, a nonequilibrium network which works as a dynamical associative memory is designed. The design is based on a new similarity measure between any stored pattern and a state of the network. Although conventional similarity measures, such as Hamming distance, direction cosine, and so on, are not detectable in a cross-coupled network, the similarity measure proposed in this paper is. The new similarity measure is employed in our design. The network should include the following properties in its output pattern sequence, so that the dynamics of cross-coupled network may be designed: 1) Stored patterns are frequently associated in the dynamical association. 2) The dynamical association is very robust against variation of distributed parameters. Property 1) is achieved by introducing the next two operation modes with inverse N-shaped function into the dynamics of the proposed network. 1) When the state of the network is close enough to a stored pattern at a time step, the state is forced to evolve at the next time step. 2) The state of the network converges to a stored one while it is not close to any stored patterns. By considering these two operation modes, the frequency of associating stored patterns is increased. The authors emphasize the property 2) which is very important for a silicon implementation of the proposed network. In the silicon implementation, parameters of the network must be represented by transistors, resistors, capacitors, and other electric components which exhibit variation in their characteristics. Thus the second property guarantees the easy silicon implementation of the nonequilibrium network proposed in this paper.

Fusion performance of reversed shear discharges with an {ital L}-mode edge has been significantly improved in a thermonuclear dominant regime with up to 2.8 MA of plasma current in the JT-60U tokamak. The core plasma energy is efficiently confined due to the existence of persistent internal transport barriers formed for both ions and electrons at a large minor radius of r/a{approximately}0.7 near the boundary of the reversed shear region. In an assumed deuterium-tritium fuel, the peak fusion amplification factor defined for transient conditions involving the dW/dt term would be in excess of unity. {copyright} {ital 1997} {ital The American Physical Society}

To evaluate the reliability of metal-carbon eutectic systems as fixed points for the next generation of high-temperature standards the effect of thermodynamic properties related to the shape of eutectic phase diagram on the freezing temperature is investigated within the context of the numerical multi-phase-field model. The partition coefficient and liquidus slopes of the two solids involved in the eutectic reaction are varied deliberately and independently. The difference between the eutectic temperature and the freezing temperature is determined in dependence of the solid/liquid (s/l) interface shape and concentration. Where appropriate reference is made to the Jackson-Hunt analytical theory. It is shown that there are mainly two typical conditions to decrease the undercooling: 1) a small liquidus slope and 2) the associated difference between the eutectic composition and the liquid composition during solidification.

To provide personal services in a ubiquitous environment, it is necessary to identify users without giving a psychological pressure to them. This paper proposes a configuration of the sensor network used to identify a user based on his or her sole pressure distribution on a sensor mat that uses a hetero-core optical fiber. Specifically, it presents a filtering algorithm used to determine the pressure and the center of gravity of the sole, which are significant and stable observational data useful for personal identification. In addition, it discusses the assignment of functions to the sensor node and the home server, and the communication protocols used. Finally, it evaluates the sensor network configuration based on experiments with an experimental personal identification system developed.

Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide, PBZ) is a chemical inducer of resistance against plant pathogens and has long been practically used for protecting rice plants against a blast fungus, Magnaporthe grisea. We have been investigating the expression profiles of rice genes in response to PBZ using cDNA microarray technique. An array composed of 1265 rice expressed sequenced tag (EST) clones from various source including shoots, calli etc. was targeted by Cy5 labeled mRNAs from PBZ treated and untreated rice plants, respectively. As a result, ten cDNA clones exhibited greater than three-fold over-expression in the PBZ treated plants compared to untreated controls. Some of these clones have identities with disease resistance, pathogenesis-related and cell maintenance/development-related genes. The enhanced gene expression was confirmed for nine out of ten clones by using Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses. Several clones were further tested for Northern blot analysis using total RNA from blast fungus infected rice. Under the conditions used, three out of seven clones showed enhanced level of mRNA accumulation in infected plants. This may suggest that the enhanced expression of some genes by PBZ may contribute to the disease resistance in host plants. Furthermore cDNA library was constructed using mRNAs from leaves of PBZ treated rice plants and a microarray of the randomly selected 2880 clones from the library was used for choosing clones whose expression was changed in response to PBZ. Thirty nine clones were found to change their expression levels by a factor of 3 folds after PBZ treatment. Characterization including sequencing is now underway for these clones.

The purpose of this study was to qualitate the penetration of the major components of 4-META/MMA-TBB adhesive resin (4-META resin) and to characterize their influence on the in vitro and in vivo wound healing of dental pulp tissues. Fresh 4-META resin was applied to rabbit mesentery; its components penetrated the mesentery to form three of layers, depending on the amounts of monomer components in the tissue. The superficial layer was a soft-tissue hybrid layer (STHL), the intermediate layer contained small particles of polymerized 4-META resin, while the deepest layer contained unpolymerized monomer components including MMA and butanol, which were detected by gas chromatography (GC). To characterize the in vivo effects of the deepest layer, we immersed the pulp tissue in MMA or in 5% 4-META/MMA and autotransplanted it to placement beneath a rabbit kidney capsule. The MMA-immersed pulp was positive for osteocalcin and presented osteodentin formation at 7 days, as did the untreated control pulp tissue. In contrast, the 5% 4-META/MMA-immersed pulp collapsed into the cell-deficient fibrous connective tissue, with slight calcification by 7 days and less osteodentin formation at 14 days. Analysis of these data suggests that MMA does not inhibit osteogenic activity of pulp tissue, while 5% 4-META/MMA does inhibit osteogenic activity to some extent.

The authors have already proposed that the internal value of the cross coupled network can work as a similarity measure between a state of the network and one of patterns embedded in the network. The measure was applied to design a dynamic of a novel activation. Moreover, we proposed a nonequilibrium cross-coupled network which works as a dynamical associative memory. In this paper, we apply the similarity measure, that is the internal value, to achieve convergence of the state of the network to the global minimum.

The purpose of the study is to investigate the behavior of Merkel cells and nerve tissue in peri-implant tissue using immunohistochemistry, electron microscopy, and confocal laser scanning microscopy. These results suggested that even though the regeneration of epithelium and nerve tissue occurred around the periimplant region, Merkel cells did not regenerate in peri-implant. Therefore, it has to be considered that MC—neurite complexes are not formed in the peri-implant tissue.

In this study, we investigated Merkel cells which are found in large numbers in the palatal rugae area functioning as mechanoreceptors. The morphological changes occurring as a consequence of the abnormal mechanical stimulation exerted by the denture base over the palatal mucosa were observed. Degeneration of Merkel cells and sensory nerve fibers was recognized on the first day after the denture plate was placed. Thus, continuous mechanical stimulation, even for a very short term can influence the nature and property of the sensory nerve fibers. Further, necrosis or apoptosis of Merkel cells was induced by strong continuous mechanical stimulation exerted by the denture base on the underlying mucosa.

The authors describe the design and initial operation of a new JT-60 (JAERI Tokamak-60) man-machine interface system built in workstations. Development of the system was stimulated by the requirements of making of JT-60 operator interface more friendly on the basis of the past five years of operational experience. Eleven Sun/3 workstations and their supervisory minicomputer HIDIC V90/45 are connected through the standard network, Ethernet. The network is also connected to the existing ZENKEI minicomputer system through the shared memory on the HIDIC V90/45 minicomputer. Improved software, such as automatic setting of the discharge conditions, consistency check among the related parameters, and easy operation for discharge result data display, provides the user-friendly environments. This man-machine interface system leads to the efficient JT-60 upgrade operation. >

Discharge sequential control (DSC) is an essential control function for the intermittent and pulse discharge operation of a tokamak device, so that many subsystems may work with each other in correct order and/or synchronously. In the development of the DSC program, block diagrams of logical operation for sequential control are illustrated in its design at first. Then, the logical operators and I/O's which are involved in the block diagrams are compiled and converted to a certain particular form. Since the block diagrams of the sequential control amounts to about 50 sheets in the case of the JT-60 upgrade tokamak (JT-60U) high power discharge and the above steps of the development have been performed manually so far, a great effort has been required for the program development. In order to remove inefficiency in such development processes, a computer-aided software engineering (CASE) tool has been developed on a UNIX workstation. This paper reports how we design it for the development of the sequential control programs. The tool is composed of the following three tools: (1) Automatic drawing tool, (2) Editing tool, and (3) Trace tool. This CASE tool, an object-oriented programming tool having graphical formalism, can powerfully accelerate the cycle for the development of the sequential control function commonly associated with pulse discharge in a tokamak fusion device.

The purpose of this study was to investigate cellular responses of periodontal ligaments during tooth movement. Twenty-eight male Sprague-Dawley rats, weighing 200-250 g each, were used. To create the orthodontic force, elastic rubber blocks (0.65 mm thick) were inserted between the maxillary first and second molars on both sides. On days 3, 7, 10, 14, 21 and 28 after rubber block insertion, histopathological changes in both the tension and the pressure sides were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA) and by the TUNEL method. The ratios of PCNA-positive cells on the tension side 3 and 7 days after rubber block insertion were higher than those on the pressure side. The ratios of PCNA-positive cells on the tension side were highest at day 3 after insertion and then decreased during the remainder of the experimental period. On the pressure side, the ratios of PCNA-positive cells increased up to day 10 post insertion, then decreased from 14 to 28 days. The ratios of TUNEL-positive cells on both the tension and the pressure sides increased throughout the entire experimental period. These results indicate that the periodontal ligaments on the tension side are able to respond more promptly to orthodontic forces than those on the pressure side. The data also suggest that the ratios of cell proliferation and of cell death are closely related to the regeneration and reconstruction of periodontal ligaments which reflect the orthodontic force.

Most neoplasms arising from the thymic epithelium are considered to be 'thymomas', which are composed of cytologically benign, neoplastic epithelial cells and nonneoplastic lymphocytes. In contrast, thymic epithelial neoplasms displaying cytologically malignant features have recently been classified as thymic carcinomas of various types of histology. However, primary thymic adenocarcinoma is extremely rare and only four cases of it have been reported in the literature. We report a rare case of primary thymic adenocarcinoma of 4-year complete remission with concurrent chemoradiotherapy followed by surgery. A 61-year-old Japanese man was referred to us complaining of facial edema and general fatigue. Computed tomography scans revealed a huge mass in the anterior mediastinum obstructing the superior vena cava. He was diagnosed with thymic adenocarcinoma on needle biopsy. He was treated with induction chemoradiotherapy consisting of cisplatin, 5-FU and concurrent thoracic radiation, which yielded a partial response. He then underwent surgical resection of the remaining mass. However, pathologic examination of the resected mass revealed no malignant cells. The patient is doing well without symptoms or signs of relapse 53 months after diagnosis.

Bronchioloalveolar carcinoma (BAC) has been reported to have unique clinicopathological features.This retrospective study was performed using data base including 871 patients treated for primary lung cancer between 1981 and 1995.The patients with BAC included a larger proportion of female (P = 0.029) and smoked less (P = 0.002) than those with non-BAC. There was no difference in survival between surgically resected patients with BAC and those with non-BAC. Clinical Stage IV patients with BAC had a better response to chemotherapy than did those with non-BAC. Survival in the former group was better than that in the latter on univariate analysis, but the significance of this difference was not confirmed multivariate analysis.The patients with BAC included a larger proportion of females and smoked less than those with non-BAC. Treatment results for BAC was comparable to those for non-BAC.

Freeze-fracture and immunohistochemistry were used to elucidate the ultrastructure of gap junctions and the expression of connexins (gap junction structural proteins) Cx32 and Cx43 in the developing rat submandibular glands. Developing rat submandibular glands were examined from the 17th gestational day to the 14th day after birth. Gap junctions could be observed as clusters of particles 9-12 nm in diameter during the gestational days. The junctions were very small and consisted of about 20 particles in a relatively regular arrangement with a wide center-to-center spacing of 15-18 nm on the PF face. Fluorescence spots reacting positively to Cx43 were found between glandular cells from the 17th gestational day. Very few spots positive to Cx32 could be detected during gestation, their numbers increasing after birth. The possibility that Cx32 may have a role in the establishment of secretory regulation and that Cx43 is associated before birth with glandular growth and differentiation is discussed.

We reported a 10-year-old girl with acquired left oculomotor nerve palsy. Neurologic and radiological examinations failed to reveal the etiology. Following administration of corticosteroid and vitamin B6, diplopia improved within 6 weeks, and mydriasis has been improving over the past 9 months. Idiopathic acquired oculomotor nerve palsy is a very rare condition in childhood, and prognosis of the disease is sometimes good.

The aim of the present study was to investigate the proliferating activity of peri-implant epithelium immunohistochemically using proliferating cell nuclear antigen (PCNA). Eight ITI (Internationale Team für Implantologie) implants were placed into simulated sockets in the mandibles of two beagle dogs two months following tooth extraction. As a control, junctional epithelium of the molar teeth in the same animals were used. The nature of staining and the distribution of PCNA immunoreactivity were determined by scoring a minimum of 100 cells on two sections from each of the implants. In the junctional epithelium, the immunoreactivity to PCNA was detected mainly in the basal cells, in some of the prickle cells, and in a few cells attached to the enamel. In peri-implant epithelium, only some of the basal cells were positive for PCNA. The PCNA score of the peri-implant epithelium was significantly lower than that of junctional epithelium. These results suggest that the peri-implant epithelium maintains a lower capacity to act as a proliferative defence mechanism than does the junctional epithelium.

The first case report of a Merkel cell carcinoma arising from the palatal mucosa in a young adult is presented. The histopathological similarities of this tumour in skin and oral mucosa are also discussed. The patient was a 14-year-old female with a non-symptomatic painful swelling in the left molar region of the maxilla. Under the diagnosis of a malignant tumour, a partial maxillary resection was performed, but there was a recurrence, and finally the patient died of cerebral metastasis. The tumour was composed mainly of uniform small cells. Immunohistologically, a large number of the cells were reactive to neuron specific enolase (NSE) and cytokeratin CK19, and some of the cells were positive to CK8, CK13, CK20, PGP9.5 and CEA, focally and slightly. Pseudo-rosette formation and squamous differentiation were frequently detected. The ultrastructure of the tumour cells showed abundant Golgi bodies associated with neurosecretory granules. We conclude that it is the first case of a Merkel cell tumour arising from palatal mucosa and invading underlying bone with reactive hyperplasia. These findings closely resemble those of the same tumour occurring in the skin.

Although the adenomatoid odontogenic tumor (AOT) is categorized as an odontogenic epithelial tumor with odontogenic ectomesenchyme, AOT with induction of true tubular dentin with or without concomitant formation of enamel is exceedingly rare. This paper reports a case of AOT showing evidence of extensive induction of tubular dentin, but without concomitant formation of enamel. The patient was a 20-year-old female with a rather well-circumscribed intraosseous lesion of the maxillary incisor-premolar area without an embedded tooth. Histologically, extensive induction of a dysplastic form of tubular dentin with globular calcification was evident, in addition to the characteristic histological features of AOT. The present case lends support to the categorization of AOT as an odontogenic tumor consisting of a disorderly mixture of odontogenic epithelium and odontogenic ectomesenchyme with or without dental hard tissue formation.

The purpose of this study was to examine if the migration of human gingival fibroblasts on titanium was promoted by platelet-derived growth factor (PDGF) and whether the release of urokinase-type plasminogen activator (uPA) was correlated with it. The migration of the fibroblast on titanium was significantly promoted by PDGF in a wound healing assay (p0.001). The promotive effect was inhibited by aprotinin, a serine protease inhibitor used for the inhibition of uPA (p0.001). The conditioned medium when fibroblast migration was promoted contained a higher concentration of uPA than did that of the control. These results indicated that the promotive effect of PDGF on the migration of human gingival fibroblasts on titanium was correlated with the release of uPA from the fibroblasts.

We examined the expression and localization of the gap junction proteins connexin32 and 43 in rat submandibular and sublingual glands. Western blot analysis with anti-connexin32 and 43 antibodies showed bands of approximately 27 KD and 43 KD, respectively, in both glands. Immunofluorescence microscopy demonstrated the presence of reactive spots for connexin32 between acinar cells in both glands. The frequency of connexin32-positive spots in the submandibular glands was approximately equal to that in the sublingual glands. In contrast, reactive spots for connexin43 were observed at the periphery of the alveolar structures in both glands. The connexin43-positive spots in the sublingual glands were more frequent and larger than those in the submandibular glands. No positive spots for both connexins were detected between duct cells in either gland. Immunoelectron microscopy revealed that connexin32 was localized to the gap junctional membranes between acinar cells. Immunolabeling for connexin43 was located on the gap junctions between thin processes of myoepithelial cells. These results suggest that connexin32 of the gap junction is associated with regulation of the secretory function of acinar cells and that connexin43 is associated with that of contraction of the myoepithelial cells in rat salivary glands.

The number, size, and localization of gap junctions(GJs) in developing rat submandibular gland cells was studied by immunohistochemistry and freeze-fracture morphology. Sprague-Dawley rats from the 19th gestational day through to the 21st day after birth were used. On the 19th gestational day an assembly of GJ can be detected as clusters of particles 9-12nm in diameter on the lateral plasma membranes. Immunohistochemically fluorescence spots, which react positively to connexin(CX)32 were observed between acinar cells from birth. No GJs were detected at ductal cells in any developmental period in both specimens. The number, size and density increased during the course of development. The results of this study indicate that GJ protein CX32 of rat submandibular gland cells may be associated with functional increasing and differentiation of acinar cells.

The purpose of this study was to examine laminin localization in epithelial rests of Malassez grown on titanium and their gelatinase activity. Laminin localization was confirmed by immunocytochemistry in all epithelial cells grown on titanium. The conditioned medium from the epithelial cells grown on titanium exhibited 72kD- and 92 kD-gelatinase activities by gelatin zymography. Those results suggest that laminin contributes to the epithelial cell attachment to titanium and that gelatinases may be mobilized for epithelial cell movement on titanium.

Osteogenic activity of autografted dental pulp, periodontal ligament, and bone marrow of rat in vivo was investigated. Immunolocalization of ALPase in situ was also studied. One month after the transplantation, osteodentin was formed in all the dental pulp transplants (100%), bone or cementum like tissues were created in 20% of periodontal ligament transplants, and bone like tissues were in 20% of bone marrow transplants. After two months, osteodentin was produced in all the dental pulp transplants (100%) and bone like tissue were in 50% of both periodontal ligament and bone marrow transplants. Immunohistochemically, positive reactions to ALPase in situ were detected in cells just below the odontoblast layers in dental pulp, surface layers of alveolar bone in periodontal ligament, and endosteal membrane of bone marrow space. From these results, it was suggested that the cells of these three kinds of tissue can be termed osteogenic-fibroblasts in vivo.

The aim of this study was to examine about the etiology of large cyst formation in pleomorphic adenoma from the histopathological standpoint by examining four cases of our own as well as previously reported ones. In the first of our cases, a large cyst wall lined with keratinized squamous epithelium was observed. In the second, a large cyst containing mucinous material was lined with a single cell layer of squamous epithelium-like cells. The third case was a carcinoma in pleomorphic adenoma with some large cysts lined with multiple layers of atypical epithelial cells. In the fourth case, a hemorrhagic portion were seen on a large cyst wall without a lining of epithelial cells. From these histopathological observations and the suggestions of previous authors, we surmised that the large cyst formation in pleomorphic adenoma might originate from the squamous metaplasia of tumor cells and the enlargement of duct-like structures by outstanding secretion from tumor cells or salivary gland tissues, hemorrhagic portions, or necrosis in the malignant tumor.

Demineralized dentin pieces were implanted in 18 rat submandibular glands to examine the chondrogenesis and osteogenesis in pleomorphic adenoma of the salivary gland. After 7 days of implantation, a large amount of cartilage tissue was found next to the inner portions of the implanted pieces, and small amounts of the osteoid and cartilage tissues were detected next to the outer portions. A small amount of bone tissue was found in contact with the cartilage 10 days after the implantation. In the inner portions, invasions of capillaries and a small amount of osteoid tissue were noted. These histological findings resembled those of endochondral ossification. Large amounts of bone tissue and resorption of the implant were observed after 14 days. It has been suggested that cartilage and bone are produced by bone morphogenetic proteins (BMP) in demineralized dentin resulting in chondrogenesis followed by osteogenesis in submandibular gland. Apparently, undifferentiated mesenchymal cells are produced by implantation, undergo dedifferentiation, and are redifferentiated into chondroblasts and osteoblasts in the presence of BMP. These results suggest that chondrogenesis and osteogenesis in the submandibular gland are induced by BMP. It is possible that the chondroid tissues in pleomorphic adenoma of the salivary glands are induced by proteins such as BMP.

Freeze-fracture electron microscopy was employed to study the general morphology, membrane fusion during exocytosis, intercellular junctions in adult and developing salivary glands, and morphological changes of intercellular junctions in secretory stimulation and neoplastic disorders. Intramembranous particles distributed on plasma membranes and organelle-membranes were determined on the basis of particle density per unit. Relationship between distribution and density of particles and functions of membranes and organelles was discussed. Fused membranes took the form of smooth areas of intramembranous particles free on the PF face in the submandibular acinar cells induced by isoproterenol stimulation. The sequence of membrane fusion during secretion was discussed from these freeze-fracture observations. Tight junctions which limited solute diffusion between adjacent cells formed continuous belts around the juxtaluminal region of plasma membrane. Their permeability function was regulated by the number and the geometrical pattern of the tight-junctional strands. The junction appeared late during gestational life, and its development and morphology correlated with the establishment of electrochemical tightness. Similarity in the location and morphology between developmental and neoplastic conditions might indicate reflect the function and degree of cytodifferentiation in salivary gland. Gap junctions were detected as clusters of particles, representing voltage-regulated intercellular channels connecting adjacent cells. The junctions were developmentally regulated, and their size and frequency correlated with the functional activity and with cytodifferentiation in neoplastic disorders. Desmosomes, which appeared as round or elongated clusters of particles, provided the mechanical stability necessary to maintain the organization of acini and ducts.

Dental pulp, periodontal ligament, bone marrow and muscle tissue from the same rat were cultured in vitro in order to investigate their osteogenic activity by transmission electron microscope. Immunohistochemical methods with various antibodies were utilized and alkaline-phosphatase (ALPase) activities of these cells were also measured biochemically. Dental pulp cells were stellate in shape, showed an intense ALPase reaction, and had lipid-like droplets. Periodontal ligament cells were composed of spindle fibroblasts and epithelial cells. The former revealed a positive reaction for ALPase and possessed microfilaments. Bone marrow cells were spindle shaped, resembling fibroblasts, but some of them were similar to osteoblasts. Muscle cells were long, slender in shape, and showed no positive reaction for ALPase. The cells from pulp tissue showed the highest activity of ALPase, followed by periodontal ligament and bone marrow; there was no activity in muscle tissue. All the cells except the epithelial-like cells of the periodontal ligament and muscle cells were positive in reaction with ALPase which is a marker for osteogenic cells, and vimentin which is a marker of fibroblastic characteristics. Osteogenic activity and cellular differentiation of these cells were discussed.

The purpose of this study was to investigate the dentinogenesis of dental pulp tissue following transplantation and during regeneration in normal and germ free animals, as well as in vitro experiments.(1) Partial and complete exposure of dental pulp in germ free rats by removing the enamel and dentin of molars. (2) The central portion of rat incisor which consisted of pulp and pulp chamber were autografted into various tissues. (3) Explants of rat pulp tissue were cultured on dentin matrix. (4) Resin bonding agent, 4-META/MMA-TBB-O (Superbond), was placed directly on surgically-exposed dental pulp.(1) Dentin bridge formation was recognized at 5 days after operation in germ free rat. (2) The cut surface of the transplant exhibited dentin bridge at 7 days after implantation, and the thickness of the newly formed dentin increased gradually thereafter up to 30 days. (3) Cultured pulp cells had high alkaline phosphatase activity and bone- or dentin-like hard tissue was synthesized on the dentin matrix in vitro. (4) Dentin bridge formation was evident on the surgically-exposed dental pulp even after application of Superbond. From these results, it is suggested that pulp tissue has a high activity of dentinogenesis both in vivo and in vitro and 3 days is enough for pulp cells to express the odontoblast phenotype when inflammatory factors are not present.

This paper reports a case of multiple dens invaginatus (DI) bilaterally involving the maxillary central incisors, mandibular canines, and first premolars. The patient was a 11-year-old boy with steeple-head and mild mental retardation. The maxillary central incisors showed disproportionately large crowns and short roots. A roentgenographic survey of the skeletal system showed a sutural hyperostosis of the skull at bregma and a hypoplastic cervical vertebra. The review of the literature yields 6 cases of multiple DI, including the present case; these can be classified into 2 types, cases of only DI and cases of DI with anomalies of skeletal and other systems. Morphological differences in the central incisors are found between these 2 types.

The present paper describes the relationship between ameloblastoma and ameloblastic fibroma deduced from a case diagnosed as "ameloblastoma combined with ameloblastic fibroma" arising in the mandible of a 5-year-old boy. Histologically, the tumor consisted of ameloblastoma in the central area and ameloblastic fibroma in the peripheral area; it clinically fits the characteristics of ameloblastic fibroma based on predominant age, manner of growth, and encapsulation. We reviewed the literature and discussed the relationship between ameloblastoma a ameloblastic fibroma in terms of tumorigenesis. It is assumed that ameloblastic fibroma can also be transformed into ameloblastoma, if the succeeding hard tissues are not formed, and the collagenous connective tissue substituting for the stromal mesenchymal tissue is formed by the inductive effect of the epithelial strands or other unknown factors. Several possibilities relative to the pathogenesis of ameloblastoma have been proposed by oral pathologists; however, to our knowledge, "ameloblastic fibroma can be transformed into ameloblastoma" has not hitherto been reported. The case we experienced here may be thought as an intermediate tumor pattern between ameloblastic fibroma and ameloblastoma.

The purpose of the present study was to elucidate the biological characteristics of pocket epithelium in experimental periodontitis. Elastic rubber was inserted between the first and second molars of the left maxilla in rats. The rubber was removed after one week, and the animals were sacrificed one week after the removal, i.e., two weeks after the insertion. Sections of the teeth and surrounding tissues were examined by electron microscopy. Periodontal pockets were evident between the tooth surface and epithelial cell layer in the coronal portion. A large number of bacteria surrounded by neutrophils were observed on the cementum surface in the pocket; however, no bacterial invasion could be seen in the epithelium. The epithelial cells were spilt in the central portion by invasion of neutrophils, so that one or two layers of surviving epithelial cells were present on the cementum surface. Numerous fenestrations of capillaries were found in the connective tissue immediately below the epithelium. These results suggest that the pocket epithelium is formed by an intercellular split of the epithelium, not between cementum surface and epithelium.

Cells with both osteogenic and chondrogenic capabilities from various connective tissues, dental pulp, periodontal ligament, bone marrow, muscle and subcutaneous connective tissues of the rat were investigated by using either mineralized or demineralized bone and dentin matrix in vitro. After 28 days of the cell culture, explant cells were examined histologically. Bone and cartilage formations were assessed by counting their numbers in serial sections. Induction of cartilage was occurred only in muscle. New bone formation was occurred most frequently in dental pulp, followed in order by bone marrow and periodontal ligament. These results suggest that osteogenic cells, dental pulp, bone marrow stromal cells, and periodontal ligament can not response to inductive stimuli such as the bone morphogenetic protein, BMP.

Coagulation findings were examined in 55 cases of neonatal intracranial hemorrhages (ICH). Marked decreases of the platelet count, fibrinogen, factor XIII (F XIII) activity, were observed in these cases. However, the relatively mild increases in the alpha 2-plasmin inhibitor activity, alpha 2-plasmin inhibitor.plasmin complex and fibrin/fibrinogen degradation products level were observed and only about one third of the cases showed abnormal values. In consideration of these coagulation findings, fifty-eight cases of premature infants were randomly divided into a treated group with a F XIII concentrate and a non-treated group. Thirty cases were administered within 6 hours after delivery to investigate the preventive effects against intraventricular hemorrhages (IVH). Compared in frequencies between both groups limited to the cases with a high risk of IVH, the frequency in the treated group was two out of 13 (15.4%), significantly low (p less than 0.05), while it was six out of eight cases (75.0%) in the non-treated group. From these results it was concluded that a F XIII concentrate is effective in the prophylaxis of IVH in premature infants.

Histological, immunohistochemical, and ultrastructural studies were done on a case of congenital gingival tumor with previously undescribed histopathological findings. The present lesion clinically mimicked a congenital epulis (congenital gingival granular cell tumor); however, it histologically consisted of densely packed collagen fibers forming numerous, well demarcated bundles surrounded by flattened cells with long slender cytoplasmic precesses. Immunohistochemical and ultrastructural findings suggested that these flattened cells embracing collagen bundles were fibroblastic in nature. Intracytoplasmic lysozomal granules could not be found in any cells of the lesion. Fibrous lesions similar to the present case have not been documented previously in the literature.

Basal cell adenoma of the parotid gland was studied with immunohistochemical methods. We observed cells in the tumor with positive reaction to polyclonal keratin, prekeratin, monoclonal PKK-1, polyclonal S-100 protein, monoclonal S-100 protein (alpha), secretory component, actin and laminin. However, no cells which stained positively with monoclonal KL-1, amylase, carcinoembryonic antigen, or epithelial membrane antigen were recognized. From these immunohistochemical results and our ultrastructural observations reported previously, we conclude that the cells constituting the basal cell adenoma are ductal, myoepithelial, and squamous cells but not secretory ones. It is also suggested that the origins of basal cell ademona as well as those of pleomorphic and clear cell adenoma are undifferentiated cells of intercalated duct.

A light scattering method based on the Rayleigh-Debye approach quantifying the angular scattering from poly-disperse aggregates was tested in an attempt to measure the mean radius of gyration of diesel soot aggregates in diesel exhaust. The aggregate size measured by this method under steady operating conditions showed qualitative agreement with the mode peak mobility diameter obtained by the scanning mobility particle sizer. After the assessment, the method was applied to measure the temporal variation of the mean radius of gyration of diesel soot aggregates under transient mode operation.