Human gingival fibroblast migration promoted by platelet-derived growth factor on titanium is correlated with release of urokinase type plasminogen activator

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 (p < 0.001). The promotive effect was inhibited by aprotinin, a serine protease inhibitor used for the inhibition of uPA (p < 0.001). 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.

Connexin expression in the salivary glands

To investigate the ultrastructure of gap junctions and functional differences between connexin (gap junction structural protein) 32 and 43 in the rat submandibular and sublingual glands, tracer and freeze-fracture methods were carried out, and the expression of both connexins was examined. In both glands, western blot analysis with anti-connexin 32 and 43 antibodies revealed bands of about 27kD and 43kD, respectively. Immunofluorescence showed the presence of connexin32-positive spots between acinar cells in both glands. In contrast, connexin43-positive spots were observed at the periphery of the acinar structures in either gland. Positive spots for both connexins could not be detected between ductal cells in both glands. By immunocytochemistry, connexin32 was found on the gap junctional membranes of acinar cells and connexin43 on the gap junctional membranes of myoepithelial cells. It is surmised that connexin32 of the gap junction is related to the secretory function of acinar cells and that connexin43 is associated with the contraction of the myoepithelial cells.

Differential expression of gap junction proteins connexin32 and 43 in rat submandibular and sublingual glands

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.

Left ventricular dimensions and autonomic balance during head-up tilt differ between patients with isoproterenol-dependent and isoproterenol-independent neurally mediated syncope

OBJECTIVES

This study sought to elucidate differences in mechanisms of neurally mediated syncope between patients with syncope induced by head-up tilt alone and those requiring isoproterenol infusion to induce syncope during head-up tilt.

BACKGROUND

Some patients with neurally mediated syncope require isoproterenol to induce syncope during head-up tilt (isoproterenol dependent), and others do not (isoproterenol independent). Differences in mechanisms between these two groups have not been well elucidated.

METHODS

A 60 degrees head-up tilt test was performed in 13 patients with isoproterenol-independent syncope (Group I, mean [+/- SD] age 28 +/- 12 years), 14 patients with isoproterenol-dependent syncope (Group II, mean age 34 +/- 14 years) and 20 control subjects without syncope (Group III, mean age 32 +/- 12 years). Left ventricular size and contractility were determined by echocardiography, and sympathovagal balance was determined with power spectral analysis of heart rate variability using a maximal entropy method.

RESULTS

Group I patients had smaller left ventricular dimensions than Group II and III during baseline tilt. During head-up tilt with isoproterenol infusion (0.01 to 0.04 microgram/kg body weight per min), left ventricular dimensions decreased to the same extent in Groups II and III, but fractional shortening was greater in Group II than in Group III at the end of the tilt. The ratio of low (0.05 to 0.15 Hz) to high frequency (0.15 to 1.0 Hz) component became greater in Group I than in Groups II and III during the last period of baseline tilt. However, the ratio was greater in Group II than in Group III during the last period of the tilt with isoproterenol.

CONCLUSIONS

Patients with isoproterenol-independent syncope had an exaggerated decrease in left ventricular size and sympathetic predominance preceding syncope during head-up tilt. In contrast, in patients with isoproterenol-dependent syncope, similar changes in autonomic nervous balance were evident only during isoproterenol infusion in addition to head-up tilt.

Laminin localization and gelatinolytic activity of epithelial rest of Malassez grown on titanium

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.

Electrophysiologic effects of intravenous E-4031, a novel class III antiarrhythmic agent, in patients with supraventricular tachyarrhythmias

The electrophysiologic effects of intravenous (i.v.) E-4031, a new class III antiarrhythmic drug, were evaluated in 15 patients with supraventricular tachyarrhythmias [11 men, 4 women; mean age 41 +/- 19 (SD) years]. Eleven patients had accessory atrioventricular (AV) pathways, and 4 patients with no accessory pathway had paroxysmal atrial fibrillation. Electrophysiologic studies were performed before and after E-4031 administration (loading infusion 9 micrograms/kg for 5 min + maintenance infusion 0.15 microgram/kg/min). QT and QTc intervals were significantly prolonged by E-4031 from 0.40 +/- 0.03 (mean +/- SD) to 0.46 +/- 0.03 s (p < 0.0001) and from 0.43 +/- 0.03 to 0.49 +/- 0.04 s (p < 0.0001), respectively. No effect was observed on RR interval, PR interval, QRS duration, or AH and HV intervals. The effective refractory periods (ERPs) of the right atrium and ventricle were significantly prolonged from 219 +/- 27 to 236 +/- 26 ms (p < 0.001) and from 230 +/- 12 to 249 +/- 11 ms (p < 0.001), respectively. The ERP of the AV node did not change significantly after E-4031 administration. In patients with ventricular preexcitation, E-4031 significantly prolonged the ERP of the antegrade accessory pathway conduction from 340 +/- 101 to 362 +/- 106 ms (p < 0.001), but not retrograde accessory pathway conduction. AV reentrant tachycardia was induced in 3 of 11 patients with an accessory pathway, and repetitive atrial firing was induced in 3 of 4 patients with paroxysmal atrial fibrillation. E-4031 could prevent repetitive atrial firing in only 1 patient and could not prevent induction of AV reentrant tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

An experimental study of osteogenesis by autografted dental pulp, periodontal ligament, and bone marrow in vivo

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.

Large cyst formation in pleomorphic adenoma

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.

An experimental study of chondrogenesis and osteogenesis in rat submandibular gland induced by implantation of demineralized dentin

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 studies of salivary glands

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.

Osteogenic activity of cells from dental pulp, periodontal ligament, bone marrow and muscle in vitro: an ultrastructural study and alkaline-phosphatase activity

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.

Multiple dens invaginatus and cranio-vertebral abnormality

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.

Ameloblastoma and its relationship to ameloblastic fibroma: their histogenesis based on an unusual case and review of the literature

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.

Vacuoles and vesicles in the rat junctional epithelium: a study with serial ultrathin sections

To investigate whether the electron-lucent structures resembling vesicles and vacuoles in the rat molar junctional epithelium (JE) are in fact intracellular or extracellular, a study using serial ultrathin sections was carried out. In one series of experiments, the animals were not treated before the tissues were conventionally fixed; in another, anesthetized animals were administered horseradish peroxidase 20 min before the tissues were fixed. A large number of electron-lucent structures resembling vesicles and vacuoles were detected in both the peripheral and central cytoplasm of the JE localized at enamel and connective tissue sites. These were 70 to 800 nm in diameter and had a lucency similar to that of the extracellular space in untreated specimens fixed with conventional fixative. Serial ultrathin sectioning revealed that the electron-lucent structures gradually became part of the extracellular space in the following sections. There were also found in the middle portion of the cytoplasm in specimens pretreated with horseradish peroxidase. Numerous vacuole-like structures containing peroxidase-positive materials were found to be contiguous with the extracellular space. A small number of vesicles, also containing peroxidase-positive materials, did not appear in the previous or following sections. These results indicate that almost all electron-lucent structures resembling vesicles and vacuoles in the JE are located at the end of a long infolding, and are still in contact with the extracellular space.

An ultrastructural study of the pocket epithelium in rats

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.

Induction of cartilage and bone formation by cells from explants of various oral tissues in vitro

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.

Blood coagulation findings and the efficacy of factor XIII concentrate in premature infants with intracranial hemorrhages

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.

Immunohistochemical study of basal cell adenoma in the parotid gland

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.

Congenital fibrous epulis: an undescribed fibrous lesion studied immunohistochemically and ultrastructurally

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.

Regeneration of periodontal tissues following experimentally induced periodontitis in rats: a comparison of sucrose-rich and conventional diets

The purpose of the present study is to elucidate influences of diet on periodontal regeneration following experimental periodontitis in rats. S-D rats were divided into two groups, which were fed either a conventional diet (group A) or a sucrose-rich diet (group B). Experimental periodontitis was produced by placement of elastic bands between maxillary molar teeth. After one week, the elastic bands were removed and the animals were sacrified by perfusion fixation with formalin immediately, 1, 3, or 5 days, or 1, 2, 3, 4, 6, or 8 weeks after the removal. Sections of the teeth and surrounding tissue were examined by light microscopy. Three days after the removal, in both groups, granulation tissues with many inflammatory cells were covered by epithelial cells; the attachment site to the root surface was located more apically than the cemento-enamel junction. Distinct periodontal pockets were formed by five days after the removal in group A. In group B, the infiltrations of inflammatory cells were more prominent than in group A. Six weeks after the removal in both groups, an epithelium which resembled long junctional epithelium rather than pocket epithelium became thicker. Eight weeks after the removal, the findings were similar to those of six weeks in group A. However, a severe inflammatory cell concentration was found in group B. These results suggest that periodontal wound healing is markedly influenced by diet, and that this experimental system is useful for studying dynamic changes in both pocket and long junctional epithelia.

[Statistical study of epulis, especially in general pathology]

This report contains a statistical study of 874 cases of epulis diagnosed by the Department of Pathology of Tokyo Dental College from 1966 to 1986. 1. Of the 874 cases, 344 were epulis fibrosa, 217 were epulis granulomatosa, 78 were epulis fibromatosa, 74 were epulis fibrosaosteoplastica, 51 were epulis hemangiomatosa, 43 were epulis fibrosa teleangiectaticum, 15 were epulis cementoplastica, 14 were epulis osteomatosa, 3 were congenital epulis, 2 were giant cell epulis, and 1 was epulis cementomatosa. 2. As has been reported in other literature, there is a marked tendency for this condition to occur in females (331 male cases and 539 female cases). 3. Our data indicate a higher occurrence rate in people in their fifties, although the occurrence rates were similar in people in their twenties and in people in their sixties. 4. The epulis was observed most frequently in the maxillary incisor region.

An experimental study of osteogenesis in explants of rat dental pulp, periodontal ligament, bone marrow and muscle cells in vitro

Cells of dental pulp, periodontal ligament, bone marrow and muscle derived from the same rat were cultured in vitro. Outgrowth of cells from these four explants were examined using phase-contrast microscope, light microscope and scanning electron microscope. Furthermore, cell lengths were measured randomly from SEM photographs and growth curves were plotted by calculating cell numbers. These cells had different morphology in both shape and length. The bone marrow cells showed the most rapid proliferation rate followed by muscle, periodontal ligament and most slowly in dental pulp cells.

Ultrastructure of basal cell adenoma in the parotid gland

Basal cell adenoma of the parotid gland was studied with electron microscopy. The cells constituting this tumor were divided into three types of epithelial cells; ductal, myoepithelial, and squamous cells. The ductal cells, which were polygonal and cuboidal in shape, formed a sometimes distinct lumen. Glycogen were recognized in the cytoplasm of these cells. The myoepithelial cells appeared as plasmacytoid cells which contained abundant microfilaments. The squamous cells were characterized by the presence of well-developed tonofilaments and desmosomes. However, no secretory cells could be found, although small, electron dense granules were detected in the cytoplasm of the ductal cells. The granules were unlike secretory granules in their size, number and location. In consideration of the presence of secretory and myoepithelial cells, we reviewed previously reported literature and discussed the identification of secretory granules. From our and other reported results, we tentatively concluded that the electron dense granules described as secretory granules are not intrinsic secretory granules. Further, we suggested that the cell types and the histogenesis of basal cell adenoma are analogous to those of both pleomorphic and clear cell adenomas.