Long-term treatment with dimethylthiourea inhibits the development of autoimmune disease in NZB x NZWF1 mice

Long-term treatment with dimethylthiourea (DMTU), a scavenger of hydroxyl radical (.OH) and hypochlorous acid (HOCl), suppressed the age-related development of autoimmune disease in NZB x NZWF1 mice. Treatment reduced autoantibody production, retarded increase in blood urea nitrogen, and prolonged life. The results suggest that .OH and HOCl may, at least in part, enhance the development of autoimmune diseases in NZB x NZWF1 mice.

Effect of stopping fluoride administration on the distribution profiles of fluoride in three different kinds of rat bones

The aim of this work was to explore the reduction of fluoride concentrations in the skeleton after stopping experimental fluoride administration. Fluoride was administered to the rats at varying doses (0, 50, 100 ppm in drinking water) and for different lengths of time (4, 13, 25 weeks). A series of fluoride concentrations across the full thickness of humerus, parietal bone, and vertebra arch in rats were measured by means of an abrasive micro-sampling technique. The distribution profiles of fluoride from periosteal to endosteal surfaces, which were apparently related to the histological structure of these bones, were U shaped in the humerus, V shaped in the parietal bone, and W shaped in the vertebra arch. The average fluoride concentrations in the bones increased significantly with each increasing dose and length of fluoride administration. The relative increments were similar between the different regions or the different bones. After stopping fluoride administration, on the other hand, the relative reduction of the average fluoride concentrations in the bones were 30-100%. They were greatly related to the length after stopping fluoride administration and the dose and length of fluoride administration, but also dependent upon the type of bone and the region examined.

Effect of long-term methotrexate-induced neutropenia on experimental periodontal lesion in rats

The effects of long-term methotrexate (MTX)-induced neutropenia on the periodontal lesion in rats were investigated histologically, histometrically and bacteriologically. A nylon thread was inserted into the interdental gingiva between the 1st and 2nd right maxillary molars of the animals 3 weeks before an application of MTX. The animals were then divided into Groups A and B. Group B were injected intraperitoneally with 1.0 mg/kg of MTX 3 times per week for 9 weeks. Group A received saline as a control. Five animals were killed at the 1st, 3rd, 5th, 7th, and 9th week. In Group A, the neutrophils did not decrease during these 9 weeks. In Group B, however, the neutrophils decreased during the 3rd to 9th week. Whereas the experimental side of Group A showed only moderate alveolar bone resorption between the 7th and 9th week, [in Group B] a marked alveolar bone resorption occurred in Group B occurred in the same period. Alveolar bone loss in the experimental side of Group B was significantly greater (p < 0.01) than in Group A in the 7th to 9th weeks. The percentage of gram-negative rods increased in both control and experimental sides of Group at the 9th week. The results of the present study indicate that neutropenia is induced by a long-term application of MTX in rats and that alveolar bone destruction increases as time goes by in the area where a nylon thread was inserted.

Effect of fluoride on root resorption caused by mechanical injuries of the periodontal soft tissues in rats

The present study was carried out to investigate histologically and histometrically the effect of fluoride on root resorption induced by mechanical injuries of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injuries and fluoride administration was significantly smaller in length and area than that in animals given only mechanical injuries. Moreover, resorption lacuna in the former animals contained fewer odontoclasts than that in the latter. The results of the present study might suggest that the administration of fluoride suppressed root resorption induced by mechanical injuries of the periodontal soft tissues.

Irritating effect of formocresol after pulpectomy in vivo

A study was carried out to investigate the effect of formocresol (formalin-creosote) on the periapical tissue after pulpectomy in rats. A pulpectomy was performed on the mesial root of the right mandibular first molar, and, in group A, a paper point containing saline was inserted into the root canal. In group B, a paper point containing formocresol was inserted, and in group C, a drop of formocresol was applied and a paper point containing formocresol was inserted into the root canal. The periapical tissue was examined histologically and histometrically at 3, 7, 14, and 28 days after insertion, and the inflammatory cells and fibroblasts in the apical granulation tissue were also counted. Histologically, in group A, the inflammation observed was slight at 14 and 28 days, while in groups B and C, a moderate inflammation remained. Histometrically, the area of the apical periodontal ligament in groups B and C was increased significantly compared with that in group A at 14 and 28 days. The inflammatory cell count in groups B and C increased significantly compared with that in group A at 7, 14, and 28 days, whereas the fibroblast count in Groups B and C decreased compared with that in Group A at 7, 14, and 28 days. These results demonstrate that formocresol delayed the healing of periapical tissue after pulpectomy.

Suppression of development of glomerulonephritis in NZB x NZWF1 mice by persistent infection with lactic dehydrogenase virus: relations between intercellular adhesion molecule-1 expression on endothelial cells and leucocyte accumulation in glomeruli

The development of glomerulonephritis (GN) in autoimmune NZB x NZWF1 mice was suppressed by persistent lactic dehydrogenase virus (LDV) infection. In this study the expression of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells in glomeruli was examined during the development of GN. ICAM-1 expression on endothelial cells preceded the accumulation of leucocytes within glomeruli. The uninfected mice exhibited an age-related and profound increase in ICAM-1 expression associated with the development of a GN as evidenced by deposits of IgG and C3. Uninfected mice also showed increased accumulation of leucocytes, such as polymorphonuclear leucocytes (PMNs), macrophages, T and CD4+ cells, which express the lymphocyte function-associated antigen-1 (LFA-1) within glomeruli during the development of GN. These changes were strongly suppressed by LDV infection. Our findings suggest that the expression of ICAM-1 in glomerular endothelial cells may, at least in part, contribute to the development of GN. Suppressed expression of ICAM-1 in LDV-infected mice may be responsible for the suppression of GN seen in these animals. Thus there may be a pathogenetic role for ICAM-1 expression and for intraglomerular accumulation of leucocytes, especially PMNs, which express LFA-1 in the development of GN.

Changes in microsomal lysophospholipid acyltransferase activity are correlated with rat parotid gland enlargement induced by chronic administration of isoproterenol

Chronic (5- and 10-day) administration of isoproterenol, an agent that induces the proliferation of salivary gland cells, produced increases in microsomal 1-acyl-sn-glycero-3-phosphate acyltransferase and 1-acyl-sn-glycero-3-phosphocholine acyltransferase activity in rat parotid glands in parallel with gland enlargement. This increased activity was reduced when the treatment was stopped, the reduction corresponding to the reduction in gland weight. There were significant correlations between lysophospholipid acyltransferase activity and gland weight, and between the activities of the two types of lysophospholipid acyltransferase. However, isoproterenol treatment did not affect any of the steps of the subsequent phospholipid N-methylation. These results suggest that the cell proliferation induced by chronic administration of isoproterenol in the parotid gland is accompanied by reversible and selective increases in microsomal lysophospholipid acyltransferases.

[Effect of isoflurane and sevoflurane on evoked potentials and EEG]

Evoked potentials and EEG are used to monitor the central nervous system and the depth of anesthesia in anesthetized patients. In this study, we examined EEG, VEP, SEP and ABR at various concentrations of isoflurane or sevoflurane, and evaluated the influence of volatile agents and their usefulness for the monitoring of the depth of anesthesia. With increasing concentrations of isoflurane and sevoflurane, AE (frequency which account for 80% of total voltage) showed dose-related reduction and EEG showed a trend toward a slower wave and higher amplitude. With increasing concentrations of isoflurane and sevoflurane, P100 of VEP showed a significant dose-related reduction in its amplitude and increase in its latency. So we could not record P100 at the level of the anesthesia of 1.0 MAC with 66% N2O. N20 of SEP can be easily recorded at any depth of anesthesia. And the trend showed consistent dose-related changes in amplitude and latency. With increasing concentrations of isoflurane and sevoflurane, wave III and V of ABR increased significantly in latency, but the changes were very small. In conclusion, the effect of isoflurane and that of sevoflurane on evoked potentials and EEG are similar with each other and with other volatile agents. SEP is the most consistent and reliable factor to monitor the depth of anesthesia neurophysiologically.

Reduced streptozotocin-induced insulitis in CD-1 mice by treatment with anti-intercellular adhesion molecule-1 and anti-lymphocyte function associated antigen-1 monoclonal antibodies together with lactic dehydrogenase virus infection

Multiple low-dose streptozotocin (SZ)-induced insulitis is an animal model for insulin-dependent diabetes mellitus characterized by a mononuclear cell infiltration. SZ-induced insulitis and blood glucose concentrations were reduced by treatment with anti-intercellular adhesion molecule-1(ICAM-1) and anti-lymphocyte function associated antigen-1 (LFA-1) monoclonal antibodies. This suppressing effect was also seen in mice infected with lactic dehydrogenase virus (LDV). These results suggest that the expression of ICAM-1 in islets and LFA-1 on mononuclear cells may be important in the development of SZ-induced insulitis. The suppressive effect of LDV infection on the development of insulitis is discussed.

Inhibitory effect of aspirin on root resorption induced by mechanical injury of the soft periodontal tissues in rats

The purpose of the present study was to study histologically and histometrically the inhibitory effect of aspirin on root resorption induced by mechanical injury of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injury and aspirin administration contained fewer odontoclasts and was smaller in length and area than that in animals given only mechanical injury. The result of the present investigation indicated that the administration of aspirin might suppress root resorption induced by mechanical injury of the periodontal soft tissues.

Characterization of microsomal long-chain acyl-CoA hydrolase activity in the rat submandibular gland

1. Long-chain fatty acyl-CoA hydrolase in submandibular gland microsomes was characterized and compared to that in liver ones. 2. In rat submandibular gland, the microsomal long-chain acyl-CoA hydrolase showed a higher relative activity for polyunsaturated fatty acyl-CoAs than that of liver microsomes. 3. It was suggested that the hydrolase in rat submandibular gland microsomes may play a role in modulation in the acyl-CoA pool size.

Localization of a low Mr GTP-binding protein, rap1 protein, in plasma membranes and secretory granule membranes of rat parotid gland

Subcellular fractions were prepared from rat parotid gland by sequential centrifugation, Percoll gradient centrifugation and divalent-cation precipitation, and the localization of a low Mr GTP-binding protein, rap1 protein (rap1p) was analyzed by immunoblotting using a specific antibody. rap1p was found to be located in apical and basolateral plasma membranes, and secretory granule membranes in rat parotid gland. On the other hand, the beta gamma subunits of heterotrimeric Gt protein was localized in plasma membranes but not in granule membranes.

Pulpal and periapical tissue reactions after experimental pulpal exposure in rats

The purpose of this study was to investigate histologically and histometrically the changes in pulpal and periapical tissues after pulpal exposure in rats. All animals received a pulpal exposure in the left mandibular first molar. Animals were killed at 1 to 56 days after pulpal exposure, and their mandibles were evaluated histologically and histometrically. Histologically, pulpal necrosis extended gradually from the upper part of the pulpal tissue to the apex, with inflammation starting in the periapical tissue at an early stage. As the periapical lesion developed, alveolar bone and cementum resorption was also found. Histometrically, the length of pulpal necrosis increased gradually from 1 to 28 days. The vertical length of the periapical lesion after 14 days was significantly increased, while the horizontal length and the overall area after 7 days were also significantly increased. The periapical lesion extended in a mesiodistal direction at first and then in a vertical direction before expansion ceased.

Suppression of development of anti-nuclear antibody and glomerulonephritis in NZB x NZWF1 mice by persistent infection with lactic dehydrogenase virus: possible involvement of superoxide anion as a progressive effector

The development of anti-nuclear antibody (ANA) and glomerulonephritis (GN) in autoimmune NZB x NZWF1 mice was suppressed by persistent lactic dehydrogenase virus (LDV) infection. This observation was used to study a possible pathogenetic role for the toxic oxygen radical, superoxide anion (O2-), in the progression of ANA and GN. Compared to macrophages from NZB x NZWF1 mice with LDV infection, macrophages from uninfected NZB x NZWF1 mice exhibited an age-related and drastic increase in O2- production in association with the development of the ANA and GN (representing the late stage of disease). NZB x NZWF1 mice with or without LDV infection were then given the O2- scavenger superoxide dismutase (SOD) during the late stage of the disease. Treatment of uninfected NZB x NZWF1 mice with SOD (10,000 units/mouse/day for 3 weeks) protected animals from the development of ANA and GN. SOD treatment also suppressed the development of the lesions in NZB x NZWF1 mice with LDV infection. Our findings suggest that O2- may, at least in part, contribute to the development of ANA and GN in the late stage of disease, and that decreased O2- production in NZB x NZWF1 mice with LDV infection may be responsible for the suppression of the development of ANA and GN in the late stage of the disease.

Distribution profiles of fluoride in three different kinds of rat bones

The study was performed to reveal the detailed distribution profiles of fluoride in three different kinds of rat bone--humerus, vertebral arch, and parietal bone--and to compare this with the histological appearance of each bone type. Two groups of Wistar rats were provided water ad libitum containing 0 and 100 ppm fluoride, respectively, for 24 weeks. The fluoride distribution profiles across the bone of the three different bones from the outer to the inner surface were determined by means of an abrasive micro-sampling technique. In control animals, both humerus and parietal bones showed higher concentrations at the periosteal and endosteal surfaces, while the vertebral arch showed additional high levels in the middle (containing trabecular bone) of the tissue. In exposed animals, fluoride levels increased greatly in all three bone types. The vertebral and parietal fluoride distribution profiles were relatively unchanged, although humerus fluoride increased from periosteum to endosteum. The differences in fluoride distribution profiles were apparently related to the histological appearances of these bones. The surface area of bone available and the extent of vascularity appear to affect fluoride uptake.

Unusual gingival enlargement with rapidly progressive periodontitis. Report of a case

A 15-year-old female patients suffered from recurrent unusual enlargement of the gingiva together with rapidly progressive alveolar bone loss. The enlarged gingiva completely covered her anterior teeth and protruded from the mouth. Marked inflammatory edematous tissue, which predominantly contained plasma cells, was observed in the connective tissue. Rapidly progressive alveolar bone loss was observed radiographically. The serum antibody titer to Porphyromonas gingivalis, measured by ELISA, was much higher than that in healthy individuals. The diagnosis was unusual gingival enlargement with rapidly progressive periodontitis. Conventional periodontal therapy, including plaque control, scaling, root planing, and surgical removal of the soft tissue, did not produce complete healing of the gingival lesion, although recurrence of gingival enlargement and further loss of the periodontal attachment level were well controlled. After the periodontal treatments, the serum antibody titer to P. gingivalis decreased to normal levels. This unusual gingival enlargement was considered due to systemic factors that exaggerated the gingival response to local irritation and altered the usual clinical features of chronic gingivitis; local plaque irritation produced the extensive and recurrent enlargement of the gingiva. Under these circumstances, infection or overgrowth of periodontopathic bacteria, including P. gingivalis, might occur and the alveolar bone loss would then advance very rapidly.

Retardation of mouse odontoblast differentiation by heparin in vitro

The effect of heparin was studied histologically and immunohistochemically. Tooth germs from 15-day-old mouse embryos were cultured with or without heparin. After 6 days of culture in control medium, mesenchymal cells underlying the inner enamel epithelium had differentiated into odontoblasts and secreted predentine. In medium with heparin, mesenchymal cells were undifferentiated. In medium with other glycosaminoglycans such as chondroitin sulphate, dermatan sulphate or hyaluronate, tooth germs were similar to those in control medium, as were those in medium with heparin-Sepharose absorbed serum. After 12 days of culture in the heparin medium, mesenchymal cells in some cusps had differentiated into odontoblasts and secreted predentine but in other cusps remained undifferentiated. Immunohistochemically, exogenous heparin did not prevent the deposition of type IV collagen, laminin and fibronectin in the basement membrane and extracellular matrix. These results suggest that exogenous heparin retards differentiation of odontoblasts but not by disruption of the basement membrane nor inactivation of heparin-binding growth factors present in serum.

Properties of plasma membrane-induced amylase release from rat parotid secretory granules: effects of Ca2+ and Mg-ATP

A secretory granular fraction (SG) and a plasma membrane rich fraction (PM) have been isolated from rat parotid gland by differential and Percoll gradient centrifugation. With these two fractions, a cell-free interaction system has been reconstituted to clarify the exocytotic interaction between the secretory granules and plasma membranes, and the conditions of amylase release from SG have been characterized in vitro. The addition of PM into this assay system induced a rapid and transient release of amylase from SG. Some other membranes such as erythrocyte ghosts also mimicked the effect of PM. This release was increased by Ca2+, but was not completely blocked by EGTA. Simultaneous addition of 1 mM ATP with 1 mM MgCl2 (Mg-ATP) in the presence of Ca2+ reduced this release. However, in spite of the existence of Mg-ATP, the stimulation of PM-induced amylase release was caused by Ca2+ in a concentration-dependent manner (10(-7)-10(-3) M). These results suggest that Ca2+ and Mg-ATP should participate as important regulators in the exocytotic interaction between secretory granules and plasma membranes in this system. Furthermore, the differences between our system and intact cells are also discussed.

Parasitism of Toxocara canis larvae in Japanese quails by inoculation of the ascarid eggs

The distribution of T. canis larvae and pathological changes caused by them were studied in Japanese quails orally inoculated with 1,500, 4,000 or 15,000 embryonated eggs. Larvae were distributed mainly in the liver and, to lesser extent, in the muscles, brain, eyes and other organs. The number of larvae varied from 7 to 3,346, and from 1 to 288 in the liver and muscles (breast and legs), respectively. A small number of larvae were also recovered from the heart, gizzard, brain and eyes. In the groups of quails inoculated with 4,000 or 15,000 eggs, small white foci were observed on the surface of the liver 6 or 12 hr after inoculation. Histopathological examinations revealed necrotic lesions, leukocytic infiltration, granuloma and nodular lesions. The pathological changes became more serious with the large size of inoculum and days after inoculation.

The iron chelator deferoxamine prevents cisplatin-induced lipid peroxidation in rat kidney cortical slices

We evaluated the effect of the iron chelator deferoxamine on lipid peroxidation produced by the nephrotoxic antineoplastic drug cisplatin in rat kidney cortical slices. The addition of deferoxamine to the incubation medium prevented such lipid peroxidation in the incubated slices. Treatment of rats with deferoxamine inhibited the increase in lipid peroxidation caused by cisplatin in the medium. These results suggest that iron may be a causal agent of cisplatin-induced lipid peroxidation.

[Changes in granulocyte elastase caused by the use of ulinastatin during anesthesia for renal transplantation]

In patients with renal failure, releases of chemical mediators having inhibitory influences on organs and circulatory system have been observed. Therefore, in long-term dialysis patients, it is necessary to consider the biocompatibilities of the equipment for dialysis. On 13 cases of renal transplantations, we measured the pre- and post-operative changes of granulocyte elastase (GE) and evaluated the effect of ulinastatin. The renal transplanted patients receiving a long-term dialysis showed higher GE values than that of normal patients even before the operation. During the anesthesia, GE increased gradually and further increased after the operation. In patients given ulinastatin during anesthesia, the increase in GE during the operation was suppressed but an increase after the operation was observed. The renal transplanted patients are easily infectible. Therefore, it is useful to measure GE pre- and post-operatively for earlier diagnosis of the postoperative infection and septicemia. The administration of ulinastatin can inhibit the increase of GE. It seems that ulinastatin increases renal blood flow and improves renal function.

[Rapidly progressive periodontitis combined with plasma cell gingivitis: a case report]

A case of rapidly progressive periodontitis combined with plasma cell gingivitis with marked enlargement of the gingiva was presented. Clinically, in the plasma cell gingivitis, the gingiva appear red, friable and bleed easily; usually it does not induce loss of attachment. Histologically, a dense infiltration of the normal plasma cells in the connective tissue is a common finding. A hypersensitivity reaction to some antigens, often flavorings or spices, is generally recognized. In this case, a rapidly progressive loss of attachment was observed, so rapidly progressive periodontitis was diagnosed. Differential diagnosis of the plasma cell gingivitis could be determined by histological and ultrastructural examination. Allergens, however, could not be identified. Conventional periodontal therapy, including intensive plaque control, could not cure the plasma cell gingivitis completely but recurrence of gingival enlargement and loss of attachment could be well controlled.

Experimental odontogenic tumors produced by ethylnitrosourea injections and mechanical injuries

The present study was carried out to investigate odontogenic tumor induction in the rats by injections of carcinogen N-ethyl-N-nitrosourea (ENU) coupled with incisional wounds. The animals which received local injections of ENU in the region of incisor tooth germ of the right mandible every other day for 19 days after birth coupled with incisional wounding in the same region at 2 and 8 days, developed odontogenic carcinomas. However, the animals which were given local injections of ENU in the region of incisor tooth germ but did not receive incisional wounds, showed no pathologic changes. The animals which received both local injections of physiologic salt solution and incisional wounds in the same manner as mentioned above, did not exhibit any pathologic changes. The present results indicate that local administration of carcinogen ENU coupled with mechanical injuries, namely incisional wounding, caused the production of odontogenic carcinomas in the incisor region of the mandible in rats.

Ca(2+)-independent phospholipase A2 activity associated with secretory granular membranes in rat parotid gland

Phospholipase A2 activity was detected in a secretory granular fraction (SG) purified by Percoll gradient centrifugation from rat parotid gland using [3H]phosphatidylcholine (PC) as a substrate. High activity of this enzyme was observed at neutral pH. The enzyme was activated by Triton X-100 and did not require Ca2+ for its activity. In the absence of Ca2+, its apparent Km for exogenous PC was 28 microM while it was slightly increased by adding 5 mM CaCl2 (73 microM). Furthermore, the enzyme was located essentially in a granular membrane fraction separated from granular lysate. The deacylation activities were also detected in other subcellular fractions, which showed a different detergent-susceptibility or pH-dependency from that in SG. These results suggest that secretory granules have membrane-bound phospholipase A2 which has properties different from that found in other organelles.