Green tea extract inhibits the onset of periodontal destruction in rat experimental periodontitis.

BACKGROUND AND OBJECTIVE: Green tea extract exerts a variety of biological effects, including anti-inflammatory activities. However, there has been no report on the effect of green tea extract on loss of attachment, which is an important characteristic of periodontitis. Here, we examined the inhibitory effects of green tea extract on the onset of periodontitis in a rat model. MATERIAL AND METHODS: Rats were immunized intraperitoneally with Escherichia coli lipopolysaccharide (LPS). The LPS group (n = 12) received a topical application of LPS onto the palatal gingival sulcus every 24 h. The green tea extract group (n = 12) received a topical application of LPS mixed with green tea extract, sunphenon BG, every 24 h. The phosphate-buffered saline (PBS) group (n = 6) received a topical application of PBS every 24 h. The levels of anti-LPS immunoglobulin G (IgG) in serum were determined using ELISA. Rats in the LPS and green tea extract groups were killed after the 10th and 20th applications. Rats in the PBS group were killed after the 20th application. Loss of attachment, level of alveolar bone and inflammatory cell infiltration were investigated histopathologically and histometrically. RANKL-positive cells and the formation of immune complexes were evaluated immunohistologically. RESULTS: There was no significant difference in the serum levels of anti-LPS IgG between the LPS group and the green tea extract group. In contrast, loss of attachment, level of alveolar bone, inflammatory cell infiltration and RANKL expression in the green tea extract group were significantly decreased compared with those in the LPS group. CONCLUSION: These findings demonstrate that green tea extract suppresses the onset of loss of attachment and alveolar bone resorption in a rat model of experimental periodontitis.

Occlusal trauma accelerates attachment loss at the onset of experimental periodontitis in rats.

BACKGROUND AND OBJECTIVE: Occlusal trauma is an important factor that influences the progression of periodontitis, but it is unclear whether occlusal trauma influences periodontal destruction at the onset of periodontitis. We established an experimental periodontitis model with both site-specific loss of attachment and alveolar bone resorption. The purpose of the present study was to investigate the effects of occlusal trauma on periodontal destruction, particularly loss of attachment, at the onset of experimental periodontitis. MATERIAL AND METHODS: Sixty rats were used in the present study. Forty-eight rats immunized with lipopolysaccharide (LPS) intraperitoneally were divided into four groups. In the trauma (T) group, occlusal trauma was induced by placing an excessively high metal wire in the occlusal surface of the mandibular right first molar. In the inflammation (I) group, periodontal inflammation was induced by topical application of LPS into the palatal gingival sulcus of maxillary right first molars. In the trauma + inflammation (T+I) group, both trauma and periodontal inflammation were simultaneously induced. The PBS group was administered phosphate-buffered saline only. Another 12 nonimmunized rats (the n-(T+I) group) were treated as described for the T+I group. All rats were killed after 5 or 10 d, and their maxillary first molars with surrounding tissues were observed histopathologically. Loss of attachment and osteoclasts on the alveolar bone crest were investigated histopathologically. To detect immune complexes, immunohistological staining for C1qB was performed. Collagen fibers were also observed using the picrosirius red-polarization method. RESULTS: There were significant increases in loss of attachment and in the number of osteoclasts in the T+I group compared with the other groups. Moreover, widespread distribution of immune complexes was observed in the T + I group, and collagen fibers oriented from the root surface to the alveolar bone crest had partially disappeared in the T, T+I and n-(T+I) groups. CONCLUSION: When inflammation was combined with occlusal trauma, immune complexes were confirmed in more expanding areas than in the area of the I group without occlusal trauma, and loss of attachment at the onset of experimental periodontitis was increased. Damage of collagen fibers by occlusal trauma may elevate the permeability of the antigen through the tissue and result in expansion of the area of immune-complex formation and accelerating inflammatory reaction. The periodontal tissue destruction was thus greater in the T+I group than in the I group.

Gram-positive bacteria as an antigen topically applied into gingival sulcus of immunized rat accelerates periodontal destruction.

BACKGROUND AND OBJECTIVE: Periodontitis is generally accepted to relate to gram-negative bacteria, and the host defense system influences its onset and progression. However, little is known about the relation between gram-positive bacteria and periodontitis. In this study, we topically applied gram-positive and gram-negative bacterial suspensions to the gingival sulcus in rats after immunization, and then histopathologically examined their influence on periodontal destruction. MATERIALS AND METHODS: Rats previously immunized with heat-treated and sonicated Staphylococcus aureus or Aggregatibacter actinomycetemcomitans were used as immunized groups. The non-immunized group received only sterile phosphate-buffered saline. In each animal, S. aureus or A. actinomycetemcomitans suspension was applied topically to the palatal gingival sulcus of first molars every 24 h for 10 d. Blood samples were collected and the serum level of anti-S. aureus or anti-A. actinomycetemcomitans immunoglobulin G (IgG) antibodies was determined by enzyme-linked immunosorbent assay. The first molar regions were resected and observed histopathologically. Osteoclasts were stained with tartrate-resistant acid phosphatase (TRAP). The formation of immune complexes was confirmed by immunohistological staining of C1qB. RESULTS: Serum levels of anti-S. aureus and anti-A. actinomycetemcomitans IgG antibodies in the immunized groups were significantly higher than those in the non-immunized groups were. The loss of attachment, increase in apical migration of the junctional epithelium, and decreases in alveolar bone level and number of TRAP-positive multinuclear cells in each immunized group were significantly greater than in each non-immunized group. The presence of C1qB was observed in the junctional epithelium and adjacent connective tissue in the immunized groups. CONCLUSIONS: Heat-treated and sonicated S. aureus and A. actinomycetemcomitans induced attachment loss in rats immunized with their suspensions. Our results suggest that not only gram-negative but also gram-positive bacteria are able to induce periodontal destruction.

Topical application of lipopolysaccharide into gingival sulcus promotes periodontal destruction in rats immunized with lipopolysaccharide.

BACKGROUND AND OBJECTIVE: The causes of periodontitis are bacteria and the host immune system, but the role of the immune system in the onset and progression of periodontal disease is still unclear. Our previous report showed that the formation of an immune complex in the gingival sulcus induces periodontal destruction. This study was carried out to investigate how the immune system, particularly immunization, is involved in periodontal destruction. MATERIAL AND METHODS: Animals immunized intraperitoneally with lipopolysaccharide (LPS) were used as the immunized group. The nonimmunized group received only phosphate-buffered saline. LPS was applied daily onto the palatal gingival sulcus in both groups 1 d after the booster injection. Serum levels of anti-LPS IgG were determined. Loss of attachment and the level of alveolar bone were histopathologically and histometrically investigated. RANKL-bearing cells and the expression of C1qB were immunohistologically evaluated. RESULTS: The serum levels of anti-LPS IgG were elevated in the early experimental period in the immunized group. There were significant increases in loss of attachment, level of alveolar bone and the number of RANKL-bearing cells in the immunized group. C1qB was observed in the junctional epithelium and adjacent connective tissue. The nonimmunized group showed similar findings at and after the time when the serum level of anti-LPS IgG was elevated. CONCLUSION: Topical application of LPS as an antigen induced periodontal destruction when the serum level of anti-LPS IgG was elevated in rats immunized with LPS. The presence of C1qB suggests that the formation of immune complexes is involved in this destruction.

A study of the glycoantigens of neonatal porcine islet-like cell clusters using a lectin microarray.

BACKGROUND: The pig pancreas is considered to be the most suitable source of islets for clinical xenotransplantation. Two types of islet transplantation are: adult pig islets and neonatal porcine islet-like cell clusters (NPCC). However, besides a-Gal expression, differences in glycosylation and xenoantigenicity between both types were not clear so fat to date. In this study, we performed lectin microarray analyses of NPCCs cultured for 1, 5, or 9 days. METHODS: We studied differences in gycoantigens among several kinds of wild-type NPCCs isolated from 1- to 3-day-old neonatal wild-type pigs (Large White/Landrace × Duroc) and cultured for 1, 5 and 9 days in Ham's 10 in the presence of nicotinamide, using a previously published technique. After sonication and centrifugation, supernatant proteins from each islet were labeled with Cy3, applied to a lectin array and scanned with an SC-Profiler for evaluation using an Array Pro Analyzer. RESULTS: The overall signals of NPCC at days 5 and 9, showed almost the same values to most lectins, whereas those on day 1 showed differences, suggesting that the NPCC on day 1 contain immature cells that gradually turn to mature NPCCs in culture.

Cross-species function of the pig C1 esterase inhibitor.

BACKGROUND: The use of a bioartificial liver with pig cells for the treatment of fulminant hepatic failure will require research on the plasma complement regulatory proteins of the pig, because the liver produces most of the complement components and plasma complement regulatory proteins. In our previous study, the pig C1 esterase inhibitor (C1-INH), which functions as an inhibitor of the complement reaction in the first step of the classical pathway in the fluid phase, was cloned and some relevant features of the molecule were characterized, especially its cross-species regulation, in comparison with human C1-INH. In a further analysis, the species specificity of C1-INH was examined, using pig endothelial cells (PEC) and several types of sera. MATERIALS AND METHODS: The cDNA of pig C1-INH was used to produce the membrane type pC1-INH, pC1-INH-PI, and inserted into the cloning site of pCXN2 (chicken beta actin promoter). The pCX/pCl-INH-PI plasmid was then transfected into PEC to establish stable PEC with pCl-INH-PI. The expression of the pCl-INH-PI was evaluated by a FACS analysis, and complement-dependent cell lysis with human, dog, rabbit, and mouse sera was then assessed. RESULTS: The transfectant with pig Cl-INH-PI showed a high level of expression on PEC. The PEC transfectants showed an inhibitory effect on complement-dependent PEC lysis. Pig Cl-INH did not show the same suppressive effect for each serum. However, considering the alternative pathway activation of each serum on the pig cell membrane, it can be concluded that pCl-INH has a relatively small species restriction. CONCLUSION: Pig Cl-INH, having a similar structure to human Cl-INH, shows a strong complement regulatory function on other species sera.

Induction of apoptosis in glioma cells: an approach to control tumor growth by blocking basic fibroblast growth factor autocrine loop.

Glioma is a group of neoplasms derived from neuroepithelial tissue. High grade glioma is characterized by the presence of mitotic figures and the occurrence of vascular endothelial hyperplasia. This article reviews the effects of growth factors which are secreted by glioma cells on the proliferative activity of both glioma cells and vascular endothelial cells. Among various glioma-derived growth factors, we have found that basic fibroblast growth factor (bFGF) plays an important role in determining malignant trait of human glioma via its autocrine loop. Furthermore, we discuss candidate molecular targets for the therapy of high-grade glioma by blocking the autocrine loop of bFGF.

["Adenoid" glioblastoma].

A surgical case of glioblastoma which showed a pronounced "adenoid" (or "epithelioid") appearance was reported. The patient was an 81-year-old woman, who presented with unsteady gait. Neuroradiological examination revealed three discrete mass lesions located in the 1-frontal, 1-parieto-occipital, and r-occipito-temporal lobes. Despite the subtotal removal of two of the three lesions and postoperative chemotherapy and radiotherapy, the patient died 21 months after the onset of illness. Histopathological examination of the resected tumors revealed typical features of glioblastoma in the peripheral region of the tumor. In the central region, the tumor cells were arranged in a papillary fashion or formed solid, sheet-like cell nests and were surrounded by fibrous connective tissue septa. Although the histopathological appearance of the tumor closely resembled metastasis of adenocarcinoma, the immunohistochemical and ultrastructural studies of the tumor failed to detect evidence of a definite differentiation towards epithelial cells.

Emergent treatment of iatrogenic dissection of the internal carotid artery with the Palmaz-Schatz stent--case report.

A 67-year-old male presented with sudden onset of aphasia and right hemiparesis on January 27, 1995. Iatrogenic dissection of the left internal carotid artery occurred during attempted local thrombolytic therapy for embolic occlusion of the middle cerebral artery. His neurological condition worsened. Following an unsuccessful angioplasty for the dissection, a Palmaz-Schatz stent was deployed over the dissection. Local thrombolytic therapy was then successfully completed. Anticoagulation and antiplatelet medications were given to prevent further embolic stroke. Follow-up angiography at 2 weeks and 8 months showed good patency of the stented segment. He has experienced no cerebral ischemic events since the treatment.

Possible role of neurointerventional techniques in the diagnosis of hemifacial spasm.

We used neurointerventional techniques to conduct a functional investigation of the artery responsible for hemifacial spasm in a 48-year-old woman. Insertion of a microcatheter into the posterior inferior cerebellar artery stopped the hemifacial spasm immediately and completely. The artery was verified intraoperatively as the vessel compressing the root exit zone of the facial nerve.

Induction of apoptosis in multi-drug resistant (MDR) human glioblastoma cells by SN-38, a metabolite of the camptothecin derivative CPT-11.

The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumors. Recent studies demonstrate that SN-38, a metabolite of the camptothecin (CPT) derivative CPT-11, has antitumor effects on several tumors, but the mechanisms responsible for its cytotoxicity remain unclear. We therefore determined whether SN-38 has cytotoxic effects on MDR human glioblastoma GB-1 cells and non-MDR human glioblastoma U87-MG cells. Furthermore, we determined what role SN-38 plays in the induction of cytotoxicity in these tumor cells. In this study, we demonstrated that SN-38 had significantly stronger antitumor effects on GB-1 and U-87MG cells than did CPT (P < 0.01 and P < 0.05, respectively). In addition, findings obtained using a DNA fragmentation assay, Hoechst 33258 staining, in situ end-labeling and cell cycle analysis demonstrated that SN-38 induced apoptosis in these tumors. Our results suggest that SN-38 has a stronger antitumor effect on malignant glioma cells regardless of MDR expression than does CPT, and therefore can be considered a new chemotherapeutic agent potentially effective in the treatment of human primary or recurrent malignant gliomas resistant to chemotherapy.

Interventional neuroradiology in hemifacial spasm. Diagnostic and therapeutic implications.

SUMMARY: There have never been functional studies in the diagnosis of hemifacial spasm caused by neurovascular compression. We used neurointerventional techniques to conduct a functional investigation of the artery responsible for hemifacial spasm in seven patients. A microcatheter was inserted into the various arteries of the posterior circulation under systemic heparinization, and its effect on the spasm was evaluated clinically and electromyographically. In six patients who underwent microvascular decompression surgery, the vessels compressing the root exit zone of the facial nerve were surgically determined, and compared with the result of the procedure. The catheter was inserted into twelve arteries. The spasms were stopped immediately and completely by the insertion of the catheter into seven arteries. Six of them were surgically proven to compress the root exit zone of the facial nerve. The spasm was changed in frequency or in type by the insertion into two arteries. These arteries were also compressing the root exit zone. One artery was located at a more peripheral part of it and the other was running over another artery compressing the root exit zone. The spasms were not affected at all by the insertion into three arteries. These arteries were not observed in the operative field and had no contact with the nerve. Superselective angiograms showedpositional qnd configurational changes of the arteries. There was no arterial spasm and tight catheterization leading to stasis of contrast material within the arteries. There were no complications related to the procedures. Functional relationship between the artery and the spasms was established in all the patients, and one patient refused surgery because the frequency of the spasm was reduced by the procedure. The result of this study may suggest that a functional investigation of hemifacial spasm is feasible and seems useful for selecting good candidates for microvascular decompression surgery.

Apoptosis induced by selenium in human glioma cell lines.

Several studies have shown that selenium can inhibit tumorigenesis in tissues. However, little is known about the mechanism and the effect of selenium on DNA, especially in brain tumor cells. In this study we examined the biological effect of selenium on human glioma cell lines (A172 and T98G). Selenium exhibited an antiproliferative effect on these cell lines (and induced the typical ladder pattern of DNA fragmentation commonly found in apoptosis), which were prevented by catalase. Few effects of selenium on NT14 fibroblasts were found. These findings demonstrate that selenium may induce, by apoptosis, cell death of human glioma cell lines, which are resulting from free radical oxygen forming.

Effect of selenium on malignant tumor cells of brain.

Some reports have demonstrated that selenium can inhibit tumorigenesis in some tissues of animal. However, little is known about the inhibitory effect on malignant tumor cells of brain. The purpose of our study was to determine the biological effect of selenium on growth of rat glioma and human glioblastoma cell lines. Cell lines C6 and A172 were obtained from Japanese Cancer Research Resources Bank, Tokyo, Japan (JCRB). Cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% fetal calf serum at 37 degrees C in a humidified atmosphere of air and 5% CO2. Antiproliferative effects of selenium were evaluated using growth rate assay quantifying cell number by MTT assay. An antiproliferative effect of selenium was found in two cell lines, which was more effective on human A172 glioblastoma and less effective on rat C6 glioma.

Combination therapy with cisplatin and nifedipine induces apoptosis in cisplatin-sensitive and cisplatin-resistant human glioblastoma cells.

We attempted to determine whether calcium channel blockers (CCBs) enhance the anti-tumour activity of cis-diamminedichloroplatinum (cisplatin) against both cisplatin-sensitive human glioblastoma U87 MG cells and cisplatin-resistant U87-MG-CR cells, the latter of which we developed for resistance to cisplatin. Nifedipine, a dihydropyridine class CCB, significantly enhanced the anti-tumour effect of cisplatin on these two cell types in vitro and in vivo. Our findings also indicated that, in the absence of normal extracellular Ca2+ nifedipine was capable of enhancing the cytotoxicity of cisplatin. In addition, this anti-tumour activity was partially inhibited by actinomycin D and cycloheximide, suggesting that it is possibly dependent upon new RNA and protein synthesis. Interestingly, ultrastructural analysis, DNA fragmentation assay and cell cycle analysis demonstrated that synergism between cisplatin and nifedipine results in apoptosis (programmed cell death) at a relatively low concentration of cisplatin, which when tested alone did not induce apoptosis. Furthermore, we demonstrated that nuclei from these cells lack a Ca(2+)-dependent endonuclease that degrade chromatin in the linker region between nucleosomes. In conclusion, our studies suggest that the non-cytotoxic agent nifedipine is able to synergistically enhance the anti-tumour effects of cisplatin on U87-MG and U87-MG-CR cells lacking a Ca(2+)-dependent endonuclease and subsequently to induce apoptosis via interaction of nifedipine with an as yet uncharacterised functional site other than a calcium channel on target cells.

Interferon-gamma induces a decrease in the susceptibility of human glioma cells to lysis by lymphokine-activated killer cells.

We studied the effect that treating two types of glioblastoma cell lines, U-87 MG and U-251 MG, with interferon (IFN)-gamma had on their susceptibility to lysis by lymphokine-activated killer (LAK) cells. We also examined the participation of cell-adhesion molecules and major histocompatibility complex (MHC) class I and II antigens present on the target cells in lysis by LAK cells. Treatment with IFN-gamma (1000 U/ml) for 48 hours resulted in the increased expression of both intercellular-adhesion molecule 1 and MHC class I antigens on tumor cells. In addition, untreated tumor cells expressed neural-cell-adhesion molecules and MHC class II antigens highly, but their expression was not affected by IFN-gamma treatment. These changes in expression were accompanied by a decreased susceptibility to lysis by LAK cells. Treatment with antisense-intercellular-adhesion molecule-1 oligonucleotide further inhibited LAK lysis of target cells, following treatment with IFN-gamma. In contrast, acid treatment of tumor cells after treatment with IFN-gamma increased their susceptibility to lysis by LAK cells. These findings suggest that treatment of glioblastoma cells with IFN-gamma decreased their susceptibility to lysis by LAK cells, and that this decrease in susceptibility is attributable principally to the increased expression of MHC class I antigen on target cells.

Tumour necrosis factor-alpha induces an increase in susceptibility of human glioblastoma U87-MG cells to natural killer cell-mediated lysis.

The mechanism by which tumour necrosis factor (TNF)-alpha increases the susceptibility of U87-MG human glioblastoma cells to lysis by natural killer (NK) cells was studied. Treatment with TNF-alpha (100 units ml-1) for 48 h enhanced the susceptibility of tumour cells to lysis by NK cells. Increased susceptibility to lysis was associated with enhanced expression of intercellular adhesion molecule 1 (ICAM-1) and HLA class I antigen. Antisense ICAM-1 oligonucleotide inhibited lysis by NK cells of TNF-alpha-treated tumour cells. In contrast, acid treatment following TNF-alpha treatment increased lysis by NK cells. These findings indicate that TNF-alpha treatment of glioblastoma cells increased their susceptibility to lysis by NK cells, since ICAM-1 up-regulation would have more profound effects on NK susceptibility than would HLA class I antigen up-regulation.

Isolation and characterization of a novel microsomal membrane-bound phenol sulfotransferase from bovine liver.

A novel phenol sulfotransferase (PST) was detected in bovine liver microsomal membrane fraction. The enzyme was found to be capable of catalyzing the sulfation of simple phenolic compounds, with 3'-phosphoadenosine-5'-phosphosulfate as the sulfate donor. Detergent extracted PST showed a pH optimum of 5.7 and, among the simple phenols tested, the PST exhibited highest activity toward alpha-naphthol. No activities were detected when tyrosine and its derivatives were used as substrates. Both 2,6-dichloro-4-nitrophenol and chlorpromazine were capable of inhibiting the activity of the PST toward p-nitrophenol with inhibition Coefficient50 values of 100 nM and 4 mM, respectively.

Antitumour activity of an immunoconjugate composed of anti-human astrocytoma monoclonal antibody and neocarzinostatin.

Neocarzinostatin (NCS) linked to the thiol group on the hinge region of the Fab' fragment of GA-17, a murine monoclonal antibody reacting with tyrosine-specific phosphorylated antigens, which are exclusively expressed on the cell surface of human astrocytomas, was evaluated for in vivo activity. GA-17-NCS immunoconjugates significantly suppressed the growth of human malignant glioma cell line U87-MG subcutaneous xenografts in nude mice until day 50 when administered intravenously into the tail vein. Disulphide- and thioether-linked GA-17-NCS were nearly equipotent immunoconjugates, but thioether-linked GA-17-NCS was more effective than disulphide-linked conjugates with 250 U/kg NCS content on day 50 (P < 0.05). Thioether-linked GA-17-NCS was significantly more effective on day 50 than free NCS with 500 U/kg or 250 U/kg NCS content (P < 0.05, P < 0.01, respectively). These results suggest that GA-17-NCS may prove useful in the treatment of human malignant gliomas.

Analysis of the close relationship between human astrocytoma-specific antigens detected by murine monoclonal antibodies and c-kit proto-oncogene product.

Tyrosine-specific phosphorylated proteins found exclusively on the cell surface of human astrocytomas were previously identified with murine monoclonal antibodies, designated as GA-17, GB-4 and GC-3. The purpose of this study was to further characterize the antigens and investigate the relationship between them and c-kit protooncogene product. We demonstrated that the antigens had protein kinase activity. Moreover, GA-17 reacted with c-kit protein expressed on the membrane of A172 human glioblastoma cells.