Nitric oxide production by high molecular weight water-soluble chitosan via nuclear factor-kappaB activation

High molecular weight water-soluble chitosan (WSC), having an average molecular weight of 300000 Da and a degree of deacethylation over 90%, can be produced using a simple multi-step membrane separation process. In this study, the effect of WSC on the production of nitric oxide (NO) in RAW 264.7 macrophages was evaluated. Water-insoluble chitosan alone has been previously shown to exhibit in vitro stimulatory effect on macrophages NO production. However, WSC had no effect on NO production by itself. When WSC was used in combination with recombinant interferon-gamma (rIFN-gamma), there was a marked cooperative induction of NO synthesis in a dose-dependent manner. The optimal effect of WSC on NO synthesis was shown 24 h after treatment with rIFN-gamma. The increased production of NO from rIFN-gamma plus WSC-stimulated RAW 264.7 macrophages was decreased by the treatment with N(G)-monomethyl-L-arginine (N(G)MMA). The increase in NO synthesis was reflected, as an increased amounts of inducible NO synthase protein. In addition, synergy between rIFN-gamma and WSC was mainly dependent on WSC-induced tumor necrosis factor-alpha (TNF-alpha) and nuclear factor-kappaB (NF-kappaB) activation. The present results indicate that the capacity of WSC to increase NO production from rIFN-gamma-primed RAW 264.7 macrophages is the result of WSC-induced TNF-alpha secretion via the signal transduction pathway of NF-kappaB activation.

LPS induces direct death of IFN-gamma primed murine embryonic hepatocyte, BNL CL2 cells in a TNF-alpha independent manner

Although it has been well known that the role of LPS on liver damage is mediated through TNF-alpha, the mechanism by which LPS modulates the cytotoxicity of IFN-gamma on hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that IFN-gamma mediated apoptosis in murine embryonic hepatocyte BNL CL2 cells is potentiated by the addition of LPS (0.5 microg/ml). Consistently, LPS markedly increases the catalytic activity of caspase 3-like protease but not caspase 1-like protease in IFN-gamma treated cells. In addition, TNF-alpha alone does not affect cell viability but rather it potentiates the cytotoxic effect of IFN-gamma on BNL CL2 cells. However, the cell viability of IFN-gamma/LPS treated cells is affected by the addition of polymyxin B but not by TNF binding protein I (TNF-BPI). These data suggest that the lipid moiety of LPS may mediate direct cytotoxicity of BNL CL2 cells in a TNF-alpha independent manner.

Molecular mechanism of staurosporine-induced apoptosis in osteoblasts

Staurosporine, a microbial alkaloid, is a strong inhibitor of protein kinases. We induced apoptosis in murine osteoblast MC3T3E-1 cells by exposure to the staurosporine. Staurosporine transiently increased the phosphotransferase activity of c-Jun N-terminal kinase-1 (JNK1), which in turn may activate the transcriptional activity of activating protein-1 (AP-1). We then prepared extracts from staurosporine-treated MC3T3E-1 cells and monitored the cleavage of acetyl-YVAD-AMC and acetyl-DEVD-AMC, fluorogenic substrates of caspase-1-like and caspase-3-like proteases, respectively. Staurosporine caused a significant increase in the proteolytic activity of caspase-3-like proteases, but not in the activity of caspase-1-like proteases. Furthermore, staurosporine increased the transcriptional activity of nuclear factor- kappa B (NF- kappa B). These data suggest that staurosporine-induced apoptosis in osteoblasts may occur via activation of JNK1, caspase-3-like proteases, and transcriptional factors including AP-1 and NF- kappa B.

Development and characterization of a flavoring agent from oyster cooker effluent

The general composition of concentrated oyster cooker effluent (OCE) was 80% moisture, 6.7% total nitrogen, 2.4% glycogen, and 8.5% ash. Optimum conditions for enzymatic hydrolysis of OCE were 50 degrees C, 2 h of reaction time, 0.1% amylase mixture (alpha-amylase plus glucoamylase), and 0.2% protease NP. Hydrolysis of OCE led to an increase in free amino acids, with taurine comprising approximately 20% of the total. Inosine monophosphate was predominant (456 mg/100 g) among nucleotides and related compounds. Enzyme hydrolysis increased extractable nitrogen by approximately 2-fold. Trimethylamine, trimethylamine oxide, and total creatinine levels were not affected by enzyme treatment. Predominant aroma-active components of enzyme-hydrolyzed OCE included 2-acetyl-1-pyrroline and 3-(methylthio)propanal. Results of this study may help alleviate the wastewater disposal problem currently caused by OCE.

Neutron radiation enhances cisplatin cytotoxicity independently of apoptosis in human head and neck carcinoma cells

Recent advances in combined modality treatment of locally advanced head and neck cancer have improved local and regional disease control and survival with better functional outcome. However, the local and regional failure rate after radiation therapy is still high for tumors that respond poorly to cisplatin-based neoadjuvant chemotherapy. This clinical observation suggests a common biological mechanism for resistance to cisplatin and photon irradiation. In this report, we investigated the molecular basis underlying cisplatin resistance in head and neck squamous carcinoma (HNSCC) cells and asked if fast neutron radiation enhances cisplatin cytotoxicity in cisplatin-resistant cells. We found that cisplatin sensitivity correlates with caspase induction, a cysteine proteinase family known to initiate the apoptotic cell death pathway, suggesting that apoptosis may be a critical determinant for cisplatin cytotoxicity. Neutron radiation effectively enhanced cisplatin cytotoxicity in HNSCCs including cisplatin-resistant cells, whereas photon radiation had little effect on cisplatin cytotoxicity. Interestingly, neutron-enhanced cisplatin cytotoxicity was associated neither with apoptosis nor with cell cycle regulation, as determined by caspase activity assay, annexin V staining, and flow cytometric analysis. Taken together, the present study provides a molecular insight into cisplatin resistance and may also provide a basis for more effective multimodality protocols involving neutron radiation for patients with locally advanced head and neck cancer.

Mechanism of mitogenic effect of fluoride on fetal rat osteoblastic cells: evidence for Shc, Grb2 and P-CREB-dependent pathways

Fluoride stimulates bone cell proliferation and nodule formation in fetal rat calvarial osteoblastic cells. In addition, fluoride enhances alkaline phosphatase activity, a marker of osteoblastic differentiation, in a dose-dependent manner. The effects of fluoroalumino complex (AlFx) on cell proliferation and differentiation were markedly reduced by tyrosine kinase inhibitor; 1 mM genistein or 1 microg/ml herbimycin. It suggests that tyrosine kinase-mediated mitogenic signaling involves a series of protein-protein interactions between tyrosine-phosphorylated receptors, Shc and Grb2, resulting in an AlFx-induced mitogenic effect. The results indicate that AlFx dose-dependently enhances the tyrosine phosphorylation of the adaptor molecule Shc (p52) and its association with Grb2 in the tyrosine kinase mediated pathway. In addition, AlFx decreases the phosphorylation level of CREB without any change on the amount of CREB protein. Taken together, the results suggest that adaptor proteins, including Shc and Grb2 of the protein tyrosine kinase cascade are implicated in fluoride-induced mitogenic activity of fetal rat calvarial osteoblastic cells. Furthermore, CREB which passes signals from cAMP to transcriptional factor CRE, modulates the fluoroaluminate-induced metabolism of bone cells via a decrease of phosphorylation level.

Significance of serum and tissue carcinoembryonic antigen for the prognosis of gastric carcinoma patients

BACKGROUND AND OBJECTIVES

Carcinoembryonic antigen (CEA) has been widely accepted as a tumor marker useful in the diagnosis and management of colorectal carcinoma. When CEA levels are positive in patients with gastric carcinoma, they could be useful prognostic indicators. The value of CEA as a tumor marker for gastric carcinoma, however, remains a matter of controversy. The purpose of this study was to determine whether preoperative serum CEA value and tissue CEA staining are useful prognostic indicators for gastric carcinoma.

METHODS

We measured preoperative serum CEA levels by radioimmunoassay and stained tissue CEA production by tumor cells from gastric carcinomas using immunohistochemical staining in patients with gastric carcinoma.

RESULTS

The patients with preoperative serum CEA levels >10.0 ng/mL had a more prominent serosal invasion, much more lymph node involvement, more advanced stage and more poorly differentiated than did the patients with preoperative serum CEA levels <5.0 ng/mL. The survival rate of patients with serum CEA levels >10.0 ng/mL was poorer than those of patients with serum CEA levels between 5.0 and 10.0 ng/mL, and those of patients with serum CEA levels <5.0 ng/mL (P < 0.05). The preoperative serum CEA levels and tumor CEA-positivity were correlated (P < 0.05). In patients with lymph node metastases, the CEA-positivity (78.0%) was higher than in patients without lymph node metastasis (63.2%) (P < 0.05). A correlation was also found between the depth of tumor invasion and tissue CEA-positivity (P < 0.001). The postoperative survival rate was significantly better in the CEA-negative staining group (78.0%) than in the CEA-positive staining group (60.0%).

CONCLUSIONS

These data suggest that preoperative serum CEA levels and staining for CEA in gastric carcinoma tissue sections may have a predictive value in determining prognostic information for patients with resectable gastric carcinoma.

Mink cell focus-forming murine leukemia virus infection induces apoptosis of thymic lymphocytes

In a previous study we identified the subpopulations of thymus cells that were infected by the lymphomagenic MCF13 murine leukemia virus (MLV) (F. K. Yoshimura, T. Wang, and M. Cankovic, J. Virol. 73:4890-4898, 1999) and observed an effect on thymus size by virus infection. In this report we describe our results which demonstrate that MCF13 MLV infection of thymuses reduced the number of T lymphocytes in this organ. Histological examination showed diffuse lymphocyte depletion, which was most striking in the CD4(+) CD8(+) lymphocyte-enriched cortical zone. Consistent with this, flow cytometric analysis showed that the lymphocytes which were depleted were predominantly the immature CD3(-) CD4(+) CD8(+) and CD3(+) CD4(+) CD8(+) cells. A comparison of the percentages of live, apoptotic, and dead cells of the gp70(+) and gp70(-) thymic lymphocytes suggested that this effect on thymus cellularity is a result of virus infection. Studies of the survival of thymic T lymphocytes in culture showed that cells from MCF13 MLV-inoculated mice underwent greater apoptosis and death than cells from control animals. Assays for apoptosis included 7-amino-actinomycin D staining, DNA fragmentation, and cleavage of caspase-3 and poly(ADP-ribose) polymerase proenzymes. Our results suggest that apoptosis of thymic lymphocytes by virus infection is an important step in the early stages of MCF13 MLV tumorigenesis.

Phorbol 12-myristate 13-acetate induces alteration in mucin gene expression and biological properties of colon cancer cells

Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.

Inhibitory effect of sodium salicylate on nitric oxide production from TM4 sertoli cells

Nitric oxide (NO) has been proposed to play a role in a variety of inflammatory diseases. Sodium salicylate (NaSal) is the most commonly used anti-inflammatory agent. We investigated whether NaSal can diminish the production of NO in TM4 Sertoli cells. TM4 Sertoli cells produced a small amount of NO upon treatment with recombinant interferon-gamma (rIFN-gamma). The effect of rIFN-gamma was enhanced markedly by the addition of recombinant TNF-alpha (rTNF-alpha) in a dose-dependent manner. NaSal (10 and 20 mM) significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. In addition, rIFN-gamma in combination with rTNF-alpha showed a marked increase of the expression of inducible NO synthase (iNOS) protein. Western blot analysis revealed that NaSal (10 and 20 mM) blocked a step of iNOS protein synthesis. The rIFN-gamma plus rTNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation was significantly blocked by NaSal (10 and 20 mM). On the other hand, neither staurosporine nor polymyxin B significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. The present results indicate that NaSal inhibits rIFN-gamma plus rTNF-alpha-induced NO production in TM4 Sertoli cells via the signal transduction pathway of NF-kappaB activation.

Effects of microgravity and hypergravity on aging and longevity of insects

The effects of microgravity and hypergravity on aging are still poorly documented, particularly in mammals. However, there is a growing interest for the use of the fruit fly, Drosophila melanogaster, and this species may be now considered as a model organism in gravitational biology studies dealing with aging.

Dexamethasone suppresses tumor necrosis factor-alpha-induced apoptosis in osteoblasts: possible role for ceramide

Ceramide has been proposed as a second messenger molecule implicated in a variety of biological processes, including apoptosis. Recently, it has been reported that tumor necrosis factor-alpha (TNF-alpha) activates the release of ceramide and that ceramide acts as a mediator for the TNF-alpha-induced stimulation of the binding affinity of nuclear factor-KB (NF-KB), a ubiquitous transcription factor of particular importance in immune and inflammatory responses. In this study we demonstrate that dexamethasone, which reduces the production of ceramide, significantly inhibits TNF-alpha-induced activation of NF-KB, c-Jun N-terminal kinase, also known as stress-activating protein kinase, caspase-3-like cysteine protease, redistribution of cytochrome c, and apoptosis in MC3T3E1 osteoblasts. Compared with TNF-alpha-induced JNK activation, ceramide elicits a more rapid activation of JNK within 30 min. C2-ceramide activates NF-KB and caspase-3 like protease to the same degree and with kinetics similar to those of TNF-alpha. This study provides evidence that the release of ceramide may be required as a second messenger in TNF-alpha-induced apoptosis. These results also suggest a regulatory role for dexamethasone in TNF-alpha-induced apoptosis via inhibition of ceramide release. Therefore, our in vitro results suggest that therapies targeted at the inhibition of ceramide release may abrogate inflammatory processes in TNF-alpha-related diseases, including rheumatoid arthritis and periodontitis.

Taraxacum officinale inhibits tumor necrosis factor-alpha production from rat astrocytes

Substance P (SP) can stimulate production of tumor necrosis factor-alpha (TNF-alpha) from astrocytes stimulated with lipopolysaccharide (LPS). The objective of the current study was to determine the effect of Taraxacum officinale (TO) on the production of TNF-alpha from primary cultures of rat astrocytes. TO (100 and 1000 microg/ml) significantly inhibited the TNF-alpha production by astrocytes stimulated with LPS and SP. Interleukin-1 (IL-1) has been shown to elevate TNF-alpha production from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. We therefore examined whether IL-1 mediated inhibition of TNF-alpha production from primary astrocytes by TO. Treatment of TO (100 and 1000 microg/ml) to astrocytes stimulated with both LPS and SP decreased IL-1 production significantly. Moreover, the production of TNF-alpha by LPS and SP in astrocytes was progressively inhibited with increasing amount of IL-1 neutralizing antibody. Our results suggest that TO may inhibit TNF-alpha production by inhibiting IL-1 production and that TO has an antiinflammatory activity in the central nervous system.

Inhibition of mast cell-mediated anaphylaxis by sochungryong-tang

According to traditional Asian philosophy, sochungryong-tang (S-Tang) is a prescription for treating exterior syndrome. In this study, we investigated the effect of S-Tang on mast cell-mediated anaphylaxis. S-Tang completely inhibited compound 48/80-induced systemic anaphylactic shock at a dose of 100 mg/kg. When S-Tang was given as pretreatment at concentrations ranging from 1 to 1000 mg/kg, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. S-Tang inhibited the local anaphylaxis activated by anti-dinitrophenyl (DNP) IgE antibody, and also inhibited the histamine release from the rat peritoneal mast cells by compound 48/80 or anti-DNP IgE. These results indicate that S-Tang may contain substances with actions that inhibit mast cell degranulation.

Significance of serum and tissue carcinoembryonic antigen for the prognosis of gastric carcinoma patients

BACKGROUND AND OBJECTIVES

Carcinoembryonic antigen (CEA) has been widely accepted as a tumor marker useful in the diagnosis and management of colorectal carcinoma. When CEA levels are positive in patients with gastric carcinoma, they could be useful prognostic indicators. The value of CEA as a tumor marker for gastric carcinoma, however, remains a matter of controversy. The purpose of this study was to determine whether preoperative serum CEA value and tissue CEA staining are useful prognostic indicators for gastric carcinoma.

METHODS

We measured preoperative serum CEA levels by radioimmunoassay and stained tissue CEA production by tumor cells from gastric carcinomas using immunohistochemical staining in patients with gastric carcinoma.

RESULTS

The patients with preoperative serum CEA levels >10.0 ng/mL had a more prominent serosal invasion, much more lymph node involvement, more advanced stage and more poorly differentiated than did the patients with preoperative serum CEA levels <5.0 ng/mL. The survival rate of patients with serum CEA levels >10.0 ng/mL was poorer than those of patients with serum CEA levels between 5.0 and 10.0 ng/mL, and those of patients with serum CEA levels <5.0 ng/mL (P < 0.05). The preoperative serum CEA levels and tumor CEA-positivity were correlated (P < 0.05). In patients with lymph node metastases, the CEA-positivity (78.0%) was higher than in patients without lymph node metastasis (63.2%) (P < 0.05). A correlation was also found between the depth of tumor invasion and tissue CEA-positivity (P < 0.001). The postoperative survival rate was significantly better in the CEA-negative staining group (78.0%) than in the CEA-positive staining group (60.0%).

CONCLUSIONS

These data suggest that preoperative serum CEA levels and staining for CEA in gastric carcinoma tissue sections may have a predictive value in determining prognostic information for patients with resectable gastric carcinoma.

Biological properties and expression of mucins in 5-fluorouracil resistant HT29 human colon cancer cells

We have previously reported that HT29 human colon cancer cells selected by adaptation to 5-fluorouracil (5FU) (HT29-5FU cells) express increased levels of a major intestinal mucin MUC2 mRNA compared with parental HT29 cells. In this study, we examined in detail the changes in synthesis and secretion of mucin that occur in these cells and accompanying changes in the expression of cancer associated mucin related carbohydrate antigens and cell lineage associated biochemical markers. We further investigated their relationship to biological properties of cells. Northern blot analysis revealed a markedly increased level of MUC2 mRNA but no significant change in the mRNA levels of other mucins in HT29-5FU cells compared with parental HT29 cells. Labeling with radiolabeled precursors demonstrated increased synthesis and secretion of mucin glycoproteins by HT29-5FU cells. Immunoblot analysis showed a higher expression of mucin associated carbohydrate antigens such as T, Tn, sialyl Tn, sialyl Lea, sialyl Lex and non-O-acetylated sialic acid concomitant with significant increases in the expression of goblet cell lineage marker, MUC2 apomucin and a panepithelial cell marker, carcinoembryonic antigen. HT29-5FU cells showed significantly higher adhesion to E-selectin and to matrigel and in vitro invasive properties and significantly increased liver colonization capacity in nude mice following splenic vein injection. Nude mouse xenograft tumors produced by HT29-5FU cells showed a greater degree of differentiation, consisting of mucin secreting glands than those produced by parental HT29 cells. These results indicate that predominantly colonic type mucin, MUC2, has been selectively induced in HT29-5FU cells and that altered regulation of mucin genes associated with altered synthesis and secretion of mucin glycoproteins and the degree of differentiation in cancer cells may be responsible for the altered biological properties of these cells.

Platelet-derived growth factor (PDGF) receptor-alpha activates c-Jun NH2-terminal kinase-1 and antagonizes PDGF receptor-beta -induced phenotypic transformation

Platelet-derived growth factor (PDGF) is a potent mitogen for mesenchymal cells. The PDGF B-chain (c-sis proto-oncogene) homodimer (PDGF BB) and v-sis, its viral counterpart, activate both alpha- and beta-receptor subunits (alpha-PDGFR and beta-PDGFR) and mediate anchorage-independent growth in NIH3T3 cells. In contrast, the PDGF A chain homodimer (PDGF AA) activates alpha-PDGFR only and fails to induce phenotypic transformation. In the present study, we investigated alpha- and beta-PDGFR specific signaling pathways that are responsible for the differences between the transforming ability of PDGF AA and BB. To study PDGF BB activation of beta-PDGFR, we established NIH3T3 clones in which alpha-PDGFR signaling is inhibited by a dominant-negative alpha-PDGFR, or an antisense construct of alpha-PDGFR. Here, we demonstrate that beta-PDGFR activation alone is sufficient for PDGF BB-mediated anchorage-independent cell growth. More importantly, inhibition of alpha-PDGFR signaling enhanced PDGF BB-mediated phenotypic transformation, suggesting that alpha-PDGFR antagonizes beta-PDGFR-induced transformation. While both alpha- and beta-receptors effectively activate ERKs, alpha-PDGFR, but not beta-PDGFR, activates stress-activated protein kinase-1/c-Jun NH(2)-terminal kinase-1 (JNK-1). Inhibition of JNK-1 activity using a dominant-negative JNK-1 mutant markedly enhanced PDGF BB-mediated anchorage-independent cell growth, demonstrating an antagonistic role for JNK-1 in PDGF-induced transformation. Consistently, overexpression of wild-type JNK-1 reduced PDGF BB-mediated transformation. Taken together, the present study showed that alpha- and beta-PDGFRs differentially regulate Ras-mitogen-activated protein kinase pathways critical for regulation of cell transformation, and transformation suppressing activity of alpha-PDGFR involves JNK-1 activation.

Effective deacetylation of chitin under conditions of 15 psi/121 degrees C

Deacetylation of chitin under autoclaving conditions (15 psi/121 degrees C) was evaluated for the preparation of chitosan under different NaOH concentrations and reaction times. Deacetylation was effectively achieved by treatment of chitin under elevated temperature and pressure with 45% NaOH for 30 min and a solids/solvent ratio of 1:15. Treated chitosan showed similar nitrogen content (7.42%), degree of deacetylation (90.4%), and molecular mass (1560 kDa) but significantly higher viscosity values (2025 cP) compared with those (7.40%, 87.6%, 1304 kDa, and 143 cP, respectively) of a commercial chitosan. Reduction of the solids/solvent ratio from 1:15 to 1:10 did not affect degree of deacetylation, viscosity, and molecular mass of chitosan.

Reduced IL-2 but elevated IL-4, IL-6, and IgE serum levels in patients with cerebral infarction during the acute stage

Cytokines in the central nervous system (CNS) may play an important role in functioning as intercellular signals that orchestrate the response to injury. Whether this is a cause or result of the brain disease process is uncertain. We investigated IFN-gamma, IL-2, IL-4, IL-6, and IgE in the sera of 38 patients with cerebral infarction during the acute stage and 10 normal controls using an originally devised sensitive sandwich enzyme-linked immunosorbent assay (ELISA). We found that serum levels of IL-2 derived from T helper 1 (Th1) cells were slightly reduced in patients with cerebral infarction, whereas serum levels of IL-4 and IL-6 derived from Th2 cells were elevated significantly. IL-4 induces synthesis of IgE in human B cells. Endogenous IL-6 plays an obligatory role in IL-4-dependent human IgE synthesis. We observed that serum IgE levels were elevated significantly in patients with cerebral infarction. However, serum IFN-gamma levels were not elevated significantly in cerebral infarction patients. These findings suggest that elevated IL-4, IL-6, and IgE levels in the human serum may be an important factor in cerebral infarction during the acute stage. Decrease of IL-2 levels in the serum of patients with cerebral infarction may be a regulatory mechanism.

Inhibitory effect of anaphylactic shock by caffeine in rats

Caffeine is known to reduce evoked histamine secretion, but the effects of caffeine on anaphylactic shock have not been clarified. We have investigated the effects of caffeine on anaphylactic shock in rats. Systemic anaphylactic shock by compound 48/80 injection was monitored for 1 h. An IgE-dependent local anaphylactic shock was generated by sensitizing the skin with anti-dinitrophenyl (DNP) IgE followed 48 h later with an injection of antigen. Caffeine inhibited compound 48/80-induced anaphylatic shock to 40% with a dose of 1 mg/kg. Caffeine (0.1 mg/kg) inhibited to 56.4+/-0.4% passive cutaneous anaphylactic shock activated by anti-DNP IgE. Caffeine (5-20 mM) significantly inhibited histamine release from rat peritoneal mast cells (RPMCs) activated by compound 48/80 or anti-DNP IgE. Especially, caffeine (20 mM) inhibited by 96.7+/-0.5% histamine release activated by compound 48/80. Moreover, caffeine (1-20 mM) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production from RPMCs. The level of cAMP in RPMCs, when caffeine (20 mM) was added, increased significantly after 5-60 min compared with that of a normal control. These results indicate that caffeine inhibits immediate-type allergic reactions by inhibition of mast cell degranulation in vivo and in vitro.

Characterization of the human EPLIN (Epithelial Protein Lost in Neoplasm) gene reveals distinct promoters for the two EPLIN isoforms

EPLIN is a novel LIM domain protein that co-localizes to the actin stress fibers and focal adhesion plaques. We previously have demonstrated that two isoforms, the 600aa EPLIN-alpha and the 759aa EPLIN-beta, are generated from a single gene. In the majority of human breast and prostate cancer cell lines, the expression of EPLIN-alpha is significantly reduced, while the expression of EPLIN-beta is either up-regulated or unchanged. To understand the basis of this differential regulation, we have determined the organization of the human EPLIN gene. The human EPLIN100kb and consists of 11 exons. The EPLIN-beta mRNA requires all 11 exons, while the EPLIN-alpha mRNA requires Exons 4-11. The transcriptional start sites of EPLIN-alpha were mapped within the third intron by 5' RACE and S1 nuclease protection. Similarly, the 5' ends of EPLIN-beta were mapped upstream of Exon 1. The DNA sequences flanking the EPLIN-alpha or EPLIN-beta transcriptional start sites were capable of stimulating the expression of promoter reporter constructs. Interestingly, the endogenous transcription of EPLIN-alpha, but not EPLIN-beta, could be stimulated by serum, indicating that the expression of two EPLIN isoforms can be independently regulated. A consensus serum response element was present within 100bp upstream of the transcriptional start sites of EPLIN-alpha. The activity of 0.7kb EPLIN-alpha promoter reporter construct could be enhanced by activated RhoA, indicating that this serum response element is functional.

The stem of sinomenium acutum inhibits mast cell-mediated anaphylactic reactions and tumor necrosis factor-alpha production from rat peritoneal mast cells

The aqueous extract of Sinomenium acutum stem (SSAE) (0.1-1000 mg/kg) dose-dependently inhibited systemic anaphylactic reaction induced by compound 48/80 in mice. In particular, SSAE reduced compound 48/80-induced anaphylactic reaction with 50% at the dose of 1000 mg/kg. SSAE (100-1000 mg/kg) also significantly inhibited local anaphylactic reaction activated by anti-dinitrophenyl (DNP) IgE. When mice were pretreated with SSAE at a concentration ranging from 0.1 to 1000 mg/kg, the plasma histamine levels were reduced in a dose-dependent manner. SSAE (1-1000 microg/ml) dose-dependently inhibited histamine release from the rat peritoneal mast cells (RPMCs) activated by compound 48/80 or anti-DNP IgE. In addition, SSAE (0.1 microg/ml) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha (TNF-alpha) production. These results indicate that SSAE inhibits mast cell-mediated anaphylactic reactions and TNF-alpha production from mast cells.

Production of hydrogen peroxide by serum and its involvement in cell proliferation in ROS 17/2.8 osteoblasts

The effects of hydrogen peroxide, which fetal bovine serum (FBS) releases, on proliferation have been studied in ROS 17/2.8 osteoblasts. Cell proliferation, when activated by FBS, was inhibited by catalase in ROS 17/2.8 osteoblasts, but did not in primary osteoblast-like cells. Serum-induced extracellular signal-regulated kinase(ERK) activity was reduced by the pretreated catalase in ROS 17/2.8 osteoblasts. In addition, the present studies demonstrate that addition of FBS led to an increase of fluorescence of dihydrorhodamine 123, indicating formation of free radicals including hydrogen peroxide in ROS 17/2.8 osteoblasts, but not in primary osteoblast-like cells. These phenomena may account for the generation of reactive oxygen species during cellular proliferation in ROS 17/2.8 osteoblasts.

Inhibitory effect of mast cell-mediated immediate-type allergic reactions by sulfapyridine

We examined the effect of sulfapyridine on mast cell-mediated immediate-type allergic reactions. Sulfapyridine (1 and 10 microg/kg) significantly inhibited systemic allergic reaction induced by compound 48/80 in rats. Sulfapyridine (1 and 10 microg/kg) also inhibited significantly local mast cell-mediated immediate-type allergic reactions activated by anti-dinitrophenyl (DNP) IgE. Moreover, sulfapyridine inhibited histamine release dose-dependently in the rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. When sulfapyridine was added, the level of cAMP in RPMC, transiently and significantly increased about 4-fold compared with that of basal cells. These results indicate that sulfapyridine inhibits mast cell-mediated immediate-type allergic reactions in vivo and in vitro.