Combination Treatment of Stereotactic Body Radiation Therapy and Immature Dendritic Cell Vaccination for Augmentation of Local and Systemic Effects / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to investigate the efficacy of stereotactic body radiation therapy (SBRT) as a tumor-associated antigen (TAA) presentation method for dendritic cell (DC) sensitization and evaluate its effect in combination with immunotherapy using an intratumoral injection of immature DCs (iDCs). MATERIALS AND METHODS: CT-26 colon carcinoma cell was used as a cancer cell line. Annexin V staining and phagocytosis assays were performed to determine the appropriate radiation dose and incubation time to generate TAAs. BALB/c mice were used for in vivo experiments. Cancer cells were injected into the right legs and left flanks to generate primary and metastatic tumors, respectively. The mice were subjected to radiation therapy (RT) alone, intradermal injection of electroporated DCs alone, or RT in combination with iDC intratumoral injection (RT/iDC). Tumor growth measurement and survival rate analysis were performed. Enzyme-linked immunospot and cytotoxicity assays were performed to observe the effect of different treatments on the immune system. RESULTS: Annexin V staining and phagocytosis assays showed that 15 Gy radiation dose and 48 hours of incubation was appropriate for subsequent experiments. Maximum DC sensitization and T-cell stimulation was observed with RT as compared to other TAA preparation methods. In vivo assays revealed statistically significant delay in the growth of both primary and metastatic tumors in the RT/iDC group. The overall survival rate was the highest in the RT/iDC group. CONCLUSION: The combination of SBRT and iDC vaccination may enhance treatment effects. Clinical trials and further studies are warranted in the future.

Effects of White Radish (Raphanus sativus) Enzyme Extract on Hepatotoxicity

Raphanus sativus (Cruciferaceae), commonly known as radish is widely available throughout the world. From antiquity it has been used in folk medicine as a natural drug against many toxicants. The present study was designed to evaluate the hepatoprotective activity of radish (Raphanus sativus) enzyme extract (REE) in vitro and in vivo test. The IC50 values of REE in human liver derived HepG2 cells was over 5,000 microg/ml in tested maximum concentration. The effect of REE to protect tacrine-induced cytotoxicity in HepG2 cells was evaluated by MTT assay. REE showed their hepatoprotective activities on tacrine-induced cytotoxicity and the EC50 value was 1,250 microg/ml. Silymarin, an antihepatotoxic agent used as a positive control exhibited 59.7% hepatoprotective activitiy at 100 microg/ml. Moreover, we tested the effect of REE on carbon tetrachloride (CCl4)-induced liver toxicity in rats. REE at dose of 50 and 100 mg/kg and silymarin at dose of 50 mg/kg were orally administered to CCl4-treated rats. The results showed that REE and silymarin significantly reduced the elevated levels of serum enzyme markers induced by CCl4. The biochemical data were supported by evaluation with liver histopathology. These findings suggest that REE, can significantly diminish hepatic damage by toxic agent such as tacrine or CCl4.

Effect of Microalgal Extracts of Tetraselmis suecica against UVB-Induced Photoaging in Human Skin Fibroblasts

Exposure of cells to ultraviolet B (UVB) radiation can induce production of free radicals and reactive oxygen species (ROS), which damage cellular components. In addition, these agents can stimulate the expression of matrix metalloproteinase (MMP) and decrease collagen synthesis in human skin cells. In this study, we examined the anti-photoaging effects of extracts of Tetraselmis suecica (W-TS). W-TS showed the strongest scavenging activity against 2,2-difenyl-1-picrylhydrazyl (DPPH) and peroxyl radicals, followed by superoxide anions from the xanthine/xanthine oxidase system. We observed that the levels of both intracellular ROS and lipid peroxidation significantly increased in UVB-irradiated human skin fibroblast cells. Furthermore, the activities of enzymatic antioxidants (e.g., superoxide dismutase) and the levels of non-enzymatic antioxidants (e.g., glutathione) significantly decreased in cells. However, W-TS pretreatment, at the maximum tested concentration, significantly decreased intracellular ROS and malondialdehyde (MDA) levels, and increased superoxide dismutase and glutathione levels in the cells. At this same concentration, W-TS did not show cytotoxicity. Type 1 procollagen and MMP-1 released were quantified using RT-PCR techniques. The results showed that W-TS protected type 1 procollagen against UVB-induced depletion in fibroblast cells in a dose-dependent manner via inhibition of UVB-induced MMP-1. Taken together, the results of the study suggest that W-TS effectively inhibits UVB-induced photoaging in skin fibroblasts by its strong anti-oxidant ability.

Effect of Hydroxyapatite on Bone Integration in a Rabbit Tibial Defect Model

BACKGROUND: The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study. METHODS: Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting. RESULTS: The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged. CONCLUSIONS: We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology.

The Anti-inflammatory Effects of Water Extract from Cordyceps militaris in Murine Macrophage

The aim of this study was to determine the in vitro anti-inflammatory effect of hot water extract from Cordyceps militaris fruiting bodies (CMWE) on lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release in RAW 264.7 cells. The treatment of macrophages with various concentrations of hot CMWE significantly reduced LPS-induced production as well as NO, TNF-alpha and IL-6 secretion in a concentration-dependent manner. These results suggest that CMWE have potent inhibitory effects on the production of these inflammatory mediators.

Neuroendocrine Tumor of the Colon

Neuroendocrine tumor (NET) of the colon and rectum has been reported to have a low incidence and aggressive progression; it is frequently misdiagnosed and its treatment is not well documented. Four NET cases were collected at our hospital during the previous year of a colon cancer survey. Endoscopic mucosal biopsy of the colon was done for each case and all the cases proved to be adenocarcinomas. Curative surgery was conducted after the preoperative diagnostic and staging evaluation was completed. The locations of the primary lesions of the patients were all different; cecum, ascending colon, splenic flexure colon and sigmoid colon. The disease was advanced in all cases and the first postoperative diagnosis was poorly differentiated adenocarcinoma. Immunohistochemical tests followed and all the cases were positive for chromogranin A staining. A retrospective study was then conducted.

Normal Variation of Hepatic Artery / 한국간담췌외과학회지

PURPOSE: World wide studies have reported many cases of the normal variants of the hepatic artery in healthy individuals. Unfortunately, there are few medical reports in Korea, this study presents the results and analysis of the anatomical variants in the hepatic artery. METHODS: This study analyzed the blood supply of the liver in 131 patients who had received hepatic angiography and superior mesenteric angiography from January 1996 to September 2003 at the Maryknoll general hospital. RESULTS: The hepatic artery pattern with a normal hepatic artery pattern was observed in 101 out of 131 cases (77.1%) ; the right and left hepatic arteries arising from the proper hepatic artery, which arising from the common hepatic artery. The normal variations in the hepatic artery pattern were observed in 30 out of 131 cases (22.9%) ; the replaced right hepatic artery arising from the superior mesenteric artery was observed in 14 out of 131 cases (10.7%). The replaced left hepatic artery arising from the left gastric artery was observed in 6 out of 131 cases (4.6%). The common hepatic artery arising from the superior mesenteric artery was noted in 4 out of 131 cases (3.1%). The accessory left hepatic artery arising from the left gastric artery was observed in 1 out of 67 cases (0.7%). Other variants were noted 5 out of 131 cases (3.8%). CONCLUSION: Knowledge of the patterns and frequency of the variants in hepatic artery is increasing with the larger number of national reports on the hepatic artery variants, which can be great help in surgical operations, hepatic arterial embolization, or liver transplant.

The Role of NF-kappaB RelA Subunit for Tax-inhibition of p53 Transcriptional Activity in Human T-cell Lymphotrophic Virus Type 1

Human T-cell lymphotrophic virus type I (HTLV-I) is a causative agent of adult T-cell leukemia (ATL). The viral transcriptional activator Tax encoded by the HTLV-I genome is thought to play critical roles in the activation of nuclear factor kappaB(NF-kappaB) as well as in the transformation of human T lymphocytes and the induction of tumor and leukemia. In this report, we suggest that RelA subunit of NF-kappaB might play an important role in Tax-induced p53 inactivation. Using antisense oligonucleotides, the ability of Tax inhibiting p53 transactivation was blocked by RelA, but not p50 or c-rel, antisense oligonucleotides in C81 HTLV-1-transfected cell line. The inability of p50 or c-rel antisense oligonucleotides in blocking the Tax-mediated inhibition of p53 function was not due lack of activity, since NF-kappaB activation was specifically blocked by these oligonucleotides. Also, we demonstrate by using co-immunoprecipitation assays that p53 interacts with RelA in HTLV-I transformed cells and their binding became stronger by the overexpression of Tax in 293T cells. These results suggest the possibility that the physical interaction between p53 and RelA correlates with Tax-induced p53 inhibition.

Statin Reduced the Platelet CD63 and CD40L Expression in Atherosclerotic Ischemic Stroke with Hyperlipidemia

BACKGROUND: Statin (HMG-coA-reductase inhibitor) has been known to protect vessels from atherothrombosis through various mechanisms. In this study, we evaluated the effects of statin on reducing the platelet expressions of CD63 and CD40 ligand (CD40L) in subjects with atherosclerotic ischemic stroke. METHODS: Twenty-one patients (17 men, 4 women; mean age 59.0 +/- 10.2 years) with atherosclerotic ischemic stroke were recruited. They took simvastatin 20 mg per day for 90 days and discontinued for another 90 days. We studied the changes of platelet expressions of CD63 and CD40L in all the patients after the use and discontinuance of simvastatin using whole blood flow cytometry. RESULTS: After taking simvastatin 20mg for 90 days, the serum concentrations of LDL cholesterol decreased significantly (96.4 +/- 31.4 mg/dL, p<0.001) compared with those at the baseline (158.8 +/- 25.0 mg/dL). The platelet CD63 and C40L expressions were also significantly reduced by treatment of simvastatin 20 mg for 12 weeks (p<0.05). However, the effects of statin on CD63 and CD40L expressions disappeared after 12 weeks of cessation. Furthermore, changes of expressions of CD63 and CD40L by statin did not correlate with its cholesterol lowering effect (r=-0.311, p=0.386). CONCLUSIONS: This study demonstrates that the use of statin may be a helpful strategy to regulate the platelet activation in patients with atherosclerotic ischemic stroke.

Regulatory Mechanism of Radiation-induced Cancer Cell Death by the Change of Cell Cycle / 대한방사선종양학회지

PURPOSE: In our previous study, we have shown the main cell death pattern induced by irradiation or protein tyrosine kinase (PTK) inhibitors in K562 human myelogenous leukemic cell line. Death of the cells treated with irradiation alone was characterized by mitotic catastrophe and typical radiation-induced apoptosis was accelerated by herbimycin A (HMA). Both types of cell death were inhibited by genistein. In this study, we investigated the effects of HMA and genistein on cell cycle regulation and its correlation with the alterations of radiation-induced cell death. MATERIALS AND METHODS: K562 cells in exponential growth phase were used for this study. The cells were irradiated with 10 Gy using 6 MeV Linac (200-300 cGy/min). Immediately after irradiation, cells were treated with 250 nM of HMA or 25 microM of genistein. The distributions of cell cycle, the expressions of cell cycle-related protein, the activities of cyclin-dependent kinase, and the yield of senescence and differentiation were analyzed. RESULTS: X-irradiated cells were arrested in the G2 phase of the cell cycle but unlike the p53-positive cells, they were not able to sustain the cell cycle arrest. An accumulation of cells in G2 phase of first cell-cycle post-treatment and an increase of cyclin B1 were correlated with spontaneous, premature, chromosome condensation and mitotic catastrophe. HMA induced rapid G2 checkpoint abrogation and concomitant p53-independent G1 accumulation. HMA-induced cell cycle modifications correlated with the increase of cdc2 kinase activity, the decrease of the expressions of cyclins E and A and of CDK2 kinase activity, and the enhancement of radiation-induced apoptosis. Genistein maintained cells that were arrested in the G2-phase, decreased the expressions of cyclin B1 and cdc25C and cdc2 kinase activity, increased the expression of p16, and sustained senescence and megakaryocytic differentiation. CONCLUSION: The effects of HMA and genistein on the radiation-induced cell death of K562 cells were closely related to the cell cycle regulatory activities. In this study, we present a unique and reproducible model in which for investigating the mechanisms of various, radiation-induced, cancer cell death patterns. Further evaluation by using this model will provide a potent target for a new strategy of radiotherapy.

Changes of Platelet Activation and Clinical Outcome in Acute Atherosclerotic Cerebral Infarction Treated with Clopidogrel Loading Dose (300 mg)

BACKGROUND: Platelet activation has an important role in progression of atherosclerotic vascular events. To know the beneficial effects of clopidogrel loading dose about changes of platelet activation and clinical outcome in acute stage of atherosclerotic infarction, we performed a prospective randominized study. METHODS: Patients with large artery atherosclerotic infarction were randomized to clopidogrel loading dose (n=24) or intravenous heparin with low dose aspirin (n=28) during 7 days. We measured the surface expression of CD63 on platelets and the platelet aggregability for 7 days. The National Institute of Health Stroke Scale (NIHSS) score was recorded at 24 hours, 72 hours, and 7 days after stroke. Three-month outcome was recorded by the modified Barthel index (BI). RESULTS: As compared with intravenous heparin, the loading dose of clopidogrel was associated with significant reduction of the surface expression of CD63 on platelets, platelet aggregability, and NIHSS score. The clopidogrel loading dose-treated patients were more likely to have a very favorable outcome on BI index at 3 months. CONCLUSIONS: Our results showed that the clopidogrel loading dose has beneficial effects of clinical outcome of acute stage of large artery atherosclerotic infarction may be mediated by the platelet hyperactivity in these patients. Thus, this loading dose trial deserves further evaluation in clinical trial for treatment in large artery atherosclerotic infarction.

The Change of Platelet Aggregation with Acute Ischemic Stroke

BACKGROUND: Platelet activation has an important role in the progression of atheroclerosis and acute ischemic events. In this study, in order to know the significance of platelet functions in a large artery atherosclerotic infarction, we evaluated the serial changes of platelet aggregability in patients with a large artery atherosclerotic infarction. METHODS: We serially (within 24 hrs, at 72 hrs, and 7 days) measured the extents of platelet aggregation to ADP and collagen in 43 patients with acute ischemic stroke (LAA-22, SVD-21) and compared them with those in patients with asymptomatic carotid stenosis (n=20) and in normal controls (n=24). RESULTS: The extents of platelet aggregation to ADP and collagen were significantly increased in large artery atherosclerotic infarctions compared to small vessel disease. These differences of platelet aggregability between the two groups were maintained for seven days after an ischemic event. However, the platelet aggregability was not different between large artery atherosclerotic infarctions and asymptomatic carotid stenosis. CONCLUSIONS: This data suggests that increased platelet aggregability is important in large artery atherosclerotic infarction and is caused by pre-existing atherosclerotic changes rather than acute ischemic events.

Signal Transduction Factors on the Modulation of Radiosusceptibility in K562 Cells / 대한방사선종양학회지

PURPOSE: The human chronic myelogenous leukemia cell line, K562, expresses the chimeric bcr-abl oncoprotein, whose deregulated protein tyrosine kinase activity antagonizes the induction of apoptosis via DNA damaging agents. Previous experiments have shown that nanomolar concentrations of herbimycin A (HMA) coupled with X-irradiation have a synergistic effect in inducing apoptosis in the Ph-positive K562 leukemia cell line, but genistein, a PTK inhibitor, is non selective for the radiation-induced apoptosis of p210bcr/abl protected K562 cells. In these experiments, the cytoplasmic signal transduction pathways, the induction of a number of transcription factors and the differential gene expression in this model were investigated. MATERIALS AND METHODS: K562 cells in the exponential growth phase were used in this study. The cells were irradiated with 0.5-12 Gy, using a 6 MeV Linac (Clinac 1800, Varian, USA). Immediately after irradiation, the cells were treated with 0.25 microM of HMA and 25 microM of genistein, and the expressions and the activities of abl kinase, MAPK family, NF-kB, c-fos, c-myc, and thymidine kinase1 (TK1) were examined. The differential gene expressions induced by PTK inhibitors were also investigated. RESULTS: The modulating effects of herbimycin A and genistein on the radiosensitivity of K562 cells were not related to the bcr-abl kinase activity. The signaling responses through the MAPK family of proteins, were not involved either. In association with the radiation-induced apoptosis, which is accelerated by HMA, the expression of c-myc was increased. The combined treatment of genistein, with irradiation, enhanced NF-kB activity and the TK1 expression and activity. CONCLUSION: The effects of HMA and genistein on the radiosensitivity of the K562 cells were not related to the bcr-abl kinase activity. In this study, another signaling pathway, besides the MAPK family responses to radiation to K562 cells, was found. Further evaluation using this model will provide valuable information for the optional radiosensitization or radioprotection.

Surface Expression of P-selectin on Platelets Is Related with Clinical Worsening in Acute Ischemic Stroke

Platelet activation has a critical role in arterial disorders. In this study, we showed that the upregulation of P-selectin expression on platelets was related with clinical worsening in acute ischemic stroke. We serially (within 24 hr, at 72 hr, and 7 days) measured the expression of P-selectin on platelets in patients with acute ischemic stroke (n=45) and investigated the correlation between their extents and clinical severity of ischemic stroke. A significant relationship between the P-selectin expressions and National Institute of Health Stroke Scale (NIHSS) was observed at 72 hr and 7 days after ischemic stroke onset. Patients with clinical deterioration showed significantly increased expression of P-selectin on platelets as compared to those without deterioration. These results suggest that the P-selectin expression on platelets may contribute to the aggravation of clinical course in acute ischemic stroke. Thus, adequate manipulation of activated platelets is an important therapeutic strategy in acute ischemic stroke.

Smad6 Gene and Suppression of Radiation-Induced Apoptosis by Genistein in K562 cells / 대한방사선종양학회지

PURPOSE: The genes involved on the suppression of radiation-induced apoptosis by genistein in K562 leukemia cell line was investigated. MATERIALS AND METHODS: K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. Forx-ray irradiation and drug treatment, cultures were prepared at 2x105 cells/mL. The cells were irradiated with 10 Gy (Clinac 1800C, Varian, USA). Stock solutions of herbimycin A (HMA, Calbiochem, UK) and genistein (Calbiochem, UK) were prepared in dimethylsulfoxide (DMSO, Sigma, UK). After incubation at 37degreesC for 24 h, PCR-select cDNA subtractive hybridization, dot hybridization, DNA sequencing and Northern hybridization were examined. RESULTS: Smad6 gene was identified from the differentially expressed genes in K562 cells incubated with genistein which had been selected by PCR-select cDNA subtractive hybridization. The mRNA expression of Smad6 in K562 cells incubated with genistein was also higher than control group by Northern hybridization analysis. CONCLUSION: We have shown that Smad6 involved on the suppression of radiation-induced apoptosis by genistein in K562 leukemia cell line. It is plausible that the relationship between Smad6 and the suppression of radiation-induced apoptosis is essential for treatment development based on molecular targeting designed to modify radiation-induced apoptosis.

Circulating levels of interleukin-8 and vascular endothelial growth factor in patients with carotid stenosis

Interleukin (IL)-8 and vascular endothelial growth factor (VEGF) are important factors that induce the migration and proliferation of endothelial cells, increase the vascular permeability, and the modulate chemotaxis of monocytes. These molecules have been found in human atherosclerotic plaques. However, it is not clear whether the circulating levels of IL-8 and VEGF correlate with the extents of carotid stenosis. In this study, we investigated the relationship between circulating levels of IL-8 as well as VEGF and the extents of carotid stenosis. Sera from 41 patients with carotid stenosis were assessed for concentrations of IL-8 and VEGF by enzyme-linked immunosorbent assay. The degree of stenosis of extracranial carotid artery was calibrated by carotid B- mode ultrasonography. The serum concentration of IL-8 (r=-0.04733, p>0.05) was not correlated with the degree of stenosis. However, the serum concentration of VEGF (r=0.4974, p<0.01) was significantly correlated with the degree of carotid stenosis. These findings suggest that increased serum level of VEGF might be a marker for higher degree of stenosis of extracranial carotid artery.

Immunohistochemical Characterization on the Effect of Immunomodulating Factor (IMF) from Actinobacillus actinomycetemcomitans on Dendritic Cells, Lymphocytes and Macrophages in the Mouse Spleen / 대한해부학회지

This study was performed to investigate the effects of Immunomodulating factor (IMF), derived from Actinobacillus actinomycetemcomitans, on various immune cells in the mouse spleen. A single dose of IMF (10 microgram/kg) was administer-ed to BALB/c mice by intraperitoneal injection. After the mice were sacrificed in groups of five at 6 h and 24 h, the spleens were removed. The immunocytochemical characterization of the immune cells was carried out using the various monoclonal antibodies in cryostat-cut sections. We demonstrated in this study a strong stimulating effect of IMF on dendritic cells and B lymphocytes in the mouse spleen after IMF administration. The MOMA-1(+) immunoreactivity on the marginal metallophilic macrophages in the splenic marginal zone disappeared 6 h and reappeared 24 h after IMF treatment. However, various subpopulations of T lymphocytes, CD3(+), CD4(+), CD8(+), TCRalpha, beta(+) and Vbeta8(+) T cells in the mouse spleen did not show any significant change in their distributional pattern after IMF treatment. Dendritic cells were found to be increased in number in the periarterial lymphatitc sheath, and B lymphocytes were also increased in number in the lymphoid follicles of the spleen after IMF injection. In conclusion, IMF exhibited a potent stimulative effect on dendritic cells and B lymphocytes in vivo.

Activated platelets induce secretion of interleukin-1beta, monocyte chemotactic protein-1, and macrophage inflammatory protein-1alpha and surface expression of intercellular adhesion molecule-1 on cultured endothelial cells

Atherosclerosis is an inflammatory disease. Platelet-endothelium interaction plays an important role in the pathophysiology of atherogenesis. We investigated the role of activated platelets for secretion of interleukin (IL)-1beta, monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha and expression of intercellular adhesion molecule (ICAM)-1 on endothelial cells. Human umbilical vein endothelial cells (HUVEC) were incubated with non-stimulated or ADP-activated platelets for 6 hr. Secretion of interleukin (IL)-1beta, MCP-1 and MIP-1alpha and surface expression of ICAM-1 were measured by ELISA and flow cytometry. In the presence of activated platelets, the secretion of IL-1beta, MCP-1, and MIP-1alpha and surface expression of ICAM-1 were significantly increased compared with non-activated platelets. The present study shows that activated platelets may contribute to expression of various inflammatory mediators on endothelial cells.

Activated platelets induce secretion of interleukin-1beta, monocyte chemotactic protein-1, and macrophage inflammatory protein-1alpha and surface expression of intercellular adhesion molecule-1 on cultured endothelial cells

Atherosclerosis is an inflammatory disease. Platelet-endothelium interaction plays an important role in the pathophysiology of atherogenesis. We investigated the role of activated platelets for secretion of interleukin (IL)-1beta, monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha and expression of intercellular adhesion molecule (ICAM)-1 on endothelial cells. Human umbilical vein endothelial cells (HUVEC) were incubated with non-stimulated or ADP-activated platelets for 6 hr. Secretion of interleukin (IL)-1beta, MCP-1 and MIP-1alpha and surface expression of ICAM-1 were measured by ELISA and flow cytometry. In the presence of activated platelets, the secretion of IL-1beta, MCP-1, and MIP-1alpha and surface expression of ICAM-1 were significantly increased compared with non-activated platelets. The present study shows that activated platelets may contribute to expression of various inflammatory mediators on endothelial cells.

Apoptosis induction and associated factor of Staphylococcus aureus in J774A.1 mouse macrophage cell line

Staphylococcus aureus infections are often life-threatening. Relatively little is known about the host response to these infections, in particular, the implication of apoptosis induced by this microorganism. In this study, we have shown that S. aureus was cytotoxic to J774A.1 cell, a murine macrophage cell line. The cell death mediated by S. aureus occurred through apoptosis, as shown by increase in the proportion of fragmented host cell DNA. Although phagocytosis and NO production had important role in the induction of apoptosis, the contact between bacteria and host cells was not essential for this pathway. A certain bacterial product could also induce typical caspase-dependent apoptosis of J774A.1 cell. It is expected that new interpretation may be possible to host-parasite relationship based on these results.