A regulatory role of scavenger receptor class B type 1 in endocytosis and lipid droplet formation induced by liposomes containing phosphatidylethanolamine in HEK293T cells

We have recently reported that phosphatidylethanolamine (PE)-containing liposomes are endocytosed and then induce lipid droplets (LDs) in HEK293T cells. In this study, we elucidated a mechanism responsible for endocytosis of PE-containing liposomes and induction of LDs. By using fluorescence-labeled liposomes and flow cytometry, we found that PE-containing liposomes were very efficiently internalized in HEK293T cells. However, Block lipid transporter-1 (BLT-1) only marginally suppressed the uptake of these liposomes, indicating that entire liposomes were mostly taken up in these cells. They were therefore inferred to express abundant PE receptors responsible for endocytosis of PE-containing liposomes. We examined the expression of 52 candidate genes through transcriptomic analyses and eventually narrowed it down to four candidate genes, which were abundantly expressed in HEK293T cells. Among siRNAs targeting these candidates, scavenger receptor class B type 1 (SR-B1) siRNA showed the most profound reduction in PE liposomal uptake. Conversely, the expression of SR-B1 by transfection of an expression plasmid enhanced the uptake of PE-containing liposomes. After the internalization of PE-containing liposomes, they were colocalized with endosomes/lysosomes and SR-B1, which indicates that these liposomes are taken up in HEK293T cells at least partially through the endosomal/lysosomal pathway. A specific anti-SR-B1-antibody blocked the uptake of PE-containing liposomes in HEK293T cells while LD formation in these cells induced by PE-containing liposomes was suppressed by treatment with SR-B1 siRNA. These results demonstrate that SR-B1 functions as a receptor for the endocytosis of PE-containing liposomes and regulates the formation of LDs induced by PE-containing liposomes in HEK293T cells.

Synthesis and Physical Properties of π -Conjugated Polymers Containing Mesogenic Group

Novel side chain type liquid crystalline polymers, polythiophene and poly(aryleneethynylene) [PAE], containing a mesogenic group in the side chain were synthesized. Polythiophene derivatives were obtained by dehalogenative polycondensation with zero-valence nickel complex under mild condition. PAE type polymers were obtained by coupling dihalo aromatic compound with diethynyl aromatic compound. Their thermal properties were examined by differential scanning calorimetry, optical microscopy and X-ray diffractometry. All polymers exhibited a smectic or nematic mesophase depending upon the polymer backbone and pendant mesogenic group. Polythiophene derivatives exhibited electrochemical activity. Annealing polythiophene derivatives led to a lower oxidation potential and a higher conductivity. The degree of the orientation of the polymer backbone was supported by polarized UV-vis measurement. An effective conjugated length became longer by introducing thiophene rings into the polymer backbone. A high quantum yield of fluorescence was observed for PAE type polymers.

Endotoxin-induced lung injury in α-galactosylceramide-sensitized mice is caused by failure of interleukin-4 production in lung natural killer T cells

Administration of bacterial lipopolysaccharide (LPS) known as endotoxin into α-galactosylceramide (α-GalCer)-sensitized mice causes severe lung lesions but few hepatic lesions in lethal shock, and interferon (IFN)-γ is suggested to play a pivotal role in preparation of the lung lesions. In order to clarify the mechanism of how α-GalCer sensitization causes lung lesions exclusively in mice, we examined the differential responsiveness of lungs and livers to α-GalCer sensitization. Although lung and liver natural killer T (NK T) cells both produced IFN-γ in response to α-GalCer, IFN-γ signalling was triggered only in the lungs of α-GalCer-sensitized mice. Lung NK T cells did not produce interleukin (IL)-4 in response to α-GalCer and it did not induce the expression of suppressor of cytokine signalling 1 (SOCS1) in the lungs. Conversely, IL-4 produced by liver NK T cells led to the expression of SOCS1 in the livers of the mice. Neutralization of IL-4 reduced SOCS1 expression in the livers and exacerbated LPS-induced hepatic lesions. IL-10 was produced by liver NK T cells but not lung NK T cells. However, IL-10 was produced constitutively by alveolar epithelial cells in normal lung. Lung NK T cells and liver NK T cells might express CD8 and CD4, respectively. Based on the fact that IL-4 inhibited IFN-γ signalling in the livers of α-GalCer-sensitized mice via SOCS1 expression and signal transducer and activator of transcription 1 (STAT-1) activation, no inhibition of the IFN-γ signalling in the lungs caused LPS-induced lung lesions in α-GalCer-sensitized mice. The detailed mechanism of development of the lung lesions in α-GalCer-sensitized mice is discussed.

Metformin attenuates production of nitric oxide in response to lipopolysaccharide by inhibiting MyD88-independent pathway

Metformin is reported to ameliorate inflammation in diabetic patients. The effect of metformin on lipopolysaccharide-induced nitric oxide production was studied by using RAW 264.7 macrophage-like cells. The action of metformin was analyzed by dividing lipopolysaccharide signaling into the MyD88-dependent and -independent pathways. Metformin significantly reduced the expression of an inducible type of nitric oxide synthase and inhibited lipopolysaccharide-induced nitric oxide production. On the other hand, metformin did not inhibit lipopolysaccharide-induced tumor necrosis factor-alpha production. The expression levels of interferon-beta protein and mRNA, which is a key molecule in MyD88-independent pathway, were significantly inhibited by metformin. Compound C, a specific AMP-activated protein kinase inhibitor, did not affect the inhibitory action of metformin. Metformin was suggested to inhibit lipopolysaccharide-induced nitric oxide production via inhibition of interferon-beta production in MyD88-independent pathway. Metformin might exhibit an anti- inflammatory action on diabetic complications as well as the antidiabetic action.

Novel mechanism of U18666A-induced tumour necrosis factor-alpha production in RAW 264.7 macrophage cells

U18666A is a cholesterol transport-inhibiting agent that is used widely to mimic Niemann-Pick type C disease. The effect of U18666A on tumour necrosis factor (TNF)-alpha production in mouse macrophage cell line, RAW 264.7 cells and peritoneal macrophages was examined. U18666A induced TNF-alpha mRNA expression 48 h after the treatment, and TNF-alpha production 48 and 72 h after stimulation in RAW 264.7 cells. U18666A accumulated intracellular free cholesterol in the culture of normal medium but not cholesterol-free medium. U18666A also induced reactive oxygen species (ROS) generation in normal medium but much less in cholesterol-free medium. Anti-oxidant N-acetyl-L-cysteine (NAC) abolished U18666A-induced TNF-alpha production. U18666A led to the phosphorylation of p38 mitogen-activated protein kinase 24 and 48 h after the stimulation and the p38 activation was inhibited in presence of cholesterol-free medium or NAC. A p38 inhibitor reduced U18666A-induced TNF-alpha production. Taken together, U18666A was suggested to induce TNF-alpha production in RAW 264.7 cells via free cholesterol accumulation-mediated ROS generation.

The mechanism of development of acute lung injury in lethal endotoxic shock using alpha-galactosylceramide sensitization

The mechanism underlying acute lung injury in lethal endotoxic shock induced by administration of lipopolysaccharide (LPS) into alpha-galactosylceramide (alpha-GalCer)-sensitized mice was studied. Sensitization with alpha-GalCer resulted in the increase of natural killer T (NK T) cells and the production of interferon (IFN)-gamma in the lung. The IFN-gamma that was produced induced expression of adhesion molecules, especially vascular cell adhesion molecule-1 (VCAM-1), on vascular endothelial cells in the lung. Anti-IFN-gamma antibody inhibited significantly the VCAM-1 expression in alpha-GalCer-sensitized mice. Very late activating antigen-4-positive cells, as the counterpart of VCAM-1, accumulated in the lung. Anti-VCAM-1 antibody prevented LPS-mediated lethal shock in alpha-GalCer-sensitized mice. The administration of LPS into alpha-GalCer-sensitized mice caused local production of excessive proinflammatory mediators, such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and nitric oxide. LPS caused microvascular leakage of proteins and cells into bronchoalveolar lavage fluid. Taken together, sensitization with alpha-GalCer was suggested to induce the expression of VCAM-1 via IFN-gamma produced by NK T cells and recruit a number of inflammatory cells into the lung. Further, LPS was suggested to lead to the production of excessive proinflammatory mediators, the elevation of pulmonary permeability and cell death. The putative mechanism of acute lung injury in LPS-mediated lethal shock using alpha-GalCer sensitization is discussed.

Lipopolysaccharide augments the in vivo lethal action of doxorubicin against mice via hepatic damage

The effect of lipopolysaccharide (LPS) on the in vivo lethal action of doxorubicin (DOX) against mice was studied. DOX killed LPS-pretreated mice much earlier than untreated mice, and exhibited a stronger toxic action against LPS-pretreated mice. DOX-induced lethality in LPS-pretreated mice was due to severe hepatic damage, but there were no significant lesions in the heart, kidney and lung. Hepatic lesions were accompanied by caspase 3-positive cells and fragmented DNA-positive cells, suggesting the involvement of apoptosis. DOX induced the production of a high level of interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha in LPS-pretreated mice, but not in non-treated mice. The DOX-induced lethality was prevented significantly by anti-IFN-gamma antibody, but not anti-TNF-alpha antibody. Administration of recombinant IFN-gamma in place of LPS augmented definitively the DOX-induced lethality. LPS augmented the DOX-induced lethality in TNF-alpha-deficient mice. Taken together, LPS was suggested to enhance DOX-induced IFN-gamma production and augment the in vivo lethal action via hepatic damage.

Lipopolysaccharide and interferon-gamma enhance Fas-mediated cell death in mouse vascular endothelial cells via augmentation of Fas expression

The effect of interferon (IFN)-gamma and/or lipopolysaccharide (LPS) on Fas-mediated cell death with anti-Fas agonistic antibody in vascular endothelial cells was examined using a mouse END-D cell line. Anti-Fas agonistic antibody exhibited cytotoxic actions on END-D cells. Fas-mediated cell death was enhanced by LPS or IFN-gamma. The combination of IFN-gamma and LPS significantly enhanced cell death compared to IFN-gamma or LPS alone. IFN-gamma and LPS augmented cell surface expression of Fas, but not tumour necrosis factor (TNF) receptor 1. Inhibitors of p38 mitogen-activated protein kinase (MAPK) prevented augmentation of Fas expression in IFN-gamma and LPS-treated END-D cells. IFN-gamma and LPS-treated END-D cells did not become susceptible to TNF-alpha or nitric oxide-mediated cytotoxicity. IFN-gamma and LPS thus appear to augment selectively Fas expression via activation of p38 MAPK and enhance Fas-mediated cell death in END-D cells. Furthermore, administration of IFN-gamma and LPS into mice induced in vivo expression of Fas on vascular endothelial cells and Fas ligand (FasL) on peripheral blood leucocytes. The relationship between enhancement of Fas-mediated cell death by IFN-gamma and LPS and the development of vascular endothelial injury is discussed.

Effect of weight loss using formula diet on renal function in obese patients with diabetic nephropathy

OBJECTIVE

To evaluate the effect and safety of treatment with low-calorie formula diet on renal function and proteinuria in obese patients with diabetic nephropathy.

DESIGN

Prospective study on safety and efficacy of a 4-week low-calorie (11-19 kcal/kg/day) normal-protein (0.9-1.2 g/kg/day) diet partly supplemented with formula diet.

SUBJECTS

In all, 22 obese patients with diabetic nephropathy (BMI: 30.4+/-5.3 kg/m(2), HbA1c: 7.1+/-1.4%, serum creatinine: 172.4+/-57.5 micromol/l, urinary protein: 3.3+/-2.6 g/day).

RESULTS

The mean body weight decreased by 6.2+/-3.0 kg. The mean systolic blood pressure, creatinine, blood urea nitrogen, urinary protein, and 8-hydroxydeoxyguanosine decreased significantly by 7.5+/-12.7 mmHg, 41.6+/-23.9 micromol/l, 1.50+/-1.61 mmol/l, 1.8+/-1.7 g/day, and 3.1+/-3.6 ng/mg creatinine, respectively. No patient had increased serum creatinine and urinary protein. Mean creatinine clearance (40.6+/-17.9 to 46.1+/-14.6 ml/s/1.73 m(2)) and serum albumin showed no significant changes. Delta serum creatinine and Delta urinary protein correlated with Delta body weight (r=0.62 and 0.49, respectively) and Delta visceral fat area (r=0.58 and 0.58, respectively), but did not correlate with Delta systolic blood pressure, Delta fasting blood glucose and Delta subcutaneous fat area.

CONCLUSION

These results suggested that weight reduction using formula diet might improve renal function and proteinuria safely for a short term in obese patients with diabetic nephropathy.

Thoracoscopic enucleation of esophageal stromal tumor

Gastrointestinal stromal tumor is a rare entity, especially in the esophagus. We report a patient with a stromal tumor of the esophagus who underwent a thoracoscopic enucleation of the tumor. The patient was a 61-year-old man complaining of slight dysphagia. A submucosal tumor of the middle thoracic esophagus was found endoscopically. The tumor was approximately 4.0 cm in diameter measured by endoscopic ultrasonography. On 17 May 2001, thoracoscopic enucleation of the esophageal tumor was performed using a Kodama Di-suction. The Kodama Di-suction was useful for the thoracoscopic enucleation of the submucosal tumor of the esophagus, acting as both a dissector and a sucker. The patient's course was uneventful after surgery. Histopathologically the esophageal tumor revealed a high cellularity, consisting of spindle cells, and the tumor cells were immunohistochemically positive for CD34 and c-kit protein, but not for a-smooth muscle actin or S-100 protein. From these findings, the esophageal submucosal tumor was diagnosed as gastrointestinal stromal tumor, distinguished from leiomyoma.

Food residue at endoscopy in patients who have previously undergone distal gastrectomy: risk factors and patient preparation

BACKGROUND AND STUDY AIMS

Food residue is often seen in the gastric remnant after partial gastrectomy, making it difficult to diagnose early cancer in the residual stomach. The aims of this study were to clarify the risk factors for the accumulation of food residue, and to study methods of preparation for endoscopy in patients who had undergone distal gastrectomy.

PATIENTS AND METHODS

374 endoscopic examinations of patients who had undergone distal gastrectomy for gastric cancer were compared with 2168 endoscopic examinations in patients without a history of gastrectomy. Relationships between the presence of food residue and a number of clinical factors, including patient preparation, were evaluated by univariate and multivariate analyses.

RESULTS

Food residue in the gastric remnant was observed in 70 examinations (18.7 %), a significantly higher proportion than that found in control patients (0.3 %). From multivariate analysis, underlying diseases (endocrine, metabolic, or connective tissue disease), Billroth type I reconstruction, and postoperative gastric retention were found to be independent risk factors for the accumulation of food residue. Diet preparation (a liquid diet plus aclatonium napadisilate) significantly decreased the incidence of food residue.

CONCLUSIONS

Our diet preparation method can be recommended as a preparation for upper gastrointestinal endoscopy in patients who have undergone distal gastrectomy, especially in patients with additional risk factors.

Expression of basic fibroblast growth factor and its receptor-1 in cardiac myxoma

BACKGROUND

To clarify the significance of basic fibroblast growth factor (bFGF) in angiogenesis or proliferative activity in cardiac myxoma, the expression of bFGF and its receptor (FGFR-1) were immunohistochemically examined.

METHODS

Formalin-embedded tissues of cardiac myxomas were obtained by surgical resection from 15 patients and analyzed by immunostaining of bFGF and FGFR-1. The microvessel density was measured in the 15 myxomas using platelet derived endothelial cell adhesion molecule-1. For evaluation of proliferative activity of the cardiac myxomas, proliferating cell nuclear antigen (PCNA) immunostaining was performed, and the PCNA labeling index was measured in each section.

RESULTS

bFGF and FGFR-1 were observed in 73.3% and 67.7% of the myxomas, respectively. There was a close correlation between the expression of bFGF and FGFR-1. This co-expression was frequently observed in the myxoma cells around the microvessels appearing as a ring structure. Regarding possible relationships between the expression of bFGF or FGFR-1 and the clinicopathologic features, there were no parameters excluding the macroscopic type of myxoma. The microvessel density in the myxomas with bFGF or FGFR-1 expression was higher than that in myxomas without it. The PCNA labeling index in myxomas with bFGF expression was higher than that in myxomas without it, and the PCNA labeling index tended to be higher in myxomas with FGFR-1 expression than that in myxomas without it.

CONCLUSIONS

bFGF and/or FGFR-1 was expressed in some of cardiac myxoma, and may be an important role for tumor angiogenesis and proliferative activity.

Regulation of circulating immune complexes by complement receptor type 1 on erythrocytes in chronic viral liver diseases

BACKGROUND AND AIM

Complement receptor type 1 (CR1) is a transmembrane protein, and human erythrocyte CR1 (E-CR1) is involved in the transport of circulating immune complexes (IC) from the circulation to the reticuloendothelial system, including the liver and spleen. In chronic viral hepatitis, increased levels of IC containing viral particles and an association with various extrahepatic manifestations have been reported. However, regulatory mechanisms for IC levels are not fully understood. PATIENTS/SUBJECTS AND METHODS: We analysed IC, E-CR1, and quantitative polymorphism of the CR1 gene in 149 patients with chronic viral liver diseases and in 64 normal blood donors using an enzyme linked immunosorbent assay, radioimmunoassay, and polymerase chain reaction-restriction fragment length polymorphism, respectively. We also analysed the effect of CR1 gene polymorphism on IC binding to E-CR1 using molecular methods.

RESULTS

E-CR1 levels in patients with chronic hepatitis and chronic viral liver diseases as a whole correlated inversely with increased levels of IC. Moreover, significantly high levels of IC were observed in patients with chronic hepatitis C (CH-C) who were homozygous for the E-CR1 low density allele. We also found low levels of E-CR1 in liver cirrhosis and CH-C but not in CH-B. Low levels of E-CR1 in CH-C were observed, even after considering the polymorphism of the CR1 gene. Finally, we demonstrated CR1 gene polymorphism dependent binding of hepatitis virus containing IC.

CONCLUSIONS

Our results emphasise the important role of E-CR1 in clearance of IC from the circulation and the acquired, rather than inherited, decrease in E-CR1 in chronic viral liver diseases, especially of type C.

Differences and relationships of thymidine phosphorylase expression in tumor-associated macrophages and cancer cells in squamous cell carcinoma of the esophagus

Thymidine phosphorylase (TP), which has been shown to be identical to platelet-derived endothelial cell growth factor, is expressed in tumor-associated macrophages (TAMs) as well as cancer cells. The aim of this study was to clarify the differences or relationships of TP expression in TAMs and cancer cells in esophageal squamous cell carcinoma (SCC). Tissues samples were taken from 56 patients with esophageal SCC after curative surgery. The expression of TP in TAMs or SCC cells was examined using a monoclonal antibody to TP (clone 654-1). Microvessels in SCC that stained positively for Factor VIII-related antigen were counted (microvessel density, MVD). Macrophages in SCC that stained positively for CD68 antigen were counted (monocytic count). Ki-67 antigen was immunostained with MIB-1, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling was performed, and Ki-67 labeling index (LI) and apoptotic index were calculated. The expression of TP in stromal cells and cancer cells was observed in 43 (76.8%) and 33 patients (58.9%), respectively. There were significant correlations between TP expression in stromal cells (TAMs) as well as in cancer cells and venous invasion, distant metastasis, or MVD. There was a correlation between TP expression in cancer cells and lymph node metastasis, and there were correlations between TP expression in TAMs and monocytic count or Ki-67 LI; however, there was no correlation between TP expression in TAMs and lymph node metastasis. On the other hand, in SCCs with TP expression in both TAMs and cancer cells, higher frequencies of venous invasion and distant metastasis, higher MVD and lower apoptotic index were observed than in other SCCs. The 5-year survival rate in patients with TP expression in both TAMs and cancer cells was poorer than that in patients with TP expression in neither TAMs and cancer cell. In conclusion, these results suggest that co-expression of TP in TAMs and cancer cells is strongly associated with angiogenic promotion and distant metastasis. However, other effects of TP, such as promotion of tumor growth and lymph node metastasis, may be different depending on whether these are expressed in TAMs or cancer cells in esophageal SCCs. Patients with coexpression of TP in TAMs and cancer cells may be associated with a poor prognosis.

Protective effect of wogonin on endotoxin-induced lethal shock in D-galactosamine-sensitized mice

The effects of wogonin, a major flavonoid from Scutellaria baicalensis Georgi, on lipopolysaccharide (LPS)-induced lethal shock in mice was investigated. Wogonin pretreatment prevented the lethal shock in mice injected with D-galactosamine (D-GalN) and LPS, but not in mice injected with a high dose of LPS. Wogonin definitely inhibited the hepatic injury in mice injected with D-GalN, and LPS and reduced the level of circulating tumor necrosis factor (TNF)-alpha. The reduction was more marked in mice injected with D-GalN and LPS compared with that in mice injected with a high dose of LPS. Wogonin pretreatment did not inhibit the lipid peroxidation in mice receiving either D-GalN and LPS or a high dose of LPS. Wogonin inhibited the in vitro production of TNF-alpha and nitric oxide in LPS-stimulated RAW 264.7 cells. The mechanism of the protective effect of wogonin on the lethal shock in mice injected with D-GalN and LPS is discussed.

A case of hyperplastic polyposis of the colon with adenocarcinomas in hyperplastic polyps after long-term follow-up

A 66-year-old woman had been receiving follow-up since 1990 for hyperplastic polyposis, which remained unchanged endoscopically and radiologically. In 1999, a small (28 x 22 mm) superficial adenocarcinoma was detected in the ascending colon. Histologically, this was a hyperplastic polyp containing a well-differentiated adenocarcinoma invading into the submucosa. A review of the English and Japanese literature identified 32 cases of "hyperplastic polyposis." In about half of the 32 cases, an adenocarcinoma was also found amongst the hyperplastic polyps. Half of the adenocarcinomas were located in the right colon. Although hyperplastic polyposis is uncommon, it warrants regular surveillance, as it appears to be associated with an increased risk of colorectal cancer.

Can sedation reduce the cardiac stress during gastrointestinal endoscopy? A study with non-invasive automated cardiac flow measurement by color Doppler echocardiography

BACKGROUND

Upper gastrointestinal endoscopy (UGIE) may cause some cardiac stress. The effect of sedation on hemodynamics during UGIE has not been fully studied, and therefore the aim of this study was to clarify whether or not sedation can reduce cardiac stress dufing UGIE.

METHODS

Eight normal male volunteers undergoing UGIE with sedation (0.1 mg/kg of midazolam) and without it (two endoscopies per volunteer in random order) were monitored throughout the procedure by means of electrocardiogram, blood pressure and peripheral oxygen saturation (SpO2). Cardiac output was measured at six points before, during and after endoscopy from automated cardiac flow measurement by color Doppler echocardiography. Serum norepinephrine, epinephrine, dopamine and ACTH concentrations were measured before and after the examination.

RESULTS

No significant differences in heart rate, systolic blood pressure, rate-pressure product, cardiac output and left ventricular work index were observed between the sedated and non-sedated groups. SpO2 hardly changed during endoscopy in the non-sedated group, but decreased slightly in the sedated group (P = 0.075). Although all serum catecholamine concentration changes were within normal limits in both groups, after endoscopy only epinephrine concentration was significantly lower in the sedated group than in the non-sedated group (P = 0.0027).

CONCLUSIONS

Conscious sedation with midazolam does not reduce the cardiac stress during UGIE.

The inhibitory action of quercetin on lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophage cells

The effect of quercetin on lipopolysaccharide (LPS)-induced nitric oxide (NO) production was studied. Quercetin pretreatment significantly inhibited NO production in an LPS-stimulated RAW 264.7 murine macrophage cell line. Post-treatment with quercetin partially inhibited NO production. The inhibitory action of quercetin was due to neither the cytotoxic action nor altered LPS binding. The expression of inducible-type NO synthase (iNOS) was markedly down-regulated by quercetin. Quercetin suppressed the release of free nuclear factor (NF)-kappaB by preventing degradation of IkappaB-alpha and IkappaB-beta. Moreover, quercetin blocked the phosphorylation of extracellular signal regulated kinase 1/2 (Erk 1/2), p38, and c-Jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) and, further, the activity of tyrosine kinases in LPS-stimulated RAW cells. Quercetin also inhibited interferon (IFN)-gamma-induced NO production. Taken together, these results indicate that the inhibitory action of quercetin on NO production in LPS- and/or IFN-gamma-stimulated macrophages might be due to abrogation of iNOS protein induction by impairment of a series of intracellular signal pathways.

Flavonoids protect mice from two types of lethal shock induced by endotoxin

The protective effect of flavonoids on two types of lethal endotoxic shock was studied. A lethal endotoxic shock was induced by administration of lipopolysaccharide (LPS) into D-galactosamine (D-GalN)-sensitized mice and another one was done by administration of a high dose of LPS into normal mice. Pretreatment with a series of flavonoids protected mice from two types of endotoxin lethality. Flavonoid pretreatment reduced the serum tumor necrosis factor-alpha (TNF-alpha) level in mice injected with D-GalN and LPS, but not in mice injected with a high dose of LPS. TNF-alpha-induced lethal shock in D-GalN-sensitized mice was also protected by pretreatment with flavonoids, suggesting that flavonoids augmented the resistance to TNF-alpha lethality. On the other hand, flavonoids reduced the plasma level of lipid peroxides in mice injected with a high dose of LPS, but not in D-GalN-sensitized mice. Taken together, these results indicated that flavonoids might protect mice from two types of endotoxin lethality. The protective mechanism of flavonoids in each endotoxin lethality is discussed.

Coexpression of vascular endothelial growth factor and p53 protein in squamous cell carcinoma of the esophagus

OBJECTIVE

p53 plays a role in tumor angiogenesis, and vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The aim of the present study was to clarify how expression of p53 protein participates in angiogenesis, and whether the coexpression of VEGF and p53 protein has a significance for angiogenesis and the clinicopathological features in esophageal squamous cell carcinoma (SCC).

METHODS

Tissues samples were taken from 60 patients with esophageal SCC after surgery. The expression of VEGF and p53 protein in these SCC was examined immunohistochemically. Microvessel density (MVD) was determined by counting microvessels in tumor sections stained for Factor VIII-related antigen. Ki-67 labeling index (LI) was calculated, based on Ki-67 antigen immunostaining, as a proliferative marker. Apoptotic index (AI) was calculated, based on the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling, to evaluate apoptosis.

RESULTS

VEGF expression was observed in 58.3%, and p53 protein expression was observed in 61.7% of the 60 patients. VEGF and p53 protein were significantly coexpressed in 26 (43.4%). Histological venous invasion (p < 0.01) and distant metastasis (p < 0.05) were significantly correlated with p53 protein expression. The two parameters were more frequently observed in the SCC with VEGF/p53 coexpression than in those without the coexpression. The MVD and Ki-67 LI were significantly higher (p < 0.01 and p < 0.001), and the AI was significantly lower (p < 0.001) in the SCC with p53 protein expression than in the SCC without it. The MVD and Ki-67 LI were higher, and the AI was lower in the SCC with VEGF/p53 coexpression than in those without the coexpression. The 5-yr survival rate in patients with the coexpression was poorer than in the other patients.

CONCLUSION

These results suggest that mutant p53 expression is associated with angiogenesis and distant metastasis in esophageal SCC, and that the coexpression of p53 and VEGF may play an important role in angiogenesis, and have important clinical significance.

Hepatic resection for large hepatocellular carcinoma

BACKGROUND

Long-term survival and prognostic factors after hepatic resection for large hepatocellular carcinoma (HCC) remain to be proved.

METHODS

The surgical outcome in 133 consecutive patients with HCC in diameter of > or = 5 cm (large HCC; L group) undergoing hepatic resection was retrospectively clarified and compared with that of 253 patients with HCC in diameter of < 5 cm (small HCC; S group). Postresection prognostic factors were evaluated by univariate and multivariate analysis using Cox's proportional hazards model.

RESULTS

The disease-free 3- and 5-year survival rates between L group and S group were 26% versus 42% and 20% versus 25%, respectively (P = 0.0032). The overall 3- and 5-year survival rates between L group and S group were 38% versus 67% and 28% versus 47%, respectively (P < 0.0001). Multivariate analysis revealed that large amount of intraoperative blood transfusion was an independently significant factor of poor disease-free and overall survivals.

CONCLUSIONS

Long-term survival in patients with large HCC remains unsatisfactory compared with that in patients with non-large HCC. Restriction of intraoperative blood transfusion may play an important role in the improvement of survival and recurrence in such patients.

Prognostic factors after hepatic resection for hepatocellular carcinoma with hepatitis C viral infection: univariate and multivariate analysis

OBJECTIVES

Although the incidence of hepatocellular carcinoma (HCC) with hepatitis C virus (HCV) infection is higher than in patients with hepatitis B virus (HBV)-related HCC in Japan, the long-term prognosis and prognostic factors of HCV-related HCC after hepatic resection are poorly understood.

METHODS

The surgical outcome of HCV-related HCC in 172 consecutive patients who underwent hepatic resection between 1989 and 1997 was retrospectively clarified. Postresection prognostic factors were evaluated by univariate and multivariate analysis using Cox's proportional hazards model.

RESULTS

The overall incidence of postoperative complications was 23.2%, and 11 patients among that group had hospital deaths (6.4%) including 9 (5.2%) operative deaths. The mean and median overall survivals including hospital death after surgery were 41 months and 33 months, respectively. The 3-, 5-, and 7-yr overall survival rates after hepatic resection were 63%, 52%, and 47%, respectively. The 3-, 5-, and 7-yr disease-free survival rates after hepatic resection were 33%, 20%, and 15%, respectively. Multivariate analysis revealed that serum alpha-fetoprotein (AFP) of > or = 1000 ng/ml and the presence of vascular invasion were independent unfavorable prognostic factors affecting overall survival and that AFP of > or = 1000 ng/ml was an independently significant factor of poor disease-free survival.

CONCLUSIONS

We found the postresection survival of patients with HCV-related HCC should be stratified by the high value of AFP and the presence of vascular invasion. AFP may be the most powerful predictor of the long-term prognosis and recurrence in such patients.

A squamous cell carcinoma of the gastric cardia showing submucosal progression

We report a case of squamous cell carcinoma (SCC) of the gastric cardia showing submucosal progression with direct invasion of the liver. A 71-year-old man was admitted with dysphagia. Esophagogastroscopy showed a protruding tumor covered with normal gastric mucosa in the anterior wall of the gastric cardia, although no abnormal findings were detected in the esophagus, including the esophagogastric junction. Serum SCC-related antigen level was elevated (6.6 ng/ml; normal level, less than 2.5 ng/ml). Endoscopic biopsy specimens taken from this tumor did not show malignant cells. Based on these findings, the preoperative diagnosis was a submucosal tumor of the stomach. Laparotomy was done; however, the tumor was not resected because it had direct invasion to the left lateral segment of the liver and adjacent tissues. As the tumor showed continuous bleeding from the stomach after surgery, total gastrectomy, combined with transhiatal lower esophagectomy, left lateral segmentectomy of the liver, splenectomy, and distal pancreatectomy was performed. Because histologic findings showed poorly or moderately differentiated SCC with direct invasion of the liver, the final diagnosis was SCC of the gastric cardia showing submucosal progression with hepatic invasion. Such a case of SCC of the gastric cardia showing submucosal progression is rare, and accurate preoperative diagnosis was very difficult. However, it may be important to consider SCC of the gastric cardia in such a situation.

Expression of Nov, CYR61 and CTGF genes in human hepatocellular carcinoma

CCN family genes, Nov, CYR61 and CTGF, are immediate-early genes expressed in fibroblasts following growth stimuli. Aberrant expression of Nov has been found in human Wilms' tumor, and suggested to be involved in tumorigenesis. The aim of our experiments is to examine the expression of CCN family genes in human hepatocellular carcinomas (HCCs) and find the correlation of these gene expressions with clinicopathological parameters. A pair of tumor and surrounding non-tumor tissues were obtained from 23 patients with HCC and six with metastatic liver tumor. Total cellular RNA isolated from tissues was analyzed for the presence of mRNA of CCN family genes by the reverse-transcription polymerase chain reaction. Nov, CYR61 and CTGF mRNA were identified in 17 (73.9%), 17 (73.9%), six (26.1%) tumors, and in nine (39.1%), 16 (69.6%), one (4.3%) surrounding non-tumor tissues of 23 patients with HCC. No significant difference was found in clinicopathological parameters between cases with HCC negative and positive for these gene expressions. The prevalence of Nov and CTGF expression in HCC is significantly higher than those in surrounding non-tumor. The same tendency was found in metastatic tumors. These results suggest that Nov and CTGF is associated with the development of tumors in the liver.

Inhibition of caspase 3 abrogates lipopolysaccharide-induced nitric oxide production by preventing activation of NF-kappaB and c-Jun NH2-terminal kinase/stress-activated protein kinase in RAW 264.7 murine macrophage cells

The effect of caspase inhibitors on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 267.4 murine macrophage cells was investigated. Pretreatment of RAW cells with a broad caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK), resulted in a striking reduction in LPS-induced NO production. Z-VAD-FMK inhibited LPS-induced NF-kappaB activation. Furthermore, it blocked phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) but not that of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinases. Similarly, a caspase 3-specific inhibitor, Z-Asp-Glu-Val-Asp-fluoromethylketone, inhibited NO production, NF-kappaB activation, and JNK/SAPK phosphorylation in LPS-stimulated RAW cells. The attenuated NO production was due to inhibition of the expression of an inducible-type NO synthase (iNOS). The overexpression of the dominant negative mutant of JNK/SAPK and the addition of a JNK/SAPK inhibitor blocked iNOS expression but did not block LPS-induced caspase 3 activation. It was therefore suggested that the inhibition of caspase 3 might abrogate LPS-induced NO production by preventing the activation of NF-kappaB and JNK/SAPK. The caspase family, especially caspase 3, is likely to play an important role in the signal transduction for iNOS-mediated NO production in LPS-stimulated mouse macrophages.

Cavernous hemangioma of the liver with giant cyst formation: degeneration by apoptosis?

Cavernous hemangioma of the liver with cyst formation is a very rare condition. A case of cavernous hemangioma of the liver with unilocular giant cyst formation undergoing surgical removal is reported. Notably, the patient also had Budd-Chiari syndrome with an obstructing lesion in the inferior vena cava. The cystic degeneration of the hemangioma implied a relationship with apoptosis. This is the first reported case of Budd-Chiari syndrome caused by advanced cystic degeneration of hepatic cavernous hemangioma.

Co-occurrence of mucoepidermoid carcinoma and squamous cell carcinoma of the esophagus: report of a case

A case of co-occurrence of a mucoepidermoid carcinoma (MEC) and a squamous cell carcinoma (SCC) in the esophagus is described. The present patient was a 61-year-old man who underwent a curative esophagectomy with a regional lymph node dissection for a MEC in the lower esophagus and a SCC near the esophagogastric junction. The two lesions were endoscopically and histologically divided by a normal esophageal mucosa. The MEC of the esophagus consisted of SCC cells and signet-ring cells, and a mucin product and carcinoembryonic antigen, which were found at high levels in the blood serum before surgery, were detected histochemically in the signet-ring cells. The follow-up survey of the patients with esophageal MEC previously reported in Japan showed that most of the patients died of either local recurrence or widespread metastasis after treatment; the overall 5-year survival rate was 24.4% in the total 25 cases, and 27.7% in the 22 resected cases. However, 6 patients who died of therapeutic complications were included among these patients; furthermore, the 5-year survival rate after surgery was 29.2% in the patients treated over the last decade (1989-1998). We expect that the clinical outcome of patients treated for esophageal MEC will therefore improve in the future.

The inhibitory action of sodium arsenite on lipopolysaccharide-induced nitric oxide production in RAW 267.4 macrophage cells: a role of Raf-1 in lipopolysaccharide signaling

The effect of sodium arsenite (SA) on LPS-induced NO production in RAW 267.4 murine macrophage cells was studied. SA pretreatment of LPS-stimulated RAW cells resulted in a striking reduction in NO production. No significant difference in LPS binding was observed between RAW cells pretreated with SA and control untreated RAW cells, suggesting that SA might impair the intracellular signal pathway for NO production. SA inhibited LPS-induced NF-kappaB activation by preventing loss of IkappaB-alpha and -beta. Furthermore, SA blocked phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2), but not phosphorylation of p38 and c-Jun N-terminal kinase. SA treatment resulted in the disappearance of Raf-1, suggesting that it might cause the inhibition of the Erk1/2 mitogen-activated protein (MAP) kinase pathway. The SA-mediated loss of Raf-1 also abolished LPS-induced NF-kappaB activation as well as the Erk1/2 pathway. The dominant negative mutant of MAP kinase kinase 1 inhibited both NO production and NF-kappaB activation in LPS-stimulated RAW cells. Taken together, these results indicate that the inhibitory action of SA on NO production in LPS-stimulated macrophages might be due to abrogation of inducible NO synthase induction, and it might be closely related to inactivation of the NF-kappaB and Erk1/2 MAP kinase pathways through loss of Raf-1.

Ulcer in the gastric tube for esophageal replacement: a comparison of 12 esophageal cancer patients with or without postoperative radiotherapy

BACKGROUND AND AIMS

Ulcer in the gastric tube for esophageal replacement, which was caused by peptic factors or postoperative radiotherapy (Rx), are occasionally reported. The aim of this study was to clarify the clinicopathologic features of the ulcers in the gastric tube.

METHODS

In 62 patients with a reconstructed gastric tube, after esophagectomy for esophageal cancer, esophagogastroduodenoscopy was performed. Ulcers of the gastric tube were detected in 12 patients: six with postoperative Rx and six without Rx. The 12 patients with gastric tube ulcers (GU-group) were reviewed and compared to the remaining 50 patients without ulcers of the gastric tube (Control-group). Clinicopathologic features of gastric tube ulcers were compared between the patients with and without Rx.

RESULTS

There was no difference in any parameter between the patients of the GU- and Control-groups. Comparing the patients of the GU-group with and without Rx, the ulcers of the gastric tube in the patients without Rx were frequently located in the lower part of the gastric tube (P = 0.067), detected in a later period after surgery (P = 0.055), associated with cervical esophagitis (P = 0.03), and less associated with gastritis (P = 0.03). In three patients of the GU-group without Rx, Helicobacter pylori was detected in the gastric tube. Two of the three patients had a history of peptic ulcers before surgery, and had recurrence of the gastric tube ulcers.

CONCLUSIONS

Gastric tube ulcers without postoperative Rx may have different characteristics compared to those induced by Rx.

Production of experimental autoimmune sialadenitis in mice immunized with homologous salivary gland extract and Klebsiella O3 lipopolysaccharide

An experimental murine model for autoimmune sialadenitis was produced by repeated immunization of homologous salivary gland extract together with Klebsiella O3 lipopolysaccharides as an immunological adjuvant. The cell infiltration was observed in the salivary glands of mice immunized more than twice. Inflammatory cells consisting mainly of CD4+ T cells and CD8+ T cells accumulated at the perivascular regions. There was hyperplasia and enlargement of ductal epithelial cells in the secretory acinar units in salivary glands of repeatedly immunized mice. The repeated immunization developed delayed-type hypersensitivity and autoantibody production to the homologous salivary gland extract. The immunohistochemical analysis showed positive staining on the cuboidal cells in the intercalated ducts, and the columnar pseudostratified cells in the striated ducts. Organ-specific antigens with molecular weights ranging from 20 to 90 kDa were recognized by the sera from immunized mice. Therefore, it was suggested that the sialadenitis was produced by the autoimmune mechanism and might be a new experimental model for characterization of the pathogenesis of autoimmune sialadenitis.

Inhibition of p38 mitogen-activated protein kinase augments lipopolysaccharide-induced cell proliferation in CD14-expressing Chinese hamster ovary cells

CD14-expressing Chinese hamster ovary (CD14-CHO) cells, established by transfection of human CD14 DNA, acquired high responsiveness to lipopolysaccharide (LPS) through membrane-bound CD14 expression. LPS induced DNA synthesis and activated a series of mitogen-activated protein (MAP) kinases, extracellular signal-regulated kinase 1/2 (Erk1/2), p38, and c-Jun N-terminal kinase/stress-activated protein kinase, in CD14-CHO cells but not in mock-transfected CHO cells. Anti-CD14 antibody completely abrogated both LPS-induced DNA synthesis and LPS-induced phosphorylation of those MAP kinases, suggesting a critical role of membrane-bound CD14 in LPS signaling. A p38 MAP kinase inhibitor, SB203580, markedly augmented LPS-induced DNA synthesis in CD14-CHO cells, whereas an Erk1/2 inhibitor, PD98059, had no affect. On the other hand, SB203580 exhibited no effect on epidermal growth factor-induced DNA synthesis in CD14-CHO cells, although PD98059 inhibited it significantly. The activation and inactivation of p38 MAP kinase with dominant negative and dominant positive mutants also suggested the participation of p38 MAP kinase in LPS-induced DNA synthesis. It was therefore suggested that the activation of p38 MAP kinase can negatively regulate LPS-induced cell proliferation in CD14-CHO cells.

The expression of membrane-bound CD14 renders mouse B-1 cells susceptible to LPS

The surface expression of CD14 on mouse B-1 cells and its role on their response to lipopolysaccharide (LPS) were studied by using the murine TH2.52 B-1 cell line and peritoneal B-1 cells. TH2.52 cells with the B-1 phenotype were found to express membrane-bound CD14. Furthermore, CD14 was expressed on physiological peritoneal CD5+ B-1 cells. The stimulation of CD14-expressing TH2.52 cells with a low concentration of LPS resulted in the activation of nuclear factor (NF)-B and a mitogen-activated protein kinase (MAPK). The LPS-induced NF-B and MAPK activation was markedly inhibited by anti-CD14 antibody. These results suggest that B-1 cells may respond to LPS via membrane-bound CD14.

Portal vein thrombosis associated with hilar bile duct carcinoma and liver abscess

As most portal vein occlusion in hilar bile duct carcinoma is caused by tumor invasion to the portal vein, other mechanisms of its occlusion are very rare. We report the case of a 69-year-old man who underwent surgical resection for an advanced hilar bile duct carcinoma associated with unusual portal vein occlusion. Preoperative diagnosis was advanced hilar bile duct carcinoma with liver abscess and right portal vein occlusion due to tumor invasion. Extended right hepatectomy combined with resection of caudate lobe was performed. Intraoperatively, tumor invasion to the portal vein was not evident and resected margin of the right portal vein showed thrombosis and no evidence of malignancy histologically. To our knowledge, this is the first reported case of a patient with a combination of portal vein thrombosis and liver abscess in hilar bile duct carcinoma. Although portal vein occlusion due to thrombosis is an unusual complication in hilar bile duct carcinoma, the presence of liver abscess may be a useful diagnostic implication of this occlusion.

Hepatic resection for hepatocellular carcinoma in the elderly

BACKGROUND

Although the number of elderly people undergoing surgery for hepatocellular carcinoma (HCC) has increased because of the prolonged life expectancy rate, potential benefits of hepatectomy for elderly patients with HCC have not been fully delineated.

STUDY DESIGN

Using medical records, surgical outcomes of HCC in 103 patients 70 years of age or older undergoing hepatic resection (older group) were clarified and compared with those of 283 patients younger than 70 years of age (younger group) in this retrospective study. Postresection prognostic factors were evaluated by multivariate analysis using Cox's proportional hazards model.

RESULTS

There were no significant differences in postoperative complication, operative mortality, and overall hospital death rates between the two groups. Overall 3- and 5-year survival rates for the older group and the younger group were 51.0% versus 55.2%, and 42.2% versus 40.0%, respectively (p = 0.95). Disease-free 3- and 5-year survival rates for the older group and the younger group were 35.2% versus 37.6%, and 16.6% versus 24.2%, respectively (p = 0.66). Multivariate analysis revealed that the presence of liver cirrhosis and vascular invasion were independently significant factors of poor overall survival.

CONCLUSIONS

Selected elderly patients with HCC benefited from resection as much as young patients, and age by itself may not be a contraindication to surgery. Postresection longterm prognosis in the elderly was determined by the presence of liver cirrhosis and vascular invasion.

Mouse B1 cell line responds to lipopolysaccharide via membrane-bound CD14

The role of membrane-bound CD14 in the response of mouse B1 cell lines to lipopolysaccharide (LPS) was studied. The surface profile of mouse TH2.52 B cells was positive for CD5, IgM, B220, CD11b and F4/80, suggesting that TH2.52 cells carried the typical phenotype of B1 cells. Furthermore, TH2.52 B1 cells were found to express membrane-bound CD14, which plays a critical role in LPS recognition. TH2.52 B1 cells responded to a very low concentration of LPS and exhibited: (i) augmentation of DNA synthesis; (ii) activation of nuclear factor (NF)-kappaB; and (iii) phosphorylation of extracellular signal regulated kinase 1/2 (Erk1/2). They were markedly inhibited by anti-CD14 antibody. Therefore, the expression of membrane-bound CD14 was suggested to provide high sensitivity to LPS for TH2.52 B1 cells.

Cytokine response to human liver ischemia-reperfusion injury during hepatectomy: marker of injury or surgical stress?

BACKGROUND/AIMS

The aim of this study was to evaluate the inflammatory or antiinflammatory cytokine response to ischemia-reperfusion during hepatectomy and to find a useful marker of injury or surgical stress during hepatic ischemia-reperfusion.

METHODOLOGY

In 9 patients with liver disease who underwent hepatectomy using the Pringle maneuver, serum cytokines, including alanine transaminase, aspartate transaminase, and hyaluronic acid, were measured just prior to vascular occlusion; 5, 10 and 15 min after initial clamping; and 3 min after initial declamping.

RESULTS

The mean concentrations of aspartate transaminase and alanine transaminase did not significantly differ before and after ischemia-reperfusion during hepatectomy. However, mean concentrations of hyaluronic acid after ischemia-reperfusion were significantly (P < 0.03) higher than before clamping. Although there were no significant differences in the mean concentrations of IL-1 beta, IL-6, IL-8, IL-10 and TNF-alpha among, before and after ischemia-reperfusion, the mean concentrations of granulocyte colony-stimulating factor after ischemia-reperfusion and macrophage colony-stimulating factor after reperfusion were significantly (P < 0.05) higher than before clamping.

CONCLUSIONS

Although hepatic parenchymal cell function was maintained after ischemia-reperfusion during hepatectomy, sinusoidal endothelial cell dysfunction was found. Release of granulocyte colony-stimulating factor and macrophage colony-stimulating factor after ischemia-reperfusion were also found. These cytokines and hyaluronic acid may be useful indicators in the early phase of human ischemia-reperfusion injury during hepatectomy.

Three elderly patients with lower esophageal cancer successfully treated by transhiatal esophagectomy assisted by mediastinoscopy

Mediastinoscopy-assisted transhiatal esophagectomy recently has been applied in patients with intrathoracic esophageal cancer. Elderly patients with esophageal cancer experience several types of complications and often cannot undergo standard transthoracic esophagectomy. In this study, three elderly patients with preoperative complications underwent mediastinoscopy-assisted transhiatal esophagectomy for esophageal cancer located in the lower part of the esophagus. Patient 1 was an 80-year-old man with alcoholic liver cirrhosis. Patient 2 was a 78-year-old man with bronchial asthma. Patient 3 was an 81-year-old-man with diabetes mellitus and an atherosclerotic obstruction of the lower extremities. In these patients, mediastinoscopy-assisted transhiatal esophagectomy concomitant with reconstruction by means of a gastric tube was performed. Lymph node dissections of the middle and lower mediastinum and of the abdomen, including the regions surrounding the left gastric and celiac arteries, were performed. Postoperative complications developed only in patient 1; minor leakage of the esophagogastrostomy and high bilirubinemia were observed. Metastasis was detected in the lymph nodes surrounding the celiac artery in patient 1 and surrounding the left gastric artery in patients 2 and 3. Patient 2 died of pneumonia 18 months later, but the other patients have been well, without recurrence of the cancer after surgery. In conclusion, mediastinoscopy-assisted transhiatal esophagectomy has some benefits for elderly esophageal cancer patients who experience preoperative complications.

Expression of membrane-type 1 matrix metalloproteinase in coronary vessels of allotransplanted primate hearts

BACKGROUND

The mechanisms of intimal thickening in cardiac allograft vasculopathy (CAV) remain controversial after heart transplantation. Matrix metalloproteinase-2 (MMP-2) plays a crucial role in degrading extracellular matrix (ECM) during neointimal formation. Recently, it has been revealed that MMP-2 is activated by membrane-type 1 matrix metalloproteinase (MT1-MMP). This process involves tissue inhibitor of MMP-2 (TIMP-2), forming an MT1-MMP/TIMP-2/pro-MMP-2 complex. In this study, we hypothesize that these components contribute to the pathogenesis of CAV.

METHODS

Heterotopic cardiac allografting was performed in randomly paired Japanese monkeys with an immunosuppressive regimen of intravenous administration of antihuman CD18 monoclonal antibody. The donor hearts were harvested at Days 22, 28, 40, 41, and 95 posttransplantation. We examined expression of MMP-2, MT1-MMP, and TIMP-2 of graft vessels using immunohistochemistry and protein level by western blot analysis.

RESULTS

Pathologically, various degrees of neointimal formation were observed. In the allografts harvested at Days 22, 28, 40, and 41, MT1-MMP was expressed in the endothelial cells and smooth muscle cells (SMCs) in media of some arteries without histological change, accompanied by expression of MMP-2 and TIMP-2. In the severely thickened neointima of the allograft harvested at Day 95, MMP-2 and faint MT1-MMP were expressed in SMCs of severely thickened neointima and media; TIMP-2 expression was seen only in noncollagenous tissue of severely thickened neointima. MMP-2 protein was more intensely expressed in the allograft harvested at Day 95 than in the allograft harvest at Day 41, while TIMP-2 protein level was almost same in the 2 samples.

CONCLUSION

We observed the simultaneous expression of MMP-2, MT1-MMP, and TIMP-2. Thus, ECM degradation triggered by MT1-MMP/TIMP-2/pro-MMP-2 complex could be a novel mechanism of CAV.

Augmentation of nitric oxide production by gamma interferon in a mouse vascular endothelial cell line and its modulation by tumor necrosis factor alpha and lipopolysaccharide

The effect of gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS) on nitric oxide (NO) production in the mouse vascular aortic endothelial cell line END-D was examined. LPS, TNF-alpha, and a low concentration of IFN-gamma inhibited NO production in END-D cells, while a high concentration of IFN-gamma definitely enhanced it. The NO production induced by a high concentration of IFN-gamma was further augmented by using IFN-gamma in combination with LPS or TNF-alpha. In sequential incubations of LPS and IFN-gamma, the enhancement of NO production required prior treatment with IFN-gamma. Stimulation of END-D cells with a high concentration of IFN-gamma led to the expression of inducible NO synthase (iNOS). The augmentation of NO production by IFN-gamma alone or in combination with LPS or TNF-alpha was completely blocked by several inhibitors of iNOS. It was strongly suggested that a high concentration of IFN-gamma itself enhanced NO production in END-D cells through inducing the expression of iNOS. LPS and TNF-alpha exclusively modulated the activity of iNOS once its expression was triggered by IFN-gamma. On the other hand, a low concentration of IFN-gamma, LPS, and TNF-alpha reduced NO production through down-regulating constitutive NOS (cNOS). The differential regulation of cNOS- and iNOS-mediated NO production by IFN-gamma, TNF-alpha, and LPS is discussed.

Effects of methylmercury and inorganic mercury on the growth of nerve fibers in cultured chick dorsal root ganglia

Inhibition of the growth of nerve fibers by mercurials was quantitatively estimated by measuring the length of fibers in the cultured chick dorsal root ganglion. Morphological changes in nonneuronal cells were also evaluated. The growth rates of nerve fibers were constant for 2 to 6 days after the start of incubation. Methylmercury depressed nerve fiber growth dose- and time-dependently by 50% and completely at 3 x 10(-6) M and 7 x 10(-6) M, respectively. About 10-fold higher concentrations of inorganic mercury were required for the same extent of inhibition. The nerve fibers exposed to inorganic mercury shrank at an early stage of exposure and thereafter grew again within 24 hours. Electron microscopic examination revealed that methylmercury decreased microtubule mass extensively in nerve fibers, while inorganic mercury markedly altered surface membrane structure. These results suggested that microtubule disruption is involved in methylmercury-induced depression of nerve fibers but not in that induced by inorganic mercury. Characteristic effects on the growth of nerve fibers and the proliferation of nonneuronal cells were observed on the treatment with other metals such as cadmium, silver and chromium. Thus, dorsal root ganglion culture seems to be useful for the evaluation of toxic effects of metals in vitro.