Sphingosine 1-phosphate and activation of endothelial nitric-oxide synthase. differential regulation of Akt and MAP kinase pathways by EDG and bradykinin receptors in vascular endothelial cells

Sphingosine 1-phosphate (S1P) is a platelet-derived sphingolipid that elicits numerous biological responses in endothelial cells mediated by a family of G protein-coupled EDG receptors. Stimulation of EDG receptors by S1P has been shown to activate the endothelial isoform of nitric-oxide synthase (eNOS) in heterologous expression systems (Igarashi, J., and Michel, T. (2000) J. Biol. Chem. 275, 32363-32370). However, the signaling pathways that modulate eNOS regulation by S1P/EDG in vascular endothelial cells remain less well understood. We now report that S1P treatment of bovine aortic endothelial cells (BAEC) acutely increases eNOS enzyme activity; the EC(50) for S1P activation of eNOS is approximately 10 nm. The magnitude of eNOS activation by S1P in BAEC is equivalent to that elicited by the agonist bradykinin. S1P treatment activates Akt, a protein kinase implicated in phosphorylation of eNOS. S1P treatment of BAEC leads to eNOS phosphorylation at Ser(1179), a residue phosphorylated by Akt; an eNOS mutant in which this Akt phosphorylation site is inactivated shows attenuated S1P-induced eNOS activation. S1P-induced activation both of Akt and of eNOS is inhibited by pertussis toxin, by the phosphoinositide 3-kinase inhibitor wortmannin, and by the intracellular calcium chelator BAPTA (1,2-bis(aminophenoxy)ethane-N,N,N',N'-tetraacetic acid). By contrast to S1P, activation of G protein-coupled bradykinin B2 receptors neither activates kinase Akt nor promotes Ser(1179) eNOS phosphorylation despite robustly activating eNOS enzyme activity. Understanding the differential regulation of protein kinase pathways by S1P and bradykinin may lead to the identification of new points for eNOS regulation in vascular endothelial cells.

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.

Palliative gastrectomy for advanced gastric cancer

BACKGROUND/AIMS

Although palliative gastrectomy for advanced gastric cancer may be favorable in selected patients presenting with bleeding and obstruction, little has been reported about the clinical significance of palliative gastrectomy, including prognosis.

METHODOLOGY

A retrospective comparison between 84 patients with palliative gastrectomy (PG group) and 100 patients with unresectable operation (UO group) for advanced gastric cancer was carried out.

RESULTS

The incidence of serosal invasion, peritoneal dissemination, hepatic and lymph node metastases, and undifferentiated tissue type in the UO group were significantly higher than in the PG group. Median survival after operation in the PG group (20.6 months) was significantly longer than in the UO group (5.7 months). Also, in stage IVb patients, median survival time in the PG group (10.2 months) was significantly longer than in the UO group (5.0 months). However, median survival in the patients with synchronous liver metastasis between PG (8.4 months) and UO (4.6 months) groups was not significantly different. Survival rates after operation of 6 months, 1 year and 2 years in all patients between the palliative gastrectomy group versus UO group were 83.6% versus 38.3% (P < 0.01), 63.0% versus 9.3% (P < 0.01) and 35.2% versus 0% (P < 0.01), respectively.

CONCLUSIONS

Palliative gastrectomy compared to unresectable operation may be effective for improvement of prognosis even if stage IVb patients with peritoneal dissemination and/or distant lymph node metastasis. However, it may be unfavorable on survival of patients with synchronous liver metastasis.

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.

A primitive myoglobin from Tetrahymena pyriformis: its heme environment, autoxidizability, and genomic DNA structure

A myoglobin-like protein isolated from Tetrahymena pyriformis is composed of 121 amino acid residues. This is much smaller than sperm whale myoglobin by 32 residues, suggesting a distinct origin from the common globin gene. We have therefore examined this unique protein for its structural, spectral and stability properties. As a result, the rate of autoxidation of Tetrahymena oxymyoglobin (MbO(2)) was found to be almost comparable to that of sperm whale MbO(2) over a wide range of pH 4-12 in 0.1 M buffer at 25 degrees C. Moreover, both pH profiles exhibited the remarkable proton-assisted process, which can be performed in sperm whale myoglobin by the distal (E7) histidine as its catalytic residue. These kinetic observations are also in full accord with spectral examinations for the presence of a distal histidine in ciliated protozoa myoglobin. At the same time, we have isolated the globin genes both from T. pyriformis and Tetrahymena thermophila, and found that there is no intron in their genomic structures. This is in sharp contrast to previous reports on the homologous globin genes from Paramecium caudatum and Chlamydomonas eugametos. Rather, the Tetrahymena genes seemed to be related to the cyanobacterial globin gene from Nostoc commune. These contracted or truncated globins thus have a marked diversity in the cDNA, protein, and genomic structures.

Postoperative chemotherapy in elderly patients with advanced gastric cancer

BACKGROUND/AIMS

The definitive efficacy of postoperative chemotherapy in elderly patients with advanced gastric cancer has not been established. The aim of this study is to evaluate prognosis in elderly patients with advanced gastric cancer and the effect of postoperative chemotherapy on prognosis.

METHODOLOGY

Fifty-three patients, 75 years of age or older who underwent curative surgery for advanced gastric cancer were divided into 14 patients with postoperative chemotherapy (chemotherapy group) and 39 patients without postoperative chemotherapy (control group). Chemotherapy regimens were as follows: oral 5-FU alone (n = 11), intravenous mitomycin plus 5-FU: MF (n = 2), and MF plus oral 5-FU (n = 1). No prior chemotherapy or radiation was given.

RESULTS

There were no significant differences of clinical and pathological backgrounds between the two groups. The rate of death due to recurrent carcinoma was 50.0% in the chemotherapy group and 43.6% in the control group, the difference being insignificant. Although the median survival time of the chemotherapy group (40.4 months) was longer than in the control group (31.7 months), a significant difference did not exist between the groups. The 1-, 3-, and 5-year survival rates did not significantly differ between the chemotherapy group versus the control group, 85.7% versus 82.1%, 42.9% versus 51.3%, and 35.7% versus 46.2%, respectively.

CONCLUSIONS

Postoperative chemotherapy did not contribute to prolong survival in elderly patients with advanced gastric cancer mainly because the incidence of recurrent carcinoma was not reduced.

Hepatectomy of cavernous hemangioma with constitutional indocyanine green excretory defect

The constitutional ICG excretory defect with marked ICG retention in spite of other normal hepatic functions has not been so rare in Japan. However, there is no previous report of hepatectomy in a patient with this disease. We describe a successful case of hepatectomy for cavernous hemangioma with this disease and use of technetium-99m diethylenetriaminepentaacetic acidgalactosyl-human serum albumin (99mTC-GSA) liver scintigraphy as the preoperative assessment of the liver functional reserve. In our case, ICGR15 was more than 55%, however, a modified receptor index obtained from 99mTC-GSA liver scintigraphy was normal. Left lateral segmentectomy of the liver was performed without any perioperative complications. Hepatectomy of patients with the constitutional ICG excretory defect is possible if modified receptor index value obtained from 99mTC-GSA scintigraphy is within the normal range.

Agonist-modulated targeting of the EDG-1 receptor to plasmalemmal caveolae. eNOS activation by sphingosine 1-phosphate and the role of caveolin-1 in sphingolipid signal transduction

Plasmalemmal caveolae are membrane microdomains that are specifically enriched in sphingolipids and contain a wide array of signaling proteins, including the endothelial isoform of nitric-oxide synthase (eNOS). EDG-1 is a G protein-coupled receptor for sphingosine 1-phosphate (S1P) that is expressed in endothelial cells and has been implicated in diverse vascular signal transduction pathways. We analyzed the subcellular distribution of EDG-1 in COS-7 cells transiently transfected with cDNA constructs encoding epitope-tagged EDG-1. Subcellular fractionation of cell lysates resolved by ultracentrifugation in discontinuous sucrose gradients revealed that approximately 55% of the EDG-1 protein was recovered in fractions enriched in caveolin-1, a resident protein of caveolae. Co-immunoprecipitation experiments showed that EDG-1 could be specifically precipitated by antibodies directed against caveolin-1 and vice versa. The targeting of EDG-1 to caveolae-enriched fractions was markedly increased (from 51 +/- 11% to 93 +/- 14%) by treatment of transfected cells with S1P (5 microm, 60 min). In co-transfection experiments expressing EDG-1 and eNOS cDNAs in COS-7 cells, we found that S1P treatment significantly and specifically increased nitric-oxide synthase activity, with an EC(50) of 30 nm S1P. Overexpression of transfected caveolin-1 cDNA together with EDG-1 and eNOS markedly diminished S1P-mediated eNOS activation; caveolin overexpression also attenuated agonist-induced phosphorylation of EDG-1 receptor by >90%. These results suggest that the interaction of the EDG-1 receptor with caveolin may serve to inhibit signaling through the S1P pathway, even as the targeting of EDG-1 to caveolae facilitates the interactions of this receptor with ligands and effectors that are also targeted to caveolae. The agonist-modulated targeting of EDG-1 to caveolae and its dynamic inhibitory interactions with caveolin identify new points for regulation of sphingolipid-dependent signaling in the vascular wall.

Allelic loss of the region of chromosome 1p35-pter is associated with progression of human gastric carcinoma

In order to identify the region on distal chromosome 1p that is thought to include one or more tumor suppressor genes for gastric carcinoma, 39 gastric carcinomas were examined for allelic loss using 11 polymorphic microsatellite markers and 1 marker of single strand conformation polymorphism. Loss of heterozygosity (LOH) was found in 18 (46%) of 39 informative patients. The regions with high frequency of loss of heterozygosity were the loci at D1S548 (6 / 17; 35.3%) and D1S2843 (7 / 20; 35%), and we found three commonly deleted regions on chromosome 1p35-pter. The frequency of allelic loss in the region of chromosome 1p35-pter was significantly associated with advanced-stage gastric carcinoma, but not with early-stage tumor or with the histology. These results suggest that allelic loss at chromosome 1p35-pter may play a role in the progression of gastric carcinoma.

Histochemical study of angiogenesis in basaloid squamous carcinoma of the esophagus

Angiogenesis of esophageal basaloid squamous carcinoma (BSC) was studied immunohistochemically and compared with that of squamous cell carcinoma (SCC). In tissues taken from six patients with esophageal BSC and 35 with esophageal SCC, angiogenesis was evaluated by measuring microvessel density (MVD), defined as the microvessel count determined using factor VIII-related antigen immunostaining, and by measuring immunoreactivity of vascular endothelial growth factor (VEGF) and thymidine phosphorylase (dThdPase). Three of the six patients with BSC had distant metastases. There was no difference of MVD between BSC and SCC (22.0 +/- 4.6 vs. 27.6 +/- 9.4). VEGF expression tended to be more frequently observed in BSC than in SCC (100% vs. 60.0%; p = 0.066). Strong expression of VEGF was detected in three BSC with distant metastases; however, there was no difference in the rate of strong VEGF expression between BSC and SCC. The MVD in the cases of BSC with strong VEGF expression, i.e. in the cases with distant metastases, was higher than that in the cases of BSC with weak VEGF expression (p=0.049). There was no difference in dThdPase expression of the cancer cells between BSC and SCC (50.0% vs. 54.3%), whereas the infiltrating stromal cells of all the BSC expressed dThdPase. Strong dThdPase expression in the cancer cells or in the infiltrating stromal cells was observed in two and three BSC, respectively. However, there were no differences in the rate of cancer cells or stromal cells with strong dThdPase expression between BSC and SCC. In one BSC with high MVD and distant metastases, VEGF and dThdPase were both strongly expressed. The vascularity of esophageal BSC was not different from that of SCC. VEGF may participate in angiogenesis of esophageal BSC and may influence the rate of metastasis in esophageal BSC patients. dThdPase may play a partial rule in angiogenesis and metastasis in some cases of BSC.

Circadian rhythm of serotonin levels in planarians

In the freshwater planarian Dugesia japonica, which belongs to the most primitive metazoan phylum, serotonin (5-hydroxytryptamine) was detectable by both immunohistochemistry and high-performance liquid chromatography (HPLC) with fluorometric detection. Immunohistochemical studies showed that serotonin was localized primarily in the cephalic ganglion (brain), in the main nerve cords extending posteriorly from the brain and in the commissure axons connecting the main nerve cords. HPLC with fluorometric detection analysis revealed that the serotonin levels of planarians maintained under a 12:12h light:dark cycle showed significant diurnal variations with a trough in the middle of the dark phase. In constant darkness, the serotonin levels fluctuated with a circadian rhythm. These results demonstrate the existence of a circadian timekeeping mechanism in the planarian.

Reresection for local recurrence of rectal cancer

Local recurrence is one of the major reasons that rectal cancer surgery is unsuccessful. The aim of this study was to investigate the surgical characteristics of patients undergoing reresection for local recurrence of rectal cancer. A total of nine patients were enrolled in this study, six of whom underwent total pelvic exenteration, one, posterior exenteration, one, abdominoperineal resection with sacral resection, and one, lymph node dissection alone. The mean operative time was 8 h 15 min, and the mean operative blood loss was 2 325 ml. Although major postoperative complications occurred in four patients (44%), there were no postoperative or hospital deaths. Lateral lymph node metastasis was detected in all four patients whose lateral lymph nodes were dissected or extirpated at the reresection. Two patients survived for more than 5 years without rerecurrence, and the cumulative 5-year survival rate was 26%. The para-aortic lymph nodes were the most common site of first rerecurrence. The results of this study indicate that patients who undergo reresection for local recurrence of rectal cancer are at high risk of devel-oping lateral or para-aortic nodal metastasis. Nevertheless, reresection may be a therapeutic option for the local recurrence of rectal cancer.

Calcium-independent activation of endothelial nitric oxide synthase by ceramide

The endothelial isoform of NO synthase (eNOS) is targeted to sphingolipid-enriched signal-transducing microdomains in the plasma membrane termed caveolae. Among the caveolae-targeted sphingolipids are the ceramides, a class of acylated sphingosine compounds that have been implicated in diverse cellular responses. We have explored the role of ceramide analogues in eNOS signaling in cultured bovine aortic endothelial cells (BAEC). Addition of the ceramide analogue N-acetylsphingosine (C(2)-ceramide; 5 microM) to intact BAEC leads to a significant increase in NO synthase activity (assayed by using the fluorescent indicator 4,5-diaminofluorescein) and translocation of eNOS from the endothelial cell membrane to intracellular sites (measured by using quantitative immunofluorescence techniques); the biologically inactive ceramide N-acetyldihydrosphingosine is entirely without effect. C(2)-ceramide-induced eNOS activation and translocation are unaffected by the intracellular calcium chelator 1, 2-bis-o-aminophenoxyethane-N,N,N',N'-tetraacetic acid (BAPTA). Using the calcium-specific fluorescent indicator fluo-3, we also found that C(2)-ceramide activation of eNOS is unaccompanied by a drug-induced increase in intracellular calcium. These findings stand in sharp contrast to the mechanism by which bradykinin, estradiol, and other mediators acutely activate eNOS, in which a rapid, agonist-promoted increase in intracellular calcium is required. Finally, we show that treatment of BAEC with bradykinin causes a significant increase in cellular ceramide content; the response to bradykinin has an EC(50) of 3 nM and is blocked by the bradykinin B(2)-receptor antagonist HOE140. Bradykinin-induced ceramide generation could represent a mechanism for longer-term regulation of eNOS activity. Our results suggest that ceramide functions independently of Ca(2+)-regulated pathways to promote activation and translocation of eNOS, and that this lipid mediator may represent a physiological regulator of eNOS in vascular endothelial cells.

Proteins recognized by antibodies against isolated cytological heterochromatin from rat liver cells change their localization between cell species and between stages of mitosis (interphase vs metaphase)

Heterochromatin in the cell nucleus seems to concentrate various proteins, such as Drosophila heterochromatin protein 1, which maintain the repressed state of gene expression. However, it still remains obscure how protein composition related to chromatin structure is different between heterochromatin and euchromatin in interphase nuclei. We isolated cytological heterochromatin from sonicated interphase nuclei obtained from rat liver cells and prepared antisera against it. The dense heterochromatic bodies seen in the preparation of intact nuclei were duplicated in a relatively pure form during the preparation of heterochromatin. In the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, differences between the fractions of heterochromatin and euchromatin were noted by their protein composition. Isolated heterochromatin was then digested by DNase after partial digestion with trypsin and its dense structure changed to become highly sensitive to DNase. The prepared antibodies reacted with the heterochromatin region of rat liver cell nuclei and isolated cytological heterochromatin; however, they did not react with euchromatin. Using immunohistochemistry, the antibodies bound to each cell nucleus in all tissues observed; some cell types were distinguished by their differential stainability (e.g. staining in the cytoplasm). Staining of the mitotic cells showed that the proteins recognized by the antibodies were localized in the cytoplasm and, in part, on the chromosomes. Based on the results of molecular cloning from rat liver cDNA library using the antibodies as a probe, it seemed that the antibodies mainly recognized two proteins similar to arginase and general vesicular transport factor p115, respectively. The results obtained from these experiments reveal that some proteins located in the heterochromatin of interphase liver cell nuclei seem to play important roles in condensing a portion of the chromatin structure during interphase and suggest that proteins composing heterochromatin might be changed according to cell types or the stage of the cell cycle.

Synchronous gastric cancer associated with hepatocellular carcinoma: a study of 10 patients

BACKGROUND/AIMS

Little information regarding synchronous gastric cancer (GC) associated with hepatocellular carcinoma (HCC) is available. The aim of this study was to clarify the clinicopathologic features of synchronous GC associated with HCC, and we also discuss the diagnostic and therapeutic issues regarding them.

METHODOLOGY

In a series of 396 patients with GC and 340 patients with HCC, we investigated the clinicopathologic features of the patients with synchronous GC associated with HCC (HCC group; n=10). They were compared to the patients with resected GC without HCC (non-HCC group) which was divided into 2 groups: with chronic hepatic disease (CHD: CHD group; n=15) and without CHD (Control group; n=345).

RESULTS

The HCC group consisted of 10 of the 396 patients with GC (2.6%), and of 340 with HCC (2.9%). Eight node-negative early GC and 2 advanced GC cases were observed in the HCC group. Nine of these GC (90%) were well-differentiated adenocarcinoma. The tumor sizes of the HCC group were significantly smaller than those of the control group (p<0.05). The incidences of intestinal type and early GC in the HCC group were significantly higher than those in the control group, (p<0.05). However, there were no significant differences in any parameters between the HCC group and CHD group. With regard to early GC, there were no significant differences in any parameters, excluding the site of GC in the CHD group, between the HCC group and non-HCC group. Eight in the HCC group were surgically resected, and the post-operative period of these patients was uneventful. Although there were no significant differences in survival after surgery among the 3 groups, the survival of the patients with early GC in the HCC group was significantly worse than that in the control group (p<0.01).

CONCLUSIONS

The clinicopathologic features of synchronous GC associated with HCC are not very aggressive in most patients probably because of the early detection, and those of early GC with HCC appeared to resemble that of GC with CHD. Since early GC may not influence the clinical outcome of HCC patients, limited gastric resection can be recommended even when curative surgery for HCC is performed. By contrast, when advanced GC is present, curative gastrectomy with lymphadenectomy would be advisable to improve the long-term survival.

Laparoscopic resection of a retroperitoneal schwannoma

Although laparoscopic surgery for retroperitoneal diseases has been widely performed, there are few reports of laparoscopic resection for retroperitoneal tumors. We present the case of a 5-cm retroperitoneal tumor compressing the right common iliac vein and inferior vena cava that was successfully resected using a laparoscopic technique. Dissection between the tumor and the large vessels was performed safely using a harmonic scalpel and an ultrasonic surgical aspirator. Histopathology of the resected tumor showed a benign schwannoma. Laparoscopic surgical techniques should be considered for treatment of selected retroperitoneal tumors.

Alpha-fetoprotein-producing gastric cancer: histochemical analysis of cell proliferation, apoptosis, and angiogenesis

OBJECTIVE

Alpha-fetoprotein (AFP)-producing gastric cancer has been associated with a poor prognosis. In the present study, the cell proliferation, apoptosis, and angiogenesis of this cancer were studied histochemically to determine its malignant potential.

METHODS

Tissue samples were taken from four patients with AFP-producing gastric cancer and 26 patients with AFP-negative gastric cancer. Cell proliferation was evaluated by Ki-67 immunostaining, and the Ki-67 labeling index (LI) was determined. Apoptosis was studied by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling method, and the apoptotic index was determined. Angiogenesis was evaluated by measuring the microvessel density using factor VIII immunostaining, and immunostainings for vascular endothelial growth factor and thymidine phosphorylase were performed.

RESULTS

The Ki-67 LI of the AFP-producing gastric cancers was significantly higher than that of the AFP-negative gastric cancers (p < 0.01). The apoptotic index of the AFP-producing gastric cancers was significantly lower than that of the AFP-negative gastric cancers (p < 0.01). The microvessel density of the AFP-producing gastric cancers was significantly higher than that of the AFP-negative gastric cancers (p < 0.01). Vascular endothelial growth factor expression was observed in all four of the AFP-producing gastric cancers, whereas thymidine phosphorylase was not expressed in any of the AFP-producing gastric cancers.

CONCLUSIONS

These results suggest that AFP-producing gastric cancers have high malignant potential (high proliferative activity, weak apoptosis, and rich neovascularization) compared with that of AFP-negative gastric cancers. These biological characteristics of AFP-producing gastric cancer reflect the aggressive behavior and the poor prognosis of patients with this type of cancer.

Histochemical study of vascular endothelial growth factor in squamous cell carcinoma of the esophagus

BACKGROUND/AIMS

Vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The aim of this study was to clarify the significance of VEGF expression in esophageal squamous cell carcinoma (SCC).

METHODOLOGY

Tissues samples were taken from 52 patients with esophageal SCC after surgery. VEGF expression in these SCCs was examined immunohistochemically. Microvessels in the tumor stained for Factor VIII-related antigen were counted. Ki-67 antigen as a proliferative marker was immunostained with MIB-1, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling was performed for the evaluation of apoptosis. Ki-67 labeling index (LI) and apoptotic index were then calculated.

RESULTS

VEGF expression was observed in 30 of the patients (57.7%). The microvessel count was significantly higher (p = 0.007), and the apoptotic index was significantly lower (p < 0.0001) in the SCC with VEGF expression than in the SCC without it, but no significant difference was observed in the Ki-67 LI between these groups. There was an inverse correlation between the microvessel count and the apoptotic index (p = 0.007). In the clinicopathologic factors, histologic venous invasion of cancer cells (p = 0.039) and lymph node metastasis (p = 0.049) were significantly correlated with VEGF expression. The survival rate after curative surgery was better in the patients without VEGF expression (p < 0.05), and distant organ metastasis after surgery was frequently observed in the patients with VEGF expression (p = 0.023).

CONCLUSIONS

These results suggest that VEGF expression is associated with angiogenesis in esophageal SCC, and may be a prognostic factor in patients with esophageal SCC. Furthermore, apoptosis may be influenced by angiogenesis in esophageal SCC.

Bile leakage resulting from clip displacement of the cystic duct stump: a potential pitfall of laparoscopic cholecystectomy

We present the case of a patient who underwent successful endoscopic nasobiliary drainage (ENBD) for bile leakage resulting from clip displacement of the cystic duct stump sustained during a laparoscopic cholecystectomy (LC). This 69-year-old man was admitted with symptomatic cholecystolithiasis. After LC was performed, intraoperative cholangiography (IOC) revealed no abnormal findings. However, postoperatively, bilious material began to appear from the intraabdominal drain. Subsequent endoscopic retrograde cholangiopancreatography (ERCP) showed bile leakage from the end of the cystic duct stump. ENBD was performed. Cholangiography using the ENBD tube 14 days later failed to show a bile leak. The ENBD was subsequently removed. The patient improved rapidly with no complaints. Bile leakage due to clip displacement from the cystic duct stump is a potential pitfall of LC, especially if IOC is normal. We recommend careful cystic duct ligation, combined with the use of superior quality ligation clips, to prevent this complication. ENBD is a useful technique to prevent bile leakage after this complication.

Retroperitoneal venous hemangioma

Retroperitoneal venous hemangioma is a very rare condition. Only two cases have been reported in the English literature. We report the case of a 28-yr-old man with a retroperitoneal venous hemangioma who underwent surgical resection. Preoperative magnetic resonance imaging revealed a retroperitoneal tumor with low signal intensity on the T1-weighted image and high signal intensity on the T2-weighted image, typical of hemangiomas. In addition, it showed a partial interruption of the muscle layer surrounding the tumor. Intraoperative findings showed a large, reddish brown retroperitoneal mass with an ill defined capsule firmly attached to the muscular tissue surrounding the tumor. Retroperitoneal hemangioma is rare and is almost always of the cavernous type. Although accurate pre- and intraoperative diagnosis of retroperitoneal venous hemangiomas is difficult, magnetic resonance imaging and the presence of a firm attachment to the muscles may be helpful for the important diagnostic findings of this disease.

Correlation of prostaglandin E2 production and gastric acid secretion in infants with hypertrophic pyloric stenosis

PURPOSE

The aim of this study was to evaluate the relationship between gastric acid secretion and prostaglandin E2 (PGE2) generation in gastric mucosa and the role of PGE2 in the pathogenesis of hypertrophic pyloric stenosis (HPS).

METHODS

The authors measured the levels of PGE2 and gastric acidity in the gastric juice of HPS patients before and after a Ramstedt operation.

RESULTS

The PGE2 concentration in the gastric juice of nine HPS patients before the Ramstedt operation was significantly higher than that of eight controls, and the concentration significantly decreased after the operation. A significant inverse correlation between the PGE2 concentration and the pH level in the gastric juice was shown in HPS patients before and after the operation.

CONCLUSION

These results suggest that the enhanced generation of PGE2 in gastric mucosa in cases of HPS is a secondary phenomenon caused by hyperacidity and is not responsible for the pathogenesis of HPS.

[The role of nitric oxide in ischemia-reperfused heart]

We examined the role of nitric oxide (NO) in ischemia-reperfused hearts. In an occlusion-reperfusion model of hypercholesterolemic rabbits, the extent of myocardial infarction was increased because of the activation of neutrophils, possibly due to the impaired production of NO in atherosclerotic coronary circulation. It was reversed by the addition of exogenous NO releaser, SNAP. In a hypoxia-reoxygenation model of cultured cardiac myocytes, NO produced by endogenous cardiac iNOS augmented myocyte injury after exposure to hypoxia-reoxygenation. Inhibition of glutathione peroxidase activity was suggested to be the mechanism of sensitization to oxidative stress after exposure to NO. Therefore, NO is supposed to play two roles in ischemia-reperfused hearts, i.e., cardioprotective effect through coronary circulation and cardiotoxic effect through direct action on cardiac myocytes.

Increased serum trypsin and elastase-1 levels in patients undergoing L-asparaginase therapy

Although there is abundant literature on the association of L-asparaginase and acute pancreatitis in patients undergoing chemotherapy, few studies have investigated the usefulness of pancreatic enzyme measurement in the early diagnosis of L-asparaginase-induced acute pancreatitis. We measured levels of serum pancreatic enzymes before, during, and after L-asparaginase therapy in nine children with acute lymphocytic leukaemia or non-Hodgkin lymphoma. Serum levels of amylase, pancreatic isoamylase, and lipase did not change between the 1st and 30th day of L-asparaginase administration. However, the serum trypsin and elastase- levels, 10 and 20 days after beginning L-asparaginase therapy, were significantly higher than those prior to therapy.

CONCLUSION

L-asparaginase may induce subclinical pancreatitis and the estimation of serum trypsin and elastase-1 may be useful in the early diagnosis of L-asparaginase-induced acute pancreatitis.