Biomedical subjects

S Takao

Publications and source records attributed to S Takao.

At least 91 records · Page 5Linked to original sources

PubMed1998

Comparison of relapse and long-term survival between pylorus-preserving and Whipple pancreaticoduodenectomy in periampullary cancer.

BACKGROUND: Whether long-term survival and type of recurrence in periampullary cancer are influenced by the type of surgical procedure or not is still obscure. The purpose of this review was to analyze the results at a single institution. METHODS: Between 1982 and 1996, 113 consecutive patients with either distal bile duct or ampullary cancers underwent either pylorus-preserving pancreaticoduodenectomy (PPPD) or the Whipple procedure. The median follow-up was 30 months (range 12 to 150). Patient records were reviewed to determine type of recurrence and survival. RESULTS: In distal bile duct or ampullary cancers, comparison of actuarial survival curves between PPPD and the Whipple operation revealed no significant differences. Even in node-positive patients, the 5-year survival rates did not differ significantly between those undergoing PPPD or the Whipple operation. Tumor recurrence was not correlated with the operative method, although among types of tumor recurrence, the rate of blood-borne metastasis was higher in distal bile duct or ampullary cancers. CONCLUSIONS: PPPD is an acceptable alternative to the Whipple procedure in the treatment of periampullary cancer. Long-term survival and type of recurrence were not influenced by these types of surgical procedures.

Adult↗

PubMed1998

Endothelial cells potentiate oxidant-mediated Kupffer cell phagocytic killing.

Phagocytosis and killing of circulating organisms by Kupffer cells (KCs) are discrete, important components of host defense. However, the killing mechanism(s) are not fully understood, and the potential role of adjacent nonparenchymal cells such as hepatic endothelial cells has not been defined. Rat KCs -/+ an hepatic endothelial cell enriched cellular fraction (HECEF) were incubated with Candida parapsilosis and assayed for phagocytosis and phagocytic killing by validated fluorochromatic vital staining. The role of reactive oxygen metabolites in KC phagocytic functions was examined by inhibition with superoxide dismutase and/or catalase. Diphenyleneiodonium and allopurinol were used to examine the potential roles of NADPH oxidase and xanthine oxidase, respectively, in generating these toxic oxidants. Coculture with HECEF increased KC phagocytic activity (from 75% to 88%) and candidacidal activity (from 20% to 31%). Superoxide dismutase, catalase, diphenyleneiodonium, or allopurinol caused inhibition of candidacidal activity, but did not affect phagocytosis, and did not block the potentiation of phagocytosis or of killing caused by coculture with HECEF. Reactive oxygen intermediates generated by both NADPH oxidase and xanthine oxidase-dependent pathways are important in KC killing of Candida parapsilosis. In vitro, KC phagocytosis and killing are potentiated (via a non-oxidant-mediated mechanism) by coculture with a preparation of hepatic non-parenchymal cells composed primarily of endothelial cells.

Allopurinol↗

PubMed1998

Truncated midkine as a marker of diagnosis and detection of nodal metastases in gastrointestinal carcinomas.

Midkine (MK) is a growth factor identified as a product of a retinoic acid-responsive gene. A truncated form of MK mRNA, which lacks a sequence encoding the N-terminally located domain, was recently found in cancer cells. We investigated the expression of the truncated MK mRNA in specimens of 47 surgically removed human gastrointestinal organs using polymerase chain reaction. Truncated MK was not detected in all of the 46 corresponding non-cancerous regions. On the other hand, this short MK mRNA was expressed in the primary tumours in 12 of 16 gastric cancers, 8 of 13 colorectal carcinomas, five of nine hepatocellular carcinomas, two of two oesophageal carcinomas and one ampullary duodenal cancer. In addition, truncated MK was detectable in all of the 14 lymph node metastases but in none of three metastatic sites in the liver, suggesting that truncated MK mRNA could become a good marker of nodal metastases in gastrointestinal tract.

Biomarkers, Tumor↗

PubMed1998

MUC-1 mucin expression in invasive areas of intraductal papillary mucinous tumors of the pancreas.

The expression of MUC-1 mucin (membrane-associated mucin) and MUC-2 mucin (secretory mucin) were immunohistochemically examined in 46 invasive ductal carcinomas (IDC) and 16 intraductal papillary mucinous tumors (IPMT) of the pancreas. Intraductal papillary mucinous tumors usually reveal expansive growth. However, of the 16 IPMT examined in the present study, three showed an invasive growth pattern, which was similar to 'mucinous carcinoma', around the non-invasive growth areas. Of 46 IDC, MUC-1 mucin detected by monoclonal antibodies, DF3 and MY.1E12, was expressed in 44 cases (96%) and in 45 cases (98%), respectively, whereas MUC-2 mucin detected by polyclonal antibody, anti-MRP, was not expressed in any of the cases (0%). In contrast, in the non-invasive growth areas of the 16 IPMT, MUC-1 mucin detected by DF3 and MY.1E12 was expressed in four cases (25%) and in six cases (38%), respectively, whereas MUC-2 mucin detected by anti-MRP was expressed in 13 cases (81%). The invasive growth areas of the three IPMT showed positive expression of MUC-1 mucins detected by DF3 and MY.1E12, although the non-invasive growth areas showed negative expression of MUC-1 mucins, except for their focal positive expression in one of the three cases. These findings indicate that the invasive growth areas of IPMT acquire a characteristic of MUC-1 mucin expression that is usually seen in IDC.

Biomarkers, Tumor↗

PubMed1998

Tumor angiogenesis related to growth pattern and lymph node metastasis in early gastric cancer.

OBJECTIVE: To investigate the correlation between angiogenesis and tumor growth pattern as well as the lymph node metastasis to reveal the significance of vascularity in the early stage of gastric cancer. METHODS: 97 specimens from patients with early gastric cancer were studied by immunohistochemical method using anti-factor VIII related antigen antibody. RESULTS: Microvessel count was related to tumor growth pattern. The mean vessel count was higher in superficially spreading and penetrating types of tumors. Lymph node metastasis was correlated to microvessel count. Tumors with lymph node metastasis had higher microvessel counts than those without lymph node metastasis. CONCLUSIONS: In the early stage of gastric carcinoma, angiogenesis is correlated with tumor growth pattern and lymph node metastasis. Identification of tumors with high density of vascularization is beneficial for closer follow-up and adjuvant therapy.

Adult↗

PubMed1998

Expression of thymidine phosphorylase is associated with a poor prognosis in patients with ductal adenocarcinoma of the pancreas.

Thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor and has angiogenic activity. In this study, we investigated the expression of dThdPase in ductal adenocarcinoma of the pancreas and examined the correlation between dThdPase expression and clinicopathological factors and clinical outcome. dThdPase expression was demonstrated by immunohistochemistry in the cytoplasm of tumor cells in 59% of the 54 patients studied. The expression of dThdPase correlated significantly with a poor prognosis (P=0.013). Significant correlations were also observed between dThdPase expression and extrapancreatic neural plexus invasion and the presence of postoperative hepatic metastases (P=0.05 and 0.03, respectively). The average microvessel count in dThdPase-positive tumors was significantly higher than that in dThdPase-negative tumors (P < 0.0001). These findings suggest that dThdPase expression in pancreatic adenocarcinoma enhances the abilities of tumor invasion and/or metastasis through its angiogenic properties.

Adenocarcinoma↗

PubMed1998

[Surgical treatment of carcinoma of the cardia with special references to mediastinal extension and lymph node metastasis].

We retrospectively analyzed the clinicopathological findings in 141 patients with advanced cardiac cancer. According to histological type, 117 patients had an adenocarcinoma and 24 patients a squamous cell carcinoma. Curative resection was performed in 114 patients, whereas the remaining 27 patients underwent palliative resection. Preoperative endoscopic ultrasonography and abdominal ultrasound were useful for the diagnosis of esophageal invasion and lymph node metastases. Particularly, the classification of paraaortic lymph node metastasis by ultrasound was important in deciding on the surgical method. Mediastinal lymph node metastases were found histologically in 19 of 68 patients. The survival of patients with mediastinal lymph node metastasis was poor. However, among them, a favorable outcome was expected for patients with few involved nodes and if only perigastric node involvement in abdominal nodes was found. Paraaortic lymph node metastasis was found histologically in 15 of 48 patients (27.9%). Two of 35-year survivors had 5 or fewer lymph node metastases, and showed only perigastric and paraaortic node involvement. It is equally important that tumor extension and lymph node metastases in the mediastinum and abdomen should be determined in the surgical treatment of advanced carcinoma of the cardia.

Adenocarcinoma↗

PubMed1997

Regional differentiation of blood flow responses to microinjection of sodium nitroprusside into the nucleus tractus solitarius of anesthetized rats.

This study was undertaken to examine the effects of the activation of the neurons in the nucleus tractus solitarius (NTS) via microinjection of sodium nitroprusside (SNP), which spontaneously releases nitric oxide (NO), on the blood flows of the spleen, kidney, liver, brain and spinal cord and to investigate the regional differentiation of the blood flow changes between those organs. Employing urethane-anesthetized (1.5 g kg-1, i.p.), paralyzed and artificially ventilated rats, regional blood flows of those organs were determined simultaneously using radiolabeled microspheres (109Cd, 51Cr and 85Sr) Unilateral microinjection of SNP into the NTS (n = 9) decreased brain blood flow from 71 +/- 8 (mean +/- S.E.) to 54 +/- 6 (P < 0.01) and spinal cord blood flow from 58 +/- 8 to 43 +/- 5 ml min-1 (100 g)-1 (P < 0.05) and increased brain vascular resistance from 1.18 +/- 0.13 to 1.48 +/- 0.15 (P < 0.01) and spinal cord vascular resistance from 1.46 +/- 0.17 to 1.80 +/- 0.16 (P < 0.05) mmHg per [ml min-1 (100 g)-1]. Whereas the microinjection of SNP into the NTS increased splenic blood flow from 127 +/- 25 to 188 +/- 27 (P < 0.01) and renal blood flow from 346 +/- 28 to 371 +/- 26 ml min-1 (100 g) (P < 0.05) and decreased splenic vascular resistance from 0.77 +/- 0.13 to 0.44 +/- 0.06 (P < 0.01) and renal vascular resistance from 0.24 +/- 0.02 to 0.21 +/- 0.01 mmHg per [ml min-1 (100 g)-1] (P < 0.05). The blood flow of the liver was not significantly altered. Unilateral microinjection of NG-monomethyl-L-arginine, an inhibitor of the formation of NO from L-arginine, into the NTS (n = 10) did not significantly change the blood flows of all organs examined except for an increase in blood flow of the kidney. Unilateral microinjections of SNP into the area adjacent to the NTS (n = 9), of artificial cerebrospinal fluid into the NTS (n = 7) and of light-inactivated SNP into the NTS (n = 6) did not significantly alter the blood flows of all organs examined. These results suggest than the neurons in the NTS have a vasoconstrictor effect on the brain and spinal cord circulation and a vasodilator effect on the splenic and renal circulation. There is a regional qualitative differentiation of the blood flow responses between these organs during activation of the neurons in the NTS.

Anesthesia↗

PubMed1997

Comparison of p53 expression in proximal and distal gastric cancer: histopathologic correlation and prognostic significance.

BACKGROUND: The overexpression of p53 has been found to be correlated with prognosis of some carcinomas, including gastric cancer, but no studies have reported on its relationship to the location of gastric cancer. In the present study, we compared the p53 expression of proximal and distal gastric cancer concerning histopathology and prognosis. METHODS: A total of 170 tumors in the patients with proximal (80 cases) and distal (90 cases) gastric cancer were studied by immunohistochemical methods. RESULTS: p53 immunopositivity was detected in 28.8% of all tumors. The p53-positive expression in proximal gastric cancer was higher than in distal gastric cancer (38.8% vs. 20.0%, p < 0.05). A 5-year survival analysis showed that there is no significant difference between tumors that are p53 positive and p53 negative. No correlation was found between p53 expression and histopathology of gastric cancer. CONCLUSION: p53 nuclear staining is not useful as a prognostic indicator or as a parameter in gastric cancer.

Adult↗

PubMed1997

The invasion-MTT assay as a predictor of liver metastasis using human gastrointestinal carcinomas transplanted in nude mice.

The invasion-3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay, which evaluates invasive potential into the reconstituted basement membrane, Matrigel, was performed on 49 human gastrointestinal carcinomas transplanted in nude mice. There were 19 colorectal carcinomas, 10 pancreatic carcinomas, 10 gastric carcinomas, 8 esophageal carcinomas, and 2 bile duct carcinomas. The percent invasion (PI) value of each tumor by the invasion-MTT assay expresses the invasive rate of tumor cells into the Matrigel as a percentage. There were no significant differences in correlations between the PI values and primary tumor site, clinicopathological findings, tumor doubling time, or DNA index; however, the PI values of primary tumors and lymph nodes with liver metastases were significantly higher than those of primary tumors without liver metastasis (P < 0.05). Furthermore, the primary tumors with synchronous (P < 0.05) or asynchronous (P < 0.01) liver metastases showed significantly higher PI values compared with the primary tumors without liver metastases. These results suggest that PI is not only an independent factor to predict liver metastasis, but it also correlates closely with liver metastasis. Thus, the invasion-MTT assay for primary tumors might be clinically useful to predict liver metastasis in patients following surgery for gastrointestinal carcinomas.

Animals↗

PubMed1997

Oxygen delivery as a factor in the development of fatal postoperative complications after oesophagectomy.

BACKGROUND: This study was designed to assess the impact of oxygen transport variables on outcome in 115 patients undergoing elective surgery for oesophageal carcinoma. METHODS: Haemodynamic parameters were determined using a Swan-Ganz catheter in all patients on the day before operation, 6 h after operation, and daily for the first 4 days after operation. RESULTS: Oxygen delivery and consumption at 6 h were significantly higher in survivors than in non-survivors. However, oxygen delivery and consumption in both groups did not differ significantly after postoperative day 1. Of 17 patients with oxygen delivery levels lower than 445 ml min-1 m-2 at 6 h, eight died in hospital. Oxygen delivery in patients who developed either an anastomotic leak or severe pneumonia was significantly lower 6 h after surgery. Lower levels of oxygen delivery preceded postoperative complications. CONCLUSION: Oxygen delivery 6 h after oesophagectomy correlates with postoperative complications and may be a determinant of hospital mortality.

Aged↗

PubMed1997

MTT-hybrid assay incorporates the advantages of both clonogenic and MTT assay radiosensitivity testing for fresh tumor samples.

After devising a 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-Hybrid assay that incorporates the advantages of both the clonogenic and standard MTT assays, we evaluated the validity of this system using a malignant fibrous histiocytoma (MFH) cell and four xenografted tumors. In the MFH cells the surviving fractions were correlated with radiation dose at three assays. In xenografted tumor cells, the surviving fractions determined by the MTT assay did not show a similar dose response, possibly because of contamination by normal cells. Changes in the surviving fraction of the xenografted cells were correlated to the radiation dose as determined by the clonogenic assays, but this assay took longer performance times and was not useful for evaluating tumors with a low planting efficiency. With the MTT-hybrid assay, changes in fractions of the four xenografted tumor cells were correlated to radiation dose. The MTT-hybrid assay required a smaller optimal number seeding cells and shorter assay time than those of the clonogenic assay. Therefore, the MTT-Hybrid assay can be used successfully to assess the radiosensitivity of both established tumor cell lines and fresh tumor samples.

Animals↗

PubMed1996

Gastric acid secretion and gastroduodenal pH after pancreaticogastrostomy in dogs.

Pancreaticogastrostomy has been reintroduced as a useful alternative procedure to pancreaticojejunostomy after Whipple resection or pylorus-preserving pancreaticoduodenectomy because of the very low incidence of leakage and disruption. In this study, gastric acid secretion, serum gastrin level, and 24-hr dual gastroduodenal pH after pancreaticogastrostomy were examined on the assumption that a canine model was a pylorus-preserving pancreaticoduodenectomy. Basal acid output (BAO), maximal acid output (MAO), and dual gastroduodenal pH were measured in eight dogs with gastric fistula. After pancreaticogastrostomy, BAO levels showed a slight increase significantly, but MAO levels showed no change. Serum gastrin levels in the fasting and postprandial states showed the similar patterns between before and after surgery. In the 24-hr dual gastroduodenal pH monitoring, gastric pH and duodenal pH also did not change in the fasting and postprandial states. These results suggested that the maintenance of the normal gastric pH after pancreaticogastrostomy was caused by a little increase of BAO, and the neurohumoral relationship between the stomach, duodenum, and pancreas was preserved even after pancreaticogastrostomy. Therefore, the pancreaticogastrostomy is a recommendable reconstructive procedure physiologically after pylorus-preserving pancreaticoduodenectomy.

Anastomosis, Surgical↗

PubMed1996

Cerebral blood flow decreases following microinjection of sodium nitroprusside into the nucleus tractus solitarii of anesthetized rats.

The present study was undertaken to examine the effects of microinjection of sodium nitroprusside (SNP), which releases nitric oxide (NO) spontaneously, into the nucleus tractus solitarii (NTS) on cerebral circulation. Cerebral blood flow (CBF) was measured in urethane-anesthetized (1.5 g middle dotkg-1, i.p.), paralysed and artificially ventilated rats using labeled microspheres or laser Doppler flowmetry. The CBF was significantly decreased by microinjection of SNP (5 nmol, n=10, microsphere technique; 0.5 nmol, n=6, laser Doppler flowmetry) into the unilateral NTS. Microinjection of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO, prevented cerebral vasoconstrictor responses induced by microinjection of L-glutamate into the NTS (n=10). Microinjection of NG-monomethyl-D-arginine (D-NMMA) had no effect on the cerebral vasoconstrictor responses induced by L-glutamate (n=11). Unilateral microinjections of L-NMMA into the NTS (n=9), of SNP into the area adjacent to the NTS (n=9), of vehicle solution into the NTS (n=10), and of light-inactivated SNP into the NTS (n=6) had no effect on cerebral circulation. Cerebral autoregulation was well maintained in our protocols (n=9). These results indicate that microinjection of SNP, an NO donor, into the NTS decreases CBF.

Animals↗

PubMed1996

Spinal cord blood flow decreases following microinjection of sodium nitroprusside into the nucleus tractus solitarii of anesthetized rats.

This study was undertaken to examine whether or not nitric oxide (NO) is involved in synaptic transmission in the nucleus tractus solitarius (NTS) during control of the spinal cord circulation. Employing urethane-anesthetized, paralyzed and artificially ventilated rats, sodium nitroprusside (SNP), which produces NO, was microinjected unilaterally into the NTS and the spinal cord blood flow (SCBF) was determined using labeled microspheres. Arterial blood pressure (ABP) was decreased by unilateral microinjection of SNP into the NTS, but its value was kept within the normotensive range by blood transfusion, in order to measure SCBF at normotension. After microinjection of SNP into the NTS, the SCBFs of the cervical, thoracic and lumbar cords decreased significantly from 63 +/- 8 (mean +/- S.E.M.) to 49 +/- 7 (P < 0.05), from 54 +/- 7 to 37 +/- 7 (P < 0.05), and from 77 +/- 9 to 58 +/- 8 (P < 0.05) ml/min/(100 g), respectively (n = 10). Prior microinjection of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO from L-arginine, into the NTS blocked the spinal cord vasoconstrictor response produced by microinjection of L-glutamate into the NTS (n = 10). Prior microinjection of NG-monomethyl-D-arginine (D-NMMA), which does not inhibit the formation of NO from L-arginine, did not block the spinal cord vasoconstrictor response elicited by microinjection of L-glutamate (n = 11). Unilateral microinjection of L-NMMA into the NTS exerted no effect on the spinal cord circulation (n = 9). These findings suggest that NO may be involved in the control of the spinal cord circulation in the NTS.

Animals↗

PubMed1996

Assessment of tumor invasion of the distal esophagus in carcinoma of the cardia using endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: Esophageal invasion by carcinoma of the cardia may affect the surgical approach. Accurate assessment of esophageal invasion is difficult using endoscopy, computed tomography, or barium contrast radiography. The aim of the present study was to evaluate the use of endoscopic ultrasonography (EUS) in the prediction of esophageal invasion by carcinoma of the cardia. PATIENTS AND METHODS: EUS (using a linear-array scanner) was carried out prospectively in 47 patients with carcinoma of the cardia who underwent subsequent surgical resection. The findings were correlated with the histopathological assessment of tumor infiltration in the esophagus in the resected specimen. RESULTS: An absence of esophageal invasion was correctly predicted by EUS in 12 of 13 patients. Histopathologically confirmed invasion of the esophagus was correctly predicted in 32 of 34 patients. With a margin of error of 10 mm, the accuracy of EUS in predicting or excluding histologically confirmed invasion of the esophagus was 85.1% (40 of 47 patients). False-positive results with EUS occurred in patients with prominent edematous or fibrous changes in the distal esophagus; false-negative results with EUS were seen in patients with scattered infiltration of a small number of tumor cells into the mucosal or submucosal layer. CONCLUSIONS: EUS can provide the surgeon with additional information on the extent of esophageal infiltration in patients with carcinoma of the gastric cardia, and can therefore assist in the selection of the surgical approach.

Adult↗

PubMed1996

Role of reactive oxygen metabolites in murine peritoneal macrophage phagocytosis and phagocytic killing.

This study was designed to quantify the role of reactive oxygen metabolites (ROMs) in two distinct components of murine peritoneal macrophage activity, phagocytosis and killing, and to discriminate quantitatively the degree to which each component is dependent on NADPH oxidase and/or xanthine oxidase. A fluorochromatic vital staining technique was modified to simultaneously quantify phagocytosis and microbicidal activity of macrophages incubated with Candida parapsilosis targets. To determine the role of ROMs, macrophages were preincubated with free radical scavengers [superoxide dismutase (SOD) and/or catalase] or with selective inhibitors of xanthine oxidase (XO, e.g., allopurinol) or NADPH oxidase [diphenyleneiodonium (DPI)]. Phagocytosis was not affected by treatment of macrophages with SOD, catalase, allopurinol, or DPI. Candidacidal activity, however, was inhibited by SOD, allopurinol, or DPI. The inhibitory effects of DPI and allopurinol were additive. Histochemical and biochemical assays demonstrated substantial quantities of XO in murine peritoneal macrophages. The findings suggest that the generation of ROMs by XO- and NADPH oxidase-dependent pathways are each important for phagocytic killing by murine peritoneal macrophages.

Allopurinol↗

PubMed1996

[Evaluation of tissue oxygenation utilizing a tonometer in the stomach tube or colon used in substitutive esophagus after surgery for esophageal cancer].

We measured serial changes in mucosal pH (pHi) as an index of blood flow of the stomach tube or the colon in a substitutive esophagus using a tonometer in 18 patients following surgery for esophageal cancer. The pHi showed the lowest level at the postoperative 1 hr (PO 1 hr) and increased significantly at PO 6 hr. At PO 12 hr, pHi showed the level of more than pHi 7.3 which increased significantly compared with PO 6 hr. The oxygen delivery and oxygen consumption increased significantly from PO 1 hr at PO 6 hr but not changed between 6 and 12 hr. It was suggested that the blood flow was inadequate in the stomach tube or the colon as a substitutive esophagus within PO 12 hr following operation despite of adequate oxygen delivery systemically. In this series, the decreased pHi were shown in 2 patients with minor leakage of anastomosis and in one patients with the perforation of stomach tube. The correlation between pHi and modified respiratory index was recognized at PO 12 hr and 24 hr suggesting that pHi was associated with the pulmonary dysfunction. Therefore, it was suggested that the value and change of pHi is an useful predicting index of occurrence of anastomotic leakage or respiratory failure which may be a fatal postoperative complication after surgery for esophageal cancer.

Aged↗