Biomedical subjects

S Ishiguro

Publications and source records attributed to S Ishiguro.

At least 109 records · Page 6Linked to original sources

PubMed1998

Spiral CT during pharmacoangiography with angiotensin II in patients with pancreatic disease. Technique and diagnostic efficacy.

PURPOSE: To compare the diagnostic efficacy of pancreatic pharmacoangiographic CT using angiotensin II with conventional angiographic CT. MATERIAL AND METHODS: Eighteen patients with space-occupying pancreatic disease were examined in this study. Pharmacoangiographic CT was performed with a 1-3 micrograms/6-ml solution of angiotensin II injected through a catheter into the celiac artery during spiral CT. RESULTS: In 17 of the 18 (94%) patients, the area of pancreatic parenchymal enhancement was the same or larger at pharmacoangiographic CT than at conventional angiographic CT. The attenuation value of the pancreatic parenchyma was significantly increased at pharmacoangiographic CT (p = 0.0010). Although the attenuation value of tumors was also increased on images obtained after the injection of angiotensin II, the tumor-to-pancreas contrast was significantly greater at pharmacoangiographic CT (p = 0.0479). The mean differences in attenuation between tumor and pancreas at angiographic CT with and without angiotensin II were respectively 182 HU and 115 HU. CONCLUSION: Pharmacoangiographic CT with angiotensin II proved superior to conventional angiographic CT in the diagnosis of pancreatic disease. We therefore recommend it as a supplementary technique at the angiographic examination of patients with suspected pancreatic tumor.

Adult↗

PubMed1998

Isomerization of 11-cis-retinol to all-trans-retinol in bovine rod outer segments.

It is known that exogenous 11-cis-retinol inhibits the recovery of photosensitivity of bleached rod outer segments (ROS) and 11-cis-retinol exists in the interphotorecepter matrix. We examined the conversion of 11-cis-retinol with bovine ROS. ROS was incubated with 11-cis-retinol under dim red light. Retinoids were extracted from the reaction mixture with hexane and analyzed by HPLC coupled with a fluorescence spectrophotometer. Isomerization of 11-cis-retinol to all-trans-retinol was observed in the presence of ROS. This isomerization was not suppressed by heat treatment and did not have stereospecificity. In addition, we incubated purified rhodopsin and phospholipids extracted from ROS with 11-cis-retinol. Rhodopsin was found to isomerize 11-cis-retinol to all-trans-retinol as well as ROS, but phospholipids did not. In contrast, the phospholipids inhibited the isomerization of 11-cis-retinol to all-trans-retinol by the purified rhodopsin. Commercially available phospholipids, especially phosphatidylserine, also inhibited the isomerization. Our results suggest that rhodopsin has activity for the isomerization of 11-cis-retinol to all-trans-retinol and may play an important role in the detoxification of 11-cis-retinol in the ROS.

Animals↗

PubMed1998

Transvenous dual chamber pacing via a unilateral left superior vena cava.

A 74-year-old woman with a unilateral left superior vena cava required dual chamber permanent pacing after a radical cardiac operation for an incomplete from of endocardial cushion defect. An active fixation ventricular lead was used to prevent the instability induced by the strange course of the electrode. For atrial pacing, a ventricular passive fixation lead was used. A transvenous dual chamber pacemaker was successfully inserted via a unilateral left superior vena cava.

Aged↗

PubMed1998

Helicobacter pylori infection in patients with early gastric cancer by the endoscopic phenol red test.

BACKGROUND: An endoscopic procedure that uses a pH indicator called phenol red to assess Helicobacter pylori infected gastric mucosa has recently been developed. This test makes it possible to take biopsy specimens from H pylori infected areas. AIM: This test was applied to patients with early gastric cancers to clarify the role of H pylori in gastric carcinogenesis. SUBJECTS: Sixty five patients with early gastric cancer (50 with differentiated adenocarcinoma and 15 with undifferentiated adenocarcinoma). METHODS: Patients with early gastric cancer underwent the endoscopic phenol red test before their operation. In this test, areas infected with H pylori can be observed as "coloured" areas where phenol red was turned from yellow to red. RESULTS: H pylori infection was significantly (p < 0.001) more frequent in patients with differentiated adenocarcinomas than in those with undifferentiated adenocarcinomas. Differentiated adenocarcinomas were usually located in areas of mucosa infected with H pylori, but undifferentiated adenocarcinomas were frequently located in non-infected areas. CONCLUSION: H pylori may be a strong risk factor for differentiated early gastric cancer.

Adenocarcinoma↗

PubMed1998

Increased expression of low-affinity NGF receptor in rat retinal Müller cells after ischemia and reperfusion.

Low affinity nerve growth factor receptor (p75LNGFR) it is thought to play an important role in recovering damaged nerve. To investigate the possible role of p75LNGFR in transient retinal ischemia, we investigated p75LNGFR gene expression and localization. Using rats under anesthetized conditions, we incised the bulbar conjunctive around the limbus, and then clamped the eyes. A sham operation was performed on the contralateral eyes. Ocular ischemia was maintained for 90 minutes. The p75LNGFR gene expression in ischemic rat retinas was examined by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) at 0, 3, 6, and 72 hours after reperfusion, and the localization of p75LNGFR protein in rat retinas was examined by light and electron microscopic immunohistochemistry. The expression of p75LNGFR gene in ischemic rat retinas increased, as compared with that of the contralateral eyes after 6 hours and 3 days of reperfusion. The p75LNGFR protein increased in the outer plexiform layer and in the outer limiting membrane by immunohistochemical technique. Electron microscopic immunohistochemistry demonstrated that the staining is present in the Müller glial cells. The fact that p75LNGFR gene expression increased in Müller cells after reperfusion suggested that p75LNGFR expression may play a curative role in ischemic injury.

Animals↗

PubMed1998

Production of a monoclonal antibody reacted broadly with feline calicivirus field isolates.

A monoclonal antibody (MAb) reactive with 36 field isolates and 2 laboratory strains of feline calicivirus (FCV) was produced by immunizing mice with the mixture of FCVs. The MAb (4D7) reacted with FCVs in an enzyme-linked immunosorbent assay (ELISA), but had no neutralizing activity against the F4 strain of FCV. MAb 8G1, previously produced against the FCV F4 strain, also reacted in ELISA with all FCVs used in the present study. However, the epitopes recognized by 4D7 and 8G1 were different. Using these two MAbs and a polyclonal rabbit antibody, we attempted to develop a sandwich ELISA for detection of FCV antigen. The combination of 4D7 and the polyclonal rabbit IgG was most sensitive. Using this system, all the field isolates of FCV cultured in vitro were detected. However, among the 36 swab samples, from which FCV was isolated, 4 were negative.

Animals↗

PubMed1998

Further development of a recombinant feline herpesvirus type 1 vector expressing feline calicivirus immunogenic antigen.

We previously reported the attenuation of thymidine kinase (TK) deficient mutant (C7301dlTK) of feline herpesvirus type 1 (FHV-1) in cats and the construction of a recombinant FHV-1 (C7301dlTK-Cap) inserted a precursor capsid gene of feline calcivirus (FCV) into the TK deletion locus of the C7301dlTK. In this study, we constructed a further improved recombinant FHV-1 (dlTK(gCp)-Cap) carrying a putative FHV-1 gC promoter sequence upstream of the FCV precursor capsid gene of the C7301dlTK-Cap. Growth kinetics of the dlTK(gCp)-Cap in cell cultures was similar to those of C7301dlTK and C7301dlTK-Cap. A strong expression of FCV immunogenic antigen by dlTK(gCp)-Cap was confirmed by indirect immunofluorescence and enzyme-linked immunosorbent assays. In addition, one vaccination with dlTK(gCp)-Cap protected cats more effective against subsequent virulent FCV challenge than that with C7301dlTK-Cap.

Animals↗

PubMed1998

Preparation of liposome-encapsulating adenosine triphosphate.

Liposomes encapsulating adenosine triphosphate (ATP) were prepared by sonication, and the liposomes were evaluated for use in a drug delivery system. The liposomes, which were composed of phosphatidylcholine and cholesterol, were about 1.1 microm in size, as observed under a microscope. From their size, the vesicles were thought to be multilamellar. The maximum concentration of ATP in the liposomes was 1.0 mM, when the initial concentrations of lipid and ATP were 20 mM and 300 mM, respectively. The maximum entrapment ratio of ATP in the liposomes was 88%, when the initial concentrations of lipid and ATP were 20 mM and 500 mM, respectively. About 4% of ATP was encapsulated in these experiments. When liposomes contained 4-7% of cholesterol, about 35% of encapsulated ATP was released from the liposomes for 90 hours at 37 degrees C in vitro. These findings indicated that liposomes encapsulating ATP could be used for the treatment of ischemic retina.

Adenosine Diphosphate↗

PubMed1997

Reassessment of gastric lymphoma in light of the concept of mucosa-associated lymphoid tissue lymphoma: analysis of 53 patients.

BACKGROUND: The concept of mucosa-associated lymphoid tissue (MALT) lymphoma is now widely accepted. However, precise characterization of the features of MALT lesions in the stomach is needed. For this, extensive analysis of resected gastrectomy specimens from a large number of patients with MALT lymphoma is essential. METHODS: Fifty-three patients who underwent gastrectomy for the treatment of primary gastric lymphoma were studied. In the histologic examination, a mean of 46 specimens per case were analyzed; the distribution of lymphomatous lesions was plotted on maps of gastrectomy specimens, input into a computer, and used to measure the size of lesions. RESULTS: The median age of the patients was 56 years, and the male-to-female ratio was 27:26. Stage of disease was I(E) for 35 patients, II(E) for 15, and III for 3. Histologically, 25 patients had low grade lesions, 18 had combined high and low grade lesions, and had 10 high grade lesions. Macroscopically, low grade MALT usually had multiple instances of superficial spreading of lesions without ulceration, whereas high grade MALT exhibited a solitary tumor-forming lesion. All of the superficial spreading type without ulceration were low grade MALT. The higher the grade of tumor, the larger the tumor size. Twenty-four patients received chemotherapy. The 5-year survival rate was 67.2%. Multivariate analysis revealed that only the clinical stage was a significant factor in prognosis. CONCLUSIONS: Low grade MALT can be differentiated from other types of MALT by macroscopic findings. When the MALT concept is adopted, stage of disease is important in relation to survival.

Adult↗

PubMed1997

NO as an indicator of portal hemodynamics and the role of iNOS in increased NO production in CCl4-induced liver cirrhosis.

It is well known that nitric oxide, a vasodilator, is overproduced in liver cirrhosis. This study was designed to elucidate the role of nitric oxide (NO) in portal hemodynamics and to determine the mechanism underlying the increased serum NO levels in rats with liver cirrhosis induced by the oral intake of CCl4. Using rats, liver cirrhosis was induced by oral administration of CCl4. The serum levels of NO2-/NO3-(NOx) were measured, and portal hemodynamic parameters were evaluated with and without the administration of the NO synthase inhibitor N omega-nitro-L-arginine (NNA). Furthermore, Northern blot analysis was used to detect iNOS and cNOS mRNA, and immunohistochemical methods were used to detect iNOS-like immunoreactivity. In cirrhotic rats, the portal flow had increased significantly and the portal resistance had decreased significantly when compared with normal control rats. Hepatic capillary flow in the cirrhotic rats was similar to the control rats. NNA decreased portal flow and increased portal resistance in both groups, but the change was greater in the cirrhotic rats than in controls. The serum levels of NOx were significantly higher in cirrhotic rats than in normal control rats and were positively correlated with portal flow and negatively correlated with portal resistance. The expression of iNOS mRNA, which was barely detectable in control rats, had increased in all organs of the cirrhotic rats, whereas no significant increase in cNOS mRNA was found in any of the organs from cirrhotic rats. The immunohistochemical analysis was generally consistent with the results of the Northern blot analysis. In the control rats, only the bronchial epithelial cells were stained with the anti-iNOS antibody, but in cirrhotic rats, the bronchial cells in the lungs as well as the histiocytic mesenchymal cells in all organs, and the alveolar epithelial cells of the lungs, were stained. This study demonstrated that NO plays a significant role in portal hypertensive hemodynamics in CCl4-induced liver cirrhosis, and that NO is a useful indicator for the evaluation of portal hypertension. Furthermore, the increased serum levels of NO were found to be derived at least in part from the increased expression of iNOS mRNA in the liver, spleen, and lung.

Animals↗

PubMed1997

Immunohistochemically detected expression of motility-related protein-1 (MRP-1/CD9) in lung adenocarcinoma and its relation to prognosis.

Motility-related protein-1 (MRP-1)/CD9 is a trans-membrane glycoprotein closely associated with suppression of cell motility and reduced metastatic potential of some tumor cells. We currently report that, according to the RT-PCR method for MRP-1/CD9 gene expression, patients with low expression of MRP-1/CD9 in non-small-cell lung cancer, especially the adenocarcinoma type, showed short overall survival. Then, to determine accurately the prognostic value of MRP-1/CD9 product levels in lung-adenocarcinoma cells, we immunohistochemically investigated its expression in 132 lung-adenocarcinoma patients undergoing potentially curative surgery. Of these patients, 44 (33%) showed reduced expression of MRP-1/CD9 in cancer cells, and an inverse association was observed between its expression and factors associated with tumor progression, such as nodal involvement (p = 0.029) or stage (p = 0.028). Patients with reduced expression of MRP-1/CD9 showed a significantly worse prognosis in overall survival (p = 0.005) and disease-free survival (DFS; p < 0.0001) than those with stronger expression; and even among patients with stage-I disease, similar results were obtained (overall survival, p = 0.038; DFS, p = 0.012). In a multivariate analysis, immunohistochemical MRP-1/CD9-expression level was an independent prognostic factor for DFS (p = 0.021), but not for overall survival (p = 0.572). Thus, immunohistochemical MRP-1/CD9-expression level solely in lung-adenocarcinoma cells within the tumor tissue appears to be a prognostic factor for DFS, and may be useful for detecting a high-risk sub-group of recurrence during the post-operative clinical course of the disease.

Adult↗

PubMed1997

Influence of cathepsin D expression in lung adenocarcinoma on prognosis: possible importance of its expression in tumor cells and stromal cells, and its intracellular polarization in tumor cells.

BACKGROUND: Cathepsin D, an aspartic lysosomal proteinase, has been described to be closely associated with tumor progression and prognosis in some human malignancies. The purpose of this study was to determine clinicopathological and prognostic significance of cathepsin D expression in lung adenocarcinoma. METHODS: Expression of cathepsin D in 152 lung adenocarcinoma patients was immunohistochemically studied using the antihuman cathepsin D antibody. RESULTS: Eighty patients (53%) showed negative immunoreactivities in tumor cells. The cathepsin D-positive patients (72 patients, 47%) were divided into two subgroups; granular type expression (48 patients, 31%) with its polarized expression mainly in the luminal side of the cytoplasm of tumor cells and basal type expression (24 patients, 16%) with its polarized expression mainly in the basal or infranuclear side of the cytoplasm. Patients with basal type expression showed significantly more marked scar formation (P = 0.042), and especially among the patients with stage I disease, those with basal type tended to show poorer prognosis (P = 0.071) than the others. Cathepsin D was also expressed in stromal cells within the tumor tissues, and 86 patients (57%) with moderate to massively infiltrating cathepsin D-positive stromal cells showed a lower grade of differentiation (P = 0.005) and higher scar grade (P = 0.0003) than those with few cathepsin D-positive stromal cells. Cathepsin D status in stromal cells was significantly associated with prognosis (P = 0.014), and in a multivariate analysis, its expression status in stomal cells was marginally an independent prognostic factor only among the stage I patients. CONCLUSIONS: In determining significance of cathepsin D expression in this disease, it is important to consider separately its expression cell type and its polarization pattern in tumor cells within the tumor tissue. How ever, only cathepsin D status in stromal cells within the tumor tissue is a marginal marker influencing prognosis among stage I patients.

Adenocarcinoma↗

PubMed1997

Amelioration of sinusoidal endothelial cell damage by Kupffer cell blockade during cold preservation of rat liver.

Recent studies have shown that Kupffer cell function is enhanced in the cold-preserved liver, and blockade of Kupffer cells attenuates the injury induced by cold preservation with subsequent reperfusion. This study was designed to investigate the contribution of Kupffer cell blockade with gadolinium chloride (GdCl3) to the rescue of sinusoidal endothelial cell (SEC) damage by comparing the time-related morphological and ultrastructural changes. GdCl3 injection reduced the number of Kupffer cells reactive with monoclonal antibodies ED2 and Ki-M2R directed against macrophage. Scanning electron microscopy revealed the prominent string-like appearance of the SEC processes at 24 hr of preservation in the control; the SECs were better preserved in the GdCl3-pretreated group. Transmission electron microscopy showed detachment of the sinusoidal epithelia at 12 hr of preservation in the control; it was not seen in the GdCl3-pretreated group. At 24 hr of preservation, the SECs were better preserved in the GdCl3-pretreated group. Microvascular casts from the control group showed a disturbance in the radial arrangement of the sinusoids, significant dilation of the sinusoidal caliber at 24 hr, and discontinuity of the sinusoids with extravasation of the casting material at 36 hr of preservation. These changes were also minimized in the GdCl3-pretreated group. In conclusion, the present study demonstrates that Kupffer cells are strongly involved in the morphological integrity of SECs and that blockade of the activation of Kupffer cells would be effective for the prevention of damage to SECs and maintenance of the sinusoidal architecture during cold preservation of the liver tissure.

Animals↗

PubMed1997

Clinicopathologic features and endoscopic resection of duodenal adenocarcinomas and adenomas with the submucosal saline injection technique.

BACKGROUND: Endoscopic resection with the submucosal saline injection technique has been used to treat early duodenal cancers and adenomas. However, indications for endoscopic treatment of these cancers have not been established. METHODS: We used the submucosal saline injection method to treat 14 early duodenal cancers and adenomas to evaluate its safety and effectiveness. A 0.9% NaCl solution was injected into the submucosal layer near the tumor through needle forceps to elevate the tumor, which was then resected with electrocoagulation. Resected specimens were examined to assess depth of involvement, completeness of resection, and histologic type. Reports of early duodenal cancers in the Japanese literature were reviewed to analyze the relationship among lymph node metastasis, submucosal invasion, and tumor size. RESULTS: All tumors were completely removed "en bloc" (12 tumors) or in a "piecemeal" fashion (two tumors). The largest tumor was 20 mm in diameter. No serious complications occurred during or after treatment. Review of Japanese literature showed that lymph node metastasis did not occur when protruding or elevated tumors were less than 50 mm in diameter but did occur when depressed tumors, with or without marginal elevation, were more than 10 mm in diameter. CONCLUSIONS: Endoscopic resection with the submucosal saline injection technique is a safe and effective treatment for early duodenal cancers and adenomas. Protruding or elevated tumors less than 50 mm in diameter can be removed completely. However, because of possible lymph node metastasis, depressed tumors with or without marginal elevation should be removed surgically.

Adenocarcinoma↗

PubMed1997

Inhibition by ginsenoside Rg3 of bombesin-enhanced peritoneal metastasis of intestinal adenocarcinomas induced by azoxymethane in Wistar rats.

The effects of concomitant use of bombesin and ginsenoside Rg3 on the incidence of peritoneal metastasis of intestinal adenocarcinomas induced by azoxymethane were investigated in male inbred Wistar rats. From the start of the experiment, rats were given weekly s.c. injections of azoxymethane (7.4 mg/kg body weight) for 10 weeks and s.c. injection of bombesin (40 microg/kg body weight) every other day, and from week 20, s.c. injections of ginsenoside Rg3 (2.5 or 5.0 mg/kg body weight) every other day until the end of the experiment in week 45. Bombesin significantly increased the incidence of intestinal tumors and cancer metastasis to the peritoneum in week 45. It also significantly increased the labeling index of intestinal cancers. Although administration of a higher dose of ginsenoside Rg3 with bombesin had little or no effect on the enhancement of intestinal carcinogenesis by bombesin, the location, histologic type, depth of involvement, infiltrating growth pattern, labeling and apoptotic indices and tumor vascularity of intestinal cancers, it significantly decreased the incidence of cancer metastasis. These findings indicate that ginsenoside Rg3 inhibits cancer metastasis through activities that do not affect the growth or vascularity of intestinal cancers.

Adenocarcinoma↗

PubMed1997

Usefulness of simple endoscopic aspiration cytology of pancreatic juice for diagnosis of early pancreatic neoplasm. A prospective study.

For detection of early cancer of the pancreas, endoscopic aspiration cytology of pancreatic juice without endoscopic retrograde pancreatography was performed in 64 consecutive outpatients who had symptoms or findings that suggested pancreatic disease. Patients with positive or suspicious cytologic results or abnormal US findings were admitted and underwent detailed examinations. Positive and suspicious cytologic results were obtained in 2 and 10 patients, respectively. Of those with positive and suspicious cytologic results, two, and one patient, respectively, were ultimately found to have pancreatic neoplasms. Of these three resected specimens, one was in situ carcinoma and two presented marked atypia. All patients were alive with no evidence of recurrence. No further cases of pancreatic neoplasm were found. Complications from the procedure did not develop in any patient. This technique is useful in the diagnosis of early neoplasms of the pancreas, because it is simple and safe to perform for outpatients.

Aged↗

PubMed1997

MDM2 gene amplification and expression in non-small-cell lung cancer: immunohistochemical expression of its protein is a favourable prognostic marker in patients without p53 protein accumulation.

MDM2 is an oncoprotein that inhibits p53 tumour-suppressor protein. Amplification of the MDM2 gene and overexpression of its protein have been observed in some human malignancies, and these abnormalities have a role in tumorigenesis through inactivation of p53 function. To determine the clinicopathological and prognostic value of MDM2 abnormalities in non-small-cell lung cancer (NSCLC), MDM2 gene amplification and its protein expression status were analysed in surgically resected materials. MDM2 gene amplification was detected in only 2 (7%) of the 30 tested patients. MDM2 protein was found immunohistochemically in a total of 48 (24%) of the 201 patients. MDM2 protein was slightly frequently observed in patients with adenocarcinoma, but its presence or absence was not associated with clinicopathological factors such as T-factor, N-factor, stage, tumour size, differentiation or p53 protein status. Overall, MDM2-positive patients tended to have a better prognosis (P = 0.062). In particular, among immunohistochemically p53-negative patients (n = 110), those with positive MDM2 protein expression showed significantly better prognosis (P = 0.039) and, in a multivariate analysis, MDM2 protein status was a favourable prognostic factor (P = 0.037). In contrast, among p53-positive patients (n = 91), there was no difference in prognosis depending on MDM2 protein status. Thus, in the NSCLC patients studied, MDM2 gene amplification was a minor event, but expression of its protein, which was often observed immunohistochemically, was a favourable prognostic marker, especially among patients without p53 protein accumulation. Further study is needed to determine how MDM2 protein expression results in a better prognosis.

Adult↗

PubMed1997

Histidine-like immunoreactivity in the rat retina.

PURPOSE: Histidine is an indispensable amino acid with an imidazole ring and it is a precursor of histamine, carnosine, and anserine. Histidine has been proposed to act as a neurotransmitter or neuromodulator in mammalian central nervous system (CNS), including retina. In this study, we report histidine-like immunoreactivity in the rat retina with the use of antibodies raised against histidine coupled to bovine serum albumin (BSA) with glutaraldehyde. METHODS: In order to confirm the specificity of the antiserum toward histidine, immunodots were carried out. Only the histidine conjugate showed immunoreactivity. The rat retinas fixed with glutaraldehyde were used for immunocytochemistry. RESULTS: Histidine immunoreactivity was identified in the ganglion cell layer (GCL), inner nuclear layer (INL), inner plexiform layer (IPL), and Müller cells of rat retina. CONCLUSIONS: Histidine may be a precursor of histamine in the inner retina, and Müller cells may play some role in the metabolism of histidine.

Aging↗