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Satoru Saito

Publications and source records attributed to Satoru Saito.

At least 19 recordsLinked to original sources
PubMed2006

Undifferentiated spindle-cell carcinoma of the gallbladder: an immunohistochemical study.

A case of undifferentiated spindle-cell carcinoma of the gallbladder is described. A 72-year-old man presented with right hypochondralgia and fever. Imaging studies revealed a well-demarcated solid tumor (with a necrotic center) in the gallbladder that invaded the liver and transverse colon. On gross examination of the surgical specimen, the cut surface of the polypoid tumor showed nodular invasive growth. Microscopically, the tumor was composed of atypical spindle-shaped tumor cells that proliferated in a whirling or interlacing pattern. The tumor also showed foci with a malignant epithelial component that simulated a carcinosarcoma. Immunohistochemically, the biphasic differentiation of the tumor was highlighted by the different immunoreactivity to antibodies against cytokeratins, epithelial membrane antigen (EMA), and vimentin shown by the malignant epithelial components and the spindle-cell components. However the latter showed faint positivity for cytokeratin antibody. These results suggested that the spindle-cell carcinoma of the gallbladder originated from cholecystic mucosa and showed sarcomatous reaction or dedifferentiation, as indicated by the presence of vimentin-positive cells. The proliferation index, as detected by ki-67, in the spindle-cell component was higher than that in the epithelial component, which may account for the more aggressive biological behavior of the spindle-cell component.

Aged↗
PubMed2006

One percent ability and ninety-nine percent perspiration: a study of a Japanese memorist.

In 1987, Hideaki Tomoyori, a Japanese memorist, set a world record for reciting the first 40,000 digits of pi. The authors report results from a series of tests that give a view of Tomoyori's memory performance compared with that of a control group, matched for age and educational level. He showed very good scores on tasks with digits, such as digit memory span tasks and 5 x 5 number matrix learning, although some of the control participants were nearly as good. In contrast, his performance was not particularly good for learning word lists and story recall. Overall, his performance on the tasks does not suggest that he has superior cognitive abilities. We believe that his extraordinary memory performance in reciting the digits of pi results from his effective use of a combination of digit-syllable transformations and imagery mnemonics developed from extensive practice. These results are consistent with the skilled memory framework.

Aged↗
PubMed2006

Effects of response-stimulus interval manipulation and articulatory suppression on task switching.

We conducted three experiments using a list paradigm to examine how articulatory suppression and response-stimulus interval (RSI) manipulation affected task switching. Experiments 1 and 2 tested task-switching performance under a short and long RSI and three concurrent task conditions (control, articulatory suppression, and tapping) without external task cues. The results indicated that alternation had a greater effect under articulatory suppression than under the control and tapping conditions, and that articulatory suppression costs were unrelated to the RSI. In Experiment 3, an external task cue was provided with each stimulus, and the negative effect of articulatory suppression on alternation cost was eliminated. These results indicated that articulatory suppression effects did not differ between conditions of short and long RSI and that the availability of verbal representations of task information was independent of RSI length. This paper discussed the possible roles played by the phonological loop in task-switching paradigms.

Adult↗
PubMed2006

Characterization of portal vein thrombus with the use of contrast-enhanced sonography.

OBJECTIVES: To select an appropriate treatment regimen, it is essential to accurately characterize the nature of a thrombus. This study prospectively assessed the ability of contrast-enhanced sonography to differentiate between benign and malignant portal vein thrombosis in a population of high-risk patients. METHODS: Fifty-five patients (43 men and 12 women; mean age, 66 years; range, 55-83 years) with thrombi of the portal venous system were examined by power Doppler sonography and contrast-enhanced sonography with the intravenous contrast agent SH U 508A (Levovist; Schering AG, Berlin, Germany). Of the thrombi, 40 were characterized as malignant and 15 as benign. Pulsatile flow in the thrombus on power Doppler sonography and positive enhancement of the thrombus on contrast-enhanced sonography were judged as indications of a malignant thrombus. The sensitivity and specificity of both methods in differentiating the nature of the thrombus were evaluated. RESULTS: The detection of pulsatile flow in a portal vein thrombus as the criterion for diagnosing malignant portal vein thrombus yielded overall sensitivity of 82.5% and specificity of 100%, whereas positive enhancement of the portal vein thrombus itself as a criterion for diagnosing malignancy yielded overall sensitivity and specificity of 100% for each. CONCLUSIONS: Contrast-enhanced sonography can be helpful in discriminating between benign and malignant portal vein thrombi.

Aged↗
PubMed2006

[Clinical features of long time survivors with unresectable pancreatic cancer treated by gemcitabine alone].

The objective of this study was to clarify the clinical features of long-time survivors with unresectable pancreatic cancer treated by gemcitabine (GEM) alone and to predict survival time after the first course of treatment. Eighteen consecutive patients (median age 65.3 years, range 49-77 years; 12 males, 6 females) with unresectable pancreatic cancer and a baseline Karnofsky's performance state = or >60 were treated with GEM in a dose of 1,000 mg/m(2) weekly x 3 followed by 1 week of rest until progression. The overall response rate was 0% (CR 0, PR 0, SD 11 cases, and PD 5 cases), and the median survival time (MST) was 268 days. We observed a statistically significant difference in the patients with or without liver metastasis at the start of treatment (131.6 vs 324.9 days; p=0.0045). We also evaluated the usefulness of serial CA 19-9 measurements as a biochemical response marker and an outcome prognostic parameter in patients with unresectable pancreatic cancer receiving GEM alone. We classified two subgroups into responders (patients with a decrease of = or >10% of the baseline CA 19-9 level after 4 weeks of chemotherapy) and non-responder (patients with a increase of the baseline CA 19-9 level or with a decrease of <10% of the baseline CA 19-9 level after 4 weeks of chemotherapy). Responder had a significantly better median survival than non-responders (416.6 vs 138.3 days; p=0.009). In conclusion, CA 19-9 serum concentration serves as an early indicator of response to chemotherapy with GEM alone in unresectable pancreatic cancer.

Adenocarcinoma↗
PubMed2005

An in vitro model of hepatitis C virion production.

The hepatitis C virus (HCV) is a major cause of liver disease worldwide. The understanding of the viral life cycle has been hampered by the lack of a satisfactory cell culture system. The development of the HCV replicon system has been a major advance, but the system does not produce virions. In this study, we constructed an infectious HCV genotype 1b cDNA between two ribozymes that are designed to generate the exact 5' and 3' ends of HCV. A second construct with a mutation in the active site of the viral RNA-dependent RNA polymerase (RdRp) was generated as a control. The HCV-ribozyme expression construct was transfected into Huh7 cells. Both HCV structural and nonstructural proteins were detected by immunofluorescence and Western blot. RNase protection assays showed positive- and negative-strand HCV RNA. Sequence analysis of the 5' and 3' ends provided further evidence of viral replication. Sucrose density gradient centrifugation of the culture medium revealed colocalization of HCV RNA and structural proteins in a fraction with the density of 1.16 g/ml, the putative density of HCV virions. Electron microscopy showed viral particles of approximately 50 nm in diameter. The level of HCV RNA in the culture medium was as high as 10 million copies per milliliter. The HCV-ribozyme construct with the inactivating mutation in the RdRp did not show evidence of viral replication, assembly, and release. This system supports the production and secretion of high-level HCV virions and extends the repertoire of tools available for the study of HCV biology.

Base Sequence↗
PubMed2005

Percutaneous transhepatic gallbladder stenting for recurrent acute acalculous cholecystitis after failed endoscopic attempt.

Endoscopic gallbladder stenting is useful palliative therapy for acute cholecystitis in high-risk patients. Although the success rate of endoscopic gallbladder stenting is 79%-100%, an alternative method has not been reported. We succeeded in employing a method for percutaneous gallbladder stenting (PTGS) and herein describe this new method. A patient with acute acalculous cholecystitis related to ischemic atherosclerotic vascular disease, cholangitis due to Lemmel syndrome, and severe congestive heart failure underwent PTGS through the cystic duct from the gallbladder to the duodenal papilla, because an endoscopic method failed in the treatment of Lemmel syndrome. Because we were unable to place endoscopic transpapillary gallbladder drainage, percutaneous transhepatic gallbladder drainage (PTGBD) was performed and both the cholecystitis and cholangitis ceased. PTGS was performed as an alternative to endoscopic gallbladder stenting. Access to the cystic duct and gallbladder was obtained by the PTGBD route, using a guidewire (0.035-inch diameter) and seeking catheter (6.5 Fr) under fluoroscopic control. A 7-Fr 12-cm double-pigtail biliary polyethylene stent was placed. The patient remained asymptomatic for 3 months after the PTGS until he died, of an acute recurrent myocardial infarction. This new PTGS placement is an alternative treatment for symptomatic gallbladder disease in patients with increased operative risk when the endoscopic method is unsuccessful.

Acute Disease↗
PubMed2005

Early effects of lafutidine or rabeprazole on intragastric acidity: which drug is more suitable for on-demand use?

BACKGROUND: Medication for the relief of heartburn should have the rapid onset of action required for on-demand use. We studied the inhibition of gastric acid secretion by lafutidine and rabeprazole, given in single doses to fasting and postprandial subjects. METHODS: A total of 22 healthy male, Helicobacter pylori-negative volunteers participated in this randomized, two-way crossover study. They were randomly assigned to receive a single oral dose of 10 mg lafutidine or 20 mg rabeprazole after fasting overnight (12 subjects, fasting study) or after eating a test meal (noodles, 364 kcal; protein, 10.1 g; fat, 16 g; carbohydrates, 44.9 g; NaCl, 1.1 g; 10 subjects, postprandial study). Intragastric pH was monitored continuously for 6 h after treatment. The other drug was given after a washout period of at least 7 days, and intragastric pH was similarly monitored. RESULTS: In the fasting study, lafutidine sustained pH at >3 and >4 during the second, third, fourth, fifth, and sixth hours of the study for significantly longer than rabeprazole. During the first 6 h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole. In the postprandial study, lafutidine sustained pH >3 and >4 for longer periods than rabeprazole during the third, fourth, fifth, and sixth hours of the study. During the first 6 h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole. CONCLUSIONS: Lafutidine 10 mg produces a prompter rise in intragastric pH than rabeprazole 20 mg in fasting and postprandial Helicobacter pylori-negative male subjects.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Elevated resistive index in the hepatic artery as a predictor of fulminant hepatic failure in patients with acute viral hepatitis: a prospective study using Doppler ultrasound.

To assess the sensitivity and specificity of the resistive index of the hepatic artery, which is related to the vascular resistance of the artery, for the prediction of fulminant hepatic failure, we performed Doppler ultrasonography examinations on the hepatic arteries of 72 patients with acute viral hepatitis (25 of whom developed fulminant hepatic failure and 47 of whom recovered without developing fulminant hepatic failure) as well as the hepatic arteries of age- and sex-matched controls. The mean resistive index of the hepatic arteries in patients who developed fulminant hepatic failure was significantly larger than that of patients who recovered without developing fulminant hepatic failure (P < 0.01). When a resistive index cutoff level of 0.74 was used, an 84% sensitivity and a 94% specificity were obtained for the prediction of fulminant hepatic failure. An elevated resistive index of the hepatic artery may be useful for predicting the patient's clinical outcome and determining the need for a liver transplantation in patients with acute viral hepatitis.

Acute Disease↗
PubMed2004

Irrelevant sound disrupts speech production: exploring the relationship between short-term memory and experimentally induced slips of the tongue.

To explore the relationship between short-term memory and speech production, we developed a speech error induction technique. The technique, which was adapted from a Japanese word game, exposed participants to an auditory distractor word immediately before the utterance of a target word. In Experiment 1, the distractor words that were phonologically similar to the target word led to a greater number of errors in speaking the target than did the dissimilar distractor words. Furthermore, the speech error scores were significantly correlated with memory span scores. In Experiment 2, memory span scores were again correlated with the rate of the speech errors that were induced from the task-irrelevant speech sounds. Experiment 3 showed a strong irrelevant-sound effect in the serial recall of nonwords. The magnitude of the irrelevant-sound effects was not affected by phonological similarity between the to-be-remembered nonwords and the irrelevant-sound materials. Analysis of recall errors in Experiment 3 also suggested that there were no essential differences in recall error patterns between the dissimilar and similar irrelevant-sound conditions. We proposed two different underlying mechanisms in immediate memory, one operating via the phonological short-term memory store and the other via the processes underpinning speech production.

Acoustic Stimulation↗
PubMed2004

Effect of articulatory suppression on task-switching performance: implications for models of working memory.

In a series of experiments, we examine some effects of articulatory suppression in task switching. The results from Experiments 1a and 2a showed that switch costs in the articulatory suppression condition were larger than those in the control and tapping conditions when the switching cues were not provided. On the other hand, articulatory suppression did not have any effect on switch costs in Experiments 1b and 2b, where the switching cues were provided. In Experiment 3, using a computer-assisted experimentation, this pattern of data was replicated in a two-factor design with articulatory suppression and switching cues factors. The results indicate that a specific component in working memory, the phonological loop, might contribute to the performance in task switching, at least in situations where the external task cues were not available. The data reported here suggest that the phonological loop plays an important role in one of the executive control processes, and challenge the traditional idea that the slave systems are simply governed by the central executive in the working memory.

Adolescent↗
PubMed2004

Does test delay eliminate collaborative inhibition?

Earlier research has demonstrated that collaborative groups recall more than individuals, but less than nominal groups (pooled performance of individuals), thus exhibiting collaborative inhibition. In two experiments, all participants were first asked to recall story material on their own. Some participants were then assigned to pairs and recalled the material collaboratively. On the other hand, the participants in the individual recall condition were asked to recall the material once again on their own. In Experiment 1, the collaborative pairs recalled less than the nominal pairs in accordance with previous studies. In Experiment 2, the timing of the initial individual recall was manipulated by inserting one week between the learning and the recall. The collaborative inhibition was eliminated in this situation. Sources of the collaborative inhibition in immediate recall and its disappearance in delayed recall are discussed in terms of the effect of cross cueing in collaborative remembering.

Adolescent↗
PubMed2002

The role of hepatitis B virus-specific memory CD8 T cells in the control of viral replication.

BACKGROUND/AIMS: The aim of this study is to clarify the differences of host immune responses between acute self-limited and chronic persistent hepatitis B virus (HBV) infections by quantitative and qualitative analysis of HLA-A*2402-restricted HBV-specific CD8+ T cells. METHODS: HBV-specific CD8+ T cells in peripheral blood mononuclear cells (PBMCs) from patients infected with HBV were analyzed by flow cytometry using two HLA-A*2402-HBV peptide tetrameric complexes. RESULTS: High numbers of HBV-specific CD8+ T cells were detected in acute phase PBMCs from most individuals with acute HBV infection while the number of these cells was greatly reduced in recovery phase PBMCs. HBV-specific CD8+ T cells were not detected in PBMCs from individuals with chronic HBV infection except for one patient during acute exacerbation. HBV-specific CD8+ T cells were induced by in vitro peptide stimulation in PBMCs from chronic HBV carriers with a low level of serum HBV-DNA but not from those with a high level of serum HBV-DNA. CD28CD45RA phenotype analysis showed that HBV-specific CD8+ T cells in acute phase PBMCs predominantly express a memory T cell phenotype. CONCLUSIONS: HBV-specific memory CD8+ T cells may play a crucial role in complete clearance of HBV from patients with acute HBV hepatitis.

Acute Disease↗
PubMed2002

Lactoferrin inhibits hepatitis B virus infection in cultured human hepatocytes.

We recently reported that lactoferrin (LF), a milk protein belonging to the iron transporter family, inhibits hepatitis C virus (HCV) infection in cultured human hepatocytes (PH5CH8) and that the interaction of LF with HCV is responsible for this inhibitory effect. As PH5CH8 cells were found to be a human hepatocyte line susceptible to hepatitis B virus (HBV) infection, we therefore examined if LF could effectively prevent HBV infection in PH5CH8 cells. Preincubation of the cell with bovine LF (bLF) or human LF (hLF) was required to prevent HBV infection of cells, and preincubation of HBV with bLF or hLF had no inhibitory effect on HBV infection. We further found that bovine transferrin, casein, and lactoalbumin had no anti-HBV activity. Our findings suggest that the interaction of LF with cells was important for its inhibitory effect, and that LF may well be among the candidates for an anti-HBV reagent that could prove effective in the treatment of patients with chronic hepatitis.

Journal Article↗
PubMed2002

Dose-response trial of lactoferrin in patients with chronic hepatitis C.

Hepatitis C virus (HCV) is one of the most common causes of chronic hepatitis. Interferon is presently the only effective treatment for chronic hepatitis C (CH-C), though its effectiveness is limited. Lactoferrin (LF), which is an 80-kDa, iron-binding glycoprotein, has several biological activities including anti-viral activity, and it was recently reported to inhibit HCV infection in cultured human hepatocytes. The present trial was designed to assess the relationship between the dose of bovine LF (bLF) and the effect of bLF on serum alanine aminotransaminase (ALT) and HCV RNA levels in patients with CH-C. Forty-five patients entered at each of the three dose levels (bLF of 1.8, 3.6, and 7.2 g/day) received orally an 8-week course of bLF. There was no significant relation between the dose of bLF and the effect of bLF on serum ALT or HCV RNA levels. Biochemical (a 50% or greater decrease in the serum ALT level) and virological (a 50% or greater decrease in HCV RNA level) responses were observed in two and four patients, respectively, but all responders relapsed during the follow-up period after bLF treatment. The bLF treatment was generally well tolerated, and no patient had any serious adverse event. In conclusion, the excellent tolerance and potential anti-HCV activity of bLF shown in this trial suggest that further trials using a large number of patients are mandatory. We are currently conducting a double-blind randomized controlled trial comparing bLF with placebo to clarify the anti-HCV activity of bLF in patients with CH-C.

Adult↗
PubMed2002

[Working memory for movement patterns: a direct comparison of memory spans for body and hand movements in dual-task situations].

In this experiment, 36 participants engaged in one of three span tasks; digit span, body movement span, or hand movement span task, in which they were asked to remember visually presented sequences of digits, whole body movement patterns, or hand movement patterns, respectively. As in a standard memory span procedure, the items within each sequence were recalled in order. Participants were presented with increasingly longer sequences of the items, and span score was defined as the number of items in the longest sequence a participant could recall perfectly. The span tasks were tested under three concurrent task conditions; no concurrent task control, concurrent articulation task, and concurrent body-related movement task. The concurrent movement task interfered with performance on both body movement and hand movement span tasks, but not on the digit span task, while the concurrent articulation task interfered with performance on all of the three span tasks. It is suggested that memory for movement patterns, which is involved in the body and band movement spans, would be mediated by a common motor-processing system.

Hand↗