Biomedical subjects

M Imamura

Publications and source records attributed to M Imamura.

At least 307 records · Page 17Linked to original sources

PubMed1998

Distribution and characterization of enterostatin-like immunoreactivity in human cerebrospinal fluid.

Enterostatins belong to a family of peptides (e.g., Val-Pro-Asp-Pro-Arg, VPDPR; Ala-Pro-Gly-Pro-Arg, APGPR; and Val-Pro-Gly-Pro-Arg, VPGPR) derived from the tryptic cleavage of amino-terminal pentapeptide from procolipase. Pharmacologic studies have suggested a role for these peptides in appetite regulation and insulin secretion. Studies into the distribution of enterostatins or the role of endogenous peptides have not been possible until now due to the lack of a suitable method for assay. Using two polyclonal antibodies raised against VPDPR and APGPR and different chromatographic methods, we have examined the nature and distribution of enterostatin-like immunoreactivity in human cerebrospinal fluid. The results reported here show for the first time the presence of enterostatin-like immunoreactivity in the human cerebrospinal fluid. Further characterization of cerebrospinal fluid enterostatin-like immunoreactivity revealed that it is not due to APGPR, VPGPR, or VPDPR but to another peptide similar to VPDPR.

Adult↗

PubMed1998

Purification and some properties of IMP dehydrogenase of Bacillus cereus.

IMP dehydrogenase was purified from a crude extract of B, cereus cells. The molecular mass of the purified enzyme was estimated to be 56 kDa by SDS-PAGE and 225 kDa by gel filtration. The optimum pH of the enzyme was about 9.5. The first seven residues at N-terminus of the enzyme was determined to be Met-Trp-Glu-Ser-Lys-Phe-Val. The enzyme showed a significant specificity for inosine nucleotides among 15 purines and pyrimidines tested, but not acted on other purines and pyrimidines including inosine. Among 11 metal ions and 3 enzyme inhibitors tested, Al3+ activated the IMP dehydrogenase. The enzyme activity was strongly inhibited by Zn2+ and Fe3+.

Ammonium Sulfate↗

PubMed1998

Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides in male volunteers.

STUDY OBJECTIVES: To test the effect of stellate ganglion block on tympanic membrane temperatures. DESIGN: Prospective, observational study. SETTING: Department of Anesthesia, Yamanashi Medical University, Yamanashi, Japan. SUBJECTS: 7 healthy male volunteers. INTERVENTIONS: Stellate ganglion block, 6 ml of 1% mepivacaine hydrochloride, was administered. MEASUREMENTS AND MAIN RESULTS: Application of temperature probes (right and left tympanic membranes, eight adhesive right skin-surface temperatures at the chest, upper arm, digital fingertip, lateral calf, thigh, and great toe) was followed by a 30-minute control period. Temperatures were recorded every 15 minutes for 30 minutes before stellate ganglion block and every 5 minutes for 40 minutes after the block. The right tympanic membrane temperature increased slightly but not significantly compared with the left tympanic membrane temperature 10 minutes after stellate ganglion block and subsequently. Right skin-surface temperature gradients at the upper limb decreased slightly but not significantly after stellate ganglion block. Similarly, right skin-surface temperature gradients at the lower limb decreased slightly but not significantly after stellate ganglion block. CONCLUSIONS: Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides.

Adult↗

PubMed1998

Expression of two angiogenic factors, vascular endothelial growth factor and platelet-derived endothelial cell growth factor in human pancreatic cancer, and its relationship to angiogenesis.

Tumour angiogenesis, as assayed by microvessel density (MVD), and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) have become established as important prognostic indicators for many tumour types. In this study, MVD and the expression of VEGF and PD-ECGF were examined by immunohistochemical staining of 50 pancreatic cancer tissues, and the relationships between either MVD or the expression of these two angiogenic factors and the clinicopathological features, including survival, were analysed. The expression of VEGF and PD-ECGF proteins were confirmed by Western blot analysis and VEGF mRNA isoforms were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in five pancreatic cancer cell lines. Twenty-eight (56%) of 50 pancreatic cancers were positive for VEGF protein in cancer cells, and 16 (32%) showed strong PD-ECGF staining in cancer and infiltrating cells. VEGF121 and VEGF165 were identified as the predominant species produced in pancreatic cancer cells. The overexpression of VEGF and PD-ECGF protein significantly correlated with high MVD (P = 0.002, 0.044, respectively). Advanced stage of disease was significantly more frequent in patients with high MVD (P = 0.025). No significant association was found between the expression of VEGF or PD-ECGF and clinicopathological features, except for tumour histology. The expression of PD-ECGF correlated with poor survival (P = 0.011), but MVD and VEGF expression were not found to be useful for the prediction of overall survival. This study suggests that VEGF and PD-ECGF may play an important role in tumour angiogenesis, and that PD-ECGF expression seems to be useful for establishing prognoses for pancreatic cancer.

Blotting, Western↗

PubMed1998

Ventriculo-arterial discordance: switching the morphologically left ventricle into the systemic circulation after 3 months of age.

OBJECTIVE: To retrospectively examine a 4 year policy of restoring the morphologically left ventricle to the systemic circuit in patients presenting after 3 months of age with ventriculo-arterial discordance with or without associated atrio-ventricular discordance. This policy was stimulated by the known tendency of the morphologically right ventricle to develop dysfunction sooner or later when left in the systemic circuit. Such a policy dictates a more complex surgical approach and, at this point, it remains controversial whether or not the increased surgical complexity is warranted. METHODS: From July 1, 1993 to March 31, 1997, a total of 29 patients were entered into a protocol for placement of the morphologically left ventricle into the systemic circuit. Three groups of patients were identified. Group I; congenitally corrected transposition in 14 patients -- were treated with either a Senning plus arterial switch operation or Senning plus Rastelli procedure. Group II; failed atrial switch procedure in 12 patients of which nine proceeded to arterial switch operation with Senning or Mustard takedown and atrial reseptation. Group III; D-transposition of the great vessels presenting more than 1 year after birth in three patients who underwent arterial switch operation alone. A deconditioned morphologically left ventricle required reconditioning by means of preparatory pulmonary artery banding in 17 of 29 patients. In the patients requiring pulmonary artery banding, an average of 2.1 pulmonary artery bandings was required to prepare the morphologically left ventricle for a systemic pressure workload. RESULTS: In those patients with a deconditioned morphologically left ventricle requiring preparatory pulmonary artery banding, the mean ratio between the left ventricular and right ventricular systolic pressure increased from 0.48 to 0.95. The left ventricular mass increased from 46.6 to 81.8 g/m2 in five patients subjected to serial MRI measurement. Three patients failed the preparatory pulmonary artery banding and did not proceed to anatomical correction. Two subsequently died at a later time. In the patients proceeding to complete anatomical correction: group I -- there were no early or late deaths. Two patients required pacemaker implantation post-operatively. Group II -- there were two in-hospital deaths, one early due to intrapulmonary hemorrhage and one late, secondary to postoperative left ventricular failure with a stormy post-operative course requiring successful ECMO placement and weaning. These patients were 18 and 25 years old, respectively. One patient proceeded to cardiac transplantation 3 months after surgery due to ongoing morphologically left and right ventricular dysfunction. Group III -- all patients continue to do well. CONCLUSIONS: Late anatomic correction of ventriculo-arterial discordance with or without atrio-ventricular discordance can be performed at a relatively low risk. Reconditioning of the morphologically left ventricle can be achieved by sequential pulmonary banding but is not without risk. Failure to achieve adequate reconditioning of the morphologically left ventricle by pulmonary artery banding in the older patient probably increases the risk of non-survival and may be offset by timely transplantation. Longer follow-up and an assessment of the functional status of these patients is required to assess whether or not this complex surgical approach is indeed warranted.

Adult↗

PubMed1998

Analysis of effector cells in tumor-bearing mice pre-treated with active specific immunization followed by cyclophosphamide.

In order to analyse the effector population in an immunization model, we treated BALB/c mice with intraperitoneal (i.p.) active specific immunization (ASI), which consists of interleukin (IL)-1-beta and sonicated tumor supernatant (SS) of a plasmacytoma MOPC-104E followed by i.p. injection of cyclophosphamide (CY). This ASI-CY treatment provoked a protective immunity against i.p. tumor inoculation more strongly than that of ASI alone. The main effector cells in tumor neutralizing assay were CD4+ T cells at this pont. The number of spleen cells of the ASI-CY treated mice were significantly lower than that of ASI alone treated mice but it increased significantly 6 days thereafter while this increase was not observed on the mice treated with ASI alone. The spleen cells of the ASI-CY treated mice responded to SS in vitro in the presence of IL-2, more profoundly in CD4 enriched population which produced high amount of TNF-alpha. In vivo tumor-neutralizing activity at a later stage was dependent on CD8+ T cells in addition to CD4+ T cells. These results suggest that antitumor activity by ASI and CY is transduced by sequential population shift from CD4 alone to both of CD4 and CD8.

Adjuvants, Immunologic↗

PubMed1998

Response of human insulinoma cells to extracellular calcium is different from normal B cells.

The preoperative determination of the localization of a small insulinoma is sometimes difficult using routine imaging techniques. We have used the selective arterial calcium injection (SACI) test to determine the location of the tumor preoperatively. The pathophysiologic basis of the SACI test is based on the responsiveness of insulinomas to calcium injected into the feeding artery. In this study, we demonstrated the in vitro response of the insulinoma cells to the extracellular calcium challenge by using primary-cultured insulinoma cells. Human insulinoma cells were obtained from three patients. MIN6 cells (normal pancreatic B cells) were used as a control; their insulin response to various stimuli resembles that of normal B cells. The insulin secretory dynamics in response to extracellular calcium were observed using a perfusion system. Second, the change of the concentration of cytosolic free calcium ([Ca2+]i) was monitored by fluorometry using fura-2/AM. When the concentration of extracellular calcium ([Ca2+]o) was changed from 2.54 mM to 10 mM, insulin secretion from the insulinoma cells was markedly increased within 6 min (10- to 18-fold at maximum), and rapidly returned to the basal level; at the same time, [Ca2+]i was immediately elevated and reached a peak within 1 min. In contrast, in the MIN6 cells, the insulin secretion and [Ca2+]i were not significantly changed when [Ca2+]o was switched to 10 mM. The results of these in vitro experiments agreed with the clinical results of the SACI test. The positive response of the insulinoma to the SACI test is probably due to the different response of insulinoma cells to the extracellular calcium challenge compared with normal B cells. The role of [Ca2+]i may be important in the mechanism underlying the SACI test.

Animals↗

PubMed1998

Cytokeratin 20 mRNA in peripheral venous blood of colorectal carcinoma patients.

A highly sensitive system was previously developed by us to detect the presence of colorectal carcinoma cells in blood in the form of cytokeratin 20 (CK20) mRNA. In the present study, we used an improved version of this system to analyse the peripheral blood of 28 patients with colorectal carcinoma, five patients with non-cancerous intestinal diseases and six normal controls for the presence or absence of CK20 mRNA and to investigate the relationship between the mRNA results and prognosis. All eight patients with recurrence were positive for CK20 mRNA, as were four patients in the Dukes' C stage with either distant metastasis or dissemination. Five of the nine patients in the Dukes' C stage with neither distant metastasis nor dissemination were positive, and three of these developed recurrence within 11 months after the analysis. Only one of the seven patients in the Dukes' A or B stage was positive, and none showed recurrence during the 1-19 months of observation. None of the five patients without carcinomas or of the six normal controls was positive. Although the follow-up period is limited and the recurrences were all local at present, these results suggest that the presence of CK20 mRNA in circulation may be a useful indicator for the screening of advanced colorectal carcinoma patients with a high risk of recurrence.

Adult↗

PubMed1998

Overexpression of the rhoC gene correlates with progression of ductal adenocarcinoma of the pancreas.

It has been reported that the rho genes, which consist of a ras-related small GTPase protein family, regulate cytoskeletal structures and have the potential to transform cultured cells. To investigate the biological relevance of the rho genes in pancreatic carcinogenesis, we examined expressions of the rhoA, B and C genes by polymerase chain reaction after reverse transcription (RT-PCR) in 33 cases of ductal adenocarcinoma of the pancreas. In addition, mutations of the K-ras, rhoA, B and C genes were studied in the same series of tumour tissues to correlate with rho gene expressions. The expression levels of the rhoC gene were significantly higher in tumours than in non-malignant portions (P < 0.001). Metastatic lesions overexpressed the rhoC gene compared with primary tumours (P < 0.05). Carcinoma tissues with perineural invasion and lymph node metastasis exhibited significantly higher expressions of the rhoC gene than tumours without these manifestations (P < 0.001 and P < 0.05 respectively). Overexpression of the rhoC gene significantly correlated with poorer prognosis of patients with pancreatic adenocarcinoma (P < 0.05). In contrast, the expression levels of the rhoA and B genes showed no significant relationship with clinicopathological findings. Mutation was not found either in the rhoA, B or C gene sequences examined. K-ras gene mutation, detected in 27 out of 33 (81.8%) cases, did not affect the expression levels in any of the rho genes. These suggest that elevated expression of the rhoC gene may be involved in the progression of pancreatic carcinoma independent of K-ras gene activation.

Adult↗

PubMed1998

In oesophageal squamous cell carcinoma vascular endothelial growth factor is associated with p53 mutation, advanced stage and poor prognosis.

Vascular endothelial growth factor (VEGF) affects malignant tumours by promoting angiogenesis. The tumour-suppressor gene p53 has been thought to regulate VEGF. We investigated the effect of VEGF on oesophageal carcinoma and the connection between VEGF and p53. One hundred and nine resected oesophageal squamous cell carcinomas were examined. VEGF expression was analysed by immunohistochemical staining. Sixty-five tumours (59.6%, 65 out of 109) were classified as VEGF positive. A significant correlation was found between the VEGF expression and both the depth of invasion (P = 0.0001) and lymph node metastasis (P < 0.0001). With regard to p53, we compared the expression of VEGF with the mutation of p53, examined using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing in tumour samples obtained from 36 patients who we have reported previously. The VEGF expression was significantly correlated to p53 mutation (P = 0.0291). To evaluate the angiogenesis, microvascular density (MVD) was counted, and endothelial cells were stained immunohistochemically using anti-CD34 monoclonal antibody against 29 cases with invasion limited to the submucosal layer. The average MVD had a tendency to correlate to VEGF expression (P = 0.1626). The prognoses of patients with VEGF-positive primary tumours were significantly worse than for those with VEGF-negative primary tumours (P = 0.0077). We have assumed that VEGF contributes to aggressive characteristics in oesophageal carcinomas and that VEGF expression might be affected by p53 status.

Carcinoma, Squamous Cell↗

PubMed1998

Predictive value of vascular endothelial growth factor (VEGF) in metastasis and prognosis of human colorectal cancer.

Vascular endothelial growth factor (VEGF) may affect the phenotype of cancer cells, such as growth velocity and metastatic potential, due to its probable multifunctional property including a mitogenic activity for vascular endothelial cells. The present study was designed to investigate the association of VEGF mRNA expression with progression and metastasis of human colorectal cancer. The level of VEGF mRNA expression was quantified by Northern blot hybridization in tumorous and non-tumorous tissues obtained from 60 primary colorectal cancer patients. The ratio of the former to the latter was defined as the VEGF T/N ratio, and the prognostic significance of this ratio, following surgery, in addition to the relationship to progression and metastatic potential, was evaluated. The value of the VEGF T/N ratio was significantly correlated with the depth of tumour infiltration (P=0.046), the incidence of liver metastasis (P < 0.0001) and lymph node metastasis (P=0.036). Patient prognosis was estimated by the Kaplan-Meier method and the log-rank test. When the VEGF T/N ratio was higher than 4.8 for which the chi2 value of the log-rank test was maximal, the tumour was defined as showing overexpression of VEGF mRNA. Patients with overexpression of VEGF mRNA demonstrated poorer survival than patients without overexpression of VEGF mRNA (P < 0.001). The overall estimated hazard ratio for death in patients with overexpression of VEGF mRNA was 1.94 according to a multivariate analysis (P=0.005). Thus, VEGF is associated with the progression, invasion and metastasis of colorectal cancer, and overexpression of VEGF mRNA in the primary tumour is assumed to be closely correlated with poor prognosis in colorectal cancer patients. Moreover, the VEGF T/N ratio may be used as an independent prognostic marker in colorectal cancer patients.

Adult↗

PubMed1998

Bone marrow infarction due to acute graft-versus-host disease in an acute lymphoblastic leukemia patient after unrelated bone marrow transplantation.

We report a case of bone marrow infarction in a 20-year-old woman with acute lymphocytic leukemia (ALL) who underwent unrelated bone marrow transplantation (BMT). Hematopoietic engraftment occurred on day 9 and, thereafter, the patient developed acute dermal and hepatic graft-versus-host disease (GVHD). She also experienced severe arthralgia in her knee joints on day 21. Immunosuppressive therapy with prednisolone (PSL) for acute GVHD was given, and the arthralgia improved rapidly, correlating with the improvement in dermal and hepatic GVHD. Based on the laboratory findings and analysis of magnetic resonance images, she was diagnosed as having bone marrow infarction. The cause of the bone marrow infarction was thought to be acute GVHD-related microangiopathy.

Adult↗

PubMed1998

Significance of local recurrence of rectal cancer as a local or disseminated disease.

BACKGROUND: The nature of 'local recurrence' of rectal cancer remains unclear. METHODS: Fifty-nine patients with locally recurrent rectal cancer who underwent extended repeat resections including total pelvic exenteration (39) and sacrectomy (43) were reviewed. Twelve patients had distant metastases before or at the time of repeat resection. RESULTS: The 5-year survival rate was 25 per cent. A second recurrence occurred in 45 patients including five of the eight 5-year survivors. Thirty-six of these recurrences had locoregional manifestations and 29 had distant metastases. Of 18 prognostic factors examined, the most significant determinant was the postoperative carcinoembryonic antigen doubling time (CEADT), followed by the preoperative CEADT, carcinoembryonic antigen (CEA) level and occurrence of distant metastases, in decreasing order. Late onset of first recurrence was also a favourable indicator. Thus, the growth rate of the tumour had a more profound impact on survival than the current extent of tumour progression. After operation the CEADT was reduced in patients with second recurrence (P = 0.05). CONCLUSION: Locally recurrent rectal cancer is a manifestation of disseminated disease spreading locoregionally and often to distant organs with a low probability of long-term cure. However, survival varies widely depending on the tumour growth rate, which is biologically predetermined and is also influenced by surgery.

Adult↗

PubMed1998

An immunohistochemical study of bcl-2 and p53 protein expression in pancreatic carcinomas.

BACKGROUND: Only a few articles have examined the relationship between bcl-2 expression and clinical findings or bcl-2 expression and p53 expression in pancreatic carcinomas. METHODS: We investigated bcl-2 protein and p53 protein expression by means of immunohistochemical methods. RESULTS: The immunostaining for bcl-2 was positive in 16 (20%) of 81 cases of pancreatic carcinoma. There were no significant correlations between bcl-2 expression and the age, gender, region of sampling, or clinical stage of the patients. Bcl-2 protein was detected more frequently in histologically high-grade pancreatic carcinomas (grade III, 31%; grade II, 14%; grade I, 0%); however, there was no significant difference in prognosis between patients with and without bcl-2 protein expression. Immunostaining for the p53 protein was positive in 45 (56%) of 81 cases of pancreatic carcinoma. There was no significant correlation between bcl-2 protein expression and p53 protein expression. CONCLUSION: Bcl-2 was often detected in histologically high-grade pancreatic carcinomas, although there was no significant correlation between bcl-2 expression and the prognosis.

Adenocarcinoma↗

PubMed1998

Accuracy and precision of "deep sternal" and tracheal temperatures at high- and low-fresh-gas flows.

The accuracy of tracheal temperature as a measure of core temperature is relatively poor during high-flow ventilation (6 litre min-1 fresh-gas flow). It is unknown if accuracy improves when lower fresh-gas flow rates are used. We tested the hypothesis that tracheal temperature accuracy would improve with low-flow ventilation (1 litre min-1). We studied 20 ASA Physical Status I and II patients undergoing general anaesthesia for lower abdominal surgery. Deep body temperatures were measured at the middle of the sternum using a Coretemp "deep-tissue" thermometer. Tracheal temperatures were monitored from thermistors incorporated into the tracheal tube cuffs. Oesophageal temperatures were measured from thermocouples incorporated into stethoscopes positioned at the point of maximal heart sounds. Sternal temperature correlated reasonably well with distal oesophageal temperatures, both being within the 0.5 degree C cut-off for accuracy and precision. Tracheal temperatures were lower than oesophageal temperatures during both high- and low-flow ventilation. Tracheal temperatures were 0.7 degree C less during high-flow ventilation and 0.9 degree C less during low-flow ventilation. The precision in both cases was adequate. We conclude that tracheal temperatures were insufficiently accurate for routine clinical use, even when fresh- gas flow was restricted to 1 litre min-1. In contrast, the deep temperatures were sufficiently accurate and precise for routine clinical use.

Adult↗

PubMed1998

Hypoxemia decreases the shivering threshold in rabbits anesthetized with 0.2 minimum alveolar anesthetic concentration isoflurane.

UNLABELLED: Shivering has been proposed as an etiology of postoperative hypoxemia. The difficulty with this theory is that hypoxemia inhibits shivering in unanesthetized cats, rats, and humans. However, anesthesia inhibits many protective reflexes, including the ventilatory response to hypoxemia. We therefore tested the hypothesis that arterial hypoxemia fails to inhibit shivering in lightly anesthetized rabbits. Rabbits were intubated and instrumented during exposure to surgical concentrations of anesthesia, and anesthesia was then maintained with 0.2 minimum alveolar anesthetic concentration isoflurane. The core was cooled at a rate of 2-3 degrees C/h by perfusing water at 10 degrees C through a colonic thermode. Core temperatures were recorded from the distal esophagus. Sustained, vigorous shivering was considered physiologically significant. The core temperature that triggering significant shivering identified the thermoregulatory threshold for this response. Arterial blood was sampled for gas analysis at the shivering threshold in each rabbit. Hypoxemia linearly reduced the shivering threshold from 36.7 degrees C at 130 mm Hg to 35.4 degrees C at 50 mm Hg (threshold = PaO2.0.019 + 34.3; r2 = 0.49). We failed to confirm our hypothesis: instead, even mild hypoxemia reduced the shivering threshold >1 C. A 1 C decrease in the shivering threshold is likely to prevent or stop most postoperative shivering because it exceeds the reduction produced by many effective anti-shivering drugs. These data do not support the theory that shivering causes postoperative hypoxemia. IMPLICATIONS: Shivering has been proposed as an etiology of postoperative hypoxemia. Our data, in contrast, show that mild hypoxemia inhibits shivering. Shivering is thus unlikely to be a cause of postoperative hypoxemia.

Anesthesia, Inhalation↗

PubMed1998

Progress in the field of pancreatic endocrine tumors in Japan.

Since the first report of pancreatic endocrine tumors by Wilder et al. in 1927 and the development of radioimmunoassay of gut hormone by Berson and Yallow in 1961, Japanese clinicians and scientists have contributed significantly in the reporting, investigation, and management of patients with pancreatic endocrine tumors and other multiple endocrine neoplasia. This article summarizes our contribution in this field and contrasts our experiences with those reported in the English literature.

Adenoma, Islet Cell↗

PubMed1998

Hepatic infarction following percutaneous ethanol injection therapy for hepatocellular carcinoma.

We report on two patients who developed hepatic infarction after undergoing percutaneous ethanol injection therapy (PEIT) for hepatocellular carcinoma (HCC). In both cases, liver function parameters deteriorated immediately after the ethanol injection, and enhanced computed tomography images showed a wedge-shaped avascular low-density area due to hepatic infarction. In one patient, PEIT was performed for a nodule treated with transcatheter arterial infusion (TAI) using a suspension of styrene maleic acid neocarzinostatin (SMANCS) 4 weeks before. In the other patient, TAI with SMANCS had been carried out 14 months previously for a different nodule in the same segment where the nodule treated with PEIT was located. When PEIT is used for patients with HCC who have previously undergone TAI, especially with SMANCS, PEIT may induce hepatic infarction.

Antineoplastic Agents↗