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Biomedical subjects

S Maeda

Publications and source records attributed to S Maeda.

At least 505 records · Page 28Linked to original sources
PubMed1994

ICAM-1 expression and cellular injury in cultured endothelial cells under hypoxia/reoxygenation.

Intercellular adhesion molecule 1(ICAM-1) expression and cellular changes in human umbilical vein endothelial cells(HUVEC) and ECV304, an established cultured line derived from HUVEC, under hypoxia and hypoxia(H)/reoxygenation(R) were investigated by immunological, cytochemical, and morphological methods. ICAM-1 expression in HUVEC decreased slightly under hypoxia(92%) and was up-regulated under reoxygenation(114%), but this up-regulation was diminished by superoxide dismutase(SOD). The up-regulation of ICAM-1 expression by interleukin-1 beta(IL-1 beta) was detected at almost equal levels under hypoxia, and H/R. Using lucigenin-chemiluminescence, we demonstrated superoxide generation from HUVEC under H/R. The Ca2+ influx under hypoxia, and the Ca2+ release from the cells under H/R reduced by SOD were detected cytochemically. Vacuole formation as cell injury under hypoxia and H/R was detected by electron microscopy. The present findings provide evidence that superoxide generated from HUVEC is responsible for the up-regulation of ICAM-1 expression under H/R, and the cause of endothelial cellular injury.

Cells, Cultured↗
PubMed1994

[Circulatory effects of stellate ganglion block and high thoracic epidural block].

A comparative study of the circulatory effects of stellate ganglion block (SGB) and high thoracic epidural block (TEB) was conducted in 11 patients. Although blood pressure and heart rate showed no significant changes even after SGB, they both decreased significantly following TEB. The blood flow in the common carotid artery (CCA) increased markedly at 5 minutes after performing SGB, and at 20 minutes it reached its peak value of 163.5 +/- 7.8%, and the increase remained significant up to 75 minutes. On the other hand, it increased significantly from 5 minutes after performing TEB and reached its peak of 122.2 +/- 7.6% at 15 minutes, and this increase remained significant up to 60 minutes. In comparing these two nerve blocks, the blood flow in the CCA showed a more marked increase following SGB than after TEB from 5 to 60 minutes after performing. The blood flow rate in the CCA increased markedly from 5 minutes after performing SGB, reached its peak of 139.1 +/- 11.3% at 20 minutes, and this increase remained significant up to 60 minutes thereafter. After performing TEB no significant changes were observed. In comparing SGB and TEB, from 5 to 60 minutes after performing, the rate became markedly faster after SGB than after TEB. The vascular diameter of the CCA from 5 minutes after performing SGB showed a slight but significant enlargement, and at 20 minutes it reached its maximum of 111.7 +/- 3.0%, and this significant enlargement persisted up to 60 minutes. From 10 minutes after performing TEB, it showed a slight but significant enlargement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Quantitative assessment of scattered photons considering skull bone in brain SPECT].

A Monte Carlo simulation was performed to estimate scattered photons generated in skull bone in brain SPECT. In the simulation, we used cylindrical phantoms which consisted of water and calcium. We calculated energy spectra of planar images and the scatter fractions, which were defined by the ratio of the scattered photons to primary photons, within the energy windows of 20% centered at the photopeak energy. For radionuclides [99mTc (141 keV), 123I (159 keV)], we changed the following parameters: the thickness of the calcium layer (0.0, 0.5, 1.0, 1.5 cm) and its density (1.55, 1.70, 1.85 g/cm3). The results showed that the shape of the energy spectra depended on the photon energy, the thickness of skull and its density. Consequently, the scatter fractions within the energy windows varied from 0.23 to 0.25 (without skull) and from 0.28 to 0.42 (with skull).

Brain↗
PubMed1994

[Expression of the p53 protein in human osteosarcoma].

The expression of the p53 tumor suppressor gene protein was analyzed in 35 resected osteosarcomas, 5 resected osteochondromas, and in 2 human osteosarcoma cell lines by immunohistochemistry and flow cytometry. An abnormality in the expression of the p53 protein was found in 10(29%) of the 35 osteosarcomas. An overexpression of the p53 protein showed no correlation with the clinicopathological features, but the p53 protein staining pattern showed a tendency to be correlated with aggressive growth and the metastatic potential. Diffusely-stained tumors had a worse prognosis than those focally-stained. The relationship between the expression of p53 protein and the cell cycle was examined by flow cytometry. The maximum overexpression of p53 protein was detected in the cells at the S phase. These results indicated that the nuclear accumulation of the p53 protein, especially the staining pattern, was a potentially useful prognostic factor for osteosarcoma. However our study did not show any clear correlation between either the growth pattern or the morphological type of osteosarcoma and the immunohistochemical results for the p53 protein.

Adolescent↗
PubMed1994

A case of Behçet's disease with multiple longitudinal ulcers all over the colon.

We experienced a rare case of intestinal Behçet's disease simulating Crohn's colitis. A 70-yr-old female presented oral and genital ulcers, erythema nodosum, arthralgias, and abdominal pain. Regardless of our efforts, she died of septic shock. Autopsy showed punched-out ulcers in the terminal ileum and multiple longitudinal ulcers with inflammatory polyposis spreading from the ascending to the descending colon. The differential diagnosis of intestinal Behçet's disease versus Crohn's disease was difficult. However, microscopic findings showed nonspecific ulceration, and no evidence of Crohn's disease could be found. Clinically, the patient met the criteria of Behçet's disease, and punched-out ulcers in the ileocecal region, which is characteristic of intestinal Behçet's disease, confirmed the diagnosis of Behçet's colitis. Although rarely encountered, multiple longitudinal ulcers can involve all of the colon in Behçet's disease, like Crohn's disease.

Aged↗
PubMed1994

[Prostatic carcinoma with bilateral testicular metastasis: a case report].

A 77-year-old man was referred for the treatment of urolithiasis. The patient noticed the swelling of bilateral scrotal contents 2 weeks previously and had been suffering from bladder symptoms for several years, dysuria and pollakisuria. Therefore, he was admitted for the treatment of stones and further examination. By transrectal examination, prostatic carcinoma was suspected. Biopsy of the prostate and bilateral orchiectomy revealed the prostatic carcinoma and the metastatic adenocarcinoma of the bilateral testis. The histological or immunohistological examination indicated that the metastatic adenocarcinoma was prostate in origin.

Adenocarcinoma↗
PubMed1994

Accumulation of 2-deoxy-2[18F]fluoro-D-glucose in human cancers heterotransplanted in nude mice: comparison between histology and glycolytic status.

UNLABELLED: The success of tumor imaging with PET and 2-deoxy-2-fluoro[18F]-D-glucose (18FDG) is based on preferential accumulation of 18FDG in tumors. METHODS: Fluorine-18-FDG uptake was measured in nine human cancers heterotransplanted in nude mice and compared with histologic subclassification. RESULTS: Mean 18FDG uptake by the human cancers was considerably less than that by the host's heart, but values at 60 min after injection were about 2.5 times as high as the liver and kidney, about two times as that for the muscle and about six times that for the blood. Comparison of 18FDG uptake and histological grade in four gastric, two pancreatic and three colonic cancers showed that 18FDG uptake increased with loss of differentiation. CONCLUSION: This nude mice model system is useful for studying correlations between physiological and morphological parameters of heterotransplanted human cancers.

Animals↗
PubMed1993

Effect of prolonged administration of clonidine on [3H]PN 200-110 and [125I]omega-conotoxin binding in mouse brain.

The effect of chronic exposure to clonidine or morphine on clonidine- and morphine-induced analgesia in mice was examined. Binding of L- or N-type calcium channel antagonist to cortical membrane fractions was also compared between these groups of mice. A decrease in the analgesic effect of clonidine and morphine was observed following prolonged administration of clonidine or morphine. Binding of [3H]PN 200-110, an L-type calcium channel antagonist, decreased following prolonged administration of clonidine whereas it increased after morphine treatment. On the other hand, a significant increase of [125I]omega-conotoxin, an N-type calcium channel antagonist, binding was observed after chronic clonidine or morphine treatment. These results will be discussed in relation with the possible development of cross-tolerance between clonidine and morphine through the change in calcium channels, more specifically in N-type channels.

Animals↗
PubMed1993

Selective induction of alpha 1 isoform of (Na+ + K+)-ATPase by insulin/insulin-like growth factor-I in cultured rat astrocytes.

Treatment of cultured rat astrocytes with insulin increased (Na+ + K+)-ATPase activity expressed per protein or DNA by 1.6- to 2.1-fold, but did not affect Mg(2+)-ATPase and adenylate cyclase activities. Insulin treatment increased protein and DNA contents under the conditions, while it did not cause morphological differentiation as determined by a microscopic inspection. Insulin-like growth factor-I (IGF-I) had a similar effect on the enzyme activity in astrocytes: the effect of insulin was observed at supraphysiological concentrations, while that of IGF-I was observed at physiological concentrations. Insulin and IGF-I both stimulated DNA synthesis at the concentrations that caused an increase in enzyme activity. The effect was blocked by tyrosine kinase inhibitors such as genistein and herbimycin A and by cycloheximide. Western blot analysis showed that alpha 1 and alpha 2 isoforms of (Na+ + K+)-ATPase were present in cultured astrocytes and that insulin and IGF-I increased the content of the alpha 1 isoform but did not that of the alpha 2 isoform. Two components of ouabain inhibition were observed in the enzyme purified partially from cultured astrocytes, and treatment of the cells with IGF-I increased the ratio of the low-affinity component of the inhibition, indicating a selective increase in the activity of the alpha 1 isoform. These results indicate that insulin increases (Na+ + K+)-ATPase activity through an activation of IGF-I receptors and the increase is due to the selective induction of the alpha 1 isoform in cultured astrocytes.

Adenylyl Cyclases↗
PubMed1993

Antagonism by glibenclamide of the effect of morphine in hippocampal preparations.

We previously showed that morphine lowered the affinity of Ca2+ antagonist binding and subsequently enhanced field potentials in hippocampal preparations. In the present study, the effect of various K+ channel antagonists on these actions of morphine was studied. Higher Kd value of [3H]nitrendipine binding was obtained for membranes prepared from slices treated with morphine. Concomitant treatment of slices with morphine and tetramethylammonium (TMA) or glibenclamide attenuated the effect of morphine. Apamin and mast cell-degranulating (MCD) peptide were without effect on morphine-induced change in [3H]nitrendipine binding. In those experiments, no change in concentration of binding sites was observed. Glibenclamide reduced the morphine enhancement of field potentials. These results suggested the regulation of Ca2+ channels by morphine through K+ channel opening.

Animals↗
PubMed1993

Parathyroid hormone-related protein in gastric cancers with heterotopic ossification.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) has been regarded as one of the substances causing humoral hypercalcemia of malignancy. METHODS: The immunohistochemical localization of PTHrP was investigated in 33 cases of gastric cancer (4 with heterotopic ossification and 29 without heterotopic ossification) to clarify the role of PTHrP in heterotopic ossification by using the anti-PTHrP monoclonal antibody, 4B3. RESULTS: The four cases with heterotopic ossification showed positive staining at primary or metastatic sites, and in one case fibroblasts in the stroma surrounding the heterotopic ossifying foci also showed positive. On the other hand, of the 29 cases without heterotopic ossification, only 5 showed positive staining. CONCLUSIONS: The presence of PTHrP in ossifying gastric carcinomas at a relatively high rate indicates that PTHrP also might be related to heterotopic ossification associated with malignancies. It is speculated that PTHrP would contribute to heterotopic ossification by facilitating the process of mineralization.

Adenocarcinoma↗
PubMed1993

Cell density-dependent DNA fragmentation and its suppression by heparin in primary culture of adult rat hepatocytes.

We show here that the internucleosomal DNA fragmentation, which is a biochemical hallmark of apoptosis, was induced in a cell density-dependent manner in primary culture of adult rat hepatocytes. This DNA fragmentation could be suppressed by a gene expression inhibitor, indicating the active nature of this process. Moreover, the viability changes in high and low cell density cultures showed a tendency corresponding with the incidence of the DNA fragmentation in them. These results suggest that in hepatocytes there may be a cell density-dependent apoptosis mechanism. In this report, we also show that heparin could suppress this DNA fragmentation with high specificity, and the cell death to some extent.

Animals↗
PubMed1993

Transport of organic cation in renal brush-border membrane from rats with renal ischemic injury.

Transport of tetraethylammonium, an organic cation has been studied using renal brush-border membrane vesicles isolated from rats with ischemic and ischemia-reperfusion injury. H+ gradient-dependent uptake of tetraethylammonium slightly, but significantly, decreased in brush-border membrane vesicles from ischemic kidneys. When the kidney was reperfused after ischemia, the extent of the decrease of tetraethylammonium uptake was much greater than that after ischemia alone. The Vmax value of tetraethylammonium uptake by brush-border membrane vesicles from reperfused kidneys was decreased compared with control, without any change in the Km value. The tetraethylammonium uptake by the vesicles from reperfused kidneys was decreases both in the presence and absence of the outward H+ gradient (driving force). Uptake of D-glucose in renal brush-border membrane vesicles was also decreased by ischemia and again, reperfusion caused a further decrease of the uptake. Reperfusion also induced marked changes in the enrichment and recovery of marker enzymes in the isolated brush-border membrane fraction compared with ischemia. These findings suggest that renal ischemic injury altered the transport properties of tetraethylammonium as well as D-glucose, and that reperfusion after ischemia induced further damages on these functions in the brush-border membrane.

Animals↗
PubMed1993

Intraductal papillary neoplasm of the pancreas.

BACKGROUND: In 1989, Morohoshi et al. reported an intraductal papillary neoplasm of the pancreas (IPNP), which was a morphologically distinct, but rare tumor. METHODS: Two cases with IPNP were analyzed by immunohistochemical and DNA flow cytometric methods. RESULTS: The patients included a 67-year-old man and a 71-year-old woman. Both tumors were characterized by a well-defined papillary growth in the cystically dilated main pancreatic ducts, associated with papillary and nonpapillary hyperplasia. Immunohistochemically, the tumor cells of both cases were positive for the epithelial markers (AE1/AE3 and CAM 5.2), and in one of the two cases, the tumor cells and hyperplastic cells surrounding the tumor conspicuously revealed multiple hormonal markers such as serotonin, somatostatin, glucagon, gastrin, and pancreatic polypeptide. The nuclear DNA content of the tumor cells of the first case, which showed moderate cellular atypia, was considered to be diploid, whereas that of the second case, which revealed severe atypia, was aneuploid. CONCLUSIONS: These results suggested that these tumors arose from multipotential stem cells capable of epithelial and neuroendocrine differentiation, and results of the flow cytometric study was related to the degree of cellular atypia of the tumors.

Adenocarcinoma, Mucinous↗
PubMed1993

Common expression of parathyroid hormone-related protein and no correlation of calcium level in renal cell carcinomas.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) is the predominant cause of humoral hypercalcemia of malignancy (HHM). METHODS: Using a PTHrP-specific monoclonal antibody (MoAb), 4B3, the authors investigated the immunohistochemical localization of PTHrP in formalin-fixed and paraffin-embedded sections of normal human kidney tissues and tissues from 42 human renal cell carcinomas obtained at operation or autopsy. RESULTS: In normal renal tissues, the distal tubules and collecting ducts showed positive immunostaining. PTHrP was detected in 40 of 42 renal cell carcinoma tissues (95%). Histopathologically, the granular cell subtypes of renal cell carcinomas tended to be more strongly positive than the clear cell subtypes. There was no significant correlation between the level of immunostaining and each patient's serum calcium level. CONCLUSION: PTHrP was commonly observed in renal cell carcinomas, and no significant correlation was seen between the intensity of PTHrP staining and the serum calcium level.

Antibodies, Monoclonal↗
PubMed1993

Disruption of the transthyretin gene results in mice with depressed levels of plasma retinol and thyroid hormone.

Transthyretin (TTR) is thought to play a major role in vitamin A metabolism and thyroid hormone transport in mammals. To investigate the physiological role of the TTR protein in development of the embryo and in the adult, we used gene targeting techniques to generate a null mutation at the mouse ttr locus. The resultant mutant animals are phenotypically normal, viable, and fertile. However, levels of serum retinol, retinol-binding protein, and thyroid hormone are significantly depressed in the mutant animals. These observations demonstrate that the TTR protein maintains normal levels of these metabolites in the circulating plasma.

Animals↗