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Biomedical subjects

H Ueda

Publications and source records attributed to H Ueda.

At least 307 records · Page 17Linked to original sources
PubMed1998

Pituitary-dependent expression of the testicular angiotensin II receptor and its subtypes in rats.

Angiotensin II (AT2) has been implicated in the growth and/or differentiation of its target tissues. In the present study, testicular AT2 receptor and its subtypes in hypophysectomized rats were examined using quantitative in vitro autoradiography and Northern blot analysis in an attempt to determine possible involvement of pituitary hormones in their expression. Prepubescent (3 weeks of age) male Sprague-Dawley rats underwent hypophysectomy or sham operation. From 10 days thereafter, they were treated with vehicle, growth hormone, human chorionic gonadotrophin or human menopausal gonadotrophin for 10 days. Testicular AT2 receptors were labelled with 125I-[Sar1,Ile8] AT2 and differentiated into its subtypes (AT1 and FAT2) according to their susceptibility to AT1 (losartan, 5 microM) and AT2 (CGP42112B, 1 microM) antagonists. Hypophysectomy led to a marked increase in AT2 receptor concentration (sham-operated rats: 0.7 +/- 0.2 fmol/mg protein, hypophysectomized rats: 2.5 +/- 0.6 fmol/mg protein, mean +/- SEM, n = 11-12, p < 0.01) with predominant occurrence of AT1 receptors. Both human chorionic gonadotrophin and human menopausal gonadotrophin decreased testicular AT2 receptor concentration, whereas growth hormone did not affect AT2 receptor expression. Northern blot analysis revealed both testicular AT1 and AT2 receptor mRNA expression to be significantly increased after hypophysectomy and reduced by gonadotrophin treatment. These results suggest that the expression of testicular AT2 receptors is regulated by pituitary gonadotrophins and that AT2 may play a role in testicular growth and/or differentiation.

Angiotensin II↗
PubMed1998

Induction of 72-kDa inducible heat shock protein (HSP72) in cultured rat astrocytes after energy depletion.

Protein synthesis is important in the readaptive processes for cultured astrocytes after hypoxia and subsequent reoxygenation. We have identified 72-kDa inducible heat shock protein (HSP72) as a major stress protein in reoxygenated astrocytes. To assess the mechanism for reoxygenation-mediated induction of HSP72, a reporter gene that consists of a human HSP promoter fused to the luciferase gene was transfected into cultured astrocytes. Analysis of cellular energy nucleotides showed an increase of the ADP/ATP ratio after reoxygenation, which synchronized with activation of the HSP promoter. Activation of the HSP promoter was also observed after an addition of iodoacetic acid to hypoxic astrocytes, which reached the maximum when the ADP/ATP ratio reached 50%, but further decline in the energy profile caused inactivation of this promoter. Inhibition of protein synthesis after reoxygenation resulted in temporary restoration of the energy profile and suppression of the DNA binding activity of the heat shock factor. Addition of quercetin greatly decreased the [3H]leucine incorporation in the polysome fraction without any effect on the mature mRNA formation. These data suggest that the energy depletion in reoxygenation triggers induction of HSP72 after reoxygenation, which may act as a pivotal mediator in the stress response of reoxygenated astrocytes by facilitating protein synthesis.

Adenine Nucleotides↗
PubMed1998

Lacustrine sockeye salmon return straight to their natal area from open water using both visual and olfactory cues.

Mechanisms of the amazing ability of salmon to migrate a long distance from open water to natal streams for spawning are still unknown. Lacustrine sockeye salmon (Oncorhynchus nerka) in Lake Toya offers an excellent model system for studying the orientation mechanism in open water, because mature fish return to the natal area with a high degree of accuracy. First we examined the percentage of fish returning to the natal area after they were released 7 km south of the natal area. Forty percent of control male mature fish and 25% of the fish blinded by injection of a mixture of carbon toner and corn oil into the eyeball were captured in the natal area within 5 days. Forty-four percent of fish with brass rings (control) and 31% of fish with NdFe magnetic rings which interfere with the magnetic cue were captured in the natal area within 3 days. These experiments suggested that, although the number of blinded fish captured in the natal area was less than that of the controls, the difference was not statistically significant. In the fish captured in the natal area within 3 or 5 days, fish which found the natal area using their olfactory cue after random swimming for a long time and returned to that area may be included. Hence we tracked fish telemetrically using an ultrasonic tracking system, and found that mature males released at a long distance (3.6 or 6.8 km) from the natal area swam straight to the vicinity of the natal area. Interference of the magnetic cue by the attachment of a magnetic ring did not affect their direct return. Blockage of the visual cue caused them to move randomly. These data suggest that lacustrine sockeye salmon return straight to the vicinity of the natal area using their visual cue and finally reach the exact homing point using their olfactory cue.

Animals↗
PubMed1998

G protein gamma subunits coimmunoprecipitated with antibodies against alpha subunits: identification of major isoforms in cultured cells by silver stain and immunoblotting with conventional transfer procedure.

The betagamma subunits of G proteins were coimmunoprecipitated with antibodies against various alpha subunits, and analyzed by silver stain and immunoblotting with conventional transfer procedure and membrane-blocking buffer containing 2% BSA. Multiple isoforms of gamma were coimmunoprecipitated with no significant difference in form or ratio among the antibodies against alpha subunits used, suggesting antibodies against any alpha subunit could coimmunoprecipitate all forms of gamma. Therefore, this method was applicable to analyze gamma subunits in various cells, especially to clarify what forms of gamma subunits are major components. The major isoforms were: gamma5 in C6, NG108-15, HeLa, HEK293, and F9 cells; gamma12 in Swiss 3T3 and BRL-3A cells; and gamma3 in PC12 cells. In addition to most gamma subunits identified, unidentified gamma subunits were present in PC12, NG108-15, and BRL-3A cells. Furthermore, the method was applied to examine changes of isoforms of gamma during differentiation of HL-60 cells. Undifferentiated cells mainly contained gamma5, but retinoic acid treatment of cells replaced most gamma5 with gamma2. Thus, this method is useful to determine the major isoforms which seem to be the more important in cells.

Amino Acid Sequence↗
PubMed1998

Scanning electron microscopic study of flowing erythrocytes in hepatic sinusoids as revealed by 'in vivo cryotechnique'.

The purpose of this study is to develop a method for stabilizing erythrocytes under flowing condition in living livers, as revealed by scanning electron microscopy (SEM). After the procedure of the 'in vivo cryotechnique', both freeze-substitution and subsequent t-butyl alcohol freeze-drying methods were used for preparing SEM specimens. By freeze-fracturing with a scalpel in liquid nitrogen before the freeze-substitution, better preserved surface tissues were obtained for examination. Erythrocytes in hepatic sinusoids were clearly detected without plasma components by the freeze-substitution method, and well preserved in parts where they were flowing with their original shapes. Some were accumulated in sinusoids, especially injunctioning areas of sinusoidal networks, as compared with those in narrow lumens between hepatocyte plates. Shapes of such erythrocytes were various, locating along endothelial cells. After stopping the blood supply into livers by artificial cardiac arrest, their shapes were dramatically changed into biconcaves and they became aggregated side by side to be packed in the sinusoids. The three-dimensional shapes of flowing erythrocytes in hepatic sinusoids were demonstrated for the first time by the 'in vivo cryotechnique' combined with SEM.

Animals↗
PubMed1998

Scanning electron microscopic study of erythrocyte shapes artificially jetted through tubes at different pressures by 'in vitro cryotechnique for erythrocytes'.

A new cryotechnique for examining morphological changes of human erythrocytes at different jet pressures was developed in the present study. Human fresh or stored erythrocytes passing through a tube were jetted into precooled isopentane-propane mixture (-193 degrees C), which was named as 'in vitro cryotechnique for erythrocytes'. After the cryotechnique procedure, the routine freeze-substitution method and subsequent t-butyl alcohol freeze-drying method were used for preparing the scanning electron microscopic specimens. At 100 mmHg or higher pressures of jetting, lamellar-arranged erythrocytes were observed to have elongated shapes. The more the jetting pressure increased, the fewer discoid shapes of erythrocytes were observed. This cryofixation technique could preserve the morphology of erythrocytes jetting from tubes, and provide the three-dimensional image of erythrocyte surfaces, as followed by scanning electron microscopy.

Erythrocyte Deformability↗
PubMed1998

Differences in histopathologic findings in restenotic lesions after directional coronary atherectomy or balloon angioplasty.

BACKGROUND: Directional coronary atherectomy (DCA) and balloon angioplasty (percutaneous transluminal coronary angioplasty, PTCA) differ in their method of dilating stenotic vessels. It is not known whether there is any morphologic difference between restenotic lesions that occur after DCA and those occurring after PTCA. METHODS: To evaluate histopathologic differences between restenotic lesions after DCA or PTCA, we reviewed coronary atherectomy specimens excised from 37 patients with stable angina. Patients were classified into three groups: those with restenotic lesions after DCA (n = 8), those with restenotic lesions after PTCA (n = 14), and those with primary lesions (n = 15). Specimens were analyzed immunohistochemically using monoclonal antibodies specific for smooth muscle cells (HHF35), endothelial cells (CD31), macrophage-derived foam cells (CD6B) and cell replication activity (Ki-67). In seven patients undergoing repeat DCA, de novo plaques and restenotic plaques were compared. RESULTS: Stellate smooth muscle cell (S-SMC) content in restenotic lesions after DCA (87%) was significantly greater than that in primary lesions (40%; P = 0.032) and that in restenotic lesions after PTCA (43%; P = 0.045). Foam cells tended to be more prevalent in primary lesions (67%) than in restenotic lesions after DCA (25%; P = 0.062) or after PTCA (36%; P = 0.10). Restenotic lesions after DCA had more S-SMC proliferation and fewer foam cells than did primary lesions. There were no differences in the presence of thrombus, calcification, cholesterin, hemosiderin, the percentage of HHF35-positive cells or Ki-67-positive cells, or neovascularization among the three groups. CONCLUSIONS: Smooth muscle cell proliferation may have an important role in the development of restenosis after DCA. Fewer foam cells are present in restenotic lesions after DCA or PTCA than are present in primary lesions.

Aged↗
PubMed1998

Clock drawing test in very mild Alzheimer's disease.

OBJECTIVES: The primary objective of this study was to determine the efficacy of the clock drawing test to predict the presence of very mild Alzheimer's disease (AD). A secondary objective was to identify elements of clock drawing that were most useful in differentiating cognitively intact older adults from those with mild Alzheimer's disease. DESIGN: Cohort based comparison of retrospective data. SETTING: Academic research center. PARTICIPANTS: Clock drawings from 41 outpatient cases of mild AD with Mini-Mental State Exam scores of 24 or higher and 39 age- and education-matched older adults were scored. MEASUREMENTS: Clock drawings were blindly and independently scored by two raters using the Clock Drawing Interpretation Scale and the scoring system reported by Rouleau et al. Predictive values for positive and negative tests were calculated using cut-off scores for total score and component subscores from each of these two systems. RESULTS: Two or more errors in the depiction of the clock hands on the Clock Drawing Interpretation Scale had a positive predictive value for AD of 100% and a negative predictive value of 51%. A score of 2 or less on the 4-point hand-placement component of the Rouleau et al. scoring system provided a positive predictive value for AD of 94% and was associated with a negative predictive value of 62%. CONCLUSION: An individual who commits two errors or more in drawing the clock hands deserves further investigation for a possible dementia. Normal hand placement on the clock drawing test does not exclude AD. However, when prevalence rates of dementia in community-dwelling older adults are considered, these results argue that normal clock hand placement indicates that dementia is unlikely.

Aged↗
PubMed1998

Comparative study of 5' UTR and NS3R primers for the detection of GB virus C/hepatitis G virus RNA in Japanese.

AIMS/BACKGROUND: Many epidemiological studies of new hepatitis viruses, including GB virus C (GBV-C) and hepatitis G virus (HGV), have used polymerase chain reaction (PCR) primers designed for the third nonstructural region (NS3R). However, a homology study of GBV-C and HGV genomes revealed that the 5' untranslated region (5'UTR) was more conserved than NS3R. METHODS: We attempted to detect GBV-C/HGV using PCR primers corresponding to the 5' UTR, and compared its incidence to that derived from NS3R primers. Furthermore, PCR products amplified using the 5' UTR primers were sequenced and subjected to phylogenetic analysis. RESULTS: In patients with chronic hepatitis C, the prevalence of GBV-C/HGV by PCR with the NS3R and 5' UTR primers was 5.1% (4/78) and 17.9% (14/78), respectively, and in patients on hemodialysis, it was 0% (0/81) and 5.9% (5/85), respectively. We could not detect GBV-C/HGV in patients with non-A-C liver disease. The incidence of GBV-C/HGV by 5' UTR primers was higher than by NS3R primers. After DNA sequencing at 5' UTR, phylogenetic analysis showed two types of GBV-C/HGV, Jap and HGV types. CONCLUSION: 5' UTR primers proved highly sensitive for detection of GBV-C/HGV and were superior to the NS3R primers.

5' Untranslated Regions↗
PubMed1998

Yeast coactivator MBF1 mediates GCN4-dependent transcriptional activation.

Transcriptional coactivators play a crucial role in gene expression by communicating between regulatory factors and the basal transcription machinery. The coactivator multiprotein bridging factor 1 (MBF1) was originally identified as a bridging molecule that connects the Drosophila nuclear receptor FTZ-F1 and TATA-binding protein (TBP). The MBF1 sequence is highly conserved across species from Saccharomyces cerevisiae to human. Here we provide evidence acquired in vitro and in vivo that yeast MBF1 mediates GCN4-dependent transcriptional activation by bridging the DNA-binding region of GCN4 and TBP. These findings indicate that the coactivator MBF1 functions by recruiting TBP to promoters where DNA-binding regulators are bound.

Amino Acid Sequence↗
PubMed1998

Beta-dystroglycan localization in the photoreceptor and Müller cells in the rat retina revealed by immunoelectron microscopy.

beta-Dystroglycan (beta-DG) is a dystrophin-associated glycoprotein that is expressed in skeletal muscle and other tissues. In the retina, dystrophin is present in the outer plexiform layer (OPL), where it is enriched under the photoreceptor cell membrane. In this study we determined the immunocytochemical localization of beta-DG at both light and electron microscopic levels. beta-DG immunoreactivity was detected at the inner limiting membrane, OPL, and around blood vessels. Immunoelectron microscopy detected beta-DG immunoreactive products under the photoreceptor cell membrane, which are the same regions of dystrophin localization. In addition, beta-DG was detected under the Müller cell membrane that is attached to the paravitreous or perivascular basement membrane. Our results suggest that beta-DG may interact with dystrophin in photoreceptor membranes. However, beta-DG-related interactions between Müller cells and basement membranes appear to be independent of dystrophin and raise the possibility that beta-DG interacts with other molecules. We speculate that beta-DG plays a role in maintaining the structural relationship between photoreceptor and bipolar cells or between Müller cells and basement membranes.

Amino Acid Sequence↗
PubMed1998

Mechanism of the protective effect of sodium malate on cisplatin-induced toxicity in mice.

We examined the mechanism of the protective effect of sodium malate on cis-diamminedichloroplatinum(II) (cisplatin, CDDP)-induced nephrotoxicity in mice and obtained the following findings: 1: Sodium malate showed a maximum reduction of toxicity when it was administered at the same time as CDDP or at 30 min before the administration of CDDP; the reduction was significantly decreased when sodium malate was given after the administration of CDDP. 2: It is thought that diamminoplatinum(II) malate (DPM) is produced in the body following the administration of a combination of CDDP and sodium malate. DPM showed the same antitumor effect as CDDP and produced little nephrotoxicity. 3: When CDDP was combined with sodium malate, the time necessary for the elimination of platinum from the blood was prolonged, showing a intermediate value between the times for the elimination of CDDP and DPM from the blood. When the drug clearance was calculated based on this result, it was found that about 40% of the CDDP administered is converted to DPM in the blood. 4: In an experiment using L-[14C] malic acid, it was shown that sodium malate is distributed in the liver and the kidney at high concentrations, but in the tumor at only a low concentration. 5: When sodium malate was administered in combination with CDDP, the amount of platinum which accumulated in the kidney after 24 h was decreased by about 55% compared with the uncombined group, but there was no change in the amount of platinum which accumulated in the tumor. These results suggest that the sodium malate administered may be distributed rapidly in the blood and the tissue, and about 40% is bound to CDDP and converted to DPM, thus reducing the nephrotoxicity of CDDP.

Animals↗
PubMed1998

Reduction of cisplatin toxicity and lethality by sodium malate in mice.

The effects of oral treatment with sodium malate, an active ingredient of Juzen-taiho-to, on the nephrotoxicity, bone marrow toxicity, hepatotoxicity and gastrointestinal toxicity caused by i.p. administration of 9 doses of 3.0 mg/kg/d cisplatin (CDDP) (on days 3, 4, 5, 6, 7, 8, 10, 11 and 12) were examined in ddY mice inoculated with sarcoma 180 (S-180) cells on day 1 of the study. The CDDP-induced increases in blood urea nitrogen, serum creatinine, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminases and relative stomach weight and the decreases in food intake and body weight were inhibited nearly to the control levels without reducing the antitumor activity of CDDP against S-180 by the oral treatment with sodium malate of 12 doses of more than the equimolar amount of CDDP (on days 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14 and 15). However, the CDDP-induced decreases in white blood cell and platelet counts and relative spleen and thymus weight could not be inhibited completely by combination with sodium malate, even at a dose of twice the equimolar amount of CDDP. The sodium malate-induced reduction of CDDP-induced nephrotoxicity and hepatotoxicity was observed after oral administration, as well as with i.p., s.c. and i.v. administration, and the effect was almost the same for each route of administration. Sodium malate also reduced the toxicity induced by high doses of CDDP (4.5, 6.0, 7.5, 9.0 and 12.0 mg/kg/d) at doses of twice the equimolar amount of CDDP. Sodium malate at a dose of 10.68 mg/kg/d (twice as high as carboplatin, CBDCA) did not reduce the nephrotoxicity, bone marrow toxicity, hepatotoxicity and gastrointestinal toxicity caused by i.p. administration of 9 doses of 15.0 mg/kg/d CBDCA on days 3, 4, 5, 6, 7, 8, 10, 11 and 12 in ddY mice inoculated with sarcoma 180 (S-180) cells on day 1 of the study. From this study, it was suggested that sodium malate could become a useful agent for the reduction of CDDP-induced toxicity, particularly nephrotoxicity and hepatotoxicity.

Animals↗
PubMed1998

[Biological response modifier activity of Lactococcus lactis 332].

The biological response modifier (BRM) activity of a preparation of heat killed cells of Lactococcus lactis 332 which can produce large amount of lactate in culture, was investigated in C3H/He and ICR mice. Intraperitoneal injection of Lactococcus lactis 332 caused an accumulation of neutrophils and macrophages in the peritoneal cavity of the mice, similarly to BRMs used clinically. As a parameter of the activation of macrophages, the effect of the Lactococcus lactis 332 preparation on the production of tumor necrosis factor (TNF) was examined. The Lactococcus lactis 332 preparation was revealed to have both priming and triggering activities for the production of TNF. The TNF level in the sera reached about 1000 IU/ml in mice 2 h after the triggering injection. This preparation also stimulated peritoneal macrophages to produce TNF in vitro. Intratumoral injection of the Lactococcus lactis 332 preparation regressed MM46 tumor cells in C3H/He mice. These results suggest that the Lactococcus lactis 332 preparation is a biological response modifier (BRM) with various activities on phagocytes similarly to a streptococcal antitumor agent, OK432, used clinically.

Animals↗
PubMed1998

Effects of a triple enzyme digestion method on a diamine reaction for glycosaminoglycans of the rat aorta in electron microscopy.

Effects of a triple enzyme digestion method using glycosaminoglycans-degrading enzymes upon a diamine reaction have been tested for electron microscopic histochemical detection of glycosaminoglycans in extracellular matrix of the rat aorta. The triple enzyme digestion method consists of a sequence of chondroitinase B, testicular hyaluronidase and heparitinase. The results obtained by the present experimental and control studies indicated that dermatan sulfates, chondroitin sulfates (A and/or C) or heparan sulfates were apparently observed in various ultrastructural features of aortic extracellular matrix, such as bundle of collagen fibers and soluble matrix of interstitial space. Particularly, we found that both heparan sulfates and chondroitin sulfates (A and/or C) were detected in association with the basal lamina of smooth muscle cells and the external surface of elastic lamina, and in the latter heparan sulfates were frequently recognized as a mass, whereas chondroitin sulfates (A and/or C) were found intermittently along the external surface of elastic lamina. This suggests that the triple enzyme digestion method which combines the glycosaminoglycans-degrading enzymes with the diamine reaction can be postulated to represent efficient and useful technique for precise electron microscopic histochemical detection of the glycosaminoglycans in the extracellular matrix of the rat aorta.

Animals↗
PubMed1998

Quantitative detection of anionic sites in rat femoral cartilage using cationic colloidal gold at low pH levels.

Quantitative analyses of anionic sites in the rat cartilage were performed by using post-embedding LR-Gold method with cationic colloidal gold (CCG) at different pH levels. Alteration of the pH levels affected the CCG staining patterns. The CCG particles were more observed at low pH levels, 1.0 and 2.5, than those at high pH 7.4. So, we quantitatively examined the superficial, intermediate and deep layers at pH 1.0. Morphometric analyses showed that CCG particles were increased from the superficial layer to the deep layer in both pericellular matrix (PM) and interterritorial matrix (IM). Moreover, they were more observed in PM than in IM. After chondroitinase ABC digestion, the CCG labeling was reduced in all matrices of the superficial and intermediate layers, though many CCG particles were still observed in PM of the deep layer. After hyaluronidase digestion, the CCG labeling was markedly reduced in the PM of the deep layer. These findings suggest that anionic sites in the cartilage matrix are detected by using the CCG only at low pH levels. In addition, the PM in the deep layer may consist of different components from those of the other two layers.

Animals↗
PubMed1998

Morphological studies of glomeruli in obstructive kidneys by confocal laser scanning microscopy and quick-freezing replica method.

Morphological changes of glomeruli in obstructive kidneys were studied by using confocal laser scanning microscopy (CLSM), and quick-freezing and deep-etching (QF-DE) method. Twenty-one rabbits were divided into three groups, consisting of control, 6-hr bilateral ureteral obstruction (BUO) and 24-hr BUO. In the experimental groups, the attenuation of cell bodies, the lengthening and stretching of major processes, the cystic formation in the cytoplasm and the fusion of foot processes were observed on conventional ultrathin sections. These changes in the 24-hr BUO group were more clearly observed than those in the 6-hr BUO group. By the CLSM, cell bodies and foot processes of podocytes in the experimental groups were more intensely immunostained with anti-alpha-tubulin antibody and phalloidin-FITC. By the QF-DE method, cytoskeletons in the podocyte cell bodies and major processes were composed of numerous intermediate filaments, but distinct changes of actin filaments and microtubules were not observed in the control and experimental groups. Considering the physiological changes in BUO, the mechanical stress appeared to be brought about by hemodynamic factors rather than the change of intratubular pressure, resembling the morphological changes in experimental animals with hyperfiltration and the homeostatic adaptation of podocytes under the BUO condition.

Animals↗