Biomedical subjects

Y Yamaguchi

Publications and source records attributed to Y Yamaguchi.

At least 703 records · Page 39Linked to original sources

PubMed1993

The expression and biological activity of IL-2 receptor on a human pancreas cancer cell line.

To ascertain whether the tumor cells can regulate the host immune systems through the production of the cytokines or their receptors, we examined the expressions of tumor necrosis factor alpha (TNF alpha), tumor necrosis factor beta (TNF beta), interleukin 2 (IL-2) and interleukin 2 receptor alpha chain (IL-2R alpha) on the human cancer cell lines by Northern blot analysis. We used K562 (leukemia cell line), MCF-7 (breast cancer cell line), LS180, HT29 (colon cancer cell lines), SH101 (gastric cancer cell line) and PH101 (pancreas cancer cell line). Expressions of TNF alpha, TNF beta and IL-2 mRNA were not detected in any of the tumor cell lines. However, 1.4 and 3.5 kilobases of the IL-2R alpha mRNA were expressed in the PH101 cells, but not in the other five cell lines. Furthermore, IL-2R alpha was detected on the cell surface of the PH101 cells by the flow-cytometric analysis with an anti-IL-2R alpha monoclonal antibody. Interestingly, the soluble IL-2R alpha (sIL-2R alpha) was found in the conditioned media obtained from the PH101 cell culture with a sandwich enzyme immunoassay. Moreover, the sIL-2R alpha secreted from the PH101 cells blocked the IL-2 dependent lymphocyte proliferation. These results indicate that the expression of IL-2R alpha on PH101 might suppress the IL-2 induced lymphocyte proliferation.

Cell Division↗

PubMed1993

The role of tumor necrosis factor-alpha in the aggravation of cerulein-induced pancreatitis in rats.

Severe acute pancreatitis is often complicated by intraperitoneal infection, resulting in multiple organ failure (MOF). It is known to elevate serum tumor necrosis factor (TNF-alpha) in patients with sepsis and/or MOF. In order to study the role of TNF-alpha in the aggravation of acute pancreatitis, we investigated TNF-alpha production by peritoneal macrophages in acute pancreatitis rat using the cerulein-induced pancreatitis model. TNF-alpha production by isolated peritoneal macrophages following lipopolysaccharide (LPS) stimulation was significantly increased in pancreatitis rats as compared with nonpancreatitis control rats (p < 0.001). Serum TNF-alpha activity was elevated following intraperitoneal administration of LPS as the septic challenge both in pancreatitis rats and in control rats, being significantly higher in the former (p < 0.05). Histological findings and liver function tests revealed that LPS induced more severe liver damage in pancreatitis rats than in control rats within 24 h after LPS administration. These results indicate that increased TNF-alpha production by peritoneal macrophages in acute pancreatitis augmented LPS-induced liver injury and suggest the possibility that TNF-alpha may play a role in the development of MOF during acute pancreatitis complicated by intraabdominal sepsis.

Acute Disease↗

PubMed1993

Dental arch and palate in Taiwan aboriginals--Ami, Bunun, Paiwan and Rukai tribes.

Differences in the dental arch and palate among Taiwan Aboriginals were investigated and compared with Taiwanese and Japanese. Plaster models were taken from 315 Taiwan Aboriginal adults, 185 Taiwanese and 426 Japanese between 1979 and 1989, and various dimensions were measured. There were no clear differences in the characteristics of the dental arch and palate between Taiwan Aboriginal tribes. However, they were found to differ from those of Taiwanese and Japanese. In a dendrogram constructed from a cluster analysis, two major clusters were found. Among males, the first cluster contained Paiwan and Rukai, the second contained Japanese, Taiwanese, Ami and Bunun. Among females, the first contained Japanese, Taiwanese, Rukai and Paiwan, the second contained Ami and Bunun. The Ami were close to Bunun and the Paiwan were close to Rukai among both males and females. These results indicate that Ami and Bunun, and Paiwan and Rukai, respectively, have close affinities.

Adult↗

PubMed1993

In situ kinetics of acinar, duct, and inflammatory cells in duct ligation-induced pancreatitis in rats.

BACKGROUND: Acute pancreatitis remains a disease of uncertain pathogenesis. The resolution of the cellular events that underlie the development of pancreatitis may allow for significant advances in therapy. METHODS: A new experimental approach to acute pancreatitis in the rat, i.e., selective ligation of pancreatic ducts and immunohistochemical analysis of cellular kinetics using a panel of monoclonal antibodies, was devised. RESULTS: Immunostaining showed that the majority of the infiltrating cells bore macrophage-specific antigens (ED1-positive). Some neutrophils were also among the cellular infiltrate, but only a few T (OX19-positive) or B (His14-positive) lymphocytes were seen. At a later stage, more than half of the mononuclear cells in the stroma were neither macrophages nor lymphocytes, but possibly fibroblasts. In vivo labeling of proliferating cells with 5-bromo-2'-deoxyuridine and immunostaining showed active proliferation of duct epithelial and wall cells of the interlobular pancreatic duct on days 1 and 2, proliferation of nonacinar cells on days 1-4, and proliferation of acinar cells on days 2-28. CONCLUSIONS: These results indicate an important role of macrophages and the presence of complex processes of degeneration and regeneration in duct ligation-induced pancreatitis.

Animals↗

PubMed1993

Biliary papillomatosis with the point mutation of K-ras gene arising in congenital choledochal cyst.

Biliary papillomatosis is a rare entity. A case of biliary papillomatosis associated with congenital choledochal cyst and intrahepatic gallstones is reported here. Percutaneous transhepatic cholangioscopy revealed multiple papillary lesions of the right intrahepatic duct and the common bile duct. Microscopically, the papillary mucosal lesion showed papillary proliferations of bile duct epithelial cells with mild atypia. Furthermore, a point mutation at codon 12 of the K-ras oncogene was found in the papillary lesion. To the best of our knowledge, this is the first case of biliary papillomatosis arising in congenital choledochal cyst. Although the pathogenesis of biliary papillomatosis in our case was unclear, biliary irritation associated with choledochal cyst may be related to biliary papillomatosis with point mutation at codon 12 of K-ras gene.

Aged↗

PubMed1993

Deficiency of holo-, but not apo-, ceruloplasmin in genetically copper-intoxicated LEC mutant rat.

Long-Evans Cinnamon(LEC) mutant rats exhibited less than 5% of normal levels of serum ceruloplasmin oxidase activity, but immunoblot analysis showed normal levels of immunologically detectable ceruloplasmin protein in sera from the mutant rats. Immunostaining of cryosections from the liver tissues with anti-ceruloplasmin antibody showed no significant difference between normal and LEC rats. Results from pulse labeling of ceruloplasmin for 3 hours with [35S]methionine in primary hepatocyte culture, followed by immunoprecipitation, SDS-PAGE and fluorography, showed only minor changes in ceruloplasmin protein synthesis and secretion. These results suggest that the mutation(s) does not affect ceruloplasmin gene expression, but results in a failure in the mechanism whereby copper is incorporated into newly synthesized apoceruloplasmin to produce oxidase active holoform.

Animals↗

PubMed1993

Lecithin-cholesterol acyltransferase and lipid transfer protein activities in liver disease.

The activities of lecithin-cholesterol acyltransferase (LCAT) and lipid transfer protein (LTP) were assayed using sensitive radioassay methods in controls (n = 113) and in patients with various liver diseases (n = 72). Plasma LCAT activity decreased with progression of hepatocellular damage. Plasma LTP activity in controls was 216 +/- 68 nmol/mL/h, and there were no significant differences between controls and patients with chronic hepatitis ([CH], 193 +/- 70), compensated liver cirrhosis (LC) with or without hepatocellular carcinoma ([HCC], 197 +/- 48 and 193 +/- 62, respectively), or decompensated liver cirrhosis ([dLC], 182 +/- 65). In acute viral hepatitis, LTP activity decreased significantly; however, the degree of reduction was not as dramatic as that for LCAT. There was no correlation between LCAT and LTP activity both in controls and patients with various liver diseases. LCAT activity was positively correlated with serum albumin (r = .52, P < 0.1) and cholinesterase (r = .37, P < .01) levels, and inversely correlated with serum bilirubin level (r = -.38, P < 0.1); there was no correlation between plasma LTP activity and these parameters of liver function. That plasma LTP activity did not change with hepatocellular damage may indicate that the liver in humans may not be the primary site of LTP production.

Acute Disease↗

PubMed1993

Enhancement of aortic cholesterol deposition by dietary linoleic acid in cholesterol-fed mice: an animal model for primary screening of antiatherosclerotic agents.

We tried to develop an experimental model using mice for the primary screening of antiatherosclerotic agents. Male ICR strain mice were given a high-cholesterol diet supplemented with 10% linoleic acid for 14 weeks. Throughout the experimental period, weight gain of these mice was significantly inhibited as compared to that of control mice given a basal diet, but displayed a steady increase comparable to that of the high-cholesterol diet without linoleic acid. The cholesterol and linoleic acid-fed mice showed increased serum cholesterol and phospholipid levels, and decreased serum triglyceride and high-density lipoprotein-(HDL) cholesterol levels and lecithin/cholesterol acyltransferase (LCAT) activity, as well as a markedly increased lipid peroxide level which was a characteristic appearance in the serum of this mouse model. At the end of the experiment, uniform and significant increases in cholesterol, notably cholesteryl ester, were observed in the aorta. Also found were marked decreases in the aorta contents of desmosine and isodesmosine, which are cross-linking amino acids present only in the elastin. Histological observations showed accumulations of fatty droplets in the intima. These changes were much less in mice receiving a high-cholesterol diet without linoleic acid. In this mouse model, probucol prevented elevation of serum cholesterol, phospholipid, and cholesterol accumulation in the aorta. Increases in lipid peroxide level and decreases in LCAT activity were also prevented. These findings indicate that this mouse model is useful for primary screening of antiatherosclerotic agents with antioxidative activity.

Animals↗

PubMed1993

Detection of subtle differences in the surface structure of lysozymes by use of an immobilized Fab fragment.

A method was developed to evaluate the association constant at physiological pH (pH 7.5) between a lysozyme and the Fab fragment derived from anti-lysozyme monoclonal antibody 37-7, which was immobilized to the adsorbent for HPLC. Comparison of the association constants between lysozymes and the immobilized Fab fragment indicated that mAb 37-7 recognized the prominently exposed regions (hills and ridges) around His15 of hen lysozyme, but His15 itself was not directly involved in the binding with mAb 37-7. Moreover, the epitope was confirmed by the reactivity of His15 with monoiodoacetic acid in the presence of mAb 37-7. The association constant of 15-carboxymethylated histidine lysozyme (15CM lysozyme) with the immobilized Fab fragment was smaller by one-seventh than that of 15-carboxamidated histidine lysozyme, though the side chains introduced were almost identical in size. From the pH titration of 15CM lysozyme with 13C-enriched carboxyl group by use of 13C-NMR, the pKa of the introduced carboxyl group was evaluated to be 5.06. Since the carboxyl group was fully ionized under the conditions of measurement (pH 7.5), electrostatic repulsion was found to disturb severely the association between mAb 37-7 and hen lysozyme. Moreover, it was demonstrated that, because of the high reproducibility of measurement, the immobilized Fab fragment could detect subtle differences in the surface structure of lysozymes.

Animals↗

PubMed1993

Diagnosis of genital herpes by polymerase chain reaction amplification.

A new polymerase chain reaction (PCR) method employing type-specific primers and probes was applied to 114 clinical specimens obtained from 58 female patients with genital lesions or who had a history of genital herpes. Ten and 15 specimens, respectively, were positive for herpes simplex virus (HSV)-1 and HSV-2 by cell culture. All of 10 culture-confirmed HSV-1 cases and 11 of 15 (73%) culture-confirmed HSV-2 cases were identified by PCR. Although there were several cases with discrepancy between cell culture and PCR for HSV-2, the results suggest that this PCR procedure could be applied to clinical specimens from the female genital tract.

Base Sequence↗

PubMed1993

Morphologic variations of dense deposit disease: light and electron microscopic, immunohistochemical and clinical findings in 10 patients.

Twenty-one renal biopsy specimens obtained from 10 patients with dense deposit disease (DDD) were investigated using light microscopy, electron microscopy and immunohistochemistry. The patients included four females and six males aged 6 to 35 years (mean 16.1 years). A morphological diagnosis of DDD was made following the ultrastructural detection of continuous intramembranous dense deposits (CIMDD) in some capillary loops of at least one of the series of the repeated biopsies from each patient. With light microscopy, six patients showed membranoproliferative glomerulonephritis (MPGN). The other four patients showed diffuse proliferative glomerulonephritis (DPGN) with acute lesions showing intraglomerular neutrophilic infiltration, hump formation and endothelial swelling in three and minor glomerular abnormalities in one. Follow-up biopsies were obtained in six patients. Two patients progressed from DPGN to MPGN within 7 months, whereas three patients with MPGN showed morphologic improvement that featured increased capillary patency and regional disappearance of dense deposits along with the reduction of proteinuria. Dense deposit disease did not always feature typical amorphous and osmiophilic CIMDD spreading across the whole width of the lamina densa. This classical ultrastructural manifestation was mainly found in the patients with histologic non-MPGN and a linear peripheral pattern of complement component (C3) deposition. The MPGN patients with a granular peripheral pattern of C3 deposition also had CIMDD, but also additionally featured less dense subepithelial deposits superimposed on the CIMDD to produce an appearance simulating membranous transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Increased urinary excretion of human cytomegalovirus in children with malignancy: detection by polymerase chain reaction.

Human cytomegalovirus (HCMV) is one of the most important agents causing opportunistic infections in immunocompromised hosts. In this study, we examined the urinary excretion of HCMV in children with malignancy using polymerase chain reaction (PCR). Urine samples were collected from on-therapy, off-therapy patients with malignancy, and healthy controls. A simple DNA extraction method using glass powder was employed, and inhibitory effect of urine on PCR was prevented. For PCR, a pair of primers from the HCMV major immediate early gene sequence was used. Among patients who received intensive chemotherapy, 52.0% had urinary HCMV excretion after the chemotherapy course. In contrast, off-therapy patients and healthy controls showed a lower incidence of urinary HCMV excretion (20.4 and 8.7%, respectively). The incidence of HCMV urinary excretion in the on-therapy group was significantly higher than healthy controls (P < 0.05). In the on-therapy group, the total white blood cell count of the virus excreters was lower than that of non-excreters. The incidence of HCMV excretion was high in on-therapy patients. Most of the virus excreters were seropositive, so their viruria was thought to be caused by reactivation. Repeated monitoring of virus excretion by this rapid and simple method may be useful to detect HCMV infection early and to control it in such patients.

Adolescent↗

PubMed1993

Virucidal effects of glucose oxidase and peroxidase or their protein conjugates on human immunodeficiency virus type 1.

Glucose oxidase and peroxidase (lactoperoxidase or myeloperoxidase) are virucidal to human immunodeficiency virus type 1 (HIV-1) in the presence of sodium iodide, as assessed by the loss of viral replication in a syncytium-forming assay or by the inhibition of cytopathic effects on infected cells. In the presence of low concentrations of sodium iodide, five HIV-1 isolates were equally susceptible to this virucidal system at enzyme concentrations of a few milliunits. The loss of viral replication was linearly related to the time of incubation in the enzyme solutions, with an inactivation rate of 1 log unit every 30 min. These enzymes and this halide were also cytotoxic to chronically infected, but not to uninfected, cultured CEM cells. Protein conjugates were prepared by using the enzymes and murine antibody 105.34, which recognized the V3 loop of HIV-1 LAI isolate surface glycoprotein, or recombinant human CD4. The protein conjugates inactivated free virus at rates similar to those of the free enzymes and were more effective than antibody or recombinant CD4 alone. These in vitro findings demonstrate that the peroxidase-H2O2-halide system provides potent virucidal activity against HIV-1.

Antibodies, Monoclonal↗

PubMed1993

Hepatocyte horseradish peroxidase uptake is saturable and inhibited by mannose-terminal glycoproteins.

In the liver, horseradish peroxidase (HRP) is thought to be taken up via mannose receptor-mediated endocytosis by non-parenchymal cells (NPC) and via fluid-phase endocytosis by hepatocytes. When we attempted to inhibit NPC uptake of HRP with mannan in the whole perfused rat liver, > 80% of HRP uptake was eliminated. Liver cell fractionation revealed that mannan not only inhibited HRP uptake by NPC (91%) but also by hepatocytes (81%). In isolated hepatocytes, HRP uptake was linear over 60 min and saturable in the range of 0 to 200 mg/l (Vmax = 4.3 ng.mg protein-1.min-1; Km = 8.3 mg/l). Mannan inhibited uptake competitively (Ki = 2.0-2.5 mg/l). At high concentrations of HRP, a nonsaturable component of HRP uptake became evident (k = 2.8 pg.mg protein-1.min-1.mg HRP-1.l-1). Hepatocyte uptake of HRP was inhibited by other glycoproteins and glycopeptides with mannose-terminal groups, as well as by mannan, but not by asialofetuin (ASF) or bovine serum albumin. Hepatocyte uptake of 125I-labeled ASF, which is taken up via the asialoglycoprotein receptor, was saturable and not inhibited by mannan. HRP binding to hepatocytes, determined at 4 degrees C, was also inhibited by mannan. Quantification of contamination of the parenchymal cell fraction by NPC by cell counting and by pronase digestibility suggested our results could not be explained by contamination of hepatocytes by NPC. At concentrations used for most morphological studies (1,000-10,000 mg/l), fluid-phase endocytosis accounts for much of HRP uptake. However, at low concentrations, a saturable low-capacity mechanism is responsible for most HRP uptake by the hepatocyte.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

PAF increases capillary pressure but not vascular permeability in isolated blood-perfused canine lungs.

We determined the effects of platelet-activating factor (PAF) on pulmonary vascular resistance, lung weight, and microvascular permeability in isolated canine lungs perfused at constant pressure with autologous blood. PAF caused a dose-dependent increase in total pulmonary vascular resistance (Rt) and pulmonary capillary pressure assessed as double-occlusion pressure. PAF (33 micrograms; n = 7) caused a 10-fold increase in Rt and a decrease in precapillary-to-postcapillary vascular resistance ratio from 0.97 +/- 0.10 to 0.38 +/- 0.03, suggesting predominant pulmonary venoconstriction. Shortly after PAF, lung weight decreased transiently and then increased, reaching a plateau above baseline (112.5 +/- 1.6%) at 30 min. In lungs perfused in the antidromic direction from the pulmonary vein to the artery (n = 5), PAF (33 micrograms) produced marked precapillary vasoconstriction, consistent with pulmonary venoconstriction, and a remarkable and sustained decrease in lung weight below baseline by 30 min. Vascular permeability, measured 30 min after PAF using the capillary filtration coefficient and isogravimetric capillary pressure, did not change significantly from baseline. Thus we conclude that PAF produces lung weight gain by means of an increase in capillary pressure predominantly due to pulmonary venoconstriction without significant changes in vascular permeability in isolated blood-perfused canine lungs.

Animals↗

PubMed1993

Characteristic glomerular lesions in the ExHC rat: a unique model for lipid-induced glomerular injury.

ExHC rats were bred from the Sprague-Dawley strain and are highly susceptible to dietary hypercholesterolemic stimuli. Although chemical and histological examination of the aorta from ExHC rats fed a diet containing 3% cholesterol, 0.6% sodium cholate and 15% olive oil (high-cholesterol diet, HCD) has been reported, renal injury in this model has not been investigated to date. Therefore, we examined the renal pathological changes and proteinuria in this model. ExHC rats fed an HCD developed proteinuria and characteristic glomerular lesions within 4-8 weeks after initiation of the diet. The most striking glomerular change observed in this model was the marked accumulation of numerous lipid-filled foam cells, with a surface marker that identified them as macrophages, within the mesangial regions which could have been involved in focal and segmental glomerular sclerosis. Our study demonstrates that ExHC rats fed a cholesterol-supplemented diet develop glomerular injury that may be mediated by infiltrating macrophages. These results imply that ExHC rats may be well-suited for the use in investigations of the role of macrophages in the pathogenesis of lipid-induced glomerular injury.

Animals↗

PubMed1993

Glomerular growth in the remnant kidney after a contralateral nephrectomy.

A unilateral nephrectomy enhances growth or weight gain in the remaining kidney, although it is not known whether the mechanism involves the division of glomerular cells. We have isolated glomeruli from the remnant kidney at different time intervals after a nephrectomy and measured the percentage of cells in the G1, G2 + M and S phases by flow cytometry. All the steady-state glomerular cells remained in G1 phase, while a significant percentage had progressed into the S phase by 4 h after the uninephrectomy. The rise in the number of cells in the S phase gradually decreased to control values by 48 h, during which time the number of cells in both G1 and G2 + M phases increased concomitantly. Neither DNA nor RNA content per glomeruli was altered by 4 and 24 h after uninephrectomy. The data suggest an early division of the glomerular cells in the remnant kidney after a contralateral nephrectomy.

Animals↗

PubMed1993

Ligand-binding properties of the two isoforms of the human insulin receptor.

Tissue-specific alternative splicing of exon 11 of the insulin receptor gene results in 2 mRNAs that differ by 36 nucleotides within the coding region. The 2 transcripts encode 2 protein isoforms with (Ex11+) or without (Ex11-) 12 additional amino acids at the carboxy-terminus of the receptor alpha-subunit. Previous studies of the 2 isoforms of the human insulin receptor expressed in mammalian cell transfectants have revealed small functional differences at the levels of equilibrium insulin binding affinity and acute ligand-induced receptor internalization. In the present study, we determined the biochemical basis for differential insulin binding affinity. Further functional characterization of the 2 receptor isoforms was also performed. The results obtained were as follows. 1) Studies of ligand association demonstrated a faster (1.8-fold) "on rate" for Ex11- receptors than for Ex11+ receptors, as determined by the kinetics of [125I]insulin binding to transfected cells. In addition, dissociation of prebound [125I]insulin from Ex11- receptors was characterized by an accelerated "off rate" relative to that of Ex11+ receptors. 2) Using both intact Chinese hamster ovary (CHO) cells and partially purified solubilized insulin receptors, the ability of insulin-like growth factor-I to compete for [125I]insulin binding to either isoform differed markedly. The mean IC50 for Ex11- was 40 nM vs. 350 nM for Ex11+. 3) Both Ex11- and Ex11+ receptors were equally capable of hybrid formation with endogenous CHO cell insulin-like growth factor-I receptors. 4) The relative abilities of 2 inhibitory polyclonal antiinsulin receptor antisera to displace [125I]insulin binding did not differ between the two isoforms. 5) Studies of insulin-induced (300 nM) receptor down-regulation in CHO cell transfectants suggested preferential down-regulation of Ex11- receptors; however, no down-regulation difference was observed when Rat 1 cell transfectants expressing the two splice variants were studied. These findings further support the idea that the 2 isoforms of the insulin receptor are functionally distinct in important ways.

Animals↗