Search PubMed⌕ Search

Biomedical subjects

H Sakaguchi

Publications and source records attributed to H Sakaguchi.

At least 55 records · Page 3Linked to original sources
PubMed2001

Autoantibodies detectable in the sera of silicosis patients. The relationship between the anti-topoisomerase I antibody response and HLA-DQB1*0402 allele in Japanese silicosis patients.

Eighty-one Japanese silicosis patients and 66 healthy volunteers were analyzed for autoantibodies by ELISA, and HLA-genotyping using the PCR-RFLP method was performed. Anti-topoisomerase I (anti-topo I) autoantibodies were detected in seven patients without any clinical features of autoimmune diseases such as progressive systemic sclerosis (PSS), although anti-topo I have been mostly reported in PSS patients. Antibodies directed to RNP, ssDNA, dsDNA and cent-B were not detected among the anti-topo I positive patients. The indirect immunofluorescent staining pattern of Hep-2 cells with the sera of anti-topo I positive silicosis patients demonstrated the typical mode of anti-topo I autoantibodies observed in the patients with PSS. The allelic frequency of HLA-DQB1*0402 was significantly higher in anti-topo I positive patients (28.6%) than in anti-topo I negative patients (1.5%, P < 0.001) or healthy controls (0.8%, P<0.001). HLA-DQB1*0301, DQB1*0601 and DPB1*1801 alleles were more frequently detected in anti-topo I positive patients than in the patients without anti-topo I or in healthy volunteers, but no significant difference was observed. DQB1 allele is associated with the induction of anti-topo I autoantibodies in Japanese silicosis patients, but the allele is not the same as in Caucasian PSS patients. Another allele (DQB1*0402) plays an important role in Japanese silicosis patients. The most important factor to induce anti-topo I autoantibodies seems not to be the type of alleles themselves, but the position of some specific amino acid residues in the DQ beta first domain. These findings will be useful for preventing occupational autoimmune diseases.

Aged↗
PubMed2001

Functional connections between the HVC and the shelf of the zebra finch revealed by real-time optical imaging technique.

Auditory-motor interaction is essential for the understanding of avian song learning and maintenance. The HVC is thought to be the most important station for auditory-motor integration in the avian song system. However, little is known about where and how auditory inputs are conveyed into the HVC. The shelf, a multi-auditory recipient region located along the ventral border of the HVC, is thought to be a possible source of auditory inputs to the HVC. Here, we investigated the functional neural connections between the HVC and surrounding area of the HVC including the shelf in zebra finch brain slices, using the real-time optical recording technique. Unexpectedly electrical stimulation of the shelf region did not induce signal propagation into the HVC, but stimulation within the HVC propagated strong signals into the shelf. These results suggest that the shelf is the region that receives output signals from the HVC, rather than a major source of auditory inputs to the HVC.

2-Amino-5-phosphonovalerate↗
PubMed2001

Anti-HER2-antibody enhances irradiation-induced growth inhibition in head and neck carcinoma.

To explore the antiproliferative effects of rhumAbHER2 on head and neck squamous carcinoma cell (HNSCC) lines and breast cancer cell lines (BCCLs) and to evaluate the combined effects with irradiation, 2 human HNSCC lines and 2 BCCLs were exposed to rhumAbHER2 with or without irradiation. The results showed that combined treatment enhanced the growth and colonization inhibitory effects of rhumAbHER2 or irradiation. Interestingly, the apoptotic cell fraction produced by irradiation disappeared on combined treatment. This disappearance was associated with repression of p53 and Bax upregulation induced by irradiation, but conservation of the upregulation of p27. Based on these results, rhumAbHER2 and irradiation may be a new strategy for treating HNSCC and breast cancers. In addition, the upregulation of cyclin-dependent kinase inhibitors by rhumAbHER2 may occur upstream of irradiation-induced p53 upregulation.

Apoptosis↗
PubMed2001

A case of tuberculous peritonitis monitored by gallium-67 scintigraphy.

An 18-year-old man was admitted to our hospital for further examination of fever of unknown origin and ascites. Ga-67 scintigraphy revealed diffuse increased uptake throughout the abdomen. He was diagnosed with tuberculous peritonitis and began the treatment for tuberculosis (rifampicin, 450 mg/day orally and isoniazid, 300 mg/day orally, and 0.75 g of streptomycin by intramuscular injection 2 times a week). One year after starting the treatment, Ga-67 scintigraphy revealed accumulation of radioactivity in the upper abdomen, but the diffuse accumulation in the abdomen decreased. A specimen obtained by tumor biopsy under ultrasonic guidance revealed a tuberculous granuloma. Percutaneous injection was performed in the tumor with 1.0 g of streptomycin. On Ga-67 scintigraphy performed 2 weeks after the injection of streptomycin, the accumulation of radioactivity in the upper abdomen had disappeared. These findings suggest that Ga-67 scintigraphy is useful for diagnosis and observation during treatment of tuberculous peritonitis.

Adolescent↗
PubMed2001

In situ detection of oxidative DNA damage, 8-hydroxydeoxyguanosine, in chronic human liver disease.

BACKGROUND/AIMS: 8-Hydroxydeoxyguanosine (8-OHdG) is a promutagenic DNA lesion produced by oxygen radicals and is recognized as a useful marker in estimating DNA damage induced by oxidative stress. METHODS: Hepatic expression of 8-OHdG was immunohistochemically investigated in control and diseased human livers. RESULTS: While no positive immunolabeling for 8-OHdG was observed in control livers, 8-OHdG was widely evident in diseased livers. Nuclear expression of 8-OHdG in the hepatocytes and bile duct cells were found in various forms of chronic hepatitis. 8-OHdG-positive hepatocytes were especially abundant in the periportal area with piecemeal necrosis and prominent cell infiltration. The number of positive hepatocytes significantly increased with the progression of severity of chronic hepatitis activity (r(s)=0.68, P<0.05). In alcoholic liver disease, nuclear expression of 8-OHdG was detected in the hepatocytes in the area of alcoholic hepatitis. Regarding primary biliary cirrhosis, 8-OHdG was preferentially detected in the nuclei of injured bile ducts (11 of 12 cases, 91.7%) and occasionally (2 of 12 cases, 16.7%) in the nuclei of hepatocytes around the bile duct lesions. CONCLUSIONS: These results indicate that oxidative DNA damage is common in various forms of chronic liver disease suggesting a possible link between chronic inflammation and hepatocarcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Cell cycle analysis and expression of cell cycle regulator genes in myeloma cells overexpressing cyclin D1.

Among the recently discovered myeloma-specific gene alterations associated with chromosomal translocations, cyclin D1/PRAD1/Bcl-1 overexpression caused by t(11;14)(q13;q32) is considered to be the most frequent in myeloma patients and cell lines, and may be a prognostic factor clinically. To elucidate the cellular biological role of overexpressed cyclin D1 in myeloma cells, we examined the mRNA expression levels of cell cycle regulators including three cyclin Ds, cyclin-dependent kinase inhibitors (CDK-Is) and accelerators. Cyclin D1 overexpression was clearly demonstrated in the lines with abnormal 11q13 and associated with overexpression of S and G2 accelerator genes. The cyclin D1-overexpressing lines tended to have a shortened G1 phase compared with the non-expressing lines. In addition, artificial silencing using antisense oligonucleotides for cyclin D1 suppressed the growth rate of some but not all cyclin D1-overexpressing cells. These results indicate that overexpression of cyclin D1 caused by cytogenetic abnormalities may make cells progress through the cell cycle rapidly, but it seems that other factors such as cyclin D2 and translocation-related genes affect the cell cycle progression in myeloma cells.

Cell Cycle↗
PubMed2001

Identification of beta-lactoglobulin-derived peptides and class II HLA molecules recognized by T cells from patients with milk allergy.

BACKGROUND: Cow's milk allergy impairs the health and development of many infants since it deprives them of adequate nutrition. Cow's milk fractions contain many allergens, and beta-lactoglobulin (BLG) is one of the major allergens. OBJECTIVE: The purpose of this study was to determine T cell epitopes, antigen-presenting molecules and cytokine production by T cells in relation to BLG. The results can provide new therapeutic possibilities of using analogue peptides of BLG for infants with cow's milk allergy. METHODS: Using a mixture of a panel of overlapping synthetic peptides that cover the entire BLG molecule, we established polyclonal BLG-specific short-term T cell lines and clones from peripheral blood mononuclear cells of four patients with allergy to cow's milk carrying most of the common human leucocyte antigen (HLA) haplotypes seen in the Japanese population. We then identified the T cell epitopes and antigen-presenting molecules, and measured the production of cytokines interleukin (IL)-4, IL-5 and interferon-gamma in the culture supernatants. RESULTS: The T cell lines established from the four patients responded to seven different peptides. Three of the peptides stimulated the T cells of two donors, regardless of the HLA types. The patterns of inhibition of the proliferative responses of the cell lines by anti-HLA class II antibodies were heterogeneous; three were mainly inhibited by anti-HLA-DR mAbs, and the other was inhibited by anti-HLA-DQ mAbs. High levels of IL-5 were produced by these T cell lines. CONCLUSIONS: Patients' T cells recognized BLG in association with a variety of HLA-DR or -DQ as antigen-presenting molecules. Although some peptides did have a more potent T cell stimulatory activity than others, the T cell receptor ligands formed with the BLG molecule are heterogeneous. Peptides for the desensitization of T cells of the patients with cow's milk allergy need to be designed keeping in mind the different requirements in different ethnic groups.

Amino Acid Sequence↗
PubMed2001

Photoconductive imaging in a photon scanning tunnelling microscope capable of point-contact current sensing using a conductive fibre probe.

A photoconductive photon scanning tunnelling microscope was developed to investigate the point-contact photoconductive properties of condensed matter. In order to detect the current and the optical signal at a local point on a surface, we coated the edge of a bent type fibre probe with indium tin oxide. Thus it was possible to measure both photocurrent and optical property with subwavelength resolution. The performance of the novel microscope was evaluated by analysing an organic thin film of copper phthalocyanine (CuPc), which is known to be an efficient photoconductive material. Photocurrent and current-voltage characteristics were observed at the local point on the CuPc thin films. Furthermore, photoconductive images were obtained with topography and near-field optical imaging using this system. The photoconductive PSTM shows potential in various areas of future optics and electronics.

Journal Article↗
PubMed2001

Cardiac tamponade caused by spontaneous rupture of mediastinal lymph node metastasis of hepatocellular carcinoma.

Rupture of a hepatocellular carcinoma (HCC) is a well-known cause of death in patients with HCC. This report describes a rare case of HCC presenting as cardiac tamponade caused by a spontaneous rupture of mediastinal lymph node metastasis into the pericardial space. A transcatheter arterial embolization (TAE) of internal thoracic artery successfully controlled the bleeding, and the patient was rescued from cardiac tamponade. Although there was no rebleeding, the patient died from liver failure 2 months later. An autopsy revealed a poorly differentiated HCC in the liver, lung and mediastinal lymph nodes.

Carcinoma, Hepatocellular↗
PubMed2001

Different distribution of HLA class II alleles in anti-topoisomerase I autoantibody responders between silicosis and systemic sclerosis patients, with a common distinct amino acid sequence in the HLA-DQB1 domain.

Autoantibodies against DNA topoisomerase I (anti-topo I) have been reported to be specific to systemic sclerosis (SSc), however, anti-topo I was detected in patients with silicone breast implants, SLE without features of SSc, and rheumatic diseases. We detected anti-topo I positive silicosis patients without any symptoms of autoimmune diseases. The correlation between anti-topo I autoantibody responses and HLA class II has been established. HLA-DRB1*1502; DQB1*0601 has been reported to be the most frequent anti-topo I associated haplotype among Japanese SSc patients. In this study, haplotype HLA-DR15; DQ6 was detected in all 4 anti-topo I positive Asian Japanese SSc patients randomly selected. Furthermore, HLA-DQB1*0402 was identified in 3 of 4 anti-topo I positive silicosis patients. These findings coincide with the results of a previous study, in which all 4 Japanese patients with anti-topo I had the DQB1*04 alleles, whereas no studies among Caucasian-Americans, African-Americans and Choctaw Indians found the involvement of DQB1*04. We investigated common features among various DQB 1 alleles. HLA-DQB I with a distinct characteristic is clearly involved in the anti-topo I response irrespective of ethnic groups, the main disease, or silica exposure. A common positioning of distinct amino acids, (i.e. positions 14, 30, 57 and 77 of the DQbeta1 domain are methionine, tyrosine, aspartic acid and threonine, respectively,) seems to be associated with anti-topo I response. The above-mentioned amino acid sequence is detected in alleles *0301, *0303, *0306, *0401, *0402, *0601 and *0602.

Alleles↗
PubMed2001

Isolation of reducing oligosaccharide chains from the chondroitin/dermatan sulfate-protein linkage region and preparation of analytical probes by fluorescent labeling with 2-aminobenzamide.

The glycosaminoglycan (GAG)-protein linkage regions of various proteoglycans share the common tetrasaccharide GlcA-Gal-Gal-Xyl-attached to Ser residues in the core proteins. In previous analysis we demonstrated unique modifications by epimerization, sulfation and phosphorylation of the component sugars. Here we developed a sensitive analytical method for the linkage region oligosaccharides to detect or monitor structural variations and changes. This will be useful for investigation of their biological roles, which are largely unknown, but they have been implicated in biosynthesis. A variety of linkage region-derived hexasaccharides was first prepared as reducing sugar chains from peptide chondroitin/dermatan sulfate of whale cartilage, shark cartilage, and bovine aorta by means of chondroitinase digestion in conjunction with beta-elimination in the absence of reducing reagents, but involving a mild alkali, 0.5 M LiOH, at 4 degrees C to prevent peeling reactions. The structures of these oligosaccharides were determined by the combination of HPLC, enzymatic digestion, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and (1)H NMR spectroscopy, which revealed eleven different hexasaccharides including a novel structure, DeltaHexAalpha1-3GalNAcbeta1-4IdoAalpha1-3Gal(4-O-sulfate)beta1-3Galbeta1-4Xyl (DeltaHexA and IdoA represent unsaturated hexuronic acid and L-iduronic acid, respectively). These oligosaccharides were labeled with a fluorophore, 2-aminobenzamide, to prepare analytical probes using the recently developed procedure [Kinoshita and Sugahara (1999) Anal. Biochem. 269, 367-378]. The fluorophore-tagged hexasacharides of low picomoles were well separated by HPLC and successfully analyzed by MALDI-TOF mass spectrometry. The principle of the method should be applicable to the analysis of the linkage region oligosaccharides derived from heparin and heparan sulfate as well.

Alkaline Phosphatase↗
PubMed2001

Evaluation of accumulated mucopolysaccharides in the brain of patients with mucopolysaccharidoses by (1)H-magnetic resonance spectroscopy before and after bone marrow transplantation.

In seven patients with mucopolysaccharidoses (1 Hurler, 1 Hurler-Scheie, 4 Hunter, 1 Sly), cranial (1)H-magnetic resonance spectroscopy was performed to evaluate the accumulation of mucopolysaccharides and biochemical changes in the CNS in vivo before and after bone marrow transplantation (BMT). In two of seven patients, (1)H-magnetic resonance spectroscopy was performed before and after BMT. Nuclear magnetic resonance spectra of dermatan sulfate and chondroitin sulfate-C and magnetic resonance spectroscopy of chondroitin sulfate-C and urine from patients with mucopolysaccharidoses showed resonance higher than the chemical shift of myoinositol in the brain (3.7 ppm). The resonance was considered to contain signals from mucopolysaccharide molecules. The resonance was measured as presumptive mucopolysaccharides (pMPS). In white matter lesions detected by magnetic resonance imaging, pMPS/creatine ratios and choline/creatine ratios were consistently higher than control ratios. In white matter without lesions, choline/creatine ratios were higher than control ratios. Patients with higher developmental quotient or intelligence quotient tended to show higher N:-acetylaspartate/creatine ratios and lower pMPS/creatine ratios in basal ganglia. After BMT, the pMPS/creatine ratio in white matter lesions of patient 3, with Hunter syndrome, was slightly decreased, but in none of the patients was the ratio ever below the control ratios, even 7 y after BMT. In white matter without lesions, the pMPS/creatine ratio in patient 3 was decreased to the control ratios after BMT, but although the choline/creatine ratios were gradually decreased, they remained higher than the control ratio, 2 y after BMT. These results suggest that evaluation of pMPS, choline, and N:-acetylaspartate by (1)H-magnetic resonance spectroscopy is an important technique that may provide useful biochemical information in vivo on the neurologic process and the efficacy of BMT in patients with mucopolysaccharidoses.

Adolescent↗
PubMed2001

Quantitative analysis of estrogen receptor proteins in rat mammary gland.

Estrogen receptor alpha and beta proteins (ERalpha and ERbeta) at various stages of development of the rat mammary gland were quantified by Western blotting. ERalpha and ERbeta recombinant proteins were used as standards, and their molar concentrations were measured by ligand binding assays. In 3-week-old pregnant, lactating, and postlactating rats the ERalpha content ranged from 0.30-1.55 fmol/microg total protein (mean values). The ERbeta content of the same samples ranged between 1.06-7.50 fmol/microg total protein. At every developmental stage, the ERbeta content of the mammary gland was higher than that of ERalpha. When receptor levels were normalized against beta-actin, it was evident that ER expression changed during development, with maximum expression of both receptors during the lactation period. With an antibody raised against the 18-amino acid insert of the ERbeta variant, originally called ERbeta2 but named ERbetains in this paper, Western blots revealed that ERbetains protein was up-regulated during the lactation period. RT-PCR showed that the levels of messenger RNA of ERbetains paralleled those of the protein. Double immunohistochemical staining with anti-ERalpha and anti-ERbetains antibodies revealed that ERbetains protein colocalized with ERalpha in 70-80% of the ERalpha-expressing epithelial cells during lactation and with 30% of these cells during pregnancy. These observations indicate that expression of ERbetains is regulated not only quantitatively, but also with regard to its cellular distribution. As ERbetains acts as the dominant repressor of ERalpha, we suggest that its coexpression with ERalpha quenches ERalpha function and may be one of the factors that contribute to the previously described insensitivity of the mammary gland to estrogens during lactation.

Actins↗
PubMed2001

Expression and in vitro modification of parathyroid hormone-related protein (PTHrP) and PTH/PTHrP-receptor in human myeloma cells.

To elucidate the role of PTHrP in myeloma, we examined the expression levels of PTHrP and its receptor in human myeloma cell lines and clinical specimens from 13 myeloma cases. In vitro modification of PTHrP expression and production induced by TGF-beta and PMA in PTHrP expressing myeloma cell lines was also investigated. PTHrP expression was detected in six out of seven myeloma cell lines with an inverse correlation with the expression of its receptor, and in 10 out of 13 clinical specimens in varying degrees. The PTHrP expression and secretion into culture medium were enhanced by supplemental TGF-beta and PMA. PMA also seemed to affect PTHrP upregulation via TGF-beta activation. The fundamental role of PTHrP in bone lesions and hypercalcemia in myeloma may be important to consider even during the initial phase of the disease and particularly in the progression of bone complications with hypercalcemia.

Aged↗
PubMed2001

Establishment of CD7+ human myeloma sister cell lines, KMS-21-PE and KMS-21-BM, carrying t(11;14) and t(8;14).

Two new human myeloma cell lines were established from pleural effusion and bone marrow malignant cells derived from a single patient, who manifested hyperammonemia associated with multiple myeloma, and these were characterized. Both lines possess t(11;14)(q13;q32) and t(8;14)(q24;q32) reciprocal translocations and overexpress cyclin D1, but not c-myc. Human myeloma lines including these new lines produced and secreted excess ammonia into culture medium more than non-myelomatous hematological cell lines. In addition, these two lines were revealed to have high surface CD7 expression correlated with relatively high mRNA expression by MP-RT-PCR. Among 8 human myeloma lines, half of them revealed significant surface expression of CD7 and a positive correlation between expression levels of protein and message. CD7 message was also detected in surface negative lines. Consequently, there may be posttranslational regulation of the CD7 molecule, whose cellular biological role in expressing cells has not been elucidated.

Adult↗
PubMed2001

[Low concentration/high volume is more effective than high concentration/low volume for postoperative continuous epidural analgesia with the combination of bupivacaine and fentanyl].

In 40 females undergoing gynecologic laparotomy, lumbar epidural analgesia using a disposable infusion pump was continued for postoperative 48 hours. Then the analgesic effect of epidural bupivacaine (4.8 mg.kg-1) plus fentanyl (12 micrograms.kg-1) diluted with normal saline was prospectively compared between the two groups; high concentration/low volume group (HC/LV, 96 ml of total volume and 2 ml.h-1 of infusion rate, n = 20) versus low concentration/high volume group (LC/HV, 240 ml of total volume and 5 ml.h-1 of infusion rate, n = 20). On postoperative day 1, LC/HV group showed the significantly lower visual analog scale and verbal pain score at rest than HC/LV group (P < 0.05). No significant differences in the incidence of side effects were observed between the groups. These results suggest that when the equivalent dose is given, the volume rather than the concentration of the solution is important for postoperative continuous epidural analgesia with the combination of bupivacaine and fentanyl.

Adolescent↗