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Biomedical subjects

A Ishiguro

Publications and source records attributed to A Ishiguro.

At least 37 records · Page 2Linked to original sources
PubMed1999

Age-related changes in thrombopoietin in children: reference interval for serum thrombopoietin levels.

We studied thrombopoietin (TPO, Mpl ligand) values using a sensitive ELISA in 254 serum samples obtained from disease-free children and adult volunteers. TPO was detected in all samples, and its values ranged widely from 0.25 to 9.18 fmol/ml. When analysed by dividing the subjects into 11 age groups, the mean TPO levels from birth to 1 month of age were increased (3.73-5.92 fmol/ml). The highest values were found 2 d after birth; TPO levels then gradually decreased to adult levels (0.83 fmol/ml). The relationship between TPO values and platelet counts was not significant in all subjects (r = 0.27) or in children alone (r = 0.12). In children > 1 month of age a 95% reference interval for serum TPO values was determined from 0.58 to 3.27 fmol/ml. A significant correlation was found between TPO values in serum and plasma; serum TPO values = -0.257 + 4.039 x plasma TPO values (r = 0.951, P < 0.001, n = 22). This study is the first to report age-dependent changes in blood TPO levels throughout child development. Serum TPO values were significantly high up to 1 month of age and were correlated with plasma TPO levels.

Adolescent↗
PubMed1999

Correlation of lifting versus non-lifting and microscopic depth of invasion in early colorectal cancer.

BACKGROUND: The non-lifting sign is considered a contraindication to endoscopic resection. Our objective was to investigate whether lifting or nonlifting of a lesion is determined by the volume of normal submucosal tissue. METHODS: We measured the thickness of the submucosa and examined the relation between submucosal invasion and lesion elevation induced by submucosal injection in 60 patients with colorectal cancer with evidence of submucosal invasion. Extent of tumor elevation was classified into two groups: A, lifting; B, non-lifting. Submucosal invasion was classified as sm1, sm2, or sm3. The distance between the carcinoma and the line of resection and that between the carcinoma and the muscularis propria were measured. RESULTS: Of 31 sm1 lesions, 29 (93.5%) were group A. All 6 sm3 lesions were group B. All lesions in group A had a value for the distance between carcinoma and muscularis propria of more than 1000 microm. Group B lesions with sm3 invasion had distances of only 105 to 750 microm. CONCLUSION: Lesions classified as sm3 do not elevate in response to submucosal injection, and lesions that become elevated on injection can be resected endoscopically because they are sm1 or sm2 and have a thickness of normal submucosa of more than 1000 microm.

Adenomatous Polyps↗
PubMed1999

Serum granulocyte colony-stimulating factor levels in patients with chronic neutropenia of childhood: modulation of G-CSF levels by myeloid precursor cell mass.

The serum G-CSF levels of eight patients with severe congenital neutropenia (SCN) were found to be significantly higher than those of 22 patients with chronic benign neutropenia (CBN). The relative number of cells expressing the G-CSF receptor in light density bone marrow cells (LDBMC) was lower in patients with SCN than in patients with CBN or in normal subjects. When recombinant human G-CSF was incubated with LDBMC, G-CSF levels were decreased by LDBMC from normal subjects and CBN patients, but not by those from SCN patients. Serum G-CSF concentrations, which are affected by mature neutrophils, may also be modulated by myeloid precursor cells in the bone marrow.

Adolescent↗
PubMed1998

Two large subunits of the fission yeast RNA polymerase II provide platforms for the assembly of small subunits.

The subunit-subunit contact network was analyzed for the Schizosaccharomyces pombe RNA polymerase II consisting of ten putative subunits. Previously we carried out far-Western blot analysis of bimolecular interaction with radio-labeled subunit 3 and 5 probes. Here we extended the analysis using another six small-sized subunits as probes. Taking the results together the subunit-subunit interaction was observed for a total 18 (or 19) combinations. All eight small-sized subunits exhibited binding activities to two large subunits, Rpb1 and Rpb2. In addition, bimolecular interaction was observed for the combinations of Rpb3-Rpb5, Rpb3-Rpb11 (and Rpb5-Rpb8/11). The subunit-subunit contact within the assembled RNA polymerase was then analyzed by protein-protein cross-linking using five species of bifunctional cross-linkers with different length and specificity. Cross-linking was observed for a total of 19 combinations, including five combinations between small subunits, Rpb3-Rpb10, Rpb3-Rpb11, Rpb5-Rpb6, Rpb6-Rpb7 and Rpb6-Rpb8. The results altogether indicate that two large subunits Rpb1 and Rpb2 provide the platform for assembly of small subunits and also small subunits interact with each other for limited combinations. Direct contact of the two large subunits, Rpb1 and Rpb2, was also demonstrated by cross-linking.

Cross-Linking Reagents↗
PubMed1998

Location of subunit-subunit contact sites on RNA polymerase II subunit 3 from the fission yeast Schizosaccharomyces pombe.

RNA polymerase II from the fission yeast Schizosaccharomyces pombe consists of 10 putative subunits. Subunit 3 (Rpb3) is a homologue of prokaryotic alpha subunit, which plays a key role in the assembly of core enzyme subunits. Previously we indicated that Rpb3 also plays an essential role in subunit assembly because it interacts with at least four subunits, two large subunits (Rpb1 and Rpb2) and two medium-sized subunits (Rpb3 and Rpb5) (1), and it constitutes a core subassembly consisting of Rpb2, Rpb3, and Rpb11 (2). Using a synthetic mixture of equimolar amounts of individual subunits, which were all purified from cDNA-expressed Escherichia coli, we found here that Rpb3 also interacts with Rpb11, another alpha homologue. By making a set of Rpb3 deletion derivatives, we carried out mapping of the Rpb5- and Rpb11-contact sites on Rpb3. By far-Western blot and GST pull-down assays, we found that the amino acid sequence between residues 105-263 of Rpb3 is involved in binding Rpb5, and the sequence between residues 105-297 is required for binding Rpb11. Although the Rpb5- and Rpb11-contact sites on Rpb3 overlap each other, both subunits are able to associate with Rpb3 simultaneously. The binding of Rpb5 stabilizes the Rpb3-Rpb11 heterodimer.

Binding Sites↗
PubMed1998

Viability and pathogenicity of intersubgroup viroid chimeras suggest possible involvement of the terminal right region in replication.

To investigate the structural determinants regulating viroid replication and pathogenicity, we have examined the biological properties of four chimeric viroids containing sequences derived from hop stunt (HSVd) and citrus exocortis (CEVd) viroids. The viability of each chimera--CEHS (CEVd left half + HSVd right half), HSCE (HSVd left half + CEVd right half), CE/HS-TR (CEVd + HSVd right terminal loop), and HS/CE-TR (HSVd + CEVd right terminal loop)--was tested by inoculation onto cucumber and tomato seedlings. Chimeras CEHS and HSCE were not infectious, but CE/HS-TR and HS/CE-TR replicated stably and produced disease symptoms when inoculated onto tomato or cucumber, respectively. Progeny accumulation was reduced 10-fold or more compared to that of CEVd in tomato or HSVd in cucumber. The results suggested that the TR, like the TL and P regions, forms a relatively independent structural unit that contributes to the total function of a viroid. The effect of sequences in the right terminal loop on pathogenicity appears to be indirect, modulating the efficiency of viroid replication (or accumulation) efficiency rather than symptom expression per se.

Chimera↗
PubMed1998

Prolonged suppressed thyroid-stimulating hormone levels in hyperthyroidism in a neonate born to a mother with Graves' disease.

We report here a case of neonatal hyperthyroidism born to a mother, whose pregnancy was complicated by poorly controlled Graves' disease. The patient demonstrated exophthalmos and marked goiter at birth, indicating the existence of thyrotoxicosis in utero. The mother's Graves' disease was well controlled in the third trimester, resulting in a slightly lower level of free thyroxine (FT4) in the umbilical cord blood serum; however, thyroid-stimulating hormone (TSH) was undetectable. Thyroid-stimulating hormone remained undetectable for 2 months, while FT4 levels varied in the course. This case suggests that severe and prolonged thyrotoxicosis in utero, due to poor control of pregnancy with Graves' disease, might induce unresponsiveness of the hypothalamo-pituitary system in the newborn.

Female↗
PubMed1998

Elevation of serum thrombopoietin precedes thrombocytosis in Kawasaki disease.

Kawasaki disease (KD) is an acute systemic vasculitis causing coronary arterial aneurysms and myocardial infarction in young children. Prominent thrombocytosis with increased megakaryocytes develops during the convalescent period. To clarify the mechanisms of thrombocytosis, we studied serum levels of thrombopoietin (TPO) and other thrombopoietic cytokines in 40 patients with KD (149 samples) and 106 age-matched controls using ELISA. TPO values in the controls were 1.94 +/- 0.69 fmol/ml (mean +/- SD) with a 95% reference interval of 0.85 to 3.27 fmol/ml. In the first week of KD, platelet counts were normal but TPO values increased (approximately 15.5 fmol/ml). TPO levels peaked on day 6 +/- 2 at 5.94 +/- 2.64 fmol/ml and then fell gradually. When platelet counts peaked in the second to third weeks, TPO levels were still high or comparable with the controls. TPO levels in KD patients with normal platelet counts were significantly higher than control levels. Interleukin (IL)-6 levels in the first week rose, but neither IL-11 nor leukemia inhibitory factor was detectable. These results suggest that TPO contributes to thrombocytosis in KD in conjunction with IL-6 and TPO production may be enhanced during the acute phase.

Child↗
PubMed1997

RNA polymerase II subunits 2, 3, and 11 form a core subassembly with DNA binding activity.

RNA polymerase II purified from the fission yeast Schizosaccharomyces pombe consists of 10 species of subunit polypeptide. We introduced a histidine cluster tag sequence into the chromosomal rpb1 and rpb3 genes, which encode subunit 1 (Rpb1) and subunit 3 (Rpb3), respectively, and purified the RNA polymerase by Ni2+ affinity chromatography. After stepwise dissociation of the Rpb1- and Rpb3-tagged RNA polymerases fixed on Ni2+-resin by increasing concentrations of urea or guanidium hydrochloride, Rpb2-Rpb3-Rpb11 or Rpb2-Rpb3-Rpb11-Rpb10 complexes were obtained. Since the complex consisting of Rpb2, Rpb3, and Rpb11 cannot be dissociated even after treatment with 6 M urea buffer, we propose that this complex represents a core subassembly of the RNA polymerase II, analogous to the alpha2beta complex in the assembly of Escherichia coli RNA polymerase. Both the Rpb2-Rpb3-Rpb11 complex and the free Rpb1 protein showed DNA binding activity, although the affinity was weaker compared with the intact RNA polymerase.

Chromatography, Gel↗
PubMed1997

Effects and serum levels of thrombopoietin in a case of chronic thrombocytopenia with achondroplasia.

Thrombopoietin (TPO), produced mainly in the liver, is a major regulator of platelet production. Serum TPO levels are generally increased in thrombocytopenia. We report a case of a 12-year-old boy with chronic severe thrombocytopenia, achondroplasia and nephritis. Severe chronic thrombocytopenia was found at 9 months of age. It was resistant to any treatment. Studies on megakaryocytic colonies in vitro revealed that the marrow cells responded well to TPO and no plasma inhibitor was found. Although hepatic function test results were normal, serum TPO levels in the patient (0.94 fmol/ml) were consistent with those in age-matched children (0.49-1.75 fmol/ml). Chronic thrombocytopenia requires individual evaluation before clinical trials with TPO.

Achondroplasia↗
PubMed1997

The production of IL-8 in cerebrospinal fluid in aseptic meningitis of children.

Neutrophils accumulate initially in the cerebrospinal fluid (CSF) of aseptic meningitis, perhaps because of increased levels of granulocyte colony-stimulating factor (G-CSF), macrophage inflammatory protein-1alpha (MIP-1alpha), and IL-8 in the subarachnoid space. We studied levels of these cytokines in children with aseptic meningitis using ELISA. When meningeal symptoms existed, IL-8 levels (1399 +/- 1600 ng/l, n = 32) in the CSF were significantly higher than those either after meningeal symptoms disappeared (61 +/- 56 ng/l, n = 18) or in controls (44 +/- 63 ng/l, n = 27) (P < 0.0001). High levels of IL-8 on admission dropped sequentially. Significant correlations were found between IL-8 levels and either neutrophil counts (r = 0.612), G-CSF levels (r = 0.873) or MIP-1alpha levels (r = 0.623) in the CSF of the affected patients (P < 0.0001). IL-8 values in serum were lower than in the corresponding CSF samples from all individuals with meningeal symptoms. The IL-8 mRNA was detectable by reverse-transcribed polymerase chain reaction (PCR)-assisted amplification in fresh leucocytes from the CSF, but not from the peripheral blood of a healthy volunteer. The culture of CSF mononuclear cells produced high levels of IL-8 (approximately 2750 ng/l). These data indicate that IL-8 levels rise transiently at the initial stage of aseptic meningitis, and that mononuclear cells that migrate into the CSF are a cellular source of this chemokine. We suppose that IL-8, in addition to G-CSF and MIP-1alpha, contribute to the localized neutrophil accumulation during the disease.

Adolescent↗
PubMed1997

The production of macrophage inflammatory protein-1alpha in the cerebrospinal fluid at the initial stage of meningitis in children.

Neutrophils in the cerebrospinal fluid (CSF) increase during the initial stage of meningitis. Some cytokines induce the accumulation of such neutrophils, and we and other investigators have revealed transient increases in the levels of granulocyte-colony stimulating factor (G-csf) and IL-8 in the CSF of patients with meningitis. To explore the coordination of other cytokines with G-csf and IL-8 in the neutrophil accumulation in the CSF, we herein investigated macrophage inflammatory protein-1alpha (MIP-1alpha), which can induce the infiltration of neutrophils. The modulation of MIP-1alpha levels in the CSF in children with bacterial (n = 10) and aseptic (n = 22) meningitis was examined using an ELISA. MIP-1alpha levels in the CSF were detectable at the stage with symptoms of meningitis: 289.9 +/- 270.7 ng/L in the bacterial meningitis group and 16.1 +/- 12.5 ng/L in the aseptic meningitis group. These levels decreased with the improvement of symptoms. MIP-1alpha was not detectable (<6 ng/L) in all of the control patients without meningitis (n = 19). The MIP-1alpha levels in the CSF showed a significant correlation with the CSF neutrophil counts (r = 0.750, p < 0.0001; n = 80) of meningitis, and the values of MIP-1alpha (log ng/L)/neutrophil counts (log/L) ratio were calculated (1.003 +/- 0.576). The MIP-1alpha levels in the serum were significantly lower than those in the CSF (p = 0.0464). We found MIP-1alpha mRNA in the CSF cells by the reverse transcriptase-PCR method, and high levels of MIP-1alpha protein in the culture media from mononuclear cells in the CSF in vitro. In summary, The MIP-1alpha level increases in the CSF at the symptomatic stage of meningitis in children, and its cellular source is, in part, mononuclear cells which have infiltrated the CSF. We propose that MIP-1alpha, in addition to G-csf and IL-8, plays an important role in the accumulation of neutrophils in the CSF of patients with meningitis.

Adolescent↗
PubMed1997

[Serum levels and in vitro production of IL-5 in children with bronchial asthma].

IL-5 play important roles in inflammatory responses in bronchial asthma, but little is known about serum levels and in vitro production of IL-5 in childhood bronchial asthma. We further examined serum IL-5 levels in children with bronchial asthma and the controls. IL-5 in serum was detected in all of asthmatic and disease-free individuals. Its values during asthma exacerbation were significantly higher than during remission of asthma. Serum IL-5 values did not significantly differ among groups divided by asthma severity. We studied IL-5 production by peripheral blood mononuclear cells cultured with or without Dermatophagoides farinae (Df) in children with mite allergy. IL-5 concentrations in culture supernatant from after stimulation with Df were significantly higher than those from asthmatic patients without stimulation and from the control subjects. In contrast, IL-5 levels in culture media from the controls were not significantly different between with and without stimulation with Df. Our results suggest that IL-5 may play roles in the pathogenesis of bronchial asthma.

Asthma↗
PubMed1997

A crossreactivity at the immunoglobulin E level of the cell wall mannoproteins of Candida albicans with other pathogenic Candida and airborne yeast species.

BACKGROUND: Candida albicans crossreacts with Saccharomyces cerevisiae or Pityrosporum ovale at the IgE level. However, the extent of crossreactivity of C. albicans with other yeast species is not known. OBJECTIVE: The crossreactivity at the immunoglobulin E (IgE) level of Candida albicans with other pathogenic Candida species and to the airborne yeast species Cryptococcus and Rhodotorula was studied by immunoblot analysis. METHODS: Crude antigens, designated as heat extract, were prepared from 13 different yeast species and a dot blot test was performed to detect IgE antibodies against each of the heat extracts in 349 patients with allergies who were positive for IgE antibodies against C. albicans in a CAP system. RESULTS: In the dot blot test, most of the sera reacted with the heat extracts of not only C. albicans but also those prepared from the other yeast species. The sera of 41 of the 349 patients (11.7%) reacted with the heat extracts of all 13 yeast species. The extent of the binding of IgE antibodies to multiple yeast species correlated with both the fluorescence intensities measured in the CAP system and the intensities of dots generated by the heat extract of C. albicans in the dot blot test. In an inhibition dot blot test, mannoproteins, but not proteins, of C. albicans strongly inhibited the subsequent binding of IgE antibodies to all yeast species. CONCLUSION: Our data suggest that the C. albicans mannoproteins are responsible for the crossreactivity among these yeast species at the IgE level.

Air Microbiology↗