Biomedical subjects

T Aida

Publications and source records attributed to T Aida.

At least 37 records · Page 2Linked to original sources

PubMed1997

Differences in immune responses to antibiotics in three guinea-pig strains.

The present experiments were undertaken to clarify the differences in humoral immune response to two beta-lactam antibiotics, benzylpenicillin potassium (PcG) and cephalothin sodium (CET), in guinea-pig strains. Guinea pigs of three different strains, Hartley, Strain 2 and Strain 13, were immunized subcutaneously with PcG (10 mg/body) 1 or 3 times a week, 10 times in total, or with CET (20 mg/body) 3 times a week, 12 times in total. Humoral immune responses to the two antibiotics were assessed by passive cutaneous anaphylaxis (PCA) and active systemic anaphylaxis (ASA) reactions. The relative intensities of the responses to PcG and CET detected by PCA reaction were Hartley > Strain 2 > Strain 13. On the other hand, Hartley and Strain 13 guinea pigs displayed high responses to the two antibiotics by ASA reaction, and Strain 2 exhibited a relatively low response. Based on these results, it was clarified that the Hartley strain, which is the most common strain used in ordinary allergenicity tests, showed the highest response to the two antibiotics tested in PCA and ASA reactions.

Anaphylaxis↗

PubMed1996

Cloning, sequencing and characterization of the gene encoding a principal sigma factor homolog from the cyanobacterium Microcystis aeruginosa K-81.

We cloned and sequenced the rpoD1 gene of Microcystis aeruginosa K-81, a unicellular colony-forming cyanobacterium that can perform photosynthesis involving light-responsive gene expression. The deduced amino acid sequence of RpoD1 exhibited extensive homology to the other eubacterial principal sigma factors. Primer extension and Western blot analyses revealed that the rpoD1 gene, which encodes a principle sigma factor homolog, had two transcription start points, P1 and P2. These transcripts, and the corresponding protein, constitutively appeared in M. aeruginosa, irrespective of light or dark conditions.

Amino Acid Sequence↗

PubMed1996

Highly repetitive sequences and characteristics of genomic DNA in unicellular cyanobacterial strains.

Microcystis aeruginosa (Synechocystis) is a unicellular cyanobacterium that performs oxygenic photosynthesis. We found two novel sets of repetitive sequences, A (REP-A) and B (REP-B), on the M. aeruginosa K-81 genomic DNA, which consisted of distinct motifs of tandem repeated sequences located in the up- and downstream regions of the orf1 structural gene, respectively. Genomic Southern hybridization revealed multicopies of REP-A and -B on the genome. Furthermore, genomic Southern blots of cyanobacteria species with the REP-A and -B probes revealed that different hybridization signals appeared on the genomic DNAs of all 12 Microcystis strains, but no signal appeared on those of Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, and Anabaena sp. PCC 7120.

Amino Acid Sequence↗

PubMed1996

The rpoD1 gene product is a principal sigma factor of RNA polymerase in Microcystis aeruginosa K-81.

We performed molecular characterization of the RpoD1 protein encoded by the rpoD1 gene isolated from a cyanobacterium, Microcystis aeruginosa K-81. The deduced amino acid sequence (416 aa, 48,871 Da) of RpoD1 exhibited extensive similarity to those of proteins of the eubacterial RpoD family (Escherichia coli sigma 70 homologs). We overproduced and purified RpoD1 (54 kDa) from E. coli. Biological and biochemical analyses suggested that RpoD1 has a function homologous to that of E. coli sigma 70 as follows: (i) the RpoD1 protein complemented an rpoD mutant of E. coli strain YN543 (rpoD285) and (ii) the heterologous RNA polymerase holoenzyme reconstituted from the E. coli core enzyme and recombinant RpoD1 was specifically transcribed from E. coli promoters. Furthermore, Western blot analysis with antiserum against Synechococcus sp. strain PCC 7942 RpoD1 (a principal sigma factor of the sigma 70 type) indicated that M. aeruginosa K-81 RpoD1 (sigma A1) is the principal sigma factor, which is a major component of the sigma subunit on exponential cell growth.

Amino Acid Sequence↗

PubMed1996

The sre gene (ORF469) encodes a site-specific recombinase responsible for integration of the R4 phage genome.

The sre gene (ORF469) of the R4 phage encodes a protein similar to the resolvase-DNA invertase family proteins. Insertional gene disruption of sre prevented a lysogen from entering the lytic cycle, implying that Sre protein is a site-specific recombinase needed for excision of the R4 prophage genome (M. Matsuura, T. Noguchi, T. Aida, M. Asayama, H. Takahashi, and M. Shirai, J. Gen. Appl. Microbiol. 41:53-61, 1995). To determine whether this sre gene is also necessary for the integration reaction, we studied its function by integration plasmid analysis. When deletions, frameshifts, and site-directed mutations that caused an amino acid substitution of Ser-17 for Ala were introduced into the sre structural gene, transformation efficiency of Streptomyces parvulus 2297 with these plasmid DNAs was severely reduced. However, an adenine insertion just before the possible initiation codon of the sre gene did not significantly decrease the efficiency. These data suggest that the Sre protein is a site-specific recombinase responsible for integration of the R4 phage genome.

Bacteriophages↗

PubMed1996

Phase II study of DTIC, ACNU, and vincristine combination chemotherapy for supratentorial malignant astrocytomas.

This phase II clinical study evaluated the use of 5-(3-3'-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC) pretreatment to reduce cellular resistance and enhance the antitumor effects of chloroethyl nitrosoureas in 32 patients with supratentorial malignant gliomas, including 13 anaplastic astrocytoma and 19 glioblastoma multiforme. All patients received a total dose of 50-65 Gy radiation therapy after surgery. Chemotherapy consisted of DTIC (1 mg/kg) on days 1-5, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (2 mg/kg) on day 5, and vincristine (0.02 mg/kg) on days 1 and 15 every 5 weeks. One patient achieved complete response and 12 patients showed partial response. Median survival time was 18 months and median time-to-progression was 11 months. No significant toxicity was encountered. There was no significant benefit of this pretreatment to combination chemotherapy when compared with previous results. This study does not support a further role for DTIC as a depleter of O6-alkylguanine deoxyribonucleic acid alkyltransferase activity preceding chloroethyl nitrosourea-based chemotherapy.

Adolescent↗

PubMed1995

Immunohistochemical analysis of giant cell glioblastoma.

Giant cell glioblastoma (GCG) is one of a group of rare tumors in which the cell population is abnormally large and includes multinucleated cells of gigantic sizes. Immunohistochemical studies were performed on four GCG cases and found that all giant cells and/or tumor cells were positive for glial fibrillary acidic protein (GFAP), S-100 protein, and vimentin, thus verifying the tumor's glial origin. The nuclei of multinucleated giant cells of three adult cases were frequently immunostained for proteins expressed during the cell cycle (proliferating cell nuclear antigen (PCNA) and Ki-67), thereby demonstrating the proliferative capacity of these cells. By contrast, those of a 12 year old girl expressed these cell cycle markers rather infrequently. Alpha I-antitrypsin was detected with relatively high frequency in the giant cells, and its presence may explain their bizarre sizes and pericellular reticulin fiber formation. A literature review of 32 cases revealed that the GCG that occurs preferentially in young girls is a type of pleomorphic xanthoastrocytoma. By contrast, GCG in adult males has the same age incidence as ordinary glioblastomas and, as these, expresses high levels of cell cycle-related proteins. Thus, GCG, which is subclassified morphologically as ordinary glioblastoma, has distinct biological and clinical characteristics, with that in children requiring re-evaluation because of its similarities to pleomorphic xanthoastrocytoma.

Age Factors↗

PubMed1994

Fibronectin biosynthesis in endothelial regeneration after intimal injury.

In this experiment, we sought to identify the major fibronectin (FN) synthesizing cells, the source of FN production, and the role of FN in intimal regeneration. In rats in which vascular endothelial denudation had been induced, serial morphologic changes after intimal injury were studied by light and electron microscopic examination using immunohistochemical techniques and in situ hybridization. At 2 weeks after intimal injury, regenerated endothelial cells had pleomorphic cytoplasm and loose cellular junctions. Immunohistochemically, factor VIII-related antigen was localized in the regenerated endothelial cells, and immunoreaction products of FN were increased in the thickened neointima. Ultrastructurally, FN was localized in the proliferated endoplasmic reticulum of regenerated endothelial cells in the intima, while the alpha 5 subunit of alpha 5 beta 1 integrin, one of the fibronectin receptors, was localized in the plasma membrane and increased endoplasmic reticulum of regenerated endothelial cells. FN mRNA was localized in a large number of regenerated endothelial cells (87.2 and 89.8%) by in situ hybridization at 2 and 4 weeks after intimal injury. These findings indicate that FN may mainly contribute to endothelial cell functions such as spreading and adhesion in the regenerative stage.

Animals↗

PubMed1994

Antiproliferative effect of tumor necrosis factor-alpha on human glioblastoma cells linked with cell cycle arrest in G1 phase.

The effects of tumor necrosis factor-alpha (TNF) on proliferation and cell cycle alterations in human malignant glioma cell lines, SF-188 and LN-382, were investigated by flow cytometry with the bromodeoxyuridine-propidium iodide dual staining technique. Low concentrations of TNF (1-100 U/ml) suppressed the growth of SF-188 assessed by cell count, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, and thymidine incorporation assay, but not that of LN-382. After TNF treatment, the percentage of SF-188 cells in the G0/G1 phase increased, while the percentage of cells in the S phase decreased. LN-382 cells did not show any marked change in cell kinetics. TNF arrests certain human glioma cells in the G0/G1 phase resulting in reduction of deoxyribonucleic acid synthesis in the subsequent S phase, suppressing the proliferation pathway.

Brain Neoplasms↗

PubMed1994

Process of basement membrane re-formation after intimal denudation.

During re-endothelialization after intimal denudation induced by balloon catheter in the rat aorta, re-formation of the basement membrane (BM) was examined in samples taken 15 min, 3, 7, 14, 21 and 28 days after the balloon-induced injury. Although the luminal surface of the aortic wall was covered by round-shaped regenerating endothelial cells (ECs) by 7 days after intimal denudation, no continuous BM structure was detectable until 21 days. Periodic acid-thiosemicarbazide gelatin-methenamine silver (PATSC-GMS) staining for electron microscopy and immunostaining of type IV collagen and laminin demonstrated the accumulation of BM components underneath the regenerating ECs after 14 days. The expression of type IV collagen mRNA was revealed in regenerating ECs by in situ hybridization. A continuous BM structure first appeared 21 days after intimal denudation and was almost complete by 28 days. Simultaneously, the regenerating ECs flattened and attached more closely to the BM than in earlier phases. In conclusion, we consider that the regenerating ECs produce the BM components and suggest that reorganization of the newly formed BM is important in the process of differentiation of regenerating ECs.

Animals↗

PubMed1994

[Clinicopathologic analysis of ossification in spinal meningioma].

Calcification such as psammoma body is sometimes found especially in spinal cord meningioma but ossification of the meningeal tumor was rarely observed. Two cases of ossificated spinal cord meningiomas, located extramedullary intradurally apart from spinal bone, were clinicopathologically analyzed. The patients were 75-year-old female with meningioma at T9-10 level and 60-year-old female with one at T6-8 level. With pathological examination, concentration of psammoma bodies is not related to the formation of bone tissue. Metaplasia of arachnoid cell is seemed to be the origin of the bone structure.

Aged↗

PubMed1993

Responses of human glioblastoma cells to human natural tumor necrosis factor-alpha: susceptibility, mechanism of resistance and cytokine production studies.

Responses and susceptibility of 14 human glioblastoma cell lines to human natural tumor necrosis factor-alpha (TNF) were studied in vitro. Susceptibility of glioblastoma cells to TNF varied in experimental conditions applied. Most of glioblastoma cell lines were resistant to cytotoxic activity of TNF in a MTT assay at concentrations below 16 U/ml for 72 h exposure. However, TNF at higher dose, in prolonged exposure and against low density of target cells was antiproliferative for certain glioblastoma cultures. TNF exposure at 10 U/ml for 48 h suppressed DNA synthesis in 9 of 14 glioblastoma cultures, but increased in 3 cultures. In addition, colony forming assay showed anti-clonogenic activity of TNF in 5 of 6 glioblastoma cell lines tested. In spite of their low susceptibility to TNF, glioblastoma cells well responded to TNF stimulation at low dose (10 U/ml) for a short period in the absence of cell damage. Productions of Interleukin-6 (IL-6), IL-8-like activity, granulocyte-macrophage colony stimulating factor (GM-CSF), prostaglandin E2 (PGE2) and manganous superoxide dismutase (Mn-SOD) were enhanced or induced by the low-dose TNF stimulation. Mn-SOD, a protein protective against oxidative cell damage, was well induced in time- and dose-dependent manner, however did not correlate with TNF resistance. Whereas the levels of PGE2 in TNF-susceptible cell lines, H-4 and SF-188, were higher than those of other lines. In conclusion, most of glioblastoma cells are resistant to TNF cytotoxic effects, but highly responsive to TNF stimulation. Its effect on glioblastoma cells appears to modulate cell differentiation rather than to kill the cells.

Cell Division↗

PubMed1993

Cellular and cytokine responses of the human central nervous system to intracranial administration of tumor necrosis factor alpha for the treatment of malignant gliomas.

To elucidate the role of tumor necrosis factor alpha (TNF alpha) as a biological response modifier, we studied cellular and cytokine responses of the central nervous system to TNF alpha administered intracranially in a phase I clinical trial for patients with malignant gliomas. Six patients received injections of TNF alpha (1.25 x 10(3)-10 x 10(3) U/injection) into the tumor cavities, and regional fluids (RF) and lumbar cerebrospinal fluids (CF) were serially sampled before and after the injections. Recruitment of neutrophils occurred, mostly peaking 8 h after TNF alpha injection, and fewer numbers of CD4+ T cells and monocytes/macrophages migrated, subsequently peaking at 24 h. The CF leukocytosis persisted for 48 h and was associated with an increased level of neutrophil chemotactic activity in the CF. This neutrophil chemotactic activity was attributed to interleukin-8 (IL-8) by HPLC. The level of IL-6 activity in the CF and RF consistently increased; beginning 2 h after TNF alpha injection and reaching the maximum between 8 h and 12 h. It returned to the basal level within 48 h. IL-1 beta was detected in the CF of three patients, its level peaking at 8 h. Prostaglandin E2 also increased after injection of TNF alpha, peaking between 4 h and 12 h and then gradually decreasing. Transforming growth factor beta was found in all cases tested and one patient showed a significant change after TNF alpha injection. IL-2 activity, interferon alpha (INF alpha) activity, IFN beta, and granulocyte/macrophage-colony-stimulating factor were not detected in the CF or RF. In conclusion, TNF alpha is biologically effective in inducing migration of immune cells and generating multiple cytokine responses in the human central nervous system.

Adult↗

PubMed1993

Characteristics of DNA and multiple rpoD homologs of Microcystis (Synechocystis) strains.

The base compositions of DNAs from nine Microcystis strains, as determined by high-performance liquid chromatography, were 41 to 42 mol% G+C. Chromosomal DNAs derived from these strains were found to be extremely resistant to many restriction endonucleases, and a restriction analysis revealed the presence of a dam-like methylase or both dam- and dcm-like methylases in all of the strains examined. Genomic Southern hybridization in which a synthetic oligonucleotide probe (rpoD probe) was used showed that members of the genus Microcystis might have multiple rpoD homologs, and the hybridization signal patterns observed with the DNAs of Microcystis aeruginosa strains were different from each other.

Bacterial Proteins↗

PubMed1993

Endocrine functions in children with suprasellar germinoma.

Clinical manifestations and endocrine functions were evaluated in 17 children with suprasellar germinoma. Polyuria and growth retardation were the most common initial symptoms. Physical and neurological examinations revealed diabetes insipidus in 17, growth retardation in five, and visual disturbance in three of the patients. Assessment of hypothalamic-pituitary function before treatment revealed pituitary deficits in all patients involving growth hormone, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and adrenocorticotropic hormone. These pituitary dysfunctions persisted after tumor remission due to radiation therapy. These results indicate that children with suprasellar germinoma need long-term hormone replacement therapy to prevent growth retardation, thyroid dysfunction, and delayed secondary sexual development.

Adolescent↗

PubMed1993

Desmoplastic infantile ganglioglioma--case report.

A desmoplastic infantile ganglioglioma occurred in a 5-month-old boy, manifesting as delayed psychomotor development. Computed tomography showed a large cystic mass involving the left occipitoparietal lobes. The tumor was totally removed. He has survived for 13 years without tumor recurrence. Histological examination disclosed marked desmoplasia intermixed with mature-looking ganglion cells, neoplastic glial cells, and small, immature round cells. These clinical and histological features enabled the diagnosis of desmoplastic infantile ganglioglioma.

Brain↗

PubMed1993

Dystrophic axonal formation (spheroid body) in central neurocytoma--case report.

A 30-year-old female presented with a central neurocytoma manifesting as positional headache. Magnetic resonance imaging showed a large calcified mass in the right lateral ventricle. The tumor was completely removed surgically. Light microscopy showed a linear arrangement of well-defined cells (beaded-string pattern) containing small round nuclei with abundant perikarya. A perinuclear halo reminiscent of oligodendroglioma was prominent in some cell groups. The tumor was entirely amitotic and free of atypia. Large, plump spheroid bodies lacking nuclei but containing coarse brown pigments were present among the tumor cells. The tumor cells were immunoreactive to neuron-specific enolase and synaptophysin but not glial fibrillary acidic protein or neurofilament. The ultrastructure of the tumor cells included abundant spheroid bodies containing secretory granules around neurons, indicating a dystrophic or aborted process of neuronal differentiation rather than a completely-differentiated central neurocytoma.

Adult↗

PubMed1993

Human glioblastoma cells produce granulocyte-macrophage colony-stimulating factor in vitro, but not in vivo, without expressing its receptor.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) production and receptor expression by human glioblastomas was studied. Enzyme-linked immunosorbent assay showed four of 10 glioblastoma cell lines spontaneously released GM-CSF (2.9-9.2 pg GM-CSF protein/ml culture medium), which was enhanced by stimulation with tumor necrosis factor-alpha (TNF) (10 U/ml) up to 410 pg/ml. TNF also induced secretion of GM-CSF by another cell line. Northern blot analysis identified increasing GM-CSF gene expression by cells following TNF stimulation. However, no GM-CSF protein was detectable in the cerebrospinal fluid of three malignant glioma patients. Intratumoral administration of TNF in the patients also failed to stimulate GM-CSF levels in the cerebrospinal fluid. A binding assay using flow cytometry with biotinylated GM-CSF and Scatchard analysis using 125I-labeled GM-CSF failed to demonstrate GM-CSF receptor expression on the 13 cell lines. Exogenous GM-CSF stimulation had no effect on production of prostaglandin E2, interleukin-6, or interleukin-8 by glioma cells. Human glioblastoma cells secrete GM-CSF without expressing the receptor in vitro, but there was no evidence of GM-CSF production in vivo.

Glioblastoma↗