Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 19 recordsLinked to original sources

PubMed1997

Cathepsin G binds to human lymphocytes.

Cathepsin G is a serine protease located in the azurophil granules of neutrophils. We have shown previously that cathepsin G stimulates human lymphocytes. In this study, we demonstrate that cathepsin G exhibits specific, saturable and reversible binding to lymphocytes: B cells, CD4+ T cells, CD8+ T cells, and natural killer (NK) cells. Phenylmethylsulfonyl fluoride (PMSF) -inhibited cathepsin G also bound to lymphocytes, although both the number of binding sites and the affinity were less than those of native cathepsin G. The binding of cathepsin G to lymphocytes showed cooperativity, but that of PMSF-inhibited cathepsin G did not. PMSF-inhibited cathepsin G was able to partially displace bound cathepsin G. These results suggest that molecules on the lymphocyte surface that bind cathepsin G recognize not only the active site of cathepsin G but also other sites of this molecule, but the active site has an important function in this binding because stimulation of lymphocytes requires the binding of proteolytically active cathepsin G.

B-Lymphocytes↗

PubMed1997

Primary choriocarcinoma of the uterine cervix: clinical, MRI, and color Doppler ultrasonographic study.

Primary choriocarcinoma of the uterine cervix was diagnosed in a 38-year-old Japanese woman 4 months after a normal vaginal, term delivery. The patient had experienced irregular genital bleeding for several weeks. A cervical polypoid tumor was detected by visual inspection 4 months after delivery. Magnetic resonance imaging (MRI) and color Doppler ultrasonography revealed a hypervascular tumor (6 cm) in the uterine cervix. The patient's urinary level of human chorionic gonadotropin (hCG) was 128,000 IU/L. Histological examination of a biopsy of the cervical tumor showed choriocarcinoma. After completion of 2 courses of chemotherapy, the patient underwent a total abdominal hysterectomy. Histological examination of uterus showed no evidence of choriocarcinoma. At present, the patient is free of disease. MRI and color Doppler ultrasonography were useful for diagnosis by detecting the abundant blood flow and central necrosis of the cervical tumor.

Adult↗

PubMed1997

Clonal expansion of superantigen-reactive T cells is resistant to FK506 in mice with AIDS.

Subcutaneous injection of FK506 (10 mg/kg of body weight) completely blocked the clonal expansion of staphylococcal enterotoxin A (SEA)-reactive T cells in healthy (control) mice after SEA injection but did not disturb it in mice with murine AIDS (MAIDS) caused by infection with LP-BM5 murine leukemia virus. MAIDS mice are characterized by utilization of a FK506-insensitive pathway for clonal expansion of superantigen-reactive T cells.

Animals↗

PubMed1997

[Gamma knife radiosurgery for metastatic brain tumors: neuropathological report of two autopsy cases and review of literatures].

More than 40,000 cases have been treated with gamma knife radiosurgery, but few neuropathological reports are available. This paper describes two autopsy cases in which the patients had been treated with gamma knife. As these patients died 67 and 24 days after therapy, early neuropathological changes are reported. The first case was a 58-year-old woman diagnosed with multiple brain metastases from breast cancer. One of these lesions, in the medullaoblongata, was irradiated with a gamma knife. Sixty-seven days later, she died from heart failure. The second case was a 69-year-old man diagnosed with multiple brain metastases from lung cancer. One of these lesions, in the pons, was irradiated with a gamma knife. Twenty-four days later, he died from acute renal failure caused by hepatorenal syndrome. In both cases, the irradiated lesions were well demarcated from the undamaged surrounding tissues on light microscopy. Histologically, the tumor cells showed a variety of degenerative changes, such as pyknosis, multinuclear cells, and vacuolar degeneration in the cytoplasm. Fibrosis, more prominent in the first case, was observed spreading in the irradiation field, adhering to the hyalinized and thickened vessel walls. Demyelination was also observed in the first case. As far as we know, this report is the first published description of fibrosis in the radiosurgical irradiation field.

Aged↗

PubMed1997

ABO genotyping by PCR-direct sequencing.

The PCR-direct sequence method was applied to ABO genotyping. At the 261st nucleotide of the genes of A and B glycosyltrasferase, it was easily detected that the nucleotide was guanine in AA, AB and BB genotypes and that the nucleotide was ademine in only OO. In AO and BO, substitution of A to G was confirmed by the dye primer method, but it was difficult to detect correctly by the dye terminator method. At the 297th, nucleotide substitution between A and B alleles was confirmed by the both methods. As this position, O allele was subdivided into three types, OAOA, OGOG and OAOG. At the 703rd, nucleotide substitution between A and B alleles was easily detected by the both methods. The PCR-direct sequence method was suitable to confirm the nucleotide substitution or deletion directly and to prevent the mistyping by other methods.

ABO Blood-Group System↗

PubMed1997

[Application of stochastical analysis to maternity testing without putative mother].

In a maternity test in which the putative mother was deceased, the cumulative probability of maternity (PM) was calculated at 0.822 from 24 genetic markers by the stochastical method. This PM may not be evaluated in the same way as that of usual paternity cases. We applied the same method to two families whose blood relationships were undoubted. We compared the PMs in the cases in which maternal genotypes were estimated and were defined. Also, we calculated the PMs in the case of real maternal relationship and false maternal one. The estimated PM from real maternity relationship was significantly higher than that from false maternal one.

ABO Blood-Group System↗

PubMed1997

Laceration of the liver with delayed massive intra-abdominal hemorrhage: a case report of child abuse.

A 3-year-old girl was found unresponsive in the bedroom and expired at a hospital. Autopsy revealed massive intra-abdominal bleeding due to laceration of the liver and mesenterium with multiple rib fractures and multiple fresh and old bruises. The time of the assault causing the liver trauma was questioned because the perpetrator, her mother's boyfriend, denied any outrages on that particular day although he confessed that he had physically abused her for several months. Microscopically, numerous polymorph leucocytes infiltrated exclusively surrounding the lacerated area of the liver. Many hepatocytes were necrotic and cord arrangement of the parenchymal cells was destroyed. There should be a certain time lag between the major assault and massive intra-abdominal hemorrhage, which was not inconsistent with the statement of the perpetrator.

Abdominal Injuries↗

PubMed1996

Change in ascorbate radical production in an irradiated experimental tumor with increased tumor size.

We have reported that ascorbate radical (Asc.-) could serve as an indicator of the amount of hydroxyl radical and superoxide produced by irradiation in vivo. Using this method, we investigated the relationship between tumor size and Asc.- production after irradiation (10 Gy) and between tumor size and the radical-scavenging ability of WR-2721 (300 mg/kg). Asc.- was measured in normal muscle and SCC-VII tumors transplanted into mice (n = 6). In tumors, the increase in Asc.- significantly decreased with increasing tumor size (r = -0.483; P < 0.05). The increase in Asc.- production after irradiation was more inhibited by WR-2721 in normal muscle tissue than in tumor tissue at various sizes. In tumors, the increase in Asc.- was less inhibited by WR-2721 with increasing tumor size. These results demonstrate that the increase in radical production after irradiation and drug distribution decreased with increasing tumor size and that WR-2721 has excellent differential protection. This method is expected to measure changes in the amounts of local hydroxyl radical and superoxide modified by a change of tumor environment or drug administration.

Amifostine↗

PubMed1996

IGF2 but not H19 shows loss of imprinting in human glioma.

Genomic imprinting is a gamete-specific modification resulting in the allele-specific expression of genes in somatic cells. A loss of imprinting (LOI) has been found in many embryonal and adult tumors, suggesting that it plays a role in tumor development. The incidence of LOI, however, does not seem to be ubiquitous among tumors because neuroblastoma and colorectal cancer revealed no LOI. We examined the involvement of LOI of IGF2 and H19 genes in human gliomas. The two genes were imprinted in normal brain subcortex tissues. In glioma, 8 of 14 informative cases (57%) revealed LOI in IGF2. The frequency did not depend on the tumor grade. For H19, in contrast, all 13 informative cases maintained imprinting. These results suggest that LOI of IGF2 but not H19 plays a role in the development of human glioma.

Adult↗

PubMed1996

Characterization of mutations induced by 300 and 320 nm UV radiation in a rat fibroblast cell line.

The cytotoxic and mutagenic activities of monochromatic ultraviolet light (UV) at four wavelengths (254, 290, 300 and 320 nm) were determined using a rat fibroblast cell line CREF stably infected with a retroviral vector carrying the neo and HSV-tk markers. In this system, mutations can be positively detected as acyclovir-resistant colonies. Although the action spectra for these activities closely fit some of the previously reported spectra for photochemical DNA modifications, erythema, cell killing and mouse skin carcinogenesis, they diverge at 320 nm from the absorption spectrum for DNA and the action spectrum for bacterial inactivation and mutagenesis. Structural comparison of the HSV-tk mutants detected after irradiation with 300 and 320 nm UV revealed (1) CC dimers and C oligomers as predominant targets at both wavelengths; (2) increased incidence of relatively large deletions at 300 nm; and (3) greatly increased frequency of tandem double mutations at both wavelengths and of clustered multiple mutations at 320 nm. These results suggest the involvement of distinct mechanisms specifically operating, or becoming evident, in UV-mediated mutagenesis at these different wavelengths in mammalian cells.

Acyclovir↗

PubMed1996

Cloning and functional expression of a cDNA encoding a mouse type 2 neuropeptide Y receptor.

A cDNA clone homologous with the human neuropeptide Y (NPY)-Y2 receptor has been isolated from a mouse brain cDNA library. Analysis of the predicted amino-acid sequence indicates that the polypeptide encoded by this cDNA is 94% homologous to the human NPY-Y2 receptor. In Chinese hamster ovary (CHO) cells expressing the mouse NPY-Y2 receptor, an increase in intracellular Ca2+ and inhibition of forskolin-induced cAMP accumulation were observed due to stimulation with NPY, NPY-(13-36) and peptide YY, but not with pancreatic polypeptide or [Leu31, Pro34]NPY. The fact that the NPY-induced increase in intracellular Ca2+ and inhibition of forskolin-induced cAMP accumulation were eliminated by pretreatment with pertussis toxin suggests that the NPY-Y2 receptor couples to PTX-sensitive G-protein(s), probably Gi/Go, in CHO cells.

Amino Acid Sequence↗

PubMed1996

Enzymatic diagnosis of holocarboxylase synthetase deficiency using apo-carboxyl carrier protein as a substrate.

We developed a simple and sensitive method for assessing holocarboxylase synthetase (HCS) activity that is based on measuring incorporation of [3H]biotin into apo-carboxyl carrier protein, a subunit of acetyl-CoA carboxylase from E. coli. Kinetic analysis of HCS from normal fibroblasts showed that the Km for biotin was 260 +/- 94 nmol/l (mean +/- S.D.; n = 5). In contrast, the Km values of HCS from two cell lines derived from patients with HCS deficiency were 7200 and 3700, clearly distinguishable from the control value. The sensitivity of this assay was so high that we were able to characterize a mutant enzyme whose activity had not been previously detected. Our method is useful for enzymatic diagnosis of HCS deficiency and characterization of HCS.

Acetyl-CoA Carboxylase↗

PubMed1996

Alterations of c-fos gene methylation in the processes of aging and tumorigenesis in human liver.

The state of DNA methylation in the c-fos gene was examined in human livers of different ages, cirrhosis and hepatocellular carcinoma. The degree of methylation in the intron 1 to exon 4 region increased with age, whereas all of the 10 cirrhosis samples revealed a decrease in methylation when compared to normal livers of similar ages. The 11 hepatocellular carcinomas showed varied alterations suggesting that the alteration of the c-fos gene methylation is related to aging as well as to early-step of hepatocarcinogenesis.

Adolescent↗

PubMed1996

Functional coupling of adenosine A2a receptor to inhibition of the mitogen-activated protein kinase cascade in Chinese hamster ovary cells.

Activation of Gs-coupled receptors enhances the increase in cyclic AMP mediated by adenylate cyclases. As it has been shown that cyclic AMP inhibits the epidermal growth factor-activated mitogen-activated protein kinase (MAPK) signalling pathway, stimulation of Gs-coupled receptors may lead to the inhibition of MAPK activation. To investigate the effect of a Gs-coupled receptor on the MAPK cascade, we cloned the adenosine (Ado) A2a receptor from a guinea-pig leucocyte cDNA library, and established Chinese hamster ovary (CHO) cells stably expressing the receptor (CHOAdoA2R). The [3H]5'-N-ethylcarbamoyladenosine (NECA) binding characteristics (Kd = 91.0 +/- 5.4 nM, Bmax = 707 +/- 11 fmol/mg of protein, n = 3) and NECA-induced cyclic AMP production indicate that the cloned Ado A2a receptor was functionally expressed in the cells. In CHO cells, thrombin induced intracellular Ca2+ increase and MAPK activation through the intrinsic G-coupled receptor. In CHOAdoA2R cells, NECA partially inhibited thrombin-elicited MAPK activation. When combining NECA-treatment with 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid acetoxymethyl ester (BAPTA-AM) loading, a nearly complete inhibition of the MAPK activation occurred. Forskolin also partially inhibited the MAPK activation and synergized with BAPTA-AM, suggesting that partial inhibition of MAPK activation by NECA results from cyclic AMP production via Ado A2a receptor activation. The same synergism of MAPK inhibition between wortmannin and BAPTA-AM was observed, but not between wortmannin and NECA. These results suggest that cyclic AMP production through Ado A2a receptor inhibits thrombin-elicited MAPK activation by a Ca(2+)-independent/wortmannin-sensitive pathway in CHO cells.

Adenosine↗

PubMed1996

Phosphorylation of c-Jun stimulated in primary cultured rat liver parenchymal cells by a coplanar polychlorinated biphenyl.

Phosphorylation of c-Jun was stimulated in primary cultured rat liver parenchymal cells by treatment with a coplanar polychlorinated biphenyl congener, 3,3'4,4'5-pentachlorobiphenyl (PenCB), as well as by epidermal growth factor, but was not stimulated by the non-coplanar form. However, the amount of c-Jun mRNA did not increase with PenCB treatment. PenCB may activate a signal-transducing pathway consisting of protein kinases.

Animals↗

PubMed1996

Induction of IL-6 production by bone marrow stromal cells on the adhesion of IL-6-dependent hematopoietic cells.

Cellular interactions between hematopoietic cells and stromal cells play crucial roles in the proliferation and differentiation of the hematopoietic cells. Interleukin-6 (IL-6)-dependent 7TD1 cells markedly proliferated without IL-6 when they were co-cultured with hematopoietic-supportive bone marrow stromal cells, HESS-5 cells and HESS-1 CL.3 cells, which can support long-term hematopoiesis in vitro with but not without direct cell contact, cell contact being prevented with a microporous membrane. The production of IL-6 and the amount of IL-6 mRNA in hematopoietic-supportive stromal cells but not 7TD1 cells significantly increased only when the stromal cells were co-cultured in direct contact with 7TD1 cells. Furthermore, the amount of IL-6 mRNA increased according to the number of 7TD1 cells co-cultured. These inductions were not observed on co-culture with a murine myeloid cell line, M1 cells, or on the addition of the co-culture supernatant. These results suggest that 7TD1 cells transmit the signal to stromal cells that enhances IL-6 production by stromal cells via direct cell contact. A certain specific molecule for transduction of the signals may exist on the surface membrane of stromal cells and hematopoietic cells.

Animals↗

PubMed1996

Alteration of c-fos gene methylation in human gliomas.

In an attempt to find a common DNA alteration occurring in human glioma, we examined DNA methylation in 34 gliomas of various pathological grades and compared them with those in normal cerebral subcortex DNA. The total methylated cytosine levels in the genome did not differ appreciably between the tumors and the normal tissues; however, the degree of DNA methylation in several proto-oncogenes and suppressor oncogenes showed some alterations. Among them, the c-fos gene demonstrated deviation from that of normal tissues in all cases examined, suggesting that the alteration of c-fos gene methylation plays a role in the early steps of human glioma development.

Adult↗

PubMed1996

Recurrent placental site trophoblastic tumor of the uterus: clinical, pathologic, ultrastructural, and DNA fingerprint study.

Placental site trophoblastic tumor is a rare disease. Most benign cases of this disease show a few mitotic figures of the tumor while recurrent cases usually have more than 5 mitoses per 10 high-power fields. The present case was primarily treated by hysterectomy and chemotherapy and had 2 mitoses in 10 high-power fields. After 1 years and 4 months of therapy the patients was diagnosed as ovarian metastasis because of gradually increasing serum beta-human chorionic gonadotropin (hCG) level and abnormally high fluid levels of beta-hCG and human placental lactogen (hPL) punctured from her cystic ovarian tumor. This recurrent case was further treated with another regimen of chemotherapy for 7 courses, and the serum beta-hCG level had decreased at present. This report describes the recurrent case and discusses the histology of a few mitotic figures, electron microscopic findings, and results of the DNA fingerprint analysis of the primary tumor.

Adult↗