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Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 343 records · Page 19Linked to original sources
PubMed1996

Sudden unexpected death in childhood due to eosinophilic myocarditis.

A 12-year-old boy with no previous serious medical history experienced abdominal discomfort and chest pains for 5 days and suddenly died. The autopsy revealed diffuse and extensive infiltration of eosinophils into the myocardium, with poorly formed granulomas and few fibrotic changes. The necrotic changes was so extensive that Charcot-Leyden crystals formed. The other visceral organs had no specific pathologic changes except for mild lymphocytic infiltration with an increase in goblet cells in the bronchial areas and eosinocytosis in the blood vessels. An initial viral infection seemed to have caused subsequent eosinophil activation due to an allergic condition. Eosinophilic myocarditis is a rare cause of sudden death in apparently healthy children. Cardiac toxicity of eosinophils is, however, well established and dominates the ultimate prognosis of patients with complicated eosinophilia.

Child↗
PubMed1996

Possible roles of medullasin in nifedipine-induced human gingival overgrowth.

In order to clarify a possible pathophysiological role of medullasin, a neutrophil elastase-like proteinase, in nifedipine (NF)-induced gingival overgrowth, the distributions of medullasin-positive cells immunostained in specimens from patients with NF-induced gingival overgrowth and chronic marginal gingivitis were compared in three different biopsy areas. Twenty gingival biopsies were obtained from five patients with gingival overgrowth and 20 biopsies from another five patients with chronic marginal gingivitis. In the marginal gingivitis group, the mean percentage of positive cells in the vicinity of pocket epithelium (zone I) was significantly higher than in the areas of connective tissue of the mid-portion (zone II) and adjacent to oral epithelium ( zone III) (p < 0.05). In the gingival overgrowth group, on the contrary, the positive cells significantly increased in zone II as compared with zones I and III (p < 0.05). Further, medullasin-positive cells of zones II and III in the overgrowth group had infiltrated more extensively than those in the gingivitis group (p < 0.001), indicating the participation of this enzyme in the mechanism of NF-induced gingival overgrowth. These observations suggest that medullasin may play a part in NF-induced overgrowth both in host defence and in immunoregulation, possibly cytotoxically.

Adult↗
PubMed1996

Th0-like CD4+ T cells protect mice with murine retrovirus-induced immunodeficiency syndrome (MAIDS) against co-infection with Listeria monocytogenes.

We examined the host defence mechanism against infection with Listeria monocytogenes, a facultative intracellular bacterium, in mice with murine acquired immunodeficiency syndrome (MAIDS) caused by LP-BM5 murine leukaemia virus (MuLv) infection. Although LP-BM5 MuLV infection in C57BL/6 mice leads to a stage of immunodeficiency characterized by severe compromise of cell-mediated immunity, the mice with established MAIDS infected with LP-BM5 8 weeks previously, showed resistance to an intraperitoneal infection with Listeria monocytogenes. These MAIDS mice also showed resistance to a lethal dose of secondary listerial challenge, while the delayed-type hypersensitivity response to heat-killed Listeria (HKL.) was severely impaired in MAIDS mice. The resistance of MAIDS mice to listerial infection was mediated by CD4+ alpha beta T cells but neither by gamma delta T cells nor natural killer (NK) cells. Interferon-gamma (IFN-gamma) and interleukin-10 (IL-10) were produced by CD4+ T cells from Listeria-infected MAIDS mice in response to the in vitro stimulation with HKL, whereas IFN-gamma but not IL-10 were produced by those from Listeria-infected control mice. These results suggest that T-helper 0 (Th0)-like immune responses of CD4+ T cells occur and participate in host defence mechanisms against listerial infection in MAIDS mice.

Animals↗
PubMed1996

Development of a competitive enzyme-linked immunosorbent assay for diethylcarbamazine.

A sensitive and reproducible competitive enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of diethylcarbamazine (DEC) in biological fluids was developed. Since DEC has no functional group to conjugate with bovine serum albumin (BSA), N-(2-aminoethyl)-N-ethyl-4-methyl-1-piperazinecarboxamide (DEC-NH2) was first synthesized. This compound was then converted to carboxyl DEC (DEC-COOH) and conjugated to BSA and to poly-L-lysine for use as immunogen and solid-phase marker, respectively. The competitive ELISA was conducted by simultaneously incubating DEC with mouse anti-DEC antiserum over DEC-poly-L-lysine solid phase. Subsequently, the binding of anti-DEC antibody was detected by using sheep anti-mouse IgG peroxidase conjugate as a tracer. The reliability, determined by the coefficient of variation for inter and intra-assay, was satisfactory. The cross-reactivities of anti-DEC antibodies with DEC metabolites, related compounds and ivermectin were negligible. Using this assay, DEC levels were easily determined in serum of Mongolian jirds (Meriones unguiculatus) up to 4 hours following a single dose of DEC citrate base (100 mg/kg of body weight) via intraperitoneal route.

Animals↗
PubMed1996

Purification and characterization of novel trypsin-like serine proteases from mouse spleen.

Novel trypsin-like serine proteases (mouse trypsin-type serine proteases 1 and 2 [MTSP-1 and -2]) were purified to homogeneity from mouse spleen. Each protease consisted of a single polypeptide with a molecular mass of about 29 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions. Both were totally inhibited by diisopropylfluorophosphate, soybean trypsin inhibitor, aprotinin, antipain, and leupeptin and partially inhibited by chymostatin and dithiothreitol, suggesting that they are trypsin-like serine proteases. They hydrolyzed synthetic substrates for trypsin-like proteases but not those for chymotrypsin-like proteases, elastase and kallikrein. MTSP-1 hydrolyzed tert-butyloxycarbonyl (Boc)-Asp(OBzl)Pro-Arg-amino-4-methyl-coumaryl-7-amide (MCA) and Boc-Ile-Glu-Gly-Arg-MCA faster than Boc-Phe-Ser-Arg-MCA. On the other hand, MTSP-2 hydrolyzed Boc-Phe-Ser-Arg-MCA most rapidly, with a specific activity 15 times higher than that of MTSP-1. The N-terminal amino acid sequence of MTSP-1 was Ile-Val-Gly-Gly-Tyr-Thr-His-Leu-Asp-Asn-Gln-Val-Pro-Tyr. This sequence was 71% homologous with the N-terminal of bovine trypsin. The Boc-Phe-Ser-Arg-MCA hydrolyzing activity of mouse spleen significantly (p < 0.01) increased to about 1.5-fold the basal activity 2 weeks after an injection of Freund's complete adjuvant, suggesting that these proteases are involved in the immune response.

Amino Acid Sequence↗
PubMed1996

Prosthetic reconstruction for periacetabular malignant tumors.

This article reports the reconstruction method and functional results of a newly designed tumor hip prosthesis with a constrained joint mechanism which was used after treatment for 13 primary and 5 metastatic periacetabular malignant bone tumors. The overall 5-year survival rate for patients with primary tumors (n=13) was 50%. The local recurrence rate was 30%. More than 90% of the patients whose hips were reconstructed with the constrained tumor hip prosthesis experienced pain relief and were able to walk with a cane. No patients had greater than 3 cm shortening of the involved limb. Infection was the most serious complication. This prosthesis restored iliofemoral stability after surgical resection of periacetabular malignant tumors.

Acetabulum↗
PubMed1996

Metastatic epidural bony tumor causing spinal cord compression: a case report.

The authors report the case of a patient with breast cancer who developed spinal cord compression due to the expansion of an epidural bony tumor from an osteoblastic vertebral metastasis into the spinal canal. Magnetic resonance imaging revealed an epidural mass that was compressing the spinal cord but that did not demonstrate the bony elements contained within the epidural mass. These bony elements were demonstrable only by computed tomography. The patient did not respond to radiotherapy but did recover after surgical decompression. Therefore, the authors recommend the use of computed tomography for patients who have osteoblastic vertebral metastases and epidural spinal cord compression diagnosed by MRI. Once an epidural bony mass expanding from a vertebral metastasis into the spinal canal is demonstrated by computed tomography, surgical decompression is indicated.

Breast Neoplasms↗
PubMed1996

Measurement of intratumor pH by pH indicator used in 19F-magnetic resonance spectroscopy. Measurement of extracellular pH decrease caused by hyperthermia combined with hydralazine.

RATIONALE AND OBJECTIVES: Without affect of metabolic changes, the authors measured intratumor pH by using 19F-magnetic resonance spectroscopy (MRS) with a fluorine compound (ZK-150471) on the basis of a calibration curve by pH electrode. METHODS: Using the 4.7-tesla magnetic resonance apparatus, a fluorine compound that had acid-base equilibrial change and was impermeable within cell membranes was used. The fluorine compound was injected intravenously. The signal was obtained from mouse mammary cancer by creating an experimental tumor on the leg of mice. And the tumors, which were heated with and without hydralazine. The pH evaluated from chemical shift of the fluorine compound. The pH data was obtained from an electrode for reference. RESULTS: The pH of nontreated tumors (n = 25) were 6.94 + 0.091. The pH decreased to 6.772 + 0.169 at 20 minutes even after 20 minutes of heating, and decreased to < 6.71 at 40 minutes after every heating time. The pH decreased to 6.456 at 20 minutes after 15 minutes of heating combined with hydralazine, and to 6.416 at 40 minutes after same treatment. CONCLUSIONS: It is possible to measure the extracellular pH by 19F-MRS with the fluorine compound noninvasively in vivo, even after heating.

Animals↗
PubMed1996

Case report: an exaggerated placental site with a cervical pregnancy.

An exaggerated placental site (EXPS) is an exuberant nonneoplastic proliferation of the intermediate trophoblast at the implantation site. We had a case of an EXPS with a cervical pregnancy. We report on this case, including the patient's clinical course and immunohistological findings.

Adult↗
PubMed1996

Antifungal azoxybacilin exhibits activity by inhibiting gene expression of sulfite reductase.

Azoxybacilin, produced by Bacillus cereus, has a broad spectrum of antifungal activity in methionine-free medium and has been suggested to inhibit sulfite fixation. We have further investigated the mode of action by which azoxybacilin kills fungi. The compound inhibited the incorporation of [35S] sulfate into acid-insoluble fractions of Saccharomyces cerevisiae under conditions in which virtually no inhibition was observed for DNA, RNA, or protein synthesis. It did not interfere with the activity of the enzymes for sulfate assimilation but clearly inhibited the induction of those enzymes when S. cerevisiae cells were transferred from rich medium to a synthetic methionine-free medium. Particularly strong inhibition was observed in the induction of sulfite reductase. Northern (RNA) analysis revealed that azoxybacilin decreased the level of mRNA of genes for sulfate assimilation, including MET10 for sulfite reductase and MET4, the transactivator of MET10 and other sulfate assimilation genes. When activities of azoxybacilin were compared for mRNA and enzyme syntheses from MET10, the concentration required for inhibition of transcription of the gene was about 10 times higher (50% inhibitory concentration = 30 micrograms/ml) than that required for inhibition of induction of enzyme synthesis (50% inhibitory concentration = 3 micrograms/ml). The data suggest that azoxybacilin acts on at least two steps in the expression of sulfite reductase; the transcriptional activation of MET4 and a posttranscriptional regulation in MET10 expression. We conclude that azoxybacilin exhibits antifungal activity by interfering with the regulation of expression of sulfite reductase activity.

Aminobutyrates↗
PubMed1996

Apoptosis by CD95 (Fas)-dependent and -independent mechanisms in Peyer's patch lymphocytes in murine retrovirus-induced immunodeficiency syndrome.

CD95 (Fas)/CD95 ligand (CD95 L)-mediated apoptosis is thought to be involved in the delayed progression of murine AIDS (MAIDS) induced by LP-BM5 murine leukemia virus (MuLV). We show evidence of apoptosis in lymphocytes of Peyer's patches (PP) at the early stage of MAIDS. Both T and B cells in PP expressed CD95 at the early stage of MAIDS and decreased in number thereafter. The decrease in T cells was not evident in CD95-mutated lpr mice with MAIDS, suggesting that CD95/CD95 L interaction is involved in the apoptosis of T cells in PP during the course of MAIDS. On the other hand, the number of B cells was also decreased in PP of lpr mice with MAIDS. The proliferative ability of B cells in PP of MAIDS mice in response to immunoglobulin M cross-linking or lipopolysaccharide was severely impaired, while the B cells normally proliferated in response to anti-CD40 monoclonal antibody. These findings imply that aberrantly activated B cells in PP undergo apoptosis independently of the CD95/CD95 L system during the course of infection with MAIDS virus.

Animals↗
PubMed1996

Stimulation of Na(+)-K(+)-2Cl- cotransport in rat medullary thick ascending limb by dopamine.

Dopamine receptors are present in the medullary thick ascending limb (mTAL) of Henle, but their effect on ion transport in this nephron segment has not been tested. Therefore, we studied the short-term effects of dopamine on Na(+)-K(+)-2Cl- cotransport (assessed by 100 microM bumetanide-sensitive 86Rb uptake) in rat mTAL tubular suspensions. Dopamine (1 microM) stimulated bumetanide-sensitive 86Rb uptake (72.1 +/- 10.6% vs. control, n = 5) by increasing total 86Rb uptake and by decreasing bumetanide-insensitive 86Rb uptake; this effect was concentration dependent. The dopamine-induced stimulation of Na(+)-K(+)-2Cl- cotransport activity was mimicked by calyculin A, a protein phosphatase (PP) inhibitor, and Sp isomer of adenosine 3',5'-cyclic monophosphothioate (Sp-cAMP[S]), a protein kinase A (PKA) agonist, and blocked by Rp isomer of 8-(4-chlorophenylthio)-cAMP[S] (Rp-8-CPT-cAMP[S]), a PKA inhibitor (n = 5). Dopamine did not increase the stimulatory effect of the PP inhibitor. However, the stimulatory effect of the PP inhibitor and PKA agonist was additive and approached the stimulatory effect of dopamine. The stimulatory effects of dopamine, PP inhibitor, and PKA agonist persisted even when intracellular sodium was clamped by 5 microM monensin. When K+ channels were blocked by 1 mM BaCl2, the effects of dopamine and calyculin A on the cotransport were no longer apparent, although the stimulatory effect of the PKA agonist was attenuated. We conclude that dopamine stimulates Na(+)-K(+)-2Cl- cotransport activity. This action is mediated mainly by PKA-dependent phosphorylation/dephosphorylation processes and modulated by dopamine actions on K+ channels.

Animals↗
PubMed1996

Gamma Knife radiosurgery for brain stem metastases: two autopsy cases.

Early neuropathological findings were obtained at autopsy in two cases of brain stem metastasis treated with the Gamma Knife. In both cases, light microscopy radiation changes were strictly localized. Residual tumor tissue in the irradiation field showed marked degenerative changes including multinuclear cells, atypical nuclei and vacuolar degeneration. A characteristic finding in the irradiation field was fibrosis associated with hyalinized and thickened vessels. In more peripheral regions, demyelination and vacuolar degeneration were seen. This is the first report demonstrating extravascular fibrosis in the irradiated field following radiosurgery.

Aged↗
PubMed1996

The effects of xylazine on intrauterine pressure, uterine blood flow, maternal and fetal cardiovascular and pulmonary function in pregnant goats.

To investigate the effects of xylazine on pregnant goats, xylazine induced changes in heart rate (HR), arterial blood pressure (ABP) and arterial blood pH and gases in the mother and fetus, as well as changes in intrauterine pressure (IUP) and uterine blood flow (UBF), were studied using a chronic preparation model of pregnant goats. Intramuscular administration of xylazine (0.2 mg/kg b.w.) caused a marked decrease in HR and ABP of the mother, which remained significantly reduced up to 120 min. In the fetus, a significant decrease in HR and a significant increase in ABP were recorded after only 5 min. Significant decreases of maternal arterial blood pH and oxygen partial pressure (Po2) were observed up to 120 and 30 min after the injection, respectively. Fetal arterial blood pH and Po2 also decreased, but these changes were milder and less persistent than those of the mother. Within 2 to 5 min after the administration of xylazine, IUP began to increase and remained high for about 15 min. Thereafter, there was a frequent periodic increase in IUP. After 5 min, UBF decreased significantly and remained low up to 120 min. A fall in UBF was associated with a rise in IUP. These findings suggested that administration of xylazine to pregnant goats results in a decrease in UBF arising from the induction of uterine contractions, a decrease in circulating blood volume, hypoxemia and acidosis in the mother.

Animals↗
PubMed1996

Simple and sensitive enzyme-linked immunosorbent assay for ivermectin.

A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of ivermectin (IVM) in biological fluids was developed. A conjugate of IVM on bovine serum albumin and poly-L-lysine was used to produce antibodies in rabbits and served as a solid-phase marker for titration of antibodies, respectively. The competitive ELISA was conducted by simultaneously incubating IVM and IVM-biotin conjugate with anti-IVM antiserum over goat anti-rabbit IgG (Fc) and then determining the amount of bound IVM-biotin with avidin-peroxidase conjugate as a tracer. The coefficient of variation for the assay was less than 10% in the range of 0.3-10 ng/ml. The limit of detection was 0.1 ng/ml. The cross-reactivities of anti-IVM antiserum with some anthelmintic drugs were negligible. Using this ELISA, serum levels of IVM were easily determined in Mongolian jirds (Meriones unguiculatus) up to 72 hr following a single oral dose of 500 microgram/kg of body weight.

Animals↗
PubMed1996

[Cloning of the holocarboxylase synthetase cDNA and identification of mutations prevalent in Japanese HCS-deficient patients].

Holocarboxylase synthetase (HCS) plays an essential role in biotin utilization in cells and its deficiency causes biotin-responsive multiple carboxylase deficiency in humans. We have cloned the human HCS cDNA, which maps to chromosome 21q22.1. Two mutations in the HCS genes of Japanese patients with HCS deficiency have been identified: a transition from T to C which causes an amino acid substitution of proline for leucine at position 237 (L237P) and A single guanine base deletion (delta G1067) followed by premature termination. Transient expression in cultured fibroblasts from a patient after site-directed mutagenesis showed that the L237P mutation was responsible for decreased HCS activity. Hybridization analysis using allele-specific oligonucleotide probes demonstrated that the prevalence of the mutations--L237P and delta G1067--was 50% and 30%, respectively, among Japanese patients with HCS deficiency.

Amino Acid Sequence↗
PubMed1996

Characterization of murine stromal cell clones established from bone marrow and spleen.

Stromal cell lines were established by irradiating adherent layers of bone marrow and spleen cells in Dexter-type long-term culture with X-rays. Some of these cell lines support myelopoiesis and/or B lymphopoiesis in vitro. Furthermore, the characteristics of these stromal cell lines were studied. Cytokine activity was detected in the conditioned media from all hematopoietic-supportive and non-supportive stromal cells. Quantitative reverse transcriptase-polymerase chain reaction analysis revealed that the mRNAs of macrophage colony-stimulating factor and stem cell factor, but not that of Interleukin-3, were detectable in all the hematopoietic-supportive and non-supportive stromal cell lines. The transcripts of granulocyte colony-stimulating factor, interleukin-6, interleukin-7, and leukemia inhibitory factor were expressed in a wide variety of cell lines. Most stromal cell lines synthesized mRNA of c-mpl, the ligand of which stimulates megakaryopoiesis and thrombopoiesis. These observations indicate that the pattern of mRNA expression of cytokines is not correlated with the hematopoietic-supportive ability of stromal cell lines. There was a significant difference in the efficiency of adhesion of lineage marker-negative bone marrow cells to fibroblasts and stromal cell lines. This appears to be correlated with the hematopoietic-supportive ability of the stromal cell lines.

3T3 Cells↗