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Biomedical subjects

Y Asada

Publications and source records attributed to Y Asada.

At least 145 records · Page 8Linked to original sources
PubMed1996

Direct effects of estradiol and tamoxifen on gene expressions of inhibit alpha- and beta A-subunits in rat granulosa cells in vitro.

To analyze direct effects of estrogen on gene expressions of inhibin subunits in vitro, the mRNA levels of inhibin alpha- and beta A-subunits were measured in rat granulosa cells cultured with FSH or estradiol. Through the culture process of the granulosa cells with serum-free medium, both the alpha- and beta A subunit mRNAs decreased, and were partially increased again by adding FSH to the culture medium. To examine whether these FSH effects are mediated via estrogen production, estradiol or tamoxifen was added to the cultured granulosa cells. After 36-h culture with estradiol, the inhibin alpha-subunit decreased but the inhibin beta A-subunit increased, in a dose-responsive manner. Tamoxifen showed completely opposite effects to estradiol, and a combination of estradiol and tamoxifen resulted in similar levels of inhibin-alpha and -beta A mRNAs to the control. These results indicate that estrogen would by a certain pathway affect gene expressions of the inhibin subunits in the rat granulosa cells, and may regulate the production of inhibin and activin through the paracrine system.

Animals↗
PubMed1996

Utility of the interval mapping technique using DNA pools of inbred mice.

We report an application of the interval mapping technique using DNA pools of inbred mice. The latest challenge in molecular genetics is to use microsatellite markers for gene mapping and cloning. Little is known about the interval mapping technique for detecting candidate linkages in inbred mice. We investigated the optimum interval length of microsatellite markers for gene mapping using DNA pools on mouse chromosomes, and found that between 25 and 35 centi Morgans (cM) was sufficient. We estimated that at least two to four microsatellite markers required for interval mapping should be present on each chromosome. The number required would depend entirely on the linkage map.

Animals↗
PubMed1996

Tissue factor induces migration of cultured aortic smooth muscle cells.

Tissue factor (TF) plays a key role as a primary initiator on the extrinsic coagulation cascade. Recently, upregulation of TF has been reported in human atherosclerotic lesions. We investigated the effects of TF on migration and proliferation of cultured smooth muscle cells (SMCs) from rabbit aortas. We tested three kinds of recombinant human TF (L-TF: the full length of TF with relipidation, NL-TF: the full length of TF without relipidation, and S-TF: a soluble form of TF1-219). Only L-TF had coagulant activity. All kinds of TF showed the chemotactic migration activity for SMCs. The migration ability of TFs was comparable to those of platelet-derived growth factor (PDGF)-BB and basic fibroblast-growth factor (bFGF), and was inhibited by anti-TF polyclonal and monoclonal antibodies. On the other hand, none of the forms of TF induced SMC proliferation. These results indicate that TF is not only a coagulation factor but also a strong chemotactic factor for vascular SMCs, and suggest that TF could play an important role in atherogenesis as well as in hemostasis and thrombosis.

Animals↗
PubMed1996

Does epididymal length in men with congenital bilateral absence of the vas deferens have a correlation with the fertilization rate of epididymal sperm retrieved by micropuncture technique?

To investigate whether the variable length of the epididymis in men with congenital bilateral absence of the vas deferens (CBAVD) might have a correlation with fertilization and pregnancy rates in in vitro fertilization (IVF) treatment, we conducted a retrospective study involving a total of 60 CBAVD patients. All patients in this study had epididymal micropuncture in conjunction with perivascular nerve stimulation as part of the IVF program at the Nagoya University Hospital Reproduction Center. The patients were classified into 3 groups: group I consisted of patients having only a proximal portion of the caput epididymidis with a length of between 0.5 and 1.9 cm, group II consisted of patients with the caput and a portion of the corpus epididymidis with a length of between 2.0 and 4.0 cm, and group III consisted of patients with the caput, corpus and cauda of the epididymis measuring more than 4.0 cm. There were no differences in the sperm count, progression and normal morphology among the 3 groups; however, the motility was progressively higher in patients with a longer epididymis (12% in group 1, 18% in group II and 31% in group III). It was evident that group III showed the highest fertilization and pregnancy rate per patient (23% and 28%, respectively) among the 3 groups. This study shows that epididymal sperm from CBAVD patients with a longer epididymis have a higher IVF rate than CBAVD patients with a shorter epididymis.

Epididymis↗
PubMed1996

[Solitary plasmacytoma of sternum--a case report and review of the Japanese literature].

A 39-year-old woman complained of anterior chest pain. A lateral chest X-ray film showed destruction of bone in the body of sternum. CT scan showed a soft tissue density within the sternum. Serum protein electropheresis revealed mild monoclonal gammopathy of IgG-kappa, but the urine contained no Bence-Jones protein. A biopsy specimen showed plasmacytoma with cytoplasmic Ig IgG-kappa. Bone scintigraphy and systemic bone roentgenography revealed only the lesion in the sternum. Sternal subtotal resectin was performed. The defect of the anterior chest wall was reconstructed with double folded marlex mesh and pedicles from the major pectoral muscle. Iliac bone marrow aspiration revealed no evidence of myeloma. There was no serum evidence of monoclonal gammopathy two months after the operation. Therefore, the final diagnosis was solitary plasmacytoma of the sternum. It is now 41 months since surgery, and there have been no signs of fecurrence. Long term follow up is necessary in this case.

Adult↗
PubMed1995

Structures of genomic and complementary DNAs coding for Pleurotus ostreatus manganese (II) peroxidase.

To study the mechanism of regulation and structure/function relationship of the Pleurotus ostreatus manganese (II) peroxidase (MnP), we amplified the full-length genomic and complementary DNAs for the major isozyme of the MnP mainly by the cassette-primer PCR technique and then sequenced them. The cDNA contained an open reading frame of 1083 bp encoding for a polypeptide of 361 amino-acid residues, including the suggested signal peptide of 29 amino-acid residues with a prepro structure. The predicted amino-acid sequence of the protein shared several common characteristics with those of fungal lignin and manganese (II) peroxidases. We could find a suggested metal response element and two heat-shock element-like sequences in the 5'-flanking region of the structural gene. The structural gene contained 15 introns, many of which lie identical to those in lignin peroxidase genes rather than to those in the known MnP genes.

Amino Acid Sequence↗
PubMed1995

Ultrastructural study of TPA-induced cell motility: human well-differentiated rectal adenocarcinoma cells move as coherent sheets via localized modulation of cell-cell adhesion.

We previously found that 12-O-tetradecanoylphorbol-13-acetate (TPA)-enhanced invasion of Matrigel was associated with augmentation of cell motility but not with metalloproteinase activity in a highly metastatic variant (L-10) of human rectal adenocarcinoma cell line RCM-1. In a two-dimensional cell motility assay, TPA induced active L-10 cell locomotion with characteristic morphology; the cells moved outwards from the cell islands mainly as a localized coherent sheet of cells. The leading cells showed locomotor morphologies with fan-shaped leading lamellae while the following cells had cell contacts on all sides and appeared to lack leading lamellae. In the present ultrastructural study, the following cells frequently showed tapering cytoplasmic protrusions and leading lamella-like processes underlapping a preceding cell, indicating that the locomotion mechanism is almost the same for both the leading and following cells. For this type of locomotion as a coherent sheet we propose that localized modulation of cell-cell adhesion was induced such that wide intercellular gaps occurred at the lower portion of the cells to allow the cells to extend the tapering cytoplasmic processes and leading lamellae while close cell-cell contacts remained at the upper portion of the cells. These TPA-induced changes took place predominantly in the cells at the periphery of the cell islands, while the cells in the middle of the cell islands maintained close cell-cell contacts including complex interdigitation all around the cells, suggesting the modulation of TPA action by cell-cell interaction. Additionally, consistent with the evidence for junctional complexes between the cells moving outwards, the Lucifer-yellow dye transfer studies showed some, limited cell-cell coupling, suggesting the presence of at least some gap junctional intercellular communication in the moving cell sheets.

Actin Cytoskeleton↗
PubMed1995

Effects of suramin on metastatic ability, proliferation, and production of urokinase-type plasminogen activator and plasminogen activator inhibitor type 2 in human renal cell carcinoma cell line SN12C-PM6.

Effects of suramin, a polysulfonated naphthylurea compound, on metastatic ability, proliferation, and production of plasminogen activators and plasminogen activator inhibitors were studied using the highly metastatic human renal cell carcinoma cell line, SN12C-PM6. After renal subscapular implantation of tumor cells in nude mice, suramin significantly inhibited metastasis of tumor cells to the lungs and liver. In vitro growth of tumour cells was inhibited by suramin in a dose-dependent manner, at relatively low doses (ID50 = 105 micrograms/ml). Plasminogen activator inhibitor type 2 (PAI-2) production by tumor cells was enhanced by suramin (100 micrograms/ml), whereas urokinase-type plasminogen activator (uPA) production was suppressed. Thus, the increase in PAI-2 and the decrease in uPA production correlated with the inhibitory effects on tumour growth and metastasis by suramin. Therefore suramin may be beneficial for the treatment of patients with an early stage of renal cancer with potential risk of metastasis.

Animals↗
PubMed1995

Immunohistochemical identification of adrenomedullin in human, rat, and porcine tissue.

The histological localization was investigated of adrenomedullin (AM), a novel vasorelaxant peptide originally isolated from human pheochromocytoma. The immunohistological distribution was examined of AM in human, rat, and porcine tissues using a polyclonal antibody to a fragment comprising C-terminal amino acids 40-52 of human adrenomedullin [AM(40-52)NH2]. Almost all of the human pheochromocytoma and normal adrenal medullary cells of all three species were immunostained and found to be intensely positive for AM. Furthermore, AM-immunoreactive cells were present in the pancreatic islets, gastrointestinal neuroendocrine system, anterior pituitary, and choroid plexus with some degree of interspecies heterogeneity. These findings indicate that AM-immunoreactive cells are widely distributed in the endocrine and neuroendocrine system, suggesting that AM plays some important role in the control of systemic and local circulation and also of humoral secretion.

Adrenomedullin↗
PubMed1995

Clinicopathologic studies of immunologic fecal occult blood test for colorectal cancer.

In our hospital, 83 patients with colorectal cancer underwent the immunologic fecal occult blood test (IFOBT). The positive rate for IFOBT in all patients was 87%. Colon cancers more proximal than the transverse colon were 100% positive. Carcinomas of the ulcerative type showed a significantly higher positive rate than those of the non-ulcerative type (94% vs 73%). Carcinomas penetrating the muscularis or beyond showed a significantly higher positive rate, of 96% (52/54 cases) compared to carcinomas confined to the mucosa or submucosa, which gave positive rates of 64% and 60%, respectively. In the investigation of the 7 patients with colorectal cancer who showed negative results on the IFOBT, IFOBT had been performed only once in of these patients. Accordingly, it was considered necessary to perform IFOBT more than once. The cancers in 5 of these 7 patients were found to be carcinomas confined to the mucosa. This result suggests the advisability of annual IFOBTs. It is also considered necessary to manage patients who show undefinable but possibly positive (+/-) results with caution.

Carcinoma↗
PubMed1995

Postmenopausal bone loss in Japanese women.

OBJECTIVES: Our purpose was to detect anatomic variations in postmenopausal bone loss and to determine the risk factors most affecting bone mass in Japanese women. METHODS: One hundred sixty-six Japanese women (54 premenopausal and 112 postmenopausal), aged 40-68 years, were enrolled in the study. Bone mineral densities (BMD) of the lumbar spine (L2-4) and total body were measured by dual energy X-ray absorptiometry and the results were subjected to statistical analysis. RESULTS: Among the various sites studied, the lumbar spine (L2-4) showed the fastest bone loss after menopause. Multiple regression analysis indicated that two factors, number of years since the menopause and body mass index (BMI), affected lumbar spine (L2-4) BMD. CONCLUSION: Measurement of lumbar spine (L2-4) BMD is suitable for evaluating postmenopausal osteoporosis. The risk factors for postmenopausal bone loss were a long period after menopause and a low BMI.

Adult↗
PubMed1995

Well-differentiated fetal adenocarcinoma of lung.

Well-differentiated fetal adenocarcinoma (WDFA) histologically resembles pulmonary blastoma, and is thought to be a subtype of pulmonary blastoma which has differentiated epithelial features resembling the fetal lung among its epithelial features and sarcomatous features. We recently encountered one patient who underwent surgery for WDFA. This case is reported with a discussion of the literature. A 33-year-old woman had a tumor shadow in the lower lobe of the right lung. The tumor was diagnosed as pulmonary blastoma as a result of echographic biopsy, and right total pneumonectomy was performed. No sarcomatous features were observed on postoperative histological assessment, and the patient was diagnosed as having WDFA. Its prognosis is believed to tend to be better than that of biphasic blastoma, in which sarcomatous features are mingled with epithelial features. However, it is reported that chemotherapy or radiotherapy has seldom been effective. Complete surgical resection is essential for long-term survival.

Adenocarcinoma↗
PubMed1995

Screening of the mutations in luteinizing hormone beta-subunit in patients with menstrual disorders.

OBJECTIVE: To evaluate the clinical significance of the LH consisting of a mutant beta-subunit (Trp8 to Arg8 and Ile15 to Thr15). DESIGN: Clinical and biochemical studies. SETTING: Fertility center at the University Hospital and its research laboratory. PATIENTS: Fifty-one patients with menstrual disorders and three homozygote cases and two heterozygote cases of the mutant LH who were reported previously. INTERVENTIONS: Nucleotide mutations of the LH beta gene in patients with menstrual disorders were screened using techniques of the polymerase chain reaction and restriction fragment length polymorphism. Immunologic and biologic activities of the mutant LH and endocrinologic profiles in the affected women were evaluated. MAIN OUTCOME MEASURES: Serum LH levels measured with different immunoassay kits; serum FSH and LH on the GnRH test; serum thyroid-stimulating hormone, PRL, T, and androstenedione; ultrasound examination of the ovaries; clinical hyperandrogenic symptoms; and biologic activity of LH. RESULTS: Two cases of homozygotes and four of heterozygotes affected by the LH beta gene mutations were discovered in the current study through screening of patients with menstrual disorders. Serum LH levels in the homozygote cases were undetectable using a LH immunoassay kit, whereas levels in the heterozygote cases showed reduced detectability with the kit. However, the ratio of the mutant LH values in the bioassay to those in the immunoassay was higher in the homozygote group than that in the control subjects. Response patterns of serum gonadotropins to GnRH in the homozygote were similar to those in patients with polycystic ovary syndrome. CONCLUSION: The mutations of LH beta-subunit might be related to menstrual disorder in some patients.

Adolescent↗
PubMed1995

Evaluation of the meiotic spindle apparatus in oocytes undergoing intracytoplasmic sperm injection.

OBJECTIVE: To determine whether intracytoplasmic sperm injection has an adverse effect on the meiotic spindle of oocytes after injection of a sperm into the ooplasm. DESIGN: Hamster oocytes were injected with human sperm (Test group) and evaluated for meiotic spindle and chromosome morphology using immunofluorescent staining. Results were compared with control uninjected oocytes exposed to the microscope environment (CS group) and untreated oocytes remaining in the incubator (CI group). SETTING: Basic research center at a medical school. RESULTS: No significant differences were noted in spindle appearance and chromosome alignment between Test (13 abnormal/68 normal) and both control groups (CS 9/73 and CI 12/71; P = 0.602). CONCLUSION: Our results demonstrate that injection of human sperm into the cytoplasm of hamster oocytes may not result in a significant increase in damage to the meiotic spindle provided care is taken to orient the polar body away from the site of injection.

Animals↗
PubMed1995

International perceptions and approval of gene therapy.

Gene therapy is in clinical trials in a number of countries, raising the question of whether different ethical standards can be justified in different countries. One key issue is how divergent are the perceptions and bioethical reasoning of peoples around the world. An International Bioethics Survey with 150 questions, including 35 open ones, was developed to look at how people think about diseases, life, nature, and selected issues of science and technology, biotechnology, genetic engineering, genetic screening, and gene therapy. The mail response survey was conducted in 1993 among the public in Australia, India, Israel, Japan, New Zealand, Russia, and Thailand, and the same written survey was conducted among university students in Australia, Hong Kong, India, Japan, New Zealand, The Philippines, Russia, Singapore, and Thailand. Similar questions were included in an international high school education bioethics survey among high school teachers in Australia, Japan, and New Zealand. Further international comparisons to the United States and Europe are made. About three-quarters of all samples supported personal use of gene therapy, with higher support for children's use of gene therapy. The diversity of views was generally similar within each country. The major reasons given were to save life and increase the quality of life. About 5-7% rejected gene therapy, considering it to be playing God, or unnatural. There was very little concern about eugenics (0.5-2%), and more respondents gave supportive reasons like "improving genes," especially in Thailand and India. Support for specific applications was significantly less for "improving physical characters," "improving intelligence," or "making people more ethical" than for curing diseases like cancer or diabetes, but there was little difference between inheritable or noninheritable gene therapy.

Bioethical Issues↗
PubMed1995

The primary cytotoxicity in ultraviolet-a-irradiated riboflavin solution is derived from hydrogen peroxide.

The cytotoxic action of near-ultraviolet (UVA) radiation on cultured mammalian cells is dependent upon oxygen, suggesting that reactive oxygen species are involved in the cellular action of the radiation. Flavins are thought to be an important chromophore for photo-induced skin injury. Irradiation of riboflavin with UVA radiation is known to produce singlet oxygen, superoxide anions, and triplet-state riboflavin radicals, which, however, are immediately quenched by many constituents of the human skin. If the chemical produces a long-lived reactive oxygen species, hydrogen peroxide (H2O2), after UVA radiation, its deleterious effect is not limited to its generation site. Thus, we investigated whether H2O2, is produced in UVA-irradiated riboflavin solution and whether it plays an important role in the cytotoxic action of the solution. The solution showed a marked cytotoxic effect when placed on human fibroblasts, and cytotoxicity was retained in the solution for at least 40 min after radiation. Most of the toxicity appeared to be derived from H2O2 produced in the solution, because the solution lost its cytotoxicity as a result of catalase treatment, and the resultant restoration of survival was almost complete. Under our conditions, two molecules of riboflavin were calculated to produce one molecule of H2O2 after UVA radiation.

Catalase↗