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Biomedical subjects

M Oyama

Publications and source records attributed to M Oyama.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Complete remission of plasmablastic IgD lambda multiple myeloma induced by continuous infusion of low-dose cytarabine and etoposide].

A 67-year-old man was admitted because of thrombocytopenia in May 1998. His white blood cell count was 4,900/microliter with 3.5% blasts. Laboratory findings were as follows: hemoglobin level, 10.1 g/dl; platelet count, 1.8 x 10(4)/microliter; ALT, 56 IU/l; LDH, 3,570 IU/l; IgG, 653 mg/dl; IgA, 64 mg/dl; IgM, 49 mg/dl; IgD, 674 mg/dl. Serum immunoelectrophoresis confirmed IgD lambda M-component. Bone marrow aspiration showed 79.2% myeloma cells expressing a mostly plasmablastic morphology. No mature plasma cells were found in the bone marrow. The patient received a continuous drip infusion of 20 mg/body cytarabine (Ara-C) and 50 mg/body etoposide (VP-16) for 7 days. No plasmablastic myeloma cells were detected, but 2.1% mature plasma cells were found in his bone marrow on day 20. On day 18 his platelet count exceeded 10.8 x 10(4)/microliter, and the serum IgD level fell to 210 mg/dl. Therapy consisting of melphalan, methylprednisolone and vincristine was started from day 23. No IgD lambda M-component was detectable by serum immunoelectrophoresis seven months after the diagnosis of multiple myeloma. The patient has been in complete remission as of April 2000.

Aged↗
PubMed1999

Effects of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657, on plasma extravasation in guinea pig airways.

We investigated the effect of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657 (E)-3-(6-acetamido-3-pyridyl)-N-[N-[2.4-di-chloro-3-[(2-methyl-8-quinoli nyl)oxymethyl]phenyl]-N-methy-laminocarbonylmethyl] acrylamide), on plasma extravasation mediated by activation of sensory nerves in guinea pig airways. Plasma extravasation was assessed by the photometric measurement of the extravasated Evans blue after formamide extraction. We found that the increase in Evans blue dye extravasation evoked by an aerosol of bradykinin (0.1 mM, 2 min) in the presence of phosphoramidon (2.5 mg/kg, i.v.) was abolished completely by FR173657 (20 mg/kg, p.o.) in the trachea and main bronchi. In sensitized guinea pigs pretreated with phosphoramidon, FR173657 (20 mg/kg, p.o.) inhibited plasma extravasation evoked by ovalbumin aerosol (5%, 2 min) by 77+/-14.2% in the trachea and 65+/-11.2% in the main bronchi. FR173657 (20 mg/kg, p.o.) did not affect the plasma extravasation caused by aerosolised capsaicin. These findings suggest that FR173657 is an orally active, promising anti-inflammatory agent for kinin-dependent inflammation following antigen challenge.

Administration, Oral↗
PubMed1999

Retrovirally transduced bone marrow stromal cells isolated from a mouse model of human osteogenesis imperfecta (oim) persist in bone and retain the ability to form cartilage and bone after extended passaging.

Bone marrow stromal cells isolated from a model of osteogenesis imperfecta (oim) mice, were transduced with a retrovirus (BAG) carrying the LacZ and neor genes after passage 21. The transduced cells retained the ability to express alkaline phosphatase activity in vitro when treated with recombinant human bone morphogenetic protein two (rhBMP-2), formed cartilage in vitro in aggregate cultures and formed bone in ceramic cubes after 6 weeks of implantation in nude mice. X-gal staining of ceramic cubes seeded with the transduced cells demonstrated the presence of LacZ-positive cells on the edges of bone and also in the lacunae of the newly formed bone 6 weeks after implantation. After infusion into femurs of oim mice, the transduced cells were detected in the marrow cavity and on the edges of the trabecular bone of the injected and contralateral femurs by X-gal staining and PCR analysis at 4, 10, 20, 30 and 40 days after injection. The LacZ gene was also detected in the lung and liver of the recipient mice at 4 and 10 days after injection but not at later time-periods. The present findings suggest that long-term cultured bone marrow stromal cells from osteogenesis imperfecta (OI) animals have the potential to traffic through the circulatory system, home to bone, form bone and continue to express exogenous genes. These findings open the possibility of using these cells as vehicles to deliver normal genes to bone as an alternative approach for the treatment of some forms of OI and certain other bone acquired and genetic diseases.

Alkaline Phosphatase↗
PubMed1999

Dyschromatosis symmetrica hereditaria (reticulate acropigmentation of Dohi): report of a Japanese family with the condition and a literature review of 185 cases.

We report a Japanese family with dyschromatosis symmetrica hereditaria (DSH) (MIM 127400 in McKusick's Mendelian Inheritance in Man), a rare autosomal dominant genodermatosis, predominantly occurring among Japanese and Korean individuals. Members of the present family affected with the disease showed a mixture of hyperpigmented and hypopigmented macules distributed on the face and the dorsal aspects of the extremities, which are typical of DSH. As most of the literature on DSH has been written in Japanese, dermatologists outside Japan are not familiar with the condition. In this paper, 185 cases of DSH, most of them reported in Japanese, are reviewed and unique clinical, histological and genetic features of this condition are delineated.

Child↗
PubMed1999

Screening of blood donors for human parvovirus B19 and characterization of the results.

BACKGROUND AND OBJECTIVES: Human parvovirus B19 (B19 virus) can be transmitted through blood transfusion and plasma-derived products. In a previous report, we utilized the simple hemagglutination method based on the interaction between the B19 virus and P antigen on human erythrocytes in order to screen the blood donors. We called this method receptor-mediated hemagglutination (RHA) [Lancet 1995;346:1237-1238]. In this paper, we report on a large-scale screening of the B19 virus by RHA and discuss the results. MATERIALS AND METHODS: Donor sera from September 1995 to March 1997 and seroconversion panels were enrolled. Donor sera were examined by RHA for large-scale screening. The positive sera in the first screening were then further investigated by the RHA inhibition test, countercurrent immunoelectrophoresis (CIE), an enzyme-linked immunosorbent assay, and polymerase chain reaction (PCR). We also evaluated the infectivity and neutralizing activity of various kinds of sera by the erythroid colony forming unit (CFU-e) assay. To examine the detection limits of the B19 virus by RHA, B19-viremic sera were purified by sucrose gradient ultracentrifugation. RESULTS: Among 257,710 sera specimens, 293 sera (0.11%) gave a positive reaction in the first screening using RHA. Out of these 293 sera specimens, 31 were positive for PCR, of which 28 were also RHA inhibition-positive, and 25 of the 28 CIE-positive. In the CFU-e injury assay, all the RHA inhibition (+) sera showed a decrease in the number of erythroid colonies. The RHA inhibition (-) PCR (+) B19 antibody (+) sera did not affect the erythroid colony formation and protected CFU-e from injury by the B19 virus. By measuring the amount of purified B19 protein and its RHA titer, the detection limit of the B19 virus by RHA was calculated to the 0.37+/-0.03 ng/ml. CONCLUSION: These results suggest that the RHA(+) RHA inhibition (+) sera were infectious in vitro. The combination of RHA and the RHA inhibition test is considered to be useful for the large-scale screening of infectious B19 virus in blood donors with high specificity.

Blood Donors↗
PubMed1999

[Disappearance of residual disease confirmed by RT-PCR following induction chemotherapy in two hypoplastic leukemia patients with t(8;21)].

Reverse transcriptase-polymerase chain reaction (RT-PCR) methods often detect the AML1/MTG8 fusion transcript even in acute myelogenous leukemia (AML) patients with t(8;21) who have been in long-term remission. We encountered 2 hypoplastic leukemia patients with t(8;21) who achieved cytogenetic remission with short-term conventional chemotherapy. Patient 1 was a 42-year-old woman. Chromosomal analysis detected t(8;21) (q22;q22) and PCR analysis (35 cycles PCR amplification; detection limit 1 x 10(-5) cells) detected the AML1/MTG8 fusion transcript. Complete remission was obtained with 1 course of chemotherapy consisting of low-dose cytarabine (20 mg x 14 days) and etoposide (50 mg x 14 days). After 2 courses of consolidation chemotherapy consisting of conventional-dose cytarabine and mitoxantrone, the RT-PCR findings were negative for the AML1/MTG8 fusion transcript. Patient 2 was a 67-year-old man. Cytogenetic analysis detected t(8;21) (q22;q22), and was positive for the AML1/MTG8 fusion transcript. After 2 courses of induction chemotherapy comprising low-dose cytarabine (20 mg x 14 days) and etoposide (50 mg x 14 days), and 3 courses of conventional consolidation chemotherapy, RT-PCR analysis confirmed the disappearance of the AML1/MTG8 fusion transcript.

Adult↗
PubMed1998

Identification of types II, IX and X collagens at the insertion site of the bovine achilles tendon.

Achilles tendinous collagen fibrils insert into the calcaneus by first passing through a zone that is defined histologically as fibrocartilaginous. This zone consists of four regions: tendon proper, non-mineralized and mineralized fibrocartilage and bone. The function of this zone has not yet been clearly defined. To gain more insight into the role of this fibrocartilaginous zone, collagens present in the zone of the Achilles tendon-calcaneus interface were isolated and characterized. Types II, IX and X collagens were identified in the pepsin digests of the tissue harvested from the bovine Achilles tendon-calcaneus interface. Western blotting using specific antisera to types II, IX and X collagens confirmed the identity of these collagens. Immunofluorescence localization placed type X collagen predominantly in the mineralized zone of the tendon-calcaneus junction, while type IX collagen was distributed throughout the the insertion site. The presence of the cartilage-specific collagens at the Achilles tendon-calcaneus-interface suggests that this zone is cartilaginous in nature. The presence of type X collagen at this junction is not clear, but our present findings go along with the previous report which showed that type X collagen is present in the mineralized zone of the medial collateral ligament femoral insertion site. These data suggest that type X collagen may be a resident of mineralized fibrocartilaginous zones of tendon or ligament-bone junctions and may participate in anchoring ligament or tendon to bone.

Achilles Tendon↗
PubMed1998

Potential role for gene therapy in the enhancement of fracture healing.

Various proteins have the potential to initiate and accelerate fracture healing. Although osteogenic growth factors are the most prominent of these, there also may be important roles for other agents including growth factor receptors, angiogenic factors, and cytokine antagonists. Gene based delivery systems offer the potential to achieve therapeutic levels of these proteins locally within the fracture site for sustained times. Moreover, these delivery systems may deliver their products in a more biologically active form than that achieved by the exogenous application of recombinant proteins. Genes may be transferred to fractures by direct in vivo delivery or by indirect ex vivo delivery, using viral or nonviral vectors. Two examples are described in this article. With an ex vivo procedure, it was possible to transfer lac Z and neo(r) marker genes to the bones of mice, using retroviral transduction of bone marrow stromal cells. Gene expression in vivo persisted for several weeks. This procedure has the advantage of providing not only gene products but also osteoprogenitor cells to sites of bone healing. In vivo, local transfer of the lucerifase and lac Z marker genes was accomplished in a segmental defect model in the rabbit using adenoviral vectors. Under these conditions, gene expression in most tissues in and around the defect lasted between 2 and 6 weeks. These data encourage additional development of gene therapy for fracture healing. Such developments should go hand in hand with studies in the basic biology of fracture healing.

Adenoviridae↗
PubMed1998

Distribution and expression of mRNAs for the proto-oncogenes c-fos and c-jun in bone cells in vivo.

In this study we assessed the expression and localization of the proto-oncogenes c-fos and c-jun in normal bone so as to gain more insight into the role of these proto-oncogenes in bone tissue. Femurs of 4-week-old rats were examined by non-radioactive in situ hybridization. cDNA probes for c-fos- and c-jun-labeled digoxygenin were produced by Polymerase Chain Reaction (PCR). C-fos and c-jun exhibited similar distribution in growth plate and bone tissue. Expression of c-fos and c-jun mRNAs in growth plate was observed in the proliferative zone and partly in the upper layer of the hypertrophic zone. In spongy bone, high expression of c-fos and c-jun mRNAs was observed in the osteoblast cytoplasm. However, there was little expression in bone lining cells. In the bony trabeculae, slight expression of c-fos and c-jun was observed in the premature osteocytes situated close to the bone surface, but no expression was detected in osteocytes that possessed relatively large lacunae in the center of the trabeculae. C-fos and c-jun were also slightly expressed in osteoclasts. These data strongly suggest that c-fos and c-jun are involved in regulating chondrocyte proliferation as immediate early genes, and may also be involved in the gene expression of bone matrix proteins as transcription factor (AP-1) in vivo. In addition, the fact that strong expression was observed in osteoblasts but hardly any expression at all in bone lining cells seems to suggest that these genes are also involved in osteoblast activation.

Animals↗
PubMed1998

[A case of septic shock following incarceration of the penis].

An 84-year-old male presented to the emergency room with the chief complaint of painful, swollen penis following the use of a constriction ring to maintain penile erection. A high fever, chills and hypotension were recognized. Septic shock was presumed, and administration of antibiotics was started. Microbiologic cultures revealed Escherichia coli in blood. We herein report a rare but serious complication accompanying incarceration of the penis.

Aged↗
PubMed1998

[Cytarabine-induced pericarditis].

We report two cases of cytarabine (Ara-C) induced pericarditis. The first patient was a 61-year-old man with de novo acute myelogenous leukemia (AML) with trilineage myelodysplasia (M2). Fever and pericardial effusion developed after treatment with low-dose Ara-C and etoposide (VP16) during the patient's second leukemic relapse. The second patient was a 65-year-old man with myelodysplastic syndrome (MDS) transformed into AML (M2). He achieved a complete remission after treatment with low-dose Ara-C and VP16. However, during consolidation chemotherapy consisting of oral cytarabine ocfosfate and VP16, fever and pericardial effusion developed. In both cases, pericardiocentesis revealed exudative effusion with many neutrophils. Neither bacterial nor fungal infection was demonstrated. Chest symptoms and fever were resolved by methylprednisolone pulse therapy and pericardial drainage. Both patients were given a diagnosis of pericarditis caused by allergic reaction to Ara-C. We also report on 6 other patients with Ara-C syndrome who have been encountered by our hospital.

Aged↗
PubMed1997

Distribution and localization of galectin purified from Rana catesbeiana oocytes.

Galectins are a family of lectins that recognize beta-D-galactosides independently of calcium ions, and are widely distributed in animals. To characterize a galectin previously purified from oocytes of Rana catesbeiana (American bullfrog), we studied its distribution and localization in several tissues from this frog. Hemagglutination assay and western blotting showed that this lectin is present in many tissues including the liver, skin, kidney, skeletal muscle, and sciatic nerve, but is particularly concentrated in the ovary. Light microscopic immunohistochemistry showed that this lectin is localized in such places as cell-cell junctions, basement membranes, extracellular matrix, or secretory substances in several organs, indicating that this galectin is mainly distributed extracellularly. However, in the ovary, light microscopy showed that this lectin is present in or associated with the yolk platelet. Electron microscopy further revealed that it is localized in the periphery of the yolk platelet (the yolk plasm), but not in the cortical granule. These results indicate that Rana oocytes contain abundant galectin in their yolk platelets in contrast to Xenopus laevis oocytes, which have been found not to contain galectins but other classes of lectins in their yolk platelets and cortical granules.

Amino Acid Sequence↗
PubMed1997

Structural variations in the glycosaminoglycan-protein linkage region of recombinant decorin expressed in Chinese hamster ovary cells.

Decorin is a small fibroblast proteoglycan consisting of a core protein and a single chondroitin/dermatan sulfate chain. The structure of the carbohydrate-protein linkage region of the recombinant decorin expressed in Chinese hamster ovary cells was investigated. The decorin was secreted in the culture medium and isolated by anion-exchange chromatography. The glycosaminoglycan chain was released from the decorin by beta-elimination using alkaline NaBH4, and then digested with chondroitinase ABC. These treatments resulted in a major and a few minor hexasaccharide alditols derived from the carbohydrate-protein linkage region. Their structures were analyzed by enzymatic digestion in conjunction with high-performance liquid chromatography. Two of these compounds have the conventional hexasaccharide core, deltaHexA alpha1-3GalNAc beta1-4GlcA beta1-3Gal beta1-3Gal beta1-4Xyl-ol. One is nonsulfated, and the other is monosulfated on C4 of the GalNAc residue. They represent 12% and 60% of the total linkage region, respectively. The other compound has the hexasaccharide alditol with an internal iduronic acid residue deltaHexA alpha1-3GalNAc(4-sulfate)beta1-4IdoA alpha1-3Gal beta1-3Gal beta1-4Xyl-ol, which was previously demonstrated in one of the five linkage hexasaccharide alditols isolated from dermatan sulfate proteoglycans of bovine aorta (Sugahara et al., J. Biol. Chem., 270, 7204-7212, 1995). The compound accounts for 11% of the total linkage region. These structural variations in the linkage hexasaccharide region of the decorin strikingly contrast to the uniformity demonstrated in the linkage hexasaccharide structure of human inter-alpha-trypsin inhibitor (Yamada et al., Glycobiology, 5, 335-341, 1995) and urinary trypsin inhibitor (Yamada et al., Eur. J. Biochem., 233, 687-693, 1995), both of which have a single chondroitin sulfate chain with a uniform linkage hexasaccharide structure, deltaHexA alpha1-3GalNAc(4-sulfate)beta1-4GlcA beta1-3Gal(4-sulfate)beta1-3Gal beta1-4Xyl, containing a 4-O-sulfated Gal residue.

Alkaline Phosphatase↗
PubMed1997

H+ secretion induced by hypertonic stress in the cellular slime mold Dictyostelium discoideum.

We found that Dictyostelium amebas shrank about 50% in 10 min after a change in extracellular osmolarity from 70 mosM to 170-370 mosM. Cells shrunk by the addition of 0.1 M mannitol showed a partial recovery of cell volume in 2 h when the culture medium contained salts. A full recovery of cell volume was observed when 0.1 or 0.2 osM NaCl or KCl was added instead of mannitol. No recovery of cell volume was observed after the addition of 0.1 M mannitol or glycine when the extracellular medium did not contain any salt. An elevation in extracellular pH of starved Dictyostelium cells, which is probably due to ammonia production, was suppressed by hypertonic stress. This hypertonic stress-induced suppression of the elevation in extracellular pH was observed only when the extracellular medium contained salt. We also found that cells with artificially elevated intracellular pH withstood hypertonic stress much better than control cells. These results suggest that Dictyostelium cells under hypertonic conditions secrete protons and take up charged extracellular osmolytes in exchange. The uptake of charged osmolytes induces the elevation of intracellular osmotic strength and the recovery of cell volume. The elevation of intracellular pH, which is presumably induced by the proton secretion, plays a role in protecting cells from lysis.

Adaptation, Physiological↗
PubMed1996

cGMP accumulation induced by hypertonic stress in Dictyostelium discoideum.

The change in extracellular osmolarity from 0.07 osm to 0.38 osm caused rapid cell shrinkage and loss of pseudopodes in Dictyostelium discoideum amoebae and induced elevation of total (cellular + extracellular) cGMP with a 2.5-min lag. cGMP accumulation reached a peak at 10-15 min after the change, and then the total cGMP gradually decreased. cGMP first accumulated intracellularly and was then secreted. A roughly identical osmotic concentration was required for the accumulation when the effect of KCl and glucose was tested. The non-osmolytes, formamide and ethanol, did not induce the accumulation. We concluded that hypertonic stress induces cGMP accumulation in D. discoideum amoebae. The hypertonic stress-induced accumulation of cGMP was observed in a streamer F mutant (NP368) that lacks cGMP-specific phosphodiesterase. While Dictyostelium cells also have nonspecific phosphodiesterases that degrade both cGMP and cAMP, hypertonic stress induced only a small increase in cAMP in wild type and streamer F cells. These results suggest that hypertonic stress-induced accumulation of cGMP is due to the activation of guanylate cyclase rather than the inhibition of phosphodiesterases. Binding of folic acid to the specific receptors on the cell surface induces a rapid transient accumulation of cGMP that reaches a peak at 10 s. When cells were stimulated by folic acid after the addition of 0.31 M glucose, rapid transient cGMP accumulation was observed immediately after the stimulation by folic acid and prolonged cGMP accumulation was induced 2-3 min after the addition of glucose irrespective of the timing of folic acid stimulation. These results suggest that the hypertonic stress-induced and the receptor-mediated accumulation proceed independently of one another. 2,3-Dimercapto-1-propanol, a thiol-reducing reagent, induces prolonged cGMP accumulation similar to hypertonic stress. However, the hypertonic stress-induced cGMP accumulation was enhanced by EDTA and was not suppressed by folic acid and cAMP. These characteristics are distinct from the reducing reagent-induced accumulation that is suppressed by EDTA, folic acid, and cAMP. These findings show that hypertonic stress has a unique effect on the activation of guanylate cyclase.

3',5'-Cyclic-GMP Phosphodiesterases↗