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Biomedical subjects

J Tamura

Publications and source records attributed to J Tamura.

At least 109 records · Page 6Linked to original sources
PubMed1996

The behaviour of red cells in narrow tubes in vitro as a model of the microcirculation.

To investigate the behaviour of red cells in the microcirculation, we established a new capillary method using narrow fluorinated ethylenepropylene copolymer tubes with internal diameters of 12.5 and 25.0 microns. Red cell flow in the tubes under a given range of pressure was analysed through a video system connected to a microscope. The experimental condition was adjusted so that the velocity of the control normocytes would be compatible with that in corresponding vessels in vivo, 0.5-1.5 mm/s. In the 12.5 microns tube, normocytes obtained from 12 young normal volunteers ran in an axisymmetric edge-on orientation with a folded shape at higher pressures, but rolled along freely without deformation at lower pressures. Deformation during the passage of the microcytes obtained from four patients with polycythaemia vera complicated with iron-deficient microcytosis and 10 patients with iron deficiency anaemia was relatively mild, whereas that of the macrocytes obtained from eight patients with refractory anaemia was marked. Even after the screening effect at the tube entrance was taken into consideration, the velocities of both microcytes and macrocytes were found to be significantly lower than the control normocytes. Therefore this method may be a new way to investigate the flow properties of red cells in the microcirculation.

Adult↗
PubMed1996

[Autoimmune hemolytic anemia with eosinophilia in elderly patient].

A 70-year-old woman was admitted to our hospital in November 1992 for evaluation of anemia. Physical examination revealed anemia, jaundice, swelling of axial and inguinal lymph nodes, and splenomegaly. Abnormal hematological findings were as follows: Hb of 3.9 g/dl, reticulocyte count of 58.2% (61.7 x 10(4)/microliters), hyperplasia of normal erythroblasts in bone marrow, and eosinophilia (21.0%, 2352/microliters) in peripheral blood. Routine laboratory examinations revealed polycolonal hypergammaglobulinemia 3.0 g/dl, a high level of serum LDH (797 IU/I) and a total bilirubin of 2.4 mg/dl (indirect, 1.6 mg/dl). The serum haptoglobin level was very low (< 5 mg/dl). Results of serological examinations were as follows: IgG of 3366 mg/dl, CH50 of 16.0 U/ml, positive Coombs test 2+, and positive tests for antinuclear antibody, rheumatoid factor, and cold agglutinin. CRP was negative. PHA-stimulated lymphocyte blast formation, NK activity, and ADCC activity were found to be suppressed, and the percentage of CD4-positive lymphocytes in peripheral blood was also low. An axillary lymph node biopsy revealed reactive lymphadenitis. No signs or history suggested allergy, collagen disease, or parasitic infection. Autoimmune hemolytic anemia (AIHA) complicated by immunologic abnormalities and eosinophilia was diagnosed. Oral prednisolone markedly reduced the hemolytic anemia, eosinophilia, lymph node swelling, and splenomegaly, but NK activity remained low.

Aged↗
PubMed1996

Intercalary replacement of canine femora using a new bioactive bone cement.

We have developed a bioactive bone cement (BA cement) consisting of Bis-GMA resin and bioactive glass powder. It has high compressive and tensile strengths, a low curing temperature and its bioactivity allows it to bond directly with bone. We operated on the 18 femora of nine mongrel dogs for intercalary replacement of part of the bone by a metal prosthesis using either PMMA cement or BA cement for fixation. Three dogs were killed at each of 4, 12 and 26 weeks after surgery for the evaluation of fixation strength by a push-out test and for histological examination by Giemsa surface staining and SEM. Fixation strengths with PMMA cement at 4, 12 and 26 weeks after surgery were 46.8 +/- 18.9, 50.0 +/- 24.7, and 58.2 +/- 28.9 kgf (mean +/-sD), respectively. Those with BA cement were 56.8 +/- 26.1, 67.2 +/- 19.2, and 72.8 +/- 22.2 kgf, respectively. Fibrous tissue intervened between bone and PMMA cement but BA cement had bonded directly to bone at 12 and 26 weeks. This suggests that BA cement will be useful in providing long-lasting fixation of implants to bone under weight-bearing conditions.

Animals↗
PubMed1995

Activation of silent MDR1 genes in revertant cells by fusion with multidrug-resistant cells.

We isolated revertant and resistant clones from multidrug-resistant K562/ADM cells and evaluated the expression of P-glycoprotein and the DNA copy number of MDR1. The 9 revertant clones contained 2- to 26-fold DNA copies of MDR1; however, they expressed an extensively decreased P-glycoprotein compared with K562/ADM, while the 10 multidrug-resistant clones contained 4- to 48-fold DNA copies, and the expression level of P-glycoprotein was dependent on the copy number of MDR1 DNA. The decreased expression of P-glycoprotein in the revertants was not due only to the loss of the copy number of MDR1 DNA. To elucidate the mechanism of P-glycoprotein expression decrease in the revertants, a revertant clone (R1-5) was fused with a multidrug-resistant clone (A2-1) or with a drug-sensitive clone isolated from K562. Compared with K562 clone, the A2-1 contained 32-fold MDR1 DNA copies and showed 131-fold resistance to Adriamycin. The revertant clone R1-5 contained 26-fold MDR1 DNA copies but expressed only 5% the P-glycoprotein of A2-1 cells and showed only 2-fold resistance to Adriamycin. For selection of intraspecific hybrids, a neomycin-resistant or a blasticidin S-resistant gene was introduced into clones by electroporation of pSV2neo or pSV2bsr. The introduction of these resistant genes did not alter the copy number or expression of MDR1 in the clones. Hybrid cells between R1-5bsr and A2-1neo were found to express 136 +/- 15% of the P-glycoprotein of A2-1 cells evaluated by quantitive flow cytometry. These hybrid cells contained 41- to 48-fold MDR1 copies and showed the multidrug-resistant phenotype, such as decrease of rhodamine123 accumulation and 120- to 210-fold resistance to Adriamycin (compared with K562), indicating that the 'silent' MDR1 genes in the revertant clone R1-5 were activated by cell fusion with an MDR clone. R1-5bsr x K562neo hybrids were found to contain 8- to 11-fold MDR1 copies and there was no increase in P-glycoprotein expression as compared with R1-5.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Surgical excision of adrenal masses; a ten-year experience.

We reviewed the records of 13 patients with adrenal masses operated on over a ten-year period to clarify clinical characteristics of adrenal tumors. Tumors were found incidentally in seven of nine patients with primary adrenal tumors (78%); however, three of these seven patients (43%) proved to have shown symptoms related to adrenal hyperfunction when re-evaluated. Other adrenal tumors (metastatic in three patients and inflammatory in one) were found without any symptoms referable to the tumors. In nine of 13 patients (69%), tumors were discovered by computerized tomography (CT). All patients with primary tumors have been gotten free of disease postoperatively. In contrast, although all three patients with metastatic adrenal tumors underwent resection of all known disease tissue, they died of the recurrence of malignancies within 10 months. This study suggests that a number of functional adrenal tumors are possibly left undiagnosed until found incidentally, and that CT is the most powerful tool to detect adrenal tumors. Our data did not support surgical intervention in cases of metastatic adrenal tumors.

Adolescent↗
PubMed1995

Steroid-responsive pulmonary disorders associated with myelodysplastic syndromes with der(1q;7p) chromosomal abnormality.

We report three patients with pulmonary disorders associated with myelodysplastic syndromes (MDS). All three patients had symptoms of pyrexia and respiratory discomfort. One patient had pulmonary eosinophilia with bilateral pleural effusion, one had interstitial pneumonia, and one had bilateral pleural effusion caused by systemic vasculitis. Elevated C-reactive protein (CRP) levels, polyclonal hypergammaglobulinemia, and morphological abnormalities in peripheral blood were observed in all three patients. The bone marrow of these patients revealed trilineage dysplasia and eosinophilia. Cytogenetic analysis showed [46,XY,-7,+der(1q;7p)]. Antibiotic treatment was not effective. However, improvement was dramatic after corticosteroid treatment; CRP levels were reduced and the hypergammaglobulinemia was improved. These cases suggest that MDS with [-7,+der(1q;7p)] may be correlated with bone marrow eosinophilia and that an immunologic abnormality may be involved in the pulmonary disorders.

Adrenal Cortex Hormones↗
PubMed1995

Bioactive bone cement: the effect of amounts of glass powder and histologic changes with time.

A study was conducted to examine the influence of the amount of glass powder added to a bioactive bone cement of our formula on its mechanical and biologic properties. Serial changes in the cement with time were also examined. The bioactive bone cement consisted of CaO-SiO2-P2O5-CaF2 glass powder and bisphenol-a-glycidyl methacrylate resin. Glass powder was added to the cement in 30, 50, 70, and 80% weight ratios. The compressive strengths of the resulting cements (171-239 MPa) were more than double that of polymethylmethacrylate cement (68 MPa). Histologic examination of rat tibiae bearing artificial defects packed with each bioactive cement showed direct bone contact 4 weeks after surgery. The cement with a higher percentage of glass powder showed better direct formation of bone around its periphery with a thicker reactive layer. Under scanning electron microscopic observation, the reactive layer showed increased levels of calcium and phosphorus. Examination of histologic changes up to 26 weeks showed progressive bone formation around the cement and no sign of biodegradation.

Animals↗
PubMed1995

Significance of altered fluidity of plasma membranes of the liver and kidney in rats with sepsis.

The present study was conducted to investigate changes in plasma membrane fluidity of the liver and kidney in sepsis, which is the main cause of multiple organ failure. Male Wistar rats weighing 200-250 g were used in all experiments. Sepsis was induced by cecal ligation and puncture. As a control, a sham operation was performed. The time course of plasma membrane fluidity of the liver and the renal cortex in septicemic rats or in controls was studied. To evaluate the fluidity, fluorescence polarization was measured using 1,6-diphenyl-1,3,5-hexatriene. The fluorescence polarization values of liver plasma membranes increased after cecal ligation and puncture: 0.183 +/- 0.004 (mean +/- SEM), 0.194 +/- 0.008, 0.206 +/- 0.003, and 0.210 +/- 0.002 at 0, 24, 48, and 72 hr, respectively. Corresponding values for membranes of the renal cortex increased in a similar fashion. To determine whether factors involved in cell membrane damage exist in blood, the direct effects of lipopolysaccharide (LPS), platelet-activating factor (PAF), and serum from normal rats or from septicemic rats on membrane fluidity were studied. The fluorescence polarization of plasma membranes of the liver or renal cortex to which septicemic rat serum was added was higher than that of plasma membranes to which normal rat serum was added. The fluorescence polarization of liver plasma membranes was increased by LPS, but that of plasma membranes of the renal cortex was slightly decreased. In addition, the fluorescence polarization of liver plasma membranes was increased by PAF, but that of plasma membranes of the renal cortex was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

A stereocontrolled synthetic approach to glycopeptides corresponding to the carbohydrate-protein linkage region of cell-surface proteoglycans.

The glycopeptides 1 (Gly[O-beta-D-Xylp)-L-Ser-Gly-L-Glu) and 2 (Gly[O-[beta-D-GlcpA-(1-->3)-beta-D-Galp-(1-->3)-beta-D-Galp]-(1-- >4) -beta-D-Xylp)-L-Ser-Gly-L-Glu), carrying the core structure of serine-linked cell-surface proteoglycans were synthesized in a stereocontrolled manner. The carbohydrate key imidate xylosyl donors 3 and glycotetraosyl donors 4 and 5, as well as a tetrapeptide glycosyl acceptor 6, were coupled in the crucial glycosylation step. In these reactions, the application of either trimethylsilyl trifluoromethanesulfonate (TMSOTf) or borontrifluoride etherate (BF3-Et2O) as catalysts proved to be highly efficient. The serine linked glycopeptides 34, 36 and 37 thus obtained yielded target compounds 1 and 2 on complete deprotection.

Amino Acid Sequence↗
PubMed1995

Acquired total immunoglobulin G deficiency in a patient with primary biliary cirrhosis.

A 38-year-old Japanese woman was hospitalized for susceptibility to respiratory tract infections. Clinical examinations revealed asymptomatic primary cholestasis, abnormally elevated immunoglobulin M (IgM) and antimitochondrial antibody, being consistent with asymptomatic primary biliary cirrhosis. Three years later her serum immunoglobulin G (IgG) decreased remarkably, whereas other immunoglobulins were unchanged. Immunological examinations on the peripheral blood lymphocytes demonstrated spontaneous over-synthesis of serum IgM and decreased synthesis of IgG due to abnormal function of both T and B cells. Our case suggests a new possible association between primary biliary cirrhosis and IgG deficiency.

Adult↗
PubMed1995

[Porphyrias and drugs].

The porphyrias are a metabolic disorders of heme biosynthesis characterized by the excessive production and excretion of porphyrins and porphyrin precursors. They are caused by defects in specific enzyme activities and classified into 7 subtypes. Some of them present with photosensitivity of skin and intermittent acute attacks related to nervous system disturbance. Especially in acute intermittent porphyria, patients have recurrent acute attacks of abdominal, neurologic, and psychiatric symptoms. Some precipitating factors; including drugs, hormonal factors, starvation, and stress; induces acute attacks. In this article, pathophysiology of the neurologic symptoms and relation between precipitating factors, especially focused in drugs, and acute attacks may be reviewed.

Carbamazepine↗
PubMed1995

DNA fragmentation of human infarcted myocardial cells demonstrated by the nick end labeling method and DNA agarose gel electrophoresis.

Myocardial tissue taken from 19 autopsy cases of myocardial infarction were examined both by the nick and labeling method (NELM) and by DNA agarose gel electrophoresis in order to demonstrate the localization of cells with fragmented DNA and to confirm the internucleosomal cleavage of DNA biochemically. The nuclei corresponding to those with the histological features of acute myocardial infarction in hematoxylin and eosin (H&E)-stained sections were stained strongly positive with the nick end labeling method. Myocardial cells corresponding to those with nick end labeling method-stained nuclei, on the other hand, had mostly pyknotic and karyolytic nuclei and some unremarkable nuclei, even nuclear ghosts, and showed degenerated cytoplasm, including contraction band necrosis in H&E-stained preparations. The agarose gel electrophoresis of DNA extracted from the corresponding areas mentioned above showed the ladder pattern of internucleosomal cleavage characteristic of apoptosis. The present study revealed that infarcted myocardial cells with nuclear outlines, even nuclear ghosts, showed a distinct DNA fragmentation with the ladder pattern of internucleosomal cleavage. It is concluded from this study that the damaged myocardial cells of acute myocardial infarction represent a coagulation necrosis having the biochemical nature of apoptosis.

Aged↗
PubMed1995

Histamine excess symptoms in basophilic crisis of chronic myelogenous leukemia.

We encountered a patient with chronic myelogenous leukemia in basophilic crisis accompanied with histamine excess symptoms including bronchial asthma and gastric ulcer. The concentrations of histamine and histidine decarboxylase in leukemic cells containing granules typical for basophils were similar to those in mature basophils. His histamine excess symptoms rapidly disappeared concomitant with the reduction of blast cells after chemotherapy. We speculate that his histamine excess symptoms were induced by the leukemic cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Typical fibrolamellar hepatocellular carcinoma in Japanese patients: report of two cases.

We report herein the cases of two Japanese patients with typical fibrolamellar hepatocellular carcinoma treated at our institute. The first patient was a 19-year-old man with no hepatitis B or C viral infection and a normal, noncirrhotic liver in the nontumorous area. The second was a 36-year-old woman with no viral infection and a noncirrhotic liver in the nontumorous area. The clinicopathology, imaging appearances, and histology of both cases were similar to reports from the United States.

Adult↗