Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 433 records · Page 24Linked to original sources

PubMed1997

In vitro copper stimulation of plasma peptidylglycine alpha-amidating monooxygenase in Menkes disease variant with occipital horns.

We determined the concentrations of copper, the activities of ceruloplasmin and peptidylglycine alpha-amidating monooxygenase (PAM), and the stimulation index of PAM by the in vitro addition of copper in plasma samples obtained from three male patients with occipital horns and a milder Menkes disease phenotype, having severe copper deficiency due to the defect in copper transport. We found a decreased plasma ceruloplasmin activity and an increased copper stimulation index of plasma PAM in these patients compared with healthy control subjects. The combination of these two determinations may provide a means for the assessment of copper nutriture in humans using blood samples obtained in a single microhematocrit tube. Further investigation is warranted to evaluate whether these noninvasive measurements can be used for the diagnosis of mild copper deficiency in humans with sufficient specificity and sensitivity.

Adult↗

PubMed1997

Transcriptional induction of cyclooxygenase-2 in osteoblasts is involved in interleukin-6-induced osteoclast formation.

Interleukin-6 (IL-6) induces osteoclast-like cell (osteoclast) formation in a dose-dependent fashion in cocultures of mouse bone marrow cells and osteoblastic cells when soluble IL-6 receptor (sIL-6R) is present. Simultaneous treatment with submaximal doses of IL-1alpha and IL-6 with sIL-6R caused marked induction of osteoclast formation and PGE2 synthesis. These effects were suppressed by adding neutralizing antibodies against IL-1alpha or IL-6R and were totally abolished by adding nonsteroidal antiinflammatory drugs, such as indomethacin and a selective cyclooxygenase-2 (COX-2) inhibitor (NS398). In mouse osteoblastic cells, both IL-1alpha and IL-6 with sIL-6R markedly induced messenger RNA expression of COX-2, but not COX-1, as determined by Northern blot analysis, and luciferase activity in cells stably transfected with a COX-2 promoter-luciferase fusion construct. IL-6 and sIL-6R, when added separately, did not stimulate COX-2 messenger RNA expression. Simultaneous addition of IL-1alpha and IL-6 with sIL-6R to osteoblast cultures cooperatively induced transcription of COX-2, which was associated with a marked increase in COX activity measured by the conversion of arachidonic acid into PGE2. The increased PGE2 synthesis by osteoblasts may play an important role in osteoclastogenesis induced by submaximal doses of IL-1 and IL-6.

Aging↗

PubMed1997

Triterpene alcohols from camellia and sasanqua oils and their anti-inflammatory effects.

The nonsaponifiable lipids of camellia and sasanqua oils from the seeds of Camellia japonica L. and C. sasanqua THUNB., respectively, were investigated for their triterpene alcohol constituents. This led to the isolation of twenty-seven triterpene alcohols of which seven were novel naturally occurring compounds, tirucalla-5,7,24-trien-3 beta-ol (1), lemmaphylla-7,21-dien-3 beta-ol (2), isoeuphol (3), isotirucallol (4), (24R)-24,25-epoxybutyrospermol (5) and its 24S-epimer (6), and isoaglaiol (7). The structures were determined by spectroscopic and chemical methods. The inhibitory effects of 3, 4 a mixture of 5 and 6, a mixture of 7 and its 24S-epimer (aglaiol), and eight known triterpene alcohols isolated in this study were evaluated in ear inflammation in mice induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). The 50% inhibitory dose of these triterpenes for TPA-induced inflammation (1 microgram per ear) was 0.2-0.9 mg/ear.

Alcohols↗

PubMed1997

Effects of platelet-activating factor on left ventricular performance in dogs.

To elucidate the mechanism by which platelet-activating factor (PAF) decreases cardiac output (CO), its effects on left ventricular (LV) performance were studied using a LV pressure-volume model in 9 anesthetized dogs. LV volume was measured with a conductance catheter and LV pressure with a manometer-tipped catheter. The slopes of the end-systolic pressure-volume (Ees), stroke work-end-diastolic volume (Mw), and arterial end-systolic pressure-stroke volume relations (Ea), and of end-diastolic pressure-volume relations (EDPVRs), were obtained to evaluate changes in LV performance. The time constant of isovolumetric relaxation (T) was computed by a logarithmic and a derivative method. After intravenous administration of PAF (1 microgram/kg), LV end-diastolic volume and pressure, end-systolic pressure, maximum dP/dt and CO decreased. Ees and Mw decreased significantly, minimum dP/dt decreased, and T increased. The arterial end-systolic pressure-stroke volume relation shifted leftward with an increase in the slope (Ea), whereas EDPVRs were shifted to the left and superimposed on their potential passive diastolic properties. These findings indicate the PAF decreases CO by reducing preload and contractility and by increasing arterial load. However, despite a prolongation of relaxation, PAF may not affect passive diastolic chamber stiffness.

Animals↗

PubMed1997

Cloning and characterization of a mariner-like element in the silkworm, Bombyx mori.

We have identified a mariner-like element (MLE) in the genome of the silkworm, Bombyx mori. The cloned MLE, desiqnated as BmMLE, contained an ORF that was interrupted by insertions, stop codons, and frameshifts. The complete ORF sequence was estimated by sequencing the PCR products. The hypothetical protein coded by this ORF showed 34% homology to the Mos1 element of Drosophila mauritiana, and is phylogenetically very close to MLE of Hyalophora cecropia. BmMLE is present in 80 to 100 copies in the B. mori genome. Many BmMLEs with different lengths were identified by Southern blot analysis and LA PCR of the genomic DNA. The distribution of these BmMLEs differed in geographic races.

Amino Acid Sequence↗

PubMed1997

Effects of sexual maturation and gonadal steroids on the localization of IgG-, IgM- and IgA-positive cells in the chicken oviduct.

The effects of sexual maturation and gonadal steroids on the localization of immunoglobulin-positive cells in chicken oviducts were studied. Oviductal tissues were collected from laying hens and chicks treated with stilboestrol (DES, an analogue of oestrogen) or progesterone. Paraffin wax sections of the tissues were immunostained for IgG, IgM and IgA, and the frequency of cells staining positive was examined using an image analysis system. Some of the cells in the mucosal epithelium and plasma cell-like cells in the stroma of the oviduct stained positive for IgG, IgM or IgA. In the mucosal epithelium of laying hens, there was a significantly greater number of IgG-positive (IgG+) cells in the shell gland than in the infundibulum, magnum and isthmus, more IgM+ cells in the magnum than in the infundibulum, and more IgA+ cells in the magnum than in the other segments of the oviduct with the exception of the vagina. The frequency of IgG+ and IgM+ cells in the mucosal epithelium of all oviductal segments and IgA+ cells in the magnum, isthmus and vagina was significantly higher in laying hens than in immature birds. In the subepithelial stroma of laying hens, there was a significantly greater population of IgG+ cells in the infundibulum and vagina than in the magnum and isthmus, more IgM+ cells in the infundibulum than in the magnum, and more IgA+ cells in the uterovaginal junction and vagina than in the magnum and isthmus. The frequency of IgG+, IgM+ and IgA+ cells in the subepithelium of infundibulum, uterovaginal junction and vagina was significantly greater in laying hens than in immature birds. The number of IgM+ cells in all oviductal segments and of IgA+ cells in the magnum of the mucosal epithelium of the chicks treated with DES increased significantly compared with those of control chicks. In addition, the number of IgG+ cells in the shell gland and vagina and of IgM+ cells in the vagina of the stroma of DES-treated birds were increased. Treatment of immature birds with progesterone had no effect on the localization of Ig+ cells in the oviduct except for a decrease in the number of IgM+ cells in the shell gland. These results suggest that the local immunity in the oviduct develops during sexual maturation, possibly under the control of oestrogen.

Animals↗

PubMed1997

Patency of intermediate size side branches after Palmaz-Schatz stent implantation.

The immediate and long-term patency of intermediate size side branches was assessed by serial coronary angiography in 47 patients with 48 lesions to determine whether the presence of these side branches (1-2 mm in diameter) is unsuitable for Palmaz-Schatz stent implantation. Coronary angiography was performed at baseline, after conventional balloon angioplasty, immediately after stent implantation, at 1 week, and at 6-month follow-up. Sixty-eight lesion-associated side branches that were 1-2 mm in diameter, 11 with branch ostial stenosis (Group A) and 57 without ostial stenosis (Group B) were studied. After stent implantation, 9 (13%) branches became totally occluded and coronary flow deteriorated in 13 branches (19%). The incidence of side branch occlusion during the procedure in group A was greater than in group B (55% vs. 12%; p < 0.005). One (2%) patient suffered persistent chest pain, but no procedure was complicated by Q-wave myocardial infarction or significant elevation of creatine kinase concentration. Flow improved in 82% of the occluded side branches after 1 week and in 90% after 6 months. These results suggest that the presence of intermediate size side branches is not a contra-indication to Palmaz-Schatz stent implantation.

Angioplasty, Balloon, Coronary↗

PubMed1997

Pharmacokinetics of mitomycin C (MMC) after intraperitoneal administration of MMC-gelatin gel and its anti-tumor effects against sarcoma-180 bearing mice.

Gelatin viscous solution containing mitomycin C (MMC) was prepared and its antitumor effects were evaluated toward sarcoma-180 (S-180) ascite tumor bearing mice. Among various gelatin concentrations, 3% and 5% gelatin solutions potentiated the antitumor effects of MMC (7.5 mg/kg) against S-180 bearing mice. A "bell-shaped" profile was observed between % release of MMC from the gelatin matrix and increased life span (ILS) %. On the other hand, in the case of 10 mg/kg dose of MMC, 7.5% and 10% gelatin solutions potentiated its antitumor effects. At both doses of 7.5 and 10 mg/kg of MMC, decrease in body weight of mice after intraperitoneal administration of MMC were suppressed by increasing the concentration of gelatin. To confirm a possible mechanism for increase in ILS % after intraperitoneal (i.p.) administration of the gelatin viscous solution containing MMC, we examined the pharmacokinetics of MMC after i.p. administration into rats. By the use of 3 % gelatin solution, mean residence time (MRT) and Tmax values were significantly prolonged, and Cmax was decreased as compared with the administration of MMC solution. These results suggested that the enhancement of antitumor effect of MMC by the gelatin viscous solution could be caused by decrease in the clearance rate of MMC from the peritoneal cavity to systemic circulation due to decreasing its diffusivity in gelatin matrix.

Animals↗

PubMed1997

[Chronic neuropathy, a high level of protein in cerebrospinal fluid, and vitamin B1 and folate deficiency in a patient with normal-pressure hydrocephalus].

A 67-year-old woman presented with a 1-year history of gradual weight loss, reduced mental activity, muscle weakness, and urinary dysfunction. Neurological examination revealed mild lethargy, severe muscular atrophy, and diminished deep tendon reflexes in the extremities. The levels of vitamin B1 and folate in blood were low: 1.9 micrograms/dl (normal range 2.0-7.2) and 0.7 ng/ml (normal range 4.0-12.0). respectively. A lumbar puncture was done. The pressure of the cerebrospinal fluid was within normal limits, the level of protein was very high (467 mg/dl), and only a few lymphocytes were seen. A nerve-conduction study showed low amplitudes of action potentials and slow conduction velocities in both the motor and sensory nerves. Myelin irregularity, "onion bulb formation", and axonal atrophy were seen in a specimen obtained by sural nerve biopsy. A T2-weighted magnetic resonance image of the brain showed ventricular dilatation, high-intensity signals around the lateral ventricles, and a flow-void sign of the cerebral aqueduct. Radioisotope cisternography (111In-DTPA) disclosed ventricular reflux and slow clearance of the tracer from the ventricles. These findings indicated the presence of chronic inflammatory demyelinating polyneuropathy, nutritional polyneuropathy, vitamin B1 deficiency, folate deficiency, and normal pressure hydrocephalus. In this patient, the high level of protein in the cerebrospinal fluid may have caused the hydrocephalus.

Aged↗

PubMed1997

Upregulation of interferon-alpha receptor expression in hydroxyurea-treated leukemia cell lines.

BACKGROUND: Interferon-alpha (IFN-alpha) shows its antitumor effect through binding to specific cell surface receptors. A DNA synthesis inhibitor, hydroxyurea (HU), has been successfully combined with IFN-alpha to improve the efficiency of IFN therapy for chronic myelogenous leukemia (CML). To understand the mechanism of this combination effect, expression of IFN-alpha receptors on the CML cell line, K562, was studied before and after treatment with HU. METHODS: Cells were treated with HU at a dose of 0, 0.1, 0.2, or 0.4 mmol/L for 48 hours. Binding assays were performed using 125I-labeled IFN-alpha at 4 degrees C. Cell cycle analysis was carried out using flow cytometer following staining cellular DNA with propidium iodide. Northern blot analysis was performed to evaluate the inducibility of interferon regulatory factor-1 (IRF-1) gene expression by IFN-alpha. RESULTS: Hydroxyurea-treated cells showed a dose- and time-dependent increase in binding of 125I-labeled IFN-alpha (maximal 2.5-fold). The increase of binding was caused by an increase in the number of binding sites with a constant receptor affinity. Similar results were obtained in the Burkitt's lymphoma cell line, Daudi. Cell cycle analyses suggested that upregulation of the IFN receptor may have occurred as a result of the alteration in the cell cycle distribution. Furthermore, IFN-alpha induction of the IFN-inducible gene IRF-1 mRNA in HU-treated K562 cells was 2-fold higher than that in untreated cells. CONCLUSIONS: Thus, HU may have an ability to enhance the response to IFN-alpha probably because of its ability to upregulate the IFN-alpha receptors, suggesting that this may be involved in the mechanism of effective combination therapy of IFN-alpha with HU.

Antineoplastic Agents↗

PubMed1997

DNA damage-induced apoptosis and Ice gene induction in mitogenically activated T lymphocytes require IRF-1.

Lymphocytes are highly sensitive to DNA damage-induced apoptosis. In thymocytes, the tumor suppressor p53 has been shown to be required for this type of apoptosis. However an as yet unknown, p53-independent pathway(s) appears to mediate the same event in mitogenically activated mature T lymphocytes. By using mice with a null mutation in the IRF-1 gene, we revealed that DNA damage-induced apoptosis in the latter cell type is dependent on the anti-oncogenic transcription factor interferon regulatory factor-1 (IRF-1). Thus two different anti-oncogenic transcription factors, p53 and IRF-1, are required for distinct apoptotic pathways in T lymphocytes. Furthermore, we found that mitogen induction of the interleukin-1 beta-converting enzyme (Ice) gene, a mammalian homolog of the Caenorhabditis elegans cell death gene ced-3, is also IRF-1-dependent. An IRF-1 binding sequence was identified in the 5' flanking region of the Ice gene. In addition, ectopic overexpression of IRF-1 results in the activation of the endogenous Ice gene and enhances the sensitivity of cells to radiation-induced apoptosis. Thus, induction of Ice gene may be involved in IRF-1 dependent DNA damage-induced apoptosis in activated mature T lymphocytes.

Animals↗

PubMed1997

Serum concentrations of zinc, folate, vitamins A and E, and proteins, and their relationships to pregnancy outcome.

OBJECTIVE: To review the relationships between various laboratory measures relating to nutrition and pregnancy outcome. The data were obtained during the investigation entitled "Successive small-for-gestational-age births study". METHODS: A total of 289 pregnant women of the 1545 who participated in the study between 1986 and 1988 in Birmingham, Alabama, USA. The following determinations were done using the serum samples obtained at 18 and 30 weeks of gestation: zinc, folate, vitamins A and E, and proteins (alpha-2-macroglobulin, retinol-binding protein, prealbumin, and albumin). These laboratory values were correlated with various measures of pregnancy outcome including the incidence of fetal-growth retardation and maternal infections during the perinatal period and birth weight and Apgar score of infants. RESULTS: Serum folate concentrations showed positive relationships with the incidence of fetal-growth retardation as well as birth weight of infants, and alpha-2-macroglobulin was negatively correlated with birth weight. These relationships were significant after adjusting for factors previously known to affect the birth weight of infants. The concentrations of serum zinc, vitamins A and E, and proteins did not show significant correlation with measures of pregnancy outcome. CONCLUSION: Among the laboratory measures evaluated in this study, serum folate and alpha-2-macroglobulin concentrations correlated with pregnancy outcome. Further research is warranted to investigate the mechanism(s) of the relationship between serum alpha-2-macroglobulin and birth weight of infants.

Alabama↗

PubMed1997

The relationship between maternal dietary intake and infant birthweight.

BACKGROUND: Zinc and folate are important for fetal growth. However, the relationship between the dietary intake of these nutrients and pregnancy outcome is not settled. METHODS: A prospective study was conducted to ascertain the relationship between maternal dietary zinc and folate intake (n = 1398), serum zinc and folate levels (n = 289), and infant birthweight. Twenty-four hour recalls were used to measure energy, zinc, folate and other nutrient intakes at 18 and 30 weeks of gestation. Subjects in the study were offered daily folic acid (1.0 mg) and iron (60 mg as ferrous sulfate) at enrollment. RESULTS: Maternal zinc nutriture as assessed by serum and dietary intake was not associated with birthweight or length of gestation. There was a small but significant positive association between maternal folate intake and adjusted infant birthweight (beta = 0.05, p = 0.03). The indirect measures of maternal nutritional status including maternal pre-pregnancy weight (beta = 8.0, p = 0.0001) and weight gain during pregnancy (beta = 18.1, p = 0.0001) were stronger predictors of adjusted infant birthweight as compared to energy intake and intake of zinc and folate. An increase of 320, 290, and 48 g in infant birthweight was associated with the 90th-10th percentile difference for pre-pregnancy weight, weight gain during pregnancy, and folate intake respectively. CONCLUSION: These results indicate that pre-pregnancy weight and weight gain during pregnancy are both strong predictors of infant birthweight. Folate intake, although significantly associated with birthweight, was a weak predictor while maternal intake of zinc and other nutrients was not associated with birthweight.

Adult↗

PubMed1997

[Total intravenous anesthesia with propofol and fentanyl for laparoscopic cholecystectomy].

The postoperative antiemetic effect of total intravenous anesthesia with propofol and fentanyl was evaluated in 40 patients for laparoscopic cholecystectomy. Patients were divided into 2 groups. In group P, anesthesia was induced with intravenous fentanyl 0.1 mg and propofol 2 mg.kg-1 and maintained with continuous infusion of propofol. In group I, anesthesia was induced with intravenous thiopental 5 mg.kg-1 and maintained with nitrous oxide 60% in oxygen and isoflurane. Post-operative nausea and vomiting were recorded for 8 h after surgery. Nausea scores (range 1-4) were significantly lower in group P as compared with group I at 0 h after surgery, but no difference between the groups at 2 h, 4 h, 8 h after surgery. No significant differences were found in the incidence of vomiting between the groups. These results suggest that total intravenous anesthesia with propofol and fentanyl is superior to inhalational anesthesia with nitrous oxide and isoflurane in postoperative nausea. This antiemetic effect is, however, limited in the early period after anesthesia.

Aged↗

PubMed1997

[Graft-versus-leukemia effect induced by abrupt discontinuation of cyclosporine A following allogeneic bone marrow transplantation].

Cyclosporine A (CyA) was abruptly discontinued in an attempt to induce graft-versus-leukemia (GVL) effect following allogeneic bone marrow transplantation (BMT). It appeared that GVL effect was co-expressed with graft-versus-host disease (GVHD) in 2 of 4 patients and especially minimal residual disease was eliminated during GVHD in a patient with Philadelphia-positive acute lymphocytic leukemia. Subpopulation of cytotoxic T and natural killer cells increased significantly in patients with discontinuation of CyA. This finding suggests that GVL effect was increased following discontinuation of CyA. These results may provide a therapeutic strategy after BMT in patients with high-risk group for relapse of leukemia.

Acute Disease↗

PubMed1997

[Native aortic valve thrombus revealed by routine echocardiography: a case report].

A 75-year-old man presented with palpitations due to atrial flutter. Transthoracic echocardiography revealed a mobile aortic valve mass (17 mm in diameter) attached to the non-coronary cusp of the aortic valve. There was no evidence of hypercoagulative state. Computed tomography showed old cerebral infarction in the territory supplied by the right middle cerebral artery. The mass was surgically resected. The aortic valve was preserved because there were no organic changes in the valve. Histological examination demonstrated an organized thrombus. Only three cases of thrombus attached to the normal native aortic valve have been reported. Native aortic valve thrombus may be important in the differential diagnosis of aortic valve mass.

Aged↗

PubMed1997

[Tricorn protease].

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Amino Acid Sequence↗

PubMed1997

[Cystic renal cell carcinoma: report of four cases].

We report 4 cases of cystic renal cell carcinoma (RCC), one of simple cystic type (case 2) and three of multilocular cystic type (case 1, 3 and 4). All cases were diagnosed preoperatively as malignant neoplasms on the basis of radiological examinations, including CT scan and angiography. Pathological examination revealed that intrinsic cystic growth was the probable cause in the three cases of multilocular cystic RCC, while the simple cystic case was probably caused by secondary cyst formation as a result of tumor necrosis. Radical nephrectomy was performed in cases 1, 2 and 4 and partial nephrectomy in case 3. We recommend nephron-sparing surgery as an option in the management of select cystic RCC, given that many cystic RCCs are low grade and enveloped by distinct pseudocapsules with fibrous tissues.

Adenocarcinoma, Bronchiolo-Alveolar↗