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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 523 records · Page 29Linked to original sources
PubMed1994

[A juvenile case of radiation-induced meningioma two years after radiation for craniopharyngioma].

The patient was a 7-year-old boy who received radiation therapy of 50 Gy after total gross removal of a craniopharyngioma. After two years a follow up CT scan showed a new enhanced lesion in the right temporal tip within the previous irradiation field. Total removal of the tumor was performed and its histological examination showed it to be an atypical meningioma. This atypical meningioma satisfied Cahan's criteria. So we diagnosed this atypical meningioma as radiation-induced meningioma. Immunohistochemically this meningioma stained for Vimentin. An electron-microscopical examination showed neither desmosome nor interdigitation. The score of Ki-67 and BrdU-L. I. was very small. Compared with previously reported juvenile radiation-induced meningioma, the latency was very short. The patient received growth hormone (GH) replacement therapy. We suspected relation between GH replacement therapy and short latency. He was discharged without any new neurological deficits and we haven't detected tumor recurrence for two years.

Child↗
PubMed1994

[Tumor necrosis factor alpha in bronchoalveolar lavage fluid and its production by alveolar macrophages with asbestos exposure].

It is generally accepted that asbestos exposure causes pulmonary fibrosis and carcinogenesis. Several studies have suggested that TNF alpha is produced principally by mononuclear phagocytes and that it may play a role in inflammation, fibrosis and anti-tumor activity. We studied TNF alpha production by alveolar macrophages and the TNF alpha concentration in bronchoalveolar lavage fluid harvested from asbestos-exposed subjects and healthy controls. TNF alpha production by alveolar macrophages was significantly higher in the asbestos-exposed subjects than in healthy controls (3696 +/- 1606, 1938 +/- 753 pg/ml; p < 0.01). The period from first exposure correlated inversely with TNF alpha production (r = -0.6; p < 0.05). The TNF alpha concentration in bronchoalveolar lavage fluid was also significantly higher in the asbestos-exposed subjects than in healthy controls. These results suggest that abnormal TNF alpha production by alveolar macrophages may be related to fibrosis and carcinogenesis due to asbestos.

Adult↗
PubMed1994

[Effective combination therapy using radiation and a daily low dose of cis-platinum for advanced oropharyngeal carcinoma in an elderly patient--report of a case].

An 83-year-old male with advanced oropharyngeal carcinoma was treated with combined radiotherapy and a daily low dose of cis-platinum with excellent results. In the early part of the treatment, radiotherapy was delivered in fractions of 1.8 Gy/day (5 days/week) to a cumulative dose of 20 Gy, concomitantly with UFT (400 mg/day po), but the response was not adequate. Then, instead of UFT, a single intravenous injection of cis-platinum (5 mg) was administered within 30 min after each radiation session without intravenous hydration. The total dose of cis-platinum was 140 mg and that of radiation was 70 Gy. Moderate leukocytopenia and moderate mucositis/dermatitis were observed as side effects, but despite the lack of intravenous hydration no signs of renal toxicity were observed. Partial remission was attained by the end of the therapy, remnant lesions progressively diminished in size, and 4 months later all of them had completely disappeared on the computed tomogram. The prognosis is favorable, and neither recurrence nor metastasis has been found in the 14-month follow-up period since the lesions disappeared.

Aged↗
PubMed1993

Determination of triacylglycerol and cholesterol ester hydroperoxides in human plasma by high-performance liquid chromatography with fluorometric postcolumn detection.

Cholesterol ester (ChE) and triacylglycerol (TG) hydroperoxides in human plasma were determined by high-performance liquid chromatography with postcolumn detection with diphenyl-1-pyrenylphosphine. Human plasma was extracted once with n-hexane. 2,6-Di-tert.-butyl-4-methylphenol and N-stearylcinnamide were added to human plasma before extraction as an antioxidation agent and an internal standard, respectively. The detection limits of both ChE and TG hydroperoxides were 1 pmol. The sample size was minimized to 250 microliters for each run. The recoveries of ChE and TG hydroperoxides from fresh plasma were ca. 90 and 80%, respectively. The relative standard deviations (n = 8) of their values in frozen human plasma were 5.4% (ChE hydroperoxides, 298 nM) and 5.7% (TG hydroperoxides, 267 nM). No TG hydroperoxides and 24.5 +/- 9.6 nM (n = 15) ChE hydroperoxides were detected in fresh human plasma. The relative standard deviation (n = 8) of ChE hydroperoxides values in fresh plasma was 5.8% (27.1 nM).

Cholesterol Esters↗
PubMed1993

Neutralization and infection-enhancement epitopes of influenza A virus hemagglutinin.

We studied 18 mAb specific for the H3 hemagglutinin (HA) to analyze the relationships between neutralizing and infection-enhancing epitopes on the influenza HA. The mAb could be separated into three groups based on their neutralization (N) and enhancement (E) activity in assays with the prototype virus; group I (N+E+), group II (N+E-) and group III (N +/- E+). A representative mAb from each group was analyzed for its effect on the infectivity of a group of escape mutants, selected with mAb to three sites on the H3 HA, and wild-type H3 viruses to define the relationship between neutralizing epitopes and infection-enhancing epitopes. A group I mAb (N+E+), which recognized site A on the HA, neutralized virus infection at high concentrations of antibody and enhanced virus infection at low concentrations. A group II mAb (N+E-), which recognized site B, had high neutralizing but no enhancing activity. The failure of this mAb to enhance virus uptake was a result of the inability of the Fc portion of virus-mAb complexes to bind to Fc receptor. The addition of anti-murine IgG as a second antibody to these virus-mAb complexes augmented virus uptake. A group III mAb (N +/- E+), which recognized site C, had enhancing but little neutralizing activity. This is the first definition of distinct epitopes that induce neutralizing and/or enhancing mAb.

Amino Acid Sequence↗
PubMed1993

Inhibitory effect of angiogenesis inhibitor TNP-470 on tumor growth and metastasis of human cell lines in vitro and in vivo.

Antitumor activity of angiogenesis inhibitor TNP-470 was evaluated in eight human cultured cell lines derived from choriocarcinoma: SCH, NUC-1, and GCH-1(m); ovarian cancer; TYK and Nakajima; and uterine endometrial cancer: HEC-6, HEC-50, and HEC-1-A. After 7-day culture with TNP-470, in medium at the concentration of 10(1) to 10(-2) micrograms/ml, the inhibition of growth was observed in all of the eight cell lines. The 50% inhibitory concentration of choriocarcinona cell lines was at an extremely low level compared to that of epithelial ovarian cancer and uterine endometrial cancer. In addition, the antitumor effect of this compound was studied in in vivo experiments using nude mice with tumors of GCH-1(m), NUC-1, or Nakajima cells. When the size of the transplanted tumor reached 100-200 mm3 in volume, 3, 10, or 30 mg/kg of TNP-470 was injected s.c. every other day. The inhibitory effect of TNP-470 was obtained by the administration of 10 and 30 mg/kg in GCH-1(m) and NUC-1 cells, respectively, while in Nakajima cells no significant effect was observed. In nude mice treated with 30 mg/kg of TNP-470, lung metastasis of GCH-1(m) cells was strongly inhibited both in the number and in the size of tumor nodules, indicating that the capillary growth in the originally developed tumor was also significantly reduced. These results suggest that the clinical setting using TNP-470 may be one of the promising treatments for the metastasis of tumor cells.

Animals↗
PubMed1993

Isolation of an endogenous Na-pump specific inhibitor from normal pig urine: characterization and comparison with the inhibitor purified from bovine adrenal glands.

An endogenous Na-pump specific inhibitor has been purified to homogeneity from normal pig urine using Amberlite XAD-2 adsorption chromatography followed by five steps of reverse phase HPLC. Although most of the dose response curves for this purified Na-pump inhibitor, designated uroxin, in the various assay systems paralleled those of authentic ouabain and the specific Na-pump inhibitor previously purified from bovine adrenal glands (designated adrexin C), the cross-reactivity curve with anti-ouabain antibodies did not. The retention times of uroxin on various types of reverse phase HPLC columns were also different from those of plant-derived cardiotonic steroids and adrexin C. The cross-reaction curve of adrexin C was superimposable with that of ouabain, and adrexin C coeluted with ouabain from all of the HPLC columns tested. The results from physical and chemical characterization of both purified inhibitors suggest that uroxin is a novel Na-pump inhibitor which is structurally different from any of the known cardiotonic steroids or other substances previously reported to exhibit Na-pump inhibitory activity. The results also indicate that adrexin C is indistinguishable from ouabain. These results suggest that there are at least two different types of endogenous Na+,K(+)-ATPase inhibitors in the mammalian body.

Adrenal Glands↗
PubMed1993

Modulation of in vivo immune response by selective depletion of neutrophils using a monoclonal antibody, RP-3. I. Inhibition by RP-3 treatment of the priming and effector phases of delayed type hypersensitivity to sheep red blood cells in rats.

Recent studies on neutrophils have revealed that these cells produce various cytokines, and may be involved in regulation of the immune response. We examined whether neutrophils are involved in delayed type hypersensitivity (DTH) to SRBC in rats by selective depletion of in vivo neutrophils using a mAb designated RP-3. When the rats had been treated with RP-3 at the time of priming with SRBC, DTH to these cells was inhibited. Furthermore, RP-3 treatment was effective in inhibiting the effector phase of the DTH response to SRBC. When spleen cells from rats that had been treated with RP-3 at the time of immunization were used for local transfer of DTH, footpad swelling was significantly less than that induced by spleen cells from the RP-3-untreated immune rats.

Animals↗
PubMed1993

Enhancement of human hepatocyte growth factor production by interleukin-1 alpha and -1 beta and tumor necrosis factor-alpha by fibroblasts in culture.

Human hepatocyte growth factor (hHGF) was first purified from plasma of patients with fulminant hepatic failure (Gohda, E., Tsubouchi, H., Nakayama, H., Hirono, S., Sakiyama, O., Takahashi, K., Miyazaki, H., Hashimoto, S., and Daikuhara, Y. (1988) J. Clin. Invest. 81, 414-419) and is now identified to be the same protein as the scatter factor (Weidner, K. M., Arakaki, N., Hartmann, G., Vandekerckhove, J., Weingart, S., Rieder, H., Fonatsch, C., Tsubouchi, H., Hishida, T., Daikuhara, Y., and Birchmeier, W. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 7001-7005) and tumor cytotoxic factor (Shima, N., Nakao, M., Ogaki, F., Tsuda, E., Murakami, A., and Higashio, K. (1991) Biochem. Biophys. Res. Commun. 180, 1151-1158), and it is known to be produced by fibroblasts in culture. Here we report that inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) stimulate production of hHGF from human embryonic lung fibroblasts, MRC-5, and human gingival fibroblasts, GF-5. Recombinant human IL-1 alpha (rhIL-1 alpha) and recombinant human TNF-alpha (rhTNF-alpha) increased hHGF levels in culture supernatants of MRC-5 and GF-5 cells dose-dependently as determined by an enzyme-linked immunosorbent assay for hHGF. The half-maximal stimulatory concentrations of rhIL-1 alpha and rhTNF-alpha were about 1ng/ml and 10 units/ml, respectively. rhIL-1 beta showed almost the same effect as IL-1 alpha on stimulation of production of immunoreactive hHGF from the two cell lines. However, rhIL-6 failed to show the stimulatory effect on hHGF production by the cells in the range of 2-200 units/ml. Human interferon-beta and -gamma also did not show the stimulatory activity. Stimulation of hHGF production was observed 6-12 h after addition of rhIL-1 alpha or rhTNF-alpha and lasted at least 48 h, and the observed stimulation of hHGF production by cytokines was suppressed by addition of corresponding antiserum. hHGF mRNA levels of MRC-5 cells increased by addition of rhIL-1 alpha and rhTNF-alpha in a dose-dependent manner as determined by Northern blot analysis using cDNA for hHGF as a probe. In addition, results from nuclear run-off transcription experiments showed that the two cytokines regulated increasing hHGF gene expression at transcriptional levels rather than a change in mRNA stability. These observations indicate that the inflammatory cytokines modulate the production and secretion of hHGF by fibroblasts and may play an important role for tissue repair and regeneration.

Blotting, Northern↗
PubMed1993

Dynamic changes in cerebral oxygenation in chemically induced seizures in rats: study by near-infrared spectrophotometry.

Using near-infrared spectrophotometry, the redox state of copper in cytochrome oxidase, and the hemoglobin oxygenation state were measured in the rat brain in situ during and after chemically induced seizures. Pentylentetrazol (PTZ) administration caused the partial reduction of cytochrome oxidase in the brain just before the electroencephalogram (EEG) showed desynchronization, and then blood pressure was elevated concomitantly with an increase in cerebral blood volume. When blood pressure reached a maximum, bursts of spikes appeared on the EEG and cytochrome oxidase was reoxidized to reach the initial oxidation level, giving a rapid, transient reduction of cytochrome oxidase in the preictal period. Hemoglobin was more oxygenated than before the administration throughout the seizure. In the late postictal phase, cytochrome oxidase was partially reduced again, while blood pressure remained high and hemoglobin was more oxygenated than initially. The second administration of PTZ in the late postictal phase induced the same responses as observed after the first administration. By decreasing oxygen concentrations in the inspired gas during the seizure, cytochrome oxidase was more reduced than in the non-epileptic rat, and spike activity was observed until about 85% of cytochrome oxidase was reduced. The transient cerebral hypoxia reflected by the reduction of cytochrome oxidase in the preictal period may be a trigger for an increase in cerebral blood flow rather than the result of a delayed autonomic response. The second reduction of cytochrome oxidase observed in the late postictal phase may be due to a lasting arterio-venous shunt that opens during seizures. These results revive the classical theory that cellular hypoxia is responsible for epileptic brain damage.

Animals↗
PubMed1993

Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man.

Changes in the oxygenation state of brain hemoglobin during mental work were monitored in real time (time resolution: 1 s) using near-infrared spectrophotometry in 14 healthy volunteers. In a younger group (age range 22-30 years, n = 12), the subjects finding difficulty in solving a problem were accompanied by significant increases in both oxygenated hemoglobin and total hemoglobin, while the subjects making a correct answer without difficulty showed no significant changes in hemoglobin oxygenation. When compared with those younger subjects, observations on the older subject demonstrated a decrease in oxygenated hemoglobin and a reciprocal increase in deoxygenated hemoglobin, unaccompanied by changes in total hemoglobin.

Adult↗
PubMed1993

Gender- and handedness-related differences of forebrain oxygenation and hemodynamics.

To elucidate gender- and handedness-related differences between the hemispheres of the brain in their metabolisms and hemodynamics, simultaneous monitoring by near-infrared (NIR) spectrophotometry of hemoglobin (Hb) in both hemispheres of the forebrain during the mirror drawing task (MDT) was performed. Bilaterally simultaneous increases of oxygenated Hb and decreases of deoxygenated Hb in forebrain occurred symmetrically in all cases of volunteer subjects except for two. There were gender- and handedness-related differences of hemodynamics between the hemispheres of the brain; NIR results showed that a large majority of women used both sides of the brain when concentrating on carrying out the MDT, whilst most men, especially left-handers, reacted mainly using the hemisphere which was 'dominant' according to handedness.

Adult↗
PubMed1993

Isolation and characterization of an endogenous Na+,K(+)-ATPase-specific inhibitor from pig urine.

A Na+,K(+)-ATPase inhibitor was purified from 88.6 l pig urine with a yield of approximately 10 micrograms. It inhibits the ouabain-sensitive uptake of 86Rb into human erythrocytes and the specific binding of ouabain to Na+,K(+)-ATPase. It also exhibits cross-reactivity to anti-ouabain serum. The purification procedure consisted of adsorption chromatography on an Amberlite XAD-2 column, preparative scale C18 low-pressure liquid chromatography (LPLC), and five steps of HPLC with five different types of reverse-phase columns. The dose dependence of the purified substance for the inhibition of ouabain-sensitive Na+,K(+)-ATPase activity and 86Rb uptake into human erythrocytes, and for the ouabain-displacing activity, paralleled those of ouabain, spanning two orders of magnitude in concentration range. However, the curve obtained from the cross-immunoreactivity with anti-ouabain serum did not parallel that of ouabain. The inhibitory potencies of the purified substance against the Na(+)-pump and ouabain-binding were diminished with increasing K+ concentration, exhibiting characteristics typical of cardiac glycosides. This substance had no effect on Ca(2+)-ATPase activity in human erythrocyte plasma membrane and skeletal-muscle sarcoplasmic reticulum, nor on Mg(2+)-ATPase activity. Acid treatment with 6 M HCl at 115 degrees C for less than 1 min destroyed approximately 82% of the inhibitory activity of the purified substance against Na(+)-pump activity. Alkaline treatment with 0.2 M NaOH at 23 degrees C for 2 h and heat treatment at 150 degrees C for 30 min partially destroyed the inhibitory activity. Boiling for 10 min and digestion by various enzymes did not affect the activity. Molecular mass was estimated to be 620 Da by gel-filtration column chromatography. Preliminary MS analysis suggested that the purified substance has a molecular mass of 625 Da. An 1H-NMR study revealed that this substance does not contain a tertiary methyl group. The results suggest that the purified Na+,K(+)-ATPase inhibitor is not a peptide and is distinct from any of the known cardiotonic steroids or various substances previously reported to exhibit Na+,K(+)-ATPase inhibitory activity. Thus, the purified substance may be a novel endogenous regulator of Na+,K(+)-ATPase.

Animals↗
PubMed1993

Chronic Nocardia asteroides endophthalmitis after extracapsular cataract extraction.

A 65-year-old man underwent an uncomplicated extracapsular cataract extraction with placement of a posterior chamber intraocular lens. The patient developed delayed-onset chronic endophthalmitis caused by Nocardia asteroides. This was confirmed on multiple intraocular cultures, as well as histopathologic examination of the lens capsular bag. The patient was treated with periocular, intravitreal, and systemic antibiotic treatment, combined with intraocular lens removal, total capsulectomy, and three vitrectomies in an attempt to eradicate the organism and calm the eye. The patient went on to develop widespread endophthalmitis that required enucleation of the infected globe. To our knowledge, this is the first case of delayed-onset chronic endophthalmitis caused by N asteroides after extracapsular cataract extraction with a posterior chamber intraocular lens.

Aged↗
PubMed1993

Phosphatidic acid-induced superoxide generation in electropermeabilized human neutrophils.

The ability of phosphatidic acid to induce O2- generation was examined in intact and electropermeabilized neutrophils. In intact cells, after a long lag (approximately 11 min), 1,2-didecanoylphosphatidic acid (PA10, 10 microM) elicited O2- generation (30-40 nmol/min/10(7) cells at maximum) which lasted for 8-9 min. Electropermeabilization facilitated the response by shortening the lag (within 30 s) and enhancing the maximal rate (120-130 O2- nmol/min/10(7) cells). The induction by PA10 was concentration-dependent and the half-maximal concentrations for intact and permeabilized cells were 11 and 3 microM, respectively. In permeabilized cells, the rate of O2- release by PA10, which was similar to that by fMet-Leu-Phe or phorbol myristate acetate, was not enhanced by addition of dioctanoylglycerol. Also, the response was unaffected by propranolol, an inhibitor of phosphatidate-phosphohydrolase that converts phosphatidic acid to diacylglycerol. Phosphatidic acids with longer acyl chains (C12-C14) also activated the permeabilized cells, although the degree of activation decreased as the chain length was increased. These results indicate the ability of phosphatidic acid to induce respiratory burst independently of diacylglycerol and support the idea that phosphatidic acid can be an activator of NADPH oxidase in human neutrophils.

Cell Membrane Permeability↗
PubMed1993

Delayed brain hemorrhage associated with prophylactic whole brain irradiation for pediatric malignant brain tumor: a case report.

Intraparenchymal hemorrhage in the left frontal lobe suddenly occurred in a 7-year-old girl who had undergone partial removal of an undifferentiated brain stem glioma and received craniospinal (30 Gy) and posterior fossa booster (20 Gy) irradiation at the age of 20 months. The brain hemorrhage was thought to be delayed irradiation effect. Follow-up neuro-imaging at age 9 years showed two more small occult chronic and subacute hemorrhages in the brain. The possibility of repeated hemorrhage as a delayed reaction to brain irradiation is emphasized.

Brain Neoplasms↗