Search PubMed⌕ Search

Biomedical subjects

K Nagata

Publications and source records attributed to K Nagata.

At least 721 records · Page 40Linked to original sources
PubMed1990

Richter syndrome with two B cell clones possessing different surface immunoglobulins and immunoglobulin gene rearrangements.

A patient with two populations of B cell malignancy in the bone marrow is reported. One population consisted of mature small lymphocytes, expressing surface IgM + D, lambda and proliferating very slowly. The other population consisted of abnormal large lymphoid cells, expressing surface IgM, K and proliferating actively. We considered the former as chronic lymphocytic leukemia cells and the latter as malignant lymphoma cells. Therefore, this case was considered as Richter syndrome. The analysis of immunoglobulin heavy chain gene rearrangement showed the different patterns between the two populations. It suggested that the two populations arose from the different origins. We discussed the genetic relationship between the two clones of Richter syndrome referring to other reported cases.

Aged↗
PubMed1990

Novel ATP-binding heat-inducible protein of Mr = 37,000 that is sensitive to transformation in BALB/3T3 cells.

Using affinity chromatography on ATP-agarose, we have identified a major ATP-binding protein in Nonidet P-40 extracts of avian and mammalian cells labeled with [35S]methionine. After washing ATP-agarose beads with high-ionic-strength buffer (0.4 M NaCl), the 37-kD protein was shown to be one of the major ATP-binding proteins while p72 and grp78, which are members of the hsp70 family, also bound to ATP-agarose. This protein consisted of several spots on two-dimensional gel electrophoresis. The isoelectric point of the most basic spot was approximately 9.2 in chick embryo fibroblasts, whereas it was about 8.8 in mouse 3T3 cells. The identities of these proteins in mouse and chick cells were confirmed by peptide mapping. After heat-shock treatment of BALB/3T3 cells, the major heat-shock protein, hsp70, was shown to be induced very rapidly after heat shock and was recovered in the ATP-binding fraction. Besides hsp70, a 37-kD protein was also found to be induced by heat shock. This protein was drastically induced by treating the cells with alpha,alpha'-dipyridyl, an iron chelating reagent, but not with sodium arsenite, calcium ionophore, or tunicamycin. The synthesis and the total amount of this ATP-binding protein increased in mouse 3T3 cells transformed by simian virus 40, methylcholanthrene, or activated c-Ha-ras oncogene compared to their normal counterparts. The incorporation of [32P]orthophosphate was not detected in either normal or transformed cells. These studies established that a major ATP-binding protein of Mr = 37,000 is a heat-inducible protein and that the synthesis of this protein is regulated by malignant transformation.

2,2'-Dipyridyl↗
PubMed1990

Characterization of a temperature-sensitive mutant in the RNA polymerase PB2 subunit gene of influenza A/WSN/33 virus.

The temperature-sensitive mutant ts-1 of influenza virus A/WSN/33 carries mutations in the gene encoding RNA polymerase PB2 subunit. Effect of temperature on various steps of viral RNA synthesis was examined using disrupted virions of ts-1 mutant. The initiation of RNA synthesis with dinucleotide ApG primer was not affected by elevated temperature, whereas that with primer RNA containing 5'-terminal cap-1 structure was temperature-sensitive. The result supports the previous notion deduced from the UV-crosslinking experiments, that PB2 is involved in the cap-1 dependent initiation of RNA synthesis. In addition, the ts-1 mutant showed a defect in RNA chain elongation. Nucleotide sequence analysis of RNA segment 1 of ts-1 mutant revealed that the amino acid number 417 is essential for the recognition of cap-1 structures and/or the interaction with catalytic unit of the RNA polymerase.

Amino Acid Sequence↗
PubMed1990

Inhibition of influenza virus infection by pine cone antitumor substances.

The anti-influenza virus activity of polysaccharides and other high molecular weight fractions from pine cone extract (PCE) of Pinus parviflora Sieb. et Zucc. was investigated. None of the fractions affected the growth of MDCK cells. The acidic PCE substances markedly suppressed the growth of the influenza virus in MDCK cells. Significant inhibition of both the viral protein synthesis in infected cells and virion-associated RNA-dependent RNA polymerase activity was observed with these acidic fractions. Although amantadine inhibited virus plaque formation as effectively as PCE fractions, it was less effective in inhibiting the RNA polymerase activity. These results suggest that PCE, which has been shown to contain antitumor substance(s), also contains anti-influenza virus substance(s).

Amantadine↗
PubMed1990

Cytochrome b5 potentiation of cytochrome P-450 catalytic activity demonstrated by a vaccinia virus-mediated in situ reconstitution system.

A cDNA containing the full coding region of human cytochrome b5 was inserted into a vaccinia virus cDNA expression vector. Infection of human thymidine kinase-minus (TK-) 143 cells in culture with this recombinant virus resulted in production of 0.3 nmol of cytochrome b5 per mg of cell lysate protein. The expressed cytochrome had a reduced difference spectrum with a Soret peak at 424 nm, typical of pure cytochrome b5. TK- 143 cells have little detectable endogenous cytochrome b5, cytochrome P-450 (P450), and NADPH-P450 oxidoreductase. To test whether cytochrome b5 potentiated mixed-function monooxygenation in situ, these cells were coinfected with three recombinant vaccinia viruses individually carrying cDNAs encoding cytochrome b5, NADPH-P450 oxidoreductase, and P450 form IIB1. These triple-virus-infected cells were compared to cells infected with the P450IIB1 and NADPH-P450 oxidoreductase recombinant viruses with respect to P450IIB1-catalyzed monooxygenase activities. Cytochrome b5 specifically augmented the deethylation of p-nitrophenetole in microsomal membrane fractions of infected cells or when substrate was incubated directly with cells in situ. No significant increases were seen with P450IIB1-catalyzed testosterone, 7-ethoxycoumarin, or 7-pentoxyresorufin oxidations. These data demonstrate that cytochrome b5 is capable of specifically augmenting monooxygenase activities in intact cells.

Cell Line↗
PubMed1990

Regulation of the expression of vimentin gene during the differentiation of mouse myeloid leukemia cells.

We have examined the expression of vimentin during the differentiation of mouse myeloid leukemia cells (M1), which were induced to differentiate into macrophages by exposure to conditioned medium (CM) obtained from rat embryo fibroblasts. The synthesis of vimentin, which was examined by two-dimensional gel electrophoresis, increased after 12-24 h of incubation of M1 cells in CM and the elevated level of synthesis continued up to 96 h. A macrophage cell line (Mm1) that was derived from spontaneously differentiated M1 cells constantly synthesized much higher levels of vimentin. The amount of vimentin, which was revealed by immunoblot analysis using an mAb against human vimentin, also increased after differentiation by a factor of 7 when compared on the basis of constant protein and by a factor of 17 on the basis of constant cell numbers. Mm1 cells contained greater than 12- and 45-fold more vimentin compared with undifferentiated M1 cells on the bases of constant protein and constant cell numbers, respectively. Northern blot analysis using vimentin cDNA as a probe revealed increases in vimentin mRNA in the differentiated M1 cells and Mm1 cells. Nuclear run-on assay showed that the expression of vimentin gene during the differentiation of M1 cells was transcriptionally regulated. Observations in indirect immunofluorescence microscopy and EM clearly showed that vimentin bundles were rarely observed in undifferentiated M1 cells, and increased amounts of and large-size vimentin bundles were easily observed in differentiated M1 and Mm1 cells. These results suggest the participation of increased amounts of vimentin filaments in the maldistribution of nuclei in M1 cells during differentiation.

Animals↗
PubMed1990

The evidence for the IL-2 receptor beta chain processing from p70 to p75.

The biosynthesis of human interleukin 2 receptor (IL-2R)p75 was studied with TU27 monoclonal antibody (TU27 mAb) specific for the IL-2Rp75. TU27 mAb specifically immunoprecipitated not only p75 with a mol. wt of 70-82 kd and an isoelectric point (pl) of 4.4-4.7 but also p70 with a mol. wt of 70 kd and a pl of 4.7 from the cell lysate of MT-2, a human T cell line constitutively expressing IL-2R, labeled metabolically with [35S]cysteine. In contrast, only p75 was detected when the lysate of MT-2 cells surface-labeled with Na125I was immunoprecipitated with TU27 mAb. These results suggest that p75 is a mature form of IL-2Rp75 expressed on the cell surface. Pulse-chase experiments demonstrated that p70 could be converted into IL-2Rp75 by post-translational processing. Studies with monensin, endoglycosidase F, and neuraminidase showed that the mature IL-2Rp75 molecule is generated through N-linked glycosylation and sialylation of the p70 precursor.

Antibodies, Monoclonal↗
PubMed1990

Purification and molecular structure of RNA polymerase from influenza virus A/PR8.

The RNA-dependent RNA polymerase of influenza virus A/PR/8 was isolated from virus particles by stepwise centrifugation in cesium salts. First, RNP (viral RNA-NP-P proteins) complexes were isolated by glycerol gradient centrifugation of detergent-treated viruses and subsequently NP was dissociated from RNP by cesium chloride gradient centrifugation. The P-RNA (P proteins-viral RNA) complexes were further dissociated into P proteins and viral RNA by cesium trifluoroacetate (CsTFA) gradient centrifugation. The nature of P proteins was further analyzed by glycerol gradient centrifugation and immunoblotting using monospecific antibodies against each P protein. The three P proteins, PB1, PB2, and PA, sedimented altogether as fast as the marker protein with the molecular weight of about 250,000 Da. Upon addition of the template vRNA, the RNA-free P protein complex exhibited the activities of capped RNA cleavage and limited RNA synthesis. When a cell line stably expressing cDNAs for three P proteins and NP protein was examined, the three P proteins were found to be co-precipitated by antibodies against the individual P proteins. These results indicate that the influenza virus RNA-dependent RNA polymerase is a heterocomplex composed of one each of the three P proteins and that the RNA-free RNA polymerase can be isolated in an active form from virus particles. Furthermore, the three P proteins form a complex in the absence of vRNA.

Animals↗
PubMed1990

Purification and characterization of four catalytically active testosterone 6 beta-hydroxylase P-450s from rat liver microsomes: comparison of a novel form with three structurally and functionally related forms.

Four microsomal cytochrome P-450s (P-450), all of which are active testosterone 6 beta-hydroxylases, were purified to electrophoretic homogeneity from livers of phenobarbital-treated (P-4506 beta-1 and P-4506 beta-3) or dexamethasone-treated adult male rats (P-4506 beta-2 and P-4506 beta-4). Purified P-4506 beta-1, P-4506 beta-2, P-4506 beta-3, and P-4506 beta-4 had apparent molecular weights of 52,000, 51,000, 52,000, and 52,500 as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Absolute spectra revealed that all four P-450 forms had characteristic low-spin spectral patterns in their fully oxidized states. P-4506 beta-1 and P-4506 beta-3 displayed spectra of the reduced carbonyl complex with lambda max at 447 nm. P-4506 beta-2 and P-4506 beta-4 showed lambda max at 446 and 448 nm, respectively. Antibodies raised against each P-450 recognized all forms, although differences were observed with respect to the extents of cross-reactivities on Western blots. Form-specific peptide fragments were also detected among the four P-450 proteins after partial protease-digestion. P-4506 beta-1 was identical to P-4506 beta-3 in the first 26 residues of the NH2-terminal amino acid sequence, but differed by 13 residues from P-4506 beta-2. The amino-terminal sequence of P-4506 beta-2 was unique and was not identical with those of any rat P-450 previously reported. This P-450 form was detected in the livers of untreated male rats and was induced by treatment with dexamethasone, but not with phenobarbital.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Modulation of hepatic level of microsomal testosterone 7 alpha-hydroxylase, P-450a (P450IIA), by thyroid hormone and growth hormone in rat liver.

The effects of thyroid hormone and growth hormone on microsomal testosterone 7 alpha-hydroxylase, P-450a, were studied to understand the interaction of these hormone-mediated regulations in rats. In Western blots using anti-P-450a IgG, 1.7-fold higher content of P-450a was observed in livers of female than male adult rats, while no appreciable sex-related difference was detected in prepubertal rats and rats of 24 months of age. Treatment with n-propyl-2-thiouracil or thyroidectomy of male rats increased by 2-fold the hepatic content of P-450a, but neither regimen had a significant effect on the content in female rats. Levels of P-450a in both sexes of thyroidectomized rats were decreased by the supplementation of triiodothyronine (T3, 50 micrograms per kg, i.p. for 7 days) to levels similar to that observed in normal male rats. Hypophysectomy also caused an increase in microsomal P-450a content in male rats. Continuous infusion of human growth hormone, which mimicked the female secretion, further significantly increased the content in hypophysectomized rats to a level similar to that observed in normal female rats. In contrast, hepatic level of P-450a in hypophysectomized male and female rats was reduced by intermittent injection, which mimicked the male secretion. Clear suppression on the level of hepatic P-450a was also observed by the treatment of hypophysectomized rats with 5 or 50 micrograms/kg of T3 and of hGH-infused hypophysectomized rat with 50 micrograms/kg of T3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Clinical value of magnetic resonance imaging for cervical myelopathy.

The magnetic resonance imaging (MRI) findings in 115 cases of cervical myelopathy, 121 cases of cervical radiculopathy, and 64 cases of neck pain with no neurologic deficit were prospectively studied to investigate the clinical value of MRI for cervical myelopathy. The MRI findings in the T1-weighted sagittal projection were classified into four groups according to the degree of the compressed deformities of the cervical cord. The degree of compression of the cervical cord on MRI findings showed a significant correlation with the severity of myelopathy, the anteroposterior diameter of the spinal column, and the degree of compression of the dural tube in the myelograms (P less than 0.01). Fifty-one patients of cervical myelopathy had undergone both preoperative and postoperative MRI. Of these, the spinal canal of 47 patients that was well decompressed was recognized according to plain computed tomography (CT). However, 24 (51%) of these 47 patients showed on MRI a deformity in the spinal cord amounting to cord atrophy. The correlation between the clinical function of the spinal cord and the recovery of the cord deformity on MRI at the operative levels was accurately investigated in 34 patients who had no cord deformities in the adjacent intervertebral levels. Twenty patients with cord atrophy had slightly poor clinical results, although no significant difference was found between these 20 and 14 patients with recovery in the cord deformities. From these results, it was evident that T1-weighted MRI is useful in the accurate diagnosis of compression myelopathy, in accurately deciding the level of the disease focus, and in the accurate assessment of the surgical results.

Cervical Vertebrae↗
PubMed1990

Effects of interleukin-6 and granulocyte colony-stimulating factor on the proliferation of leukemic blast progenitors from acute myeloblastic leukemia patients.

The effects of recombinant human interleukin-6 (rh IL-6), which has homology with rh granulocyte colony-stimulating factor (rh G-CSF) at the amino acid sequence level, and rh G-CSF on normal human bone marrow cells, fresh leukemic blast progenitors from 16 acute myeloblastic leukemia (AML) patients, and G-CSF-dependent human AML cell line (OCI/AML 1a) were investigated. rh G-CSF stimulated the proliferation of leukemic blast progenitors from 13 out of 16 AML patients tested. rh IL-6 stimulated the proliferation of blasts from eight AML patients and enhanced the G-CSF-dependent proliferation of the fresh AML blasts from two out of eight patients tested. On the other hand, rh IL-6 suppressed the blast colony formation from two AML patients and OCI/AML 1a cells and also reduced the G-CSF-dependent proliferation of the blast progenitors from one of the two patients and the cell line, rh IL-6 had no effect on the colony formation of normal granulocyte-macrophage colony-forming units (CFU-GM) with or without rh G-CSF. Differentiation-induction by rh IL-6 was not observed in the fresh AML blasts but was observed in OCI/AML 1a. The effect of IL-6 on the blast colony formation and G-CSF-dependent blast cell growth was complicated and heterogenous among the AML cases; IL-6 stimulated blast colony formation in some cases and suppressed it in others. The heterogeneity of the response was supposed to be derived from the heterogeneity of the characteristics of AML cells. Although G-CSF simply stimulated the blast colony formation, IL-6 had a bimodulatory effect on the proliferation of leukemic blast progenitors from AML patients. IL-6 might be involved in the regulation of the proliferation of AML cells in vivo as well as in vitro.

Adolescent↗
PubMed1990

Changes in negative symptoms of schizophrenic patients two years later.

This study investigated the course of negative symptoms by examining the psychiatric symptoms of 59 new schizophrenic patients at the first consultation and again two years later using a structured interview--the Present State Examination. An examination of the total score of the nine negative symptoms, included in the "Chronic Schizophrenic Syndrome" by Wing, showed that 27 out of the 59 patients (45.8%) had lower symptom scores two years later than they did at the first consultation ("negative symptom improvement" group), while 20 patients (33.9%) had higher scores two years after the first consultation ("negative symptom deterioration" group). There were 12% more patients in the improvement group than in the deterioration group. No significant differences were observed between the "improvement group" and "deterioration group" in relation to the following factors--subclassification of schizophrenia, mode of onset, age at the first consultation, marital status at the time of onset, academic history, employment status prior to the onset, the history of hospitalization after the onset and maintenance therapy of neuroleptics. In relation to psychiatric symptoms at the first consultation, the patients in the "improvement group" had a variety of symptoms compared to the patients in the "deterioration group," and the presence of "incoherence of thought," "delusion of reference" and "special features of depression" was significantly higher in the improvement group than in the deterioration group.

Adolescent↗
PubMed1990

[Clinical significance of Streptococcus milleri isolated from various suppurative lesions].

Seventy-one strains of Streptococcus milleri were isolated from 68 patients admitted to Tamana Central Hospital. (1985.2-1989.1) S. milleri was isolated from the following specimens: sputum (15 strains), urine (10), ascites (9), postoperative wound (9), pleural effusate (6), bile (5), genital discharge (3), aspirated fluid from lung abscess (2) and others (12). In 12 patients (18%), S. milleri was isolated in pure culture and in 56 patients (82%) as part of a mixed flora. Other bacteria isolated in association with S. milleri were obligate anaerobes (41%), Gram-negative rods (40%), Gram-positive cocci (16%) and others (3%). In 71 strains of S. milleri, 9 strains (13%) were beta-haemolytic, 62 (87%) were alpha-haemolytic (week) or non-haemolytic. In 68 patients, type specific male-female ratio was 15:9 for S. milleri I, 20:15 for II and 1:8 for III respectively. The patient's age ranged from 7 to 86 years and 75% of patients were more than 50 years old. In respiratory infection, 10 cases (pyothorax, 6; pneumonia, 3; lung abscess, 1) were related to S. milleri infection and considered clinically significant. 8 cases had underlying disease, however, 2 cases (pyothorax, lung abscess) had no underlying disease. In these 2 cases, S. milleri was isolated in pure culture. Successful treatment of these ten cases usually required either antibiotic therapy or drainage of the lesion. S. milleri was isolated from various clinical specimens and some cases were associated with serious infections. S. milleri was more commonly associated with suppurative infections than other viridans group streptococci. S. milleri may therefore have different characteristics which other streptococcal species of normal flora have not.

Abscess↗
PubMed1990

Comparative effects of busulfan, cytosine arabinoside and adriamycin on different maturation stages of normal human bone marrow cells.

Leukemic blast progenitors in acute myeloblastic leukemia (AML) undergo terminal divisions and/or self-renewal, which can be studied by the methylcellulose culture method and suspension culture, respectively. Using these methods, we have shown that busulfan (BU) was more effective against the self-renewal of blast progenitors than against the terminal divisions. As reported previously, cytosine arabinoside (Ara-C) is more effective against self-renewal and adriamycin (ADR) is more effective against terminal divisions. To determine the reason why antileukemic drugs show different sensitivity against self-renewal and terminal divisions, we studied the effects of these drugs on normal human bone marrow cells. We have shown that BU and Ara-C suppressed the colony formation induced by interleukin-3 (IL-3) more effectively than that by granulocyte colony-stimulating factor (G-CSF). On the other hand, ADR suppressed the colonies induced by G-CSF more effectively. In normal hemopoiesis, IL-3 has been shown to stimulate the growth of more primitive hemopoietic stem cells, while G-CSF has been documented to stimulate the growth of granulopoietic committed precursors at a more differentiated stage. Therefore, BU and Ara-C are considered to be more effective against the immature cells in normal bone marrow and ADR is effective against the more differentiated cells. We suppose that the different differentiation stage of target cells may explain the difference of the effects on self-renewal and terminal divisions between BU, Ara-C and ADR.

Bone Marrow↗
PubMed1990

Effect of platelet-derived growth factor on the proliferation of blast progenitors from acute myeloblastic leukemia patients.

The effect of platelet-derived growth factor (PDGF) on self-renewal and terminal divisions of blast progenitors of acute myeloblastic leukemia was studied. The terminal divisions of blast progenitors were determined as the primary blast colony formation in methylcellulose culture; self-renewal was assessed by secondary colony formation by replating in methylcellulose and the recovery of clonogenic cells in suspension culture. PDGF neither enhanced nor suppressed primary or secondary blast colony formation in methylcellulose culture nor recovery of clonogenic cells in suspension. The results show that PDGF does not affect the self-renewal or terminal divisions of leukemic blast progenitors.

Adolescent↗
PubMed1990

Functional image of dynamic computed tomography for the evaluation of cerebral hemodynamics.

We report the usefulness of functional image of dynamic computed tomography as a technique for evaluating cerebral hemodynamics. Although the technique itself has been reported, the advance of computer technology has made it possible to obtain high-resolution functional images within only a few minutes. We conducted 70 examinations on 57 patients with cerebral ischemia and correlated the findings with clinical outcome. Those patients whose abnormalities were detected on all corrected mean transit time, time to peak, and peak value images developed massive cortical infarcts. On the other hand, patients with abnormalities detected only on the corrected mean transit time image had only partial low-density lesions on follow-up computed tomograms. Patients with abnormalities detected only on the time to peak image suffered repeated transient ischemic attacks, but follow-up computed tomograms showed no low-density lesion in most cases. Single-photon emission computed tomography with N-isopropyl-p-(123I)iodoamphetamine performed at the time of functional image of dynamic computed tomography showed a high concordance of the findings in many cases, especially those with hyperacute-stage cerebral ischemia, in which the concordance rate was 90.5% (19 of 21). Comparing images constructed from different parameters, functional image of dynamic computed tomography can delineate other than hemodynamic factors, such as extent of the vascular bed or the degree of collateral circulation. Thus, functional image of dynamic computed tomography is a potentially important and useful technique for the further analysis of cerebral hemodynamics.

Adult↗