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Biomedical subjects

K Nagata

Publications and source records attributed to K Nagata.

At least 937 records · Page 52Linked to original sources

[A quantitative study of brain atrophy on computed tomography--multivariate analysis for comparison between the linear measurement method and the pixel count method].

We previously reported the newly developed quantitative measurement of the cerebral atrophy. The data indicated that the volume of the cerebrospinal fluid not always gradually increases during the life course but remains relatively constant until age 50 and thereafter increases with a wide variation. Though the technique, which is called the pixel count method, is highly quantitative, it is quite troublesome as it needs the computer to count out each pixels. On the other hand, the linear measurement method is easier than the pixel count method, but is far less quantitative. We examined seventy four subjects using both the linear measurement method and the pixel count method, and compared them by means of the multivariant analysis. Three different linear measurement methods were selected by the stepwise multiple regression analysis, those are B (distance between the caudate nuclei), E (greatest distance between the lateral ventricles at the level of the cella media) and G (number of visible sulci whose width are more than 3.1 mm at the level of 3 cm above the corpus callosum). B and E were calibrated by the maximum internal width of the skull (H). The highest correlation was achieved with a formula employing these parameters as follows; y = 42.66 X B/H + 12.52 X E/H + 0.232 X G - 2.92 (y means the estimated value of the CCR (CSF-cranial ratio), which is obtained by dividing the CSF volume by the cranial cavity). Multiple correlation coefficient was 0.76, and was statistically significant (p less than 0.001). The authors emphasized that using this formula we can easily predict CCR as the index of the brain atrophy without any computer.

Adult↗

[Effects of combination chemotherapy M-VEMFH including mitoxantrone in advanced breast cancer].

The effects of combination chemotherapy including mitoxantrone (MXN) "M-VEMFH" for advanced breast cancer were studied. The M-VEMFH regimen consisted of MXN 7 mg/m2, VCR 0.7 mg/m2, EX 333 mg/m2, MTX 13.3 mg/m2 i.v. on day 1, 5-FU 333 mg/m2 i.v. from day 1 to day 5 and pred. (H) 60 mg/m2 p.o. with tapering off in 2 weeks. In 7 cases heavily pretreated with combination chemotherapy including ADR, CR 2, PR 2, NC 2 and PD 1 were observed (response rate 57.1%). In 5 cases without prior ADR, PR 1, NC 2 and PD 2 were obtained. One case given 586 mg/m2 of prior ADR died of congestive heart failure after administration of 47 mg/m2 of NXN. One case died of sepsis. The other side effects were stomatitis, vulvitis, abnormal gustation, nausea, vomiting and alopecia. M-VEMFH is effective combination chemotherapy for advanced breast cancer resistant to ADR, but care must be exerted due to the accompanying cardiotoxicity and leukopenia.

Adult↗

Purification and properties of glucose-6-phosphate dehydrogenase from Bacillus stearothermophilus.

Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase, EC 1.1.1.49) from the thermophilic bacteria, Bacillus stearothermophilus, was purified and its properties were examined. The enzyme was shown to consist of four identical subunits, each of about Mr 50,000. This enzyme utilized both NADP+ and NAD+ as cofactors, and the maximum velocity for both cofactors was similar. However, the Km values were quite different from each other, being 0.016 and 1.64 mM for NADP+ and NAD+, respectively. From the analysis of sulfhydryl groups it was shown that there is one sulfhydryl group and one disulfide bridge per subunit. This sulfhydryl group had no reactivity with 5,5'-dithiobis(2-nitrobenzoic acid) in the absence of guanidine hydrochloride. The enzyme showed a remarkable thermostability as well as storage stability.

Amino Acids↗

Protein-primed replication of plasmids containing the terminus of the adenovirus genome. I. Characterization of an in vitro DNA replication system dependent on adenoviral DNA sequences.

An in vitro system which replicates plasmid DNA containing the replication origin of adenovirus DNA has been established. Replication of plasmid pLA1 DNA, which contains the left-hand terminus (0-9.4 map units) of adenovirus serotype 5 DNA but which lacks the 55,000-dalton terminal protein, is initiated by a protein-primed mechanism in a manner similar to that found with adenovirus DNA. Initiation of DNA replication using plasmid pLA1 as a template requires (i) that the cloned adenovirus sequence be present at the terminus of a linearized (form III) DNA molecule ( Tamanoi , F., and Stillman , B. W. (1982) Proc. Natl. Acad. Sci. U. S. A., 79, 2221-2225; van Bergen, B. G. M., van der Ley , P. A., van Driel , W., van Mansfield , A. D. M., and van der Vliet , P. A. (1983) Nucleic Acid Res. 11, 1975-1979), and (ii) the presence of the 80,000-dalton precursor to the 55,000-dalton terminal protein and the adenovirus coded DNA-dependent DNA polymerase. In the presence of the four deoxy-nucleoside triphosphates, the preterminal protein, the adenovirus coded DNA binding protein, and an extract prepared from uninfected HeLa nuclei, the adenovirus DNA polymerase can elongate the preterminal-protein dCMP initiation complex formed on pLA1 DNA to full length (6.6 kilobase) DNA molecules. These results suggest that the 55,000-dalton terminal protein covalently linked to the 5' termini of adenovirus DNA is not essential for the replication of this DNA.

Adenoviridae↗

Protein-primed replication of plasmids containing the terminus of the adenovirus genome. II. Purification and characterization of a host protein required for the replication of DNA templates devoid of the terminal protein.

A host protein, which is required for the replication of a plasmid DNA (pLA1), has been purified from extracts of uninfected HeLa nuclei. This plasmid DNA contains the origin of adenovirus DNA replication but lacks the 55,000-dalton terminal proteins. The purified host protein has been designated factor pL. Factor pL is essential for the initiation of DNA replication of EcoRI-digested pLA1 DNA, which proceeds via the formation of a covalent complex between the 80,000-dalton adenovirus coded preterminal protein and 5' dCMP. Factor pL has been purified approximately 120-fold to greater than 75% homogeneity. It is a heat labile and N-ethylmaleimide-sensitive protein with a native Mr = 39,000 (+/- 2,000). Initiation of DNA replication using EcoRI-digested pLA1 DNA as the template requires the 80,000-dalton preterminal protein and the 140,000-dalton adenovirus DNA polymerase, in addition to factor pL, and is stimulated as much as 10-fold by nuclear factor I ( Nagata , K., Guggenheimer , R. A., Enomoto , T., Lichy , J. H., and Hurwitz , J. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 6438-6442). Factor pL has no effect on in vitro DNA replication when adenovirus DNA covalently linked to the 55,000-dalton terminal protein is used as the template, however the replication of adenovirus DNA treated with Pronase, becomes totally dependent upon the addition of factor pL.

Adenoviridae↗

Topographic electroencephalographic study of transient ischemic attacks.

Twenty-five patients with TIAs in the carotid artery distribution were studied by means of computed mapping of EEG (CME) and conventional EEG. In addition, CT scan and cerebral angiography, and in 10 patients rCBF measurements were performed. The CME provided topographic maps of the average power spectra for each of 6 frequency bands from 2.0 to 29.5 Hz which were displayed two-dimensionally in a color-coded isopower format. EEG abnormalities were analyzed and the results of the two different methods of EEG interpretation were compared. Sixty-eight percent of the patients showed unilateral abnormalities on CME appropriately lateralized to the clinical symptoms even after these symptoms had cleared completely. Furthermore, 88% of those who were examined within 2 weeks of last TIA showed corresponding CME abnormalities. Only 3 out of 10 TIA patients who had rCBF studies showed reduction of blood flow on the appropriate hemisphere, whereas 7 of the 10 patients had corresponding CME abnormalities. Comparing the results of the CME and of conventional EEG reading revealed the CME to be slightly more sensitive in detecting asymmetrical voltage depression of background activity than the conventional reading of the EEG, while the latter detected low amplitude sporadic activities which were missed by CME. Both methods were equally sensitive in detecting slow wave foci and non-transient symmetrical changes. The two most significant points of this report are the following: first, 68% of the TIA patients studied had residual unilateral abnormalities in CME in their symptom-free period. In the subset of patients subjected to rCBF studies only 30% showed residual flow aberrations, whereas 70% of the same subset demonstrated unilateral abnormalities in CME. Second, though conventional EEG reading by an experienced electroencephalographer can nearly match the performance of CME the CME format makes subtle but useful EEG findings readily available to the uninitiated. The CME also quantifies the data making objective comparisons more amenable to software manipulations for further studies.

Adult↗

Interstitial and glomerular immune cell populations in idiopathic nephrotic syndrome.

Tissue samples from patients with idiopathic nephrotic syndrome [seven with minimal change (MC) and seven with mesangial proliferation (MP)] were examined for evidence of interstitial and glomerular immune cell infiltration using monoclonal antibodies to identify T cells (OKT3, TA-1), T cell subsets (OKT4, OKT8), B cells (BA-1), and monocytes and null cells (OKM1) by indirect immunofluorescence. A nuclear counterstain permitted precise enumeration of reactive and unreactive cells in comparison with five normal tissue samples, eight endstage (ES) tissue samples, and five tissue samples from patients with miscellaneous ( misc ) types of nephrotic syndrome. Interstitial cell populations in MC and MP were similar to normals except for an increase in OKM1 reactive cells in MP. ES had more numerous interstitial cells reactive with each of the monoclonal antibodies than did normal, MC, or MP. Reactive glomerular cells were most numerous in MP, intermediate in MC but only rarely observed in normal tissue samples. Most identifiable glomerular cells reacted with OKT3 or OKM1. T-cell subset populations in MC and MP glomeruli were similar. These studies reveal the presence of infiltrating immune cells in the glomeruli but not the renal interstitium of patients with idiopathic nephrotic syndrome. Whether these cells mediate proteinuria or simply mark tissue injury remains to be discerned.

Adolescent↗

DNA sequences required for the in vitro replication of adenovirus DNA.

Initiation of adenovirus (Ad) DNA replication occurs on viral DNA containing a 55-kilodalton (kDa) protein at the 5' terminus of each viral DNA strand and on plasmid DNAs containing the origin of Ad replication but lacking the 55-kDa terminal protein (TP). Initiation of replication proceeds via the synthesis of a covalent complex between an 80-kDa precursor to the TP (pTP) and the 5'-terminal deoxynucleotide, dCMP. Formation of the covalent pTP-dCMP initiation complex with Ad DNA as the template requires the viral-encoded pTP and DNA polymerase and, in the presence of the Ad DNA binding protein, is dependent upon a 47-kDa host protein, nuclear factor I. Initiation of replication with recombinant plasmid templates requires the aforementioned proteins and an additional host protein, factor pL. Deletion mutants of the Ad DNA replication origin contained within the 6.6-kilobase plasmid pLA1 were used to analyze the nucleotide sequences required for the formation and subsequent elongation of the pTP-dCMP initiation complex. The existence of two domains within the first 50 base pairs of the Ad genome, both of which are required for the efficient use of recombinant DNA molecules as templates in an in vitro DNA replication system, was demonstrated. The first domain, consisting of a 10-base-pair "core" sequence located at nucleotide positions 9-18, has been identified tentatively as a binding site for the pTP [ Rijinders , A. W. M., van Bergen, B. G. M., van der Vliet , P. C. & Sussenbach , J. S. (1983) Nucleic Acids Res. 11, 8777-8789]. The second domain, consisting of a 32-base-pair region spanning nucleotides 17-48, was shown to be essential for the binding of nuclear factor I.

Adenoviruses, Human↗

Isolation of human DNA sequences that bind to nuclear factor I, a host protein involved in adenovirus DNA replication.

Nuclear factor I is a 47,000-dalton protein isolated from human HeLa cells that is required for the in vitro replication of adenovirus DNA. This protein was previously shown to bind specifically to nucleotides 17-48 of the left-hand terminus of cloned adenovirus serotype 5 DNA. An in vitro assay for DNA sequences that compete with adenovirus DNA for the binding of nuclear factor I has been developed. With this assay, we have shown specific binding of human DNA sequences to nuclear factor I. Using the DNA binding activity of nuclear factor I, we have isolated and cloned segments of human DNA that bind tightly to this protein. One nuclear factor I binding site is present about every 100,000 base pairs in the HeLa cell genome. The binding of these DNA molecules to nuclear factor I resembles the binding of cloned adenovirus DNA to the protein and is resistant to high ionic strength. The isolation of DNA sequences from HeLa cells that bind specifically to nuclear factor I suggests that this protein interacts with host DNA in vivo.

Adenoviruses, Human↗

Purification and characterization of a factor stimulating DNA polymerase alpha activity from mouse FM3A cells.

A protein factor which stimulates DNA polymerase alpha activity on heat-denatured DNA has been purified from mouse FM3A cells. The final preparation had a specific activity of 43,000 units/mg protein and lacked detectable DNA polymerase, RNA polymerase, DNA-dependent- and independent ATPase, exo- and endodeoxyribonuclease and phosphatase activities. The stimulating factor sedimented at 2.9S in a glycerol gradient. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the glycerol gradient fraction revealed the presence of a major band of 36,000 daltons, the amount of which corresponded well with the level of stimulating activity. The stimulation by the factor was specific for heat-denatured DNA, and a little or no stimulation was observed with native DNA, ribo- and deoxyribohomopolymers and single stranded circular DNA. Alkaline sucrose gradient sedimentation analysis of the reaction products revealed that newly synthesized DNA was covalently linked to the termini of heat-denatured DNA. The average chain length of the elongated span determined by the digestion with micrococcal nuclease and phosphodiesterase II, did not differ between in the presence and absence of the stimulating factor, suggesting that the stimulation by the factor was due to the increase in the initiation frequency of DNA synthesis from the 3'-hydroxyl terminus of heat-denatured DNA.

Animals↗

Interaction between trypsin-like enzyme from Streptomyces erythraeus and chicken ovomucoid.

Chicken ovomucoid (CO), an effective inhibitor of bovine trypsin, has a reactive site in each of three tandem domains. When CO was subjected to inhibition assay by the method of Green and Work, the second domain (CO Domain II) inhibited bovine trypsin but not TLE-Se, a trypsin-like enzyme from Streptomyces erythraeus, and the first domain (CO Domain I) inhibited neither bovine trypsin nor TLE-Se. However, when the interaction between CO and TLE-Se was analyzed by means of a Lineweaver-Burk plot, it was found that the ovomucoid exhibited competitive inhibition of the bacterial protease at pH 8.0 (Ki = 5.2 microM). In this case, the reactive-site peptide bonds of the first and second domains were specifically hydrolyzed. The isolated CO Domain I also exhibited competitive inhibition of TLE-Se (Ki = 3.1 microM), which specifically hydrolyzed its reactive-site peptide bond.

Amino Acids↗

Nature of adult T-cell leukemia-associated membrane antigen on the surface of adult T-cell leukemia virus-carrying cells as revealed by membrane immunofluorescence.

Adult T-cell leukemia-associated membrane antigen (ATLMA) expressed on the surface of living ATL virus (ATLV)-carrying cells was investigated by an indirect membrane immunofluorescence method using natural antibodies to ATLV in human sera. All the ATLV-positive cell lines tested that had cytoplasmic ATL-associated antigen (ATLA) detectable in acetone-fixed cell smears were also positive for ATLMA, but ATLMA was not detected in any ATLV-negative cell lines. The frequencies of ATLA- and ATLMA-bearing cells in seven cell lines tested were roughly parallel. The frequency of expression of both ATLMA and ATLA in cultures of MT-1 cells increased in the presence of 5-iodo-2'-deoxyuridine. All human sera having ATLA antibody had ATLMA antibody and the titers of the two were similar in most of the sera. The anti-ATLMA titers of human sera determined by using an ATLV-bound non-ATL T-cell line as antigen were also similar to the anti-ATLA titers. Absorption of anti-ATLMA-positive sera with living MT-2 cells, in which almost 100% of the cells express ATLA and ATLMA, caused parallel decreases in the anti-ATLA and anti-ATLMA titers. Analysis of the 125I-labeled surface of MT-2 cells by immunoprecipitation with anti-ATLMA-positive human serum followed by gel electrophoresis revealed that p19, p24, p28, and p46 polypeptides were specifically precipitated. These data suggest that ATLMA on the cell surface is not distinguishable from ATLA in the cytoplasm.

Antigens, Surface↗

Postoperative evaluation of extracranial-intracranial arterial bypass by means of ultrasonic quantitative flow measurement and computed mapping of the electroencephalogram.

As an objective evaluation of extracranial-intracranial (EC/IC) bypass operation, we studied 10 patients with occlusive cerebrovascular disease after EC/IC bypass operation using ultrasonic quantitative flow measurement (UQFM) and the computed mapping of the electroencephalogram (CME). After the operation, to evaluate the efficacy of the bypass operation, we studied all patients by UQFM and CME before and during compression of the superficial temporal artery (STA). In a control series of cases, the change in common carotid blood flow during STA compression was not statistically significant, and the findings of CME were unchanged during STA compression. In the cases with bypass surgery, reduction of the common carotid blood flow during STA compression was obvious and statistically significant (P less than 0.001). Additionally, in 5 of the 10 cases, the CME findings were aggravated during STA compression. Therefore, in these 5 cases the brain with bypass seems functionally dependent upon the bypass flow. It is suggested that the EC/IC bypass is effective at least in these 5 cases. The UQFM and the CME, which are noninvasive and simple, are very useful for postoperative evaluation of EC/IC bypass grafts from a hemodynamic and functional point of view.

Adult↗