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Biomedical subjects

N Kamiya

Publications and source records attributed to N Kamiya.

At least 19 recordsLinked to original sources
PubMed1992

The restriction endonuclease map of Marek's disease virus (MDV) serotype 2 and collinear relationship among three serotypes of MDV.

A BamHI, EcoRI, and XhoI restriction endonuclease map of Marek's disease virus (MDV) serotype 2 (MDV2) DNA was constructed by double-digest analyses of 28 cloned BamHI and 11 cloned EcoRI fragments of MDV2 DNA, followed by hybridization tests of these cloned BamHI DNA fragments with electrophoretically separated digests of MDV2-infected cell DNA. On this map, MDV2 genome consisted of two segments which have unique regions inserted between two inverted repeat regions as observed in MDV serotype 1 and 3 genomes. Further, the DNA homology among three serotypes of MDV was examined by hybridization under less stringent conditions using cloned BamHI fragments of MDV2 DNA. Most of the MDV2 fragments located within the unique regions hybridized with MDV serotype 1 and 3 DNAs, indicating the presence of the collinear relationship among three serotypes. In addition, MDV2 DNA fragments which hybridized with the DNA fragments encoding MDV1 gp57-65 (or A antigen) or MDV1 gp100, gp60, gp49 (or B antigen) were identified and these fragments of serotypes 1 and 2 found to be collinear.

Animals↗
PubMed1991

Crystallization of a photosensitive nitrile hydratase from Rhodococcus sp. N-771.

A photosensitive nitrile hydratase from Rhodococcus sp. N-771 has been crystallized in two different crystal forms in its inactive form. One crystal form belongs to an orthorhombic space group P2(1)2(1)2 with unit cell dimensions of a = 117.4 A, b = 145.7 A and c = 52.1 A, and the other form belongs to a hexagonal space group P6(3)22 with unit cell dimensions of a = 110.2 A and c = 412.1 A.

Crystallization↗
PubMed1990

Simultaneous measurement of CA 125, CA 19-9, tissue polypeptide antigen, and immunosuppressive acidic protein to predict recurrence of ovarian cancer.

We studied the utility and limitations of CA 125 for the early diagnosis of recurrence of ovarian cancer and investigated whether the precision of diagnosis could be enhanced by combining CA 125 with other tumor markers. Of 181 patients with epithelial ovarian cancer, 149 were in clinical remission and 35 had developed recurrence. Thirty-four women with recurrence had preoperative CA 125 values of 35 U/mL or more, and 21 (62%) had CA 125 levels of 35 U/mL or more at the time of detection of clinical recurrence. Eleven had levels that remained elevated 3 months before identification of the recurrence. However, in 13 cases CA 125 was below 35 U/mL at the time recurrence was detected. To enhance the efficacy of tumor markers to predict recurrence, patients in whom multiple tumor markers had been measured were studied retrospectively. At the time of clinical recurrence and 3 months earlier, the diagnostic sensitivity of CA 125 alone for recurrence was 64 and 33%, respectively, whereas the sensitivity of a combination of tumor markers (CA 125, CA 19-9, tissue polypeptide antigen, and immunosuppressive acidic protein) was 89 and 66%. Thus, prediction of recurrence of ovarian cancer can be improved by the use of a combination of these tumor markers.

Adenocarcinoma↗
PubMed1989

Defective homologous pairing and proficient processive unwinding by the recA430 mutant protein and intermediates of homologous pairing by recA protein.

The recA protein promotes the formation and processing of joint molecules of homologous double- and single-stranded DNAs in vitro. Under a set of specified conditions, we found that the substitution of a single amino acid in the recA protein (recA430 mutation) depresses its activity for the homologous pairing to about 1/100 of that by the wild type protein when compared by the rate for the first 2-3 min of the reaction, but that the mutation only slightly, if at all, affects its ability to bind progressively to double-stranded DNA to unwind the double helix ("processive unwinding"). This is in striking contrast to an anti-recA protein monoclonal IgG, ARM193, which severely inhibits the processive unwinding but not the homologous pairing, providing further support for our conclusion that the homologous pairing and processive unwinding are functionally independent of each other. Antibody ARM193 caused the breakdown of spontaneously formed filaments of the recA protein, but the recA430 mutation did not affect the self-polymerization of the protein. The recA430 protein was apparently proficient in the functional binding to a single-stranded DNA and in the hydrolysis of ATP. However, we found that under the above conditions the mutant protein was defective as to homology-independent conjunction of DNA molecules to form a "ternary complex" (of macromolecules). These results suggest that (i) only one DNA-binding site is sufficient for the recA protein to promote the processive unwinding (the ability of the protein to form spontaneous filaments is closely related to this process) and that (ii) two DNA-binding sites on each of the recA polypeptides or those composed of a dimer (or oligomer) of the polypeptide are required for the recA protein to promote both the conjunction of parental DNA molecules and the homologous pairing (the ability to form the spontaneous filaments is not essential to this process). (iii) The simultaneous inactivation of the activity to promote the homologous pairing and that to form the ternary complex by the single substitution of the amino acid provides a physical support for the conclusion that the ternary complex is an indispensable intermediate in the homologous pairing.

Adenosine Triphosphatases↗
PubMed1989

Hydrogen evolution of Enterobacter aerogenes depending on culture pH: mechanism of hydrogen evolution from NADH by means of membrane-bound hydrogenase.

The pH dependency of cell mass productivity, the hydrogen evolution rate and the yield of hydrogen from glucose was measured by controlling the pH of the culture automatically. The cell mass productivity of Enterobacter aerogenes increased in a linear fashion up to a pH value of approx. 7.0. In contrast, both the evolution rate and the yield of hydrogen showed convex relationships up to a pH value of 7.0, both having maximum values at a pH of approx. 5.8. The maximum evolution rate was approx. 11.3 mmol H2 per g dry cell per h at 38 degrees C. A hypothetical mechanism for hydrogen evolution was proposed by taking our results and other research work into consideration. The proposed mechanism of hydrogen evolution was that NADH was oxidized on the inside surface of the cell membrane and protons were reduced on the outside surface by means of membrane-bound hydrogenase. This mechanism explains in a thermodynamic context the relation between the activity of the hydrogen evolution and the pH of the culture.

Cell Membrane↗
PubMed1989

Propulsive force of Paramecium as revealed by the video centrifuge microscope.

Using the video centrifuge microscope we constructed, we observed the behavior of Paramecium cells in a solution of graded densities under centrifugal acceleration. Beyond 300g, they not only gather in the zone where the density is closest to theirs, but also orient themselves with their longitudinal axis parallel to the direction of centrifugation turning their anterior ends toward either centripetal or centrifugal direction. Since all of them retain still active swimming capacity, it is possible to calculate their propulsive force from the difference in density between theirs (1.04 g cm-3) and that of the upper or lower layer which they can reach. The propulsive force of single Paramecium cells thus obtained was calculated to be about 7 x 10(-4) dyn.

Animals↗
PubMed1989

Three-year prospect of patients with common epithelial carcinoma of the ovary.

In order to forecast the survival of patients, we collected 417 cases of common epithelial carcinoma of the ovary as a population for this study, then selected 141 cases who had survived more than 3 years and 131 cases who had died within 3 years as a sample of statistical inference. The sample was computerized inputting 25 factors which were obtained mainly on the first surgery. We selected 8 factors with 46 items considering their weight to forecast the prognosis on convenience. The selection of factors was carried out by following three basic principles. First, we selected factors that retained high partial correlation coefficients. Second, we selected factors which did not overlap each other in their contents. Third, we selected factors which were not decided intentionally. Accordingly, the score for forecasting the 3-year survival of patients with ovarian carcinoma was framed. The correct discrimination rate of the score when it was judged at the 0 point was 86.8% in the sample group. However, in the sample group outside the population, it was 83.1%.

Adult↗
PubMed1989

Genotoxic effects of o-phenylphenol metabolites in CHO-K1 cells.

The effects of microsomal activation and/or deactivation on the induction of chromosomal aberrations and sister-chromatid exchanges (SCEs) in cultured Chinese hamster ovary cells (CHO-K1 cells) by o-phenylphenol (OPP) were studied, and concurrently the metabolites were determined. After a 3-h incubation in the presence of 15% S9 mix (45 microliters/ml of S9), OPP (25-150 micrograms/ml) dose-independent SCEs and chromosomal aberrations were induced, while the amount of phenylhydroquinone (PHQ) metabolite produced from OPP did not increase linearly in the higher doses. The maximum induction of chromosomal aberrations was 18% at the 150 micrograms/ml dose, and of SCEs 13.8/cell at 75 micrograms/ml. The corresponding control values were 3% and 5.8/cell. The lowest dose required to induce SCEs in the presence of S9 mix was 25 micrograms/ml. Changing the percent of S9 mix (0-50%) while holding the OPP dose constant (100 micrograms/ml) produced a correlation between SCEs and the production of PHQ. PHQ caused cytogenetic effects both with and without S9 mix, however, in the absence of S9 mix it was more lethal and was oxidized to phenylbenzoquinone (PBQ). These results suggest that the enhanced cytogenetic effects of OPP by the addition of S9 mix correlated with the amount of PHQ produced or with the further oxides of PHQ such as phenylsemiquinone and/or PBQ which are capable of being produced from PHQ spontaneously or by the mixed-function oxidase system.

Animals↗
PubMed1988

Dynamic organization of Physarum plasmodium.

Birefringent fibrils (BRFs) with a positive sign composed of bundles of F-actin were found throughout the Physarum plasmodium with the mode of existence differing regionally. In the zone behind the leading edge of an advancing plasmodium, where cytoplasmic sol and gel were still not well differentiated, more BRFs came to the foreground when the endoplasm flowed backward (emptying phase), and a substantial portion disappeared when the endoplasm flowed forward (filling phase), except for nodes, from which BRFs were reorganized in the early emptying phase of each cycle. BRFs found in the wall of the streaming channel in the posterior network and the branched vein section ran in parallel to or helically around the channel. They were much more stable and maintained strong birefringence irrespective of the direction of the cytoplasmic flow. When the fan-like expanse ceased moving forward, the BRFs no longer appeared and disappeared cyclically but persisted in the area which had previously been the front. We concluded that the site of the active contraction-relaxation rhythm in an advancing plasmodium with antero-posterior polarity is restricted to its frontal zone and that the rest of the plasmodium is in a state of "tonus" which continuously imparts a certain level of hydrostatic pressure to the interior. The meaning of the tonus and the mechanics of tensile force production in the plasmodium are discussed in terms of a working hypothesis arrived at from the phase relationship between isometric and isotonic contraction waves.

Birefringence↗
PubMed1988

Immunoassay for the beta gamma subunits of GTP-binding proteins and their regional distribution in bovine brain.

Antibodies were raised in rabbits against the beta gamma subunits of bovine brain GTP-binding proteins, and were purified with a beta gamma-coupled Sepharose column. Purified antibodies reacted strongly with 36,000-dalton beta subunit and slightly with 35,000-dalton beta and gamma subunits, but not with other proteins in an immunoblot assay. Using these purified antibodies, a sensitive enzyme immunoassay method for the quantification of brain beta gamma was developed. The assay system consisted of polystyrene balls with immobilized antibody F(ab')2 fragments and the same antibody Fab' fragments labeled with beta-D-galactosidase from Escherichia coli. The minimum detection limit of the assay was 3 fmol, or 130 pg. Samples from various regions of bovine brain were solubilized with 2% sodium cholate and 1 M NaCl, and the concentrations of beta gamma were determined. The beta gamma were detected in all the regions, and the highest concentrations were observed in the cerebral cortex and nucleus caudatus. The concentrations of beta gamma were higher than those of alpha subunit of GTP-binding protein, Go, in all the regions.

Animals↗
PubMed1988

Ontogeny of the GTP-binding protein Go in rat brain and heart.

We determined the ontogeny of the GTP-binding protein Go in rat brain and heart by employing highly sensitive enzyme immunoassay methods. In the brain, the alpha subunit of Go (Go alpha) gradually increased and reached adult levels approximately 20 and 30 days after birth in cerebral cortex and cerebellum, respectively. Concentrations of beta subunits, which were also quantified by the immunoassay, were almost equal to those of Go alpha in the brain of rats younger than 10 days, but were higher than those of Go alpha after 10 days. These results suggest that late development of GTP-binding proteins other than Go. Go alpha was immunohistochemically positive in neuropils and negative in cell bodies at any age tested. In the heart, the concentrations of Go alpha increased up to several times of the adult level just after birth, and then gradually decreased after the 20th postnatal day. The level of Go alpha in the liver, however, was very low and constant throughout ontogenic development. An immunohistochemical study indicated that Go alpha was positive in the cardiac muscle of young rat, but negative in that of adult rat. These results indicate that Go alpha exists in cells other than those of nervous tissues and neuroendocrine cells in some periods of ontogenic development.

Aging↗
PubMed1988

Go, a GTP-binding protein: immunochemical and immunohistochemical localization in the rat.

The tissue and cellular distribution of a GTP-binding protein, Go, was investigated in the rat by immunochemical and immunohistochemical methods. Because the specific antibody for the alpha subunit of bovine Go (Go alpha) cross-reacted with rat Go alpha, an enzyme immunoassay method developed for bovine Go alpha was applied for measuring the tissue concentration of Go alpha in the rat. Go alpha was detected in all tissues examined except blood cells. The concentration of Go alpha was highest in the CNS (approximately 7.7 and 4.4 nmol/g in the cerebrum and cerebellum, respectively), followed by the pituitary gland and sciatic nerve. Among the other peripheral tissues, relatively high concentrations of Go alpha were observed in the urinary bladder, stomach, and intestines; however, these values were less than 2% of the concentration in the cerebrum. Go alpha in the intestine was located mostly in the muscle layer. Immunohistochemical study showed that Go alpha was associated mostly with the neural elements but not with cells particular to each peripheral organ. Go alpha was also present in the membranes of neuroendocrine cells, including glandular cells in the anterior lobe of the pituitary gland, chromaffin cells in the medulla of the adrenal gland, islets cells in the pancreas, and parafollicular cells in the thyroid. These results indicate that Go is localized exclusively in the nervous tissues and neuroendocrine cells.

Animals↗
PubMed1988

[A case of HBs antigen negative hepatocellular carcinoma without liver cirrhosis in a young woman].

A 27-year-old woman, post parturition, was admitted to hospital because of epigastric pain. Ultrasonography and abdominal computerized tomography revealed a giant mass in the left lobe of the liver. Celiac angiography showed a hypervascular mass with irregular vascularity. Serum HBs antigen proved negative. A left hepatic lobectomy was performed in March, 1985. Histology of the tumor revealed the trabecular type of a hepatocellular carcinoma with Edmondson grade 2 atypism, whereas the non-cancerous region of the liver showed chronic inactive hepatitis. This case is presented, because of the rarity of a hepatocellular carcinoma developing in such a young patient. In addition, reported cases of a hepatocellular carcinoma in the young in Japan are reviewed.

Adult↗
PubMed1988

Effect of lipophilic extract of Chlorella vulgaris on alimentary hyperlipidemia in cholesterol-fed rats.

The effect of glycolipid (GL) and phospholipid (PL) fractions obtained from Chlorella on serum lipid level and fecal excretion of steroids were examined in cholesterol-fed rats. The increase of the level of serum lipids were inhibited by the feeding of GL, PL and Chlorella powder almost the same degree. Fecal excretion of steroids (mostly of cholesterol, deoxycholic and lithocholic acid) were increased by feeding of GL and PL fractions. It is concluded that the feeding of each fraction inhibits the absorption of exogenous steroids and promotes turnover of bile acids in liver to suppress the increase of serum cholesterol level caused by administration of high cholesterol diet.

Animals↗
PubMed1987

Production of the alpha subunit of guanine nucleotide-binding protein GO by neuroendocrine tumors.

We have found that neuroendocrine tumors (including neuroblastoma, ganglioneuroma, gut carcinoid, pheochromocytoma, medullary thyroid carcinoma, insulinoma, glucagonoma, prolactinoma, carotid body tumor, and small cell lung carcinoma) produce considerable amounts (about 1000-80,000 ng/g tissue) of the alpha subunit of guanine nucleotide-binding protein, GO (GO alpha), whereas nonneuroendocrine tumors contain less than 300 ng of GO alpha/g tissue. GO alpha in the neuroendocrine tumors was present both in the soluble fraction, and cholate-extractable membrane-bound fraction of tissues. Immunoblots of membrane fractions of neuroblastoma and carcinoid tissues confirmed that the immunoreactive substance in the tumor tissues was GO alpha. Immunohistochemically, GO alpha was localized consistently in the cell membrane and occasionally in the cytoplasm of neuroendocrine tumors. GO alpha was also detected in sera of 73% patients with neuroblastoma at diagnosis, whereas serum GO alpha concentrations in control children, or patients with nonneuroendocrine tumors were lower than the detection limit of the immunoassay method employed. Serum GO alpha concentrations in patients with neuroblastoma changed with the clinical course; they fell in patients responding to treatment and increased in patients who relapsed. Since GO alpha, a specific protein in the neural and neuroendocrine cells, was found to be produced in considerable amounts by all types of neuroendocrine tumors but not in nonneuroendocrine tumors, GO alpha might be a useful biomarker for neuroendocrine tumors.

Adrenal Gland Neoplasms↗
PubMed1987

[Significance of tumor markers in the treatment of patients with ovarian malignancies].

Seven tumor markers (CA125, CA19-9, TPA, IAP, CEA, ferritin, LDH) were measured in 24 patients with ovarian cancer. The positive rates in untreated cases of ovarian cancer were 87.5% for CA125, 35.5% for CA19-9, 10% for CEA, 77.8% for IAP, 63.6% for TPA, 28.6% for LDH and 35.3% for ferritin. Among these, CA125 was the most available marker for detecting tumor growth or regression during each respective clinical course by serial measurement. Serial changes in serum alpha-fetoprotein (AFP) levels during treatment were studied among 27 patients with ovarian embryonal carcinoma. AFP decreased with a half-life of about 7 days, and was restored to the normal range within 10 weeks after the initial surgery and chemotherapy (VAC) in all cases. In subsequently fatal cases, AFP rose again during 10 to 30 weeks after the initial treatment.

Antigens, Neoplasm↗