Biomedical subjects

S Okada

Publications and source records attributed to S Okada.

At least 739 records · Page 41Linked to original sources

PubMed1994

[The Cyclandelate Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw cyclandelate material was tested for preparation of the "Cyclandelate Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 57.4 degrees C; ultraviolet spectrum, lambdamax = 252.0, 258.1 and 264.1 nm and E 1cm 1% = 5.85 (252.0 nm), 6.95 (258.1 nm), 5.30 (264.1 nm), respectively; infrared spectrum, the same as that of the JP Cyclandelate Reference Standard; thin-layer chromatography, no impurities were detected up to 1000 micro g; high-performance liquid chromatography (HPLC), no impurities were detected; loss on drying, 0.03%; assay result, 101.4% by HPLC. Based on the above findings, the raw material was authorized as the JP Cyclandelate Reference Standard (Control 931).

Chemical Phenomena↗

PubMed1994

[The Alprostajil Reference Standard (Control 921) of the National Institute of Health Sciences].

Raw alprostajil material was examined for preparation of the "Alprostajil Reference Standard (Control 921)". Analytical data obtained were as follows: infrared spectrum, the same as that of the USP Alprostajil Reference Standard; thin-layer chromatography, no impurities were detected up to 20 micro g; high-performance liquid chromatography (HPLC), no impurities were detected; assay result, 99.6% by HPLC. Based on the above findings, this raw material was authorized as the NIHS Alprostajil Reference Standard (Control 921).

Alprostadil↗

PubMed1994

[The Thiamine Hydrochloride Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw thiamine hydrochloride material was tested for preparation of the "Thiamine Hydrochloride Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 242.7 degrees C (decomposition); infrared spectrum, the same as that of the JP Thiamine Hydrochloride Reference Standard; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of one impurity was detected; assay results, 100.4% by UV spectrophotometry and 100.0% by HPLC, respectively. Based on the above findings, the raw material was authorized as the JP Thiamine Hydrochloride Reference Standard (Control 931).

Chemical Phenomena↗

PubMed1994

[The Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences].

Raw testosterone propionate material was tested for preparation of the "Testosterone Propionate Reference Standard (Control 881)". Analytical data obtained were as follows: loss on drying, 0.1%; melting point, 120.6 degrees C; optical rotation [alpha]20D = + 85.4 degrees; ultraviolet spectrum, lambdamax = 241 nm and specific absorbance E 1cm1% (241 nm) = 483; infrared spectrum, the same as that of the NIHS Testosterone Propionate Reference Standard; thin-layer chromatography, no impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; assay result, 100.6% by UV spectrophotometry. Based on the above findings, the raw material was authorized as the Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences.

Chemical Phenomena↗

PubMed1993

Molecular cloning of partial cDNAs for rat DNA topoisomerase II isoforms and their differential expression in brain development.

cDNA segments for DNA topoisomerase II were amplified from rat brain RNA after reverse transcription by the polymerase chain reaction, using degenerate oligonucleotide primers deduced from the conserved regions of topoisomerase II of higher eukaryotes. The cDNA product from a successful amplification was homogeneous in length but heterogeneous in sequence. Restriction mapping of the cloned cDNA fragments revealed that they consisted of two distinct sequence groups. DNA sequencing of representative clones from each group, designated A and B, showed that they are highly homologous to cDNAs of human topoisomerase II isoforms, alpha and beta, respectively. Northern blot analysis indicated that the transcript level for rat topoisomerase II alpha was high in embryonic brain and in the cerebellum of 2-day newborns, followed by rapid decrease to a undetectable level at 4 weeks after birth. In contrast, rat topoisomerase II beta transcript was present throughout the embryonic and postnatal stages. In the developing cerebellum, cells expressing topoisomerase II alpha were confirmed exclusively to the outer mitotic zone of the external granular layer, whereas the transcript of topoisomerase II beta was detected over the entire cortical region. These results clearly indicate that the isoform alpha is expressed only in proliferating cells. The differential expression of topoisomerase II isozymes was also observed among developed tissues. Therefore, the isozymes are most likely to be involved in the following different physiological processes: topoisomerase II alpha in cell proliferation, and topoisomerase II beta in some processes unrelated to cell proliferation.

Amino Acid Sequence↗

PubMed1993

Molecular mass determination of low-molecular-mass heparins. Application of wide collection angle measurements of light scattering using a high-performance gel permeation chromatographic system equipped with a low-angle laser light-scattering photometer.

A high-performance gel permeation chromatographic system with on-line low-angle laser light-scattering detection (HPGPC-LALLS) was used to determine molecular masses of low-molecular-mass heparins (LMMHs). Measurements at wide and narrow collection angles were compared and the application of the HPGPC-LALLS method to small molecules, with molecular masses in the range 1000-10,000, was assessed. The molecular mass averages of fractionated heparins and commercially available LMMHs were also determined by ordinary HPGPC analysis using an LMMH molecular-mass calibrant, supplied by the National Institute for Biological Standards and Control for the calibration of columns. The LALLS intensity at the routinely used narrow collection angle (theta col = 1 degree) about doubled at the wide collection angle (theta col = 2 degrees) and the signal-to-noise ratio was improved. The present study thus indicates that wide collection angle measurement of light scattering allows the application of the HPGPC-LALLS method to very small biopolymers of molecular mass < 10,000.

Chromatography, Gel↗

PubMed1993

Case of ring chromosome 7: the first report of neuropathological findings.

We report on a boy with ring chromosome 7 who had severe mental retardation, growth failure, microcephaly, cleft lip and palate, café-au-lait spots, nevus flammeus, and genital abnormalities, and died of pneumonia at age 20 months. On autopsy he had fusion of the anterior cerebral hemispheres, accompanied by agenesis of olfactory bulbs and tracts, closely resembling those found in semilobar holoprosencephaly. In addition, heterotopic Purkinje cell clusters in the cerebellar white matter, absence of pigmentation within the brainstem pigmented neurons, and severe hypomyelination in the whole brain were noted. The patient may represent the most severe manifestation of ring chromosome 7, and this is the first detailed neuropathological report on this subject.

Abnormalities, Multiple↗

PubMed1993

Procolipase mRNA: tissue localization and effects of diet and adrenalectomy.

Northern blot analysis has identified procolipase mRNA in rat pancreas, stomach and duodenum. Pancreatic colipase mRNA was increased by high-fat diets. Adrenalectomy increased pancreatic procolipase mRNA, an effect enhanced by high-fat diets. The results suggest that colipase is not unique to the pancreas and that diet and glucocorticoids interact in regulating the transcription of its gene.

Actins↗

PubMed1993

Identification and characterization of a nuclear scaffold protein that binds the matrix attachment region DNA.

The association of nuclear DNA with the nuclear matrix (scaffold) is mediated by defined segments of DNA called matrix association region (MAR). By using a plasmid harboring a portion of the Ig kappa gene within which MAR had been located, we searched for proteins recognizing MAR in the nuclear scaffold components electrophoretically separated and blotted onto a membrane. In the presence of nonspecific competitor DNA, the labeled plasmid selectively bound to a protein with apparent molecular weight of 120,000 (designated SP120). The protein was purified directly from SDS-polyacrylamide gels and renatured by a guanidine hydrochloride procedure. The DNA region in the plasmid responsible for the binding to the solubilized SP120 coincided with the 365-base pair HindIII-HinfI fragment that had been identified as MAR. In solution, SP120 exhibited a cooperative mode of interaction with the end-labeled MAR fragment. Measurement of relative affinities of MAR subfragments to SP120 showed that the whole region is required for efficient binding. This is consistent with the minimal length for MAR estimated thus far by in situ mapping experiments. The MAR derived from another gene, fushitarazu, also bound specifically to SP120. Immunostaining of whole cells and isolated nuclei with a monoclonal antibody raised against SP120 indicated that the protein is localized in a nuclear skeletal structure. These results suggest the involvement of SP120 in the MAR-mediated anchorage of nuclear DNA to the nuclear scaffold.

Animals↗

PubMed1993

Sequential analysis of hematopoietic reconstitution achieved by transplantation of hematopoietic stem cells.

We confirmed that murine hematopoietic stem cells express the c-kit molecule but not lymphohematopoietic lineage markers. These lineage marker-negative c-kit-positive (Lin- c-kit+) cells were further divided according to the uptake of rhodamine-123 (Rh-123). Approximately 1,000 Lin- c-kit+ rhodamine-123dull cells, which contained 4.0 +/- 1.3 and 12.5 +/- 1.9 day 8 and day 12 spleen colony-forming units (CFU-S), respectively, rescued the 100% of lethally irradiated mice. One third of these cells formed colonies in the presence of interleukin-3 plus erythropoietin. The time course of the hematopoietic reconstitution of this primitive hematopoietic stem cell fraction was investigated by using Ly-5 congenic mice. Although myeloid cells and B lymphocytes were detected in the peripheral blood 2 to 3 weeks after transplantation, T lymphocytes were not detected until 4 weeks after transplantation. It is generally assumed that myeloid cells and B lymphocytes grow in the bone marrow and that T lymphocytes must pass through the thymus. For the first 2 to 3 weeks after transplantation, donor-type T lymphocytes were not dominant in the thymus, and most donor type cells were CD4/CD8 double-negative or double-positive (including CD4low and CD8low). Four weeks after transplantation, donor-type T lymphocytes were dominant and the ratio of CD4/CD8 cells had recovered to the normal pattern. However, significant numbers of T lymphocytes were detected in the peripheral blood at this stage. Sequential analysis of hematopoietic reconstitution from primitive stem cells demonstrates that myeloid and B-lymphoid lineages occurred earlier than that of the T-lymphoid lineages.

Animals↗

PubMed1993

Gene damage induced in human alveolar type II (L-132) cells by exposure to dimethylarsinic acid.

To analyze the mechanisms of arsenic-induced gene damage, found previously in lungs of mice and rats orally administered dimethylarsinic acid (DMAA), a major metabolite of inorganic arsenics, we employed an in vitro system using human alveolar type II (L-132) cells. The exposure to 10 mM DMAA for 10 hr caused significant single-strand breaks in DNA of the cells. At an earlier period of the exposure, the replicative DNA synthesis was markedly suppressed, and the chain length of the nascent DNA was shorter than that of the control, suggesting that the template DNA received some modification other than strand breaks. The modification, being repairable, was sensitive to ultraviolet irradiation to cause strand breaks. These results suggest the possibility of DNA-adduct formation at the early period of DMAA exposure in L-132 cells.

Cacodylic Acid↗

PubMed1993

Crosslink formation between DNA and nuclear proteins by in vivo and in vitro exposure of cells to dimethylarsinic acid.

DNA damage induced by arsenics, particularly by dimethylarsinic acid (DMAA), a main metabolite of inorganic arsenics in mammals, was investigated. DNA-protein crosslinks, similarly to DNA single-strand breaks, were induced in mouse and human culture cells by the treatment with DMAA. The crosslinks were sensitive to treatment with guanidine and hydroxylamine, suggesting that the DNA linkage sites in proteins were serine and threonine residues of H1 histone and of nonhistone proteins and that the linkage occurred through a phospho-nitrogen bond. The type of crosslinks was different from that induced by X-ray radiation. Of the radicals produced in the further metabolic processing of DMAA, the dimethylarsenic peroxyl radical rather than the superoxide anion radical is likely responsible for the formation of crosslinks, similar to the case of DNA single-strand breaks.

Animals↗

PubMed1993

[Sequential MR images of the uterus after Gd-DTPA injection--studies of normal volunteers and uterine endometrial malignant tumors].

To investigate the sequential changes in signal intensity (SI) of normal and abnormal uteri, T1 WIs were taken repeatedly after the injection of Gd-DTPA. Six volunteers and 19 patients with known uterine body malignancy (18 carcinomas, one carcinosarcoma) were examined. The results in volunteers were as follows. In the secretory phase, SI of the endometrium was stronger in the late images than in the early ones, whereas in the proliferative phase, SI was stronger in the early images. SI of the myometrium decreased rapidly and there were no differences in SI between menstrual phases. In 17 of 18 endometrial carcinomas, the tumors showed hypointensity relative to the myometrium, and the contrast between the tumor and the myometrium was better in the early images. In the remaining two cases, the tumor showed hyperintensity and the contrast was better in the late images. After the injection of Gd-DTPA, the endometrium appeared differently according to the menstrual cycle in normal volunteers, and the appearance of uterine structures and endometrial malignant tumors changed sequentially. These findings must be kept in mind when evaluating uterine diseases by Gd-DTPA enhanced MRI.

Adult↗

PubMed1993

Glutathione cycle dependency of ferric nitrilotriacetate-induced lipid peroxidation in mouse proximal renal tubules.

Parenteral administration of ferric nitrilotriacetate (Fe-NTA), a known carcinogen in mouse and rat kidneys, enhances iron-dependent lipid peroxidation (LP) and causes acute renal tubular necrosis. We assume that filtered Fe-NTA in vivo is rapidly reduced by cysteine, a component of glutathione which is hydrolyzed by gamma-GTP and dipeptidase, and that this reduced iron initiates lipid peroxidation in the lumen. In addition, the fatty acid composition of phospholipids between the cortex and the medulla may differ, because only the proximal tubules (which are located mainly in the cortex) are known to be vulnerable to LP. We tested these assumptions in the present study. Gas chromatographic determination of fatty acid composition in five male and five female 6-week-old normal ddY mice showed the ratio of polyunsaturated fatty acids to saturated fatty acids plus C18: 1, a single double-bond fatty acid, to be 0.98 +/- 0.08 (av +/- SD) in the male cortex and 1.00 +/- 0.08 in the female cortex. In the male and female medulla, however, it was 0.78 +/- 0.09 (P < 0.05, vs cortex) and 0.68 +/- 0.04 (P < 0.01, vs cortex), respectively. Pretreatment of the animals with buthionine sulfoximine, a glutathione synthetase inhibitor, and a procedure that reduces total glutathione content in the kidneys, suppressed LP. Reduced thiobarbituric acid reactive substances were also observed in animals treated with AT-125, a gamma-GTP inhibitor, and in animals with immature gamma-GTP activity. These results are consistent with our assumptions.

Aging↗

PubMed1993

Disproportionating enzyme (4-alpha-glucanotransferase; EC 2.4.1.25) of potato. Purification, molecular cloning, and potential role in starch metabolism.

Disproportionating enzyme (D-enzyme, 4-alpha-glucanotransferase; EC 2.4.1.25) has been purified to homogeneity from potato tubers and its activity characterized. The enzyme catalyzes the transfer of maltooligosaccharides from one 1,4-alpha-D-glucan molecule to another, or to glucose. Maltooligosaccharides are effective donor molecules, but short chain amylose and amylopectin may also function as donors. Enzyme activity is not affected by inorganic phosphate, 3-phosphoglycerate, or hexose phosphates. A cDNA clone encoding the enzyme was isolated using oligonucleotide probes derived from partial peptide sequences of the purified enzyme. The identity of the cDNA clone was confirmed by expression in Escherichia coli resulting in D-enzyme activity. The amino acid sequence deduced from the cDNA shows significant homology with a 4-alpha-glucanotransferase from Streptococcus. The deduced sequence indicates the presence of an amino-terminal plastid transit peptide of 52 amino acid residues and a mature polypeptide of 524 residues. D-enzyme mRNA is present in leaves, stems, roots, and stolons but is most abundant in developing and mature tubers. The amount of mRNA in leaves increases in response to light and to sucrose added to the medium. These results are discussed in terms of the function of D-enzyme in potato starch metabolism.

Amino Acid Sequence↗

PubMed1993

The effect of spermine on the disaccharidase activities in suckling rats of different age.

The influence of the age of the rat on the maturation of disaccharidase activities induced by spermine was studied. Three-day- and 9-day-old rats were used in the experiment. Spermine was administered orally or directly into the stomach using thin tubing daily for 3 days, and disaccharidase activities in the jejunum were measured. While spermine caused maturation of not only lactase activity but also maltase and sucrase activities in 9-day-old rats, it only caused maturation of lactase activity in 3-day-old rats. Histological studies showed no significant changes in the jejunum of 3-day-old rats treated with spermine.

Age Factors↗

PubMed1993

Intrapleural rupture of a pulmonary arteriovenous fistula occurring just beneath the pleura: report of a case.

We report herein a rare case of a 21-year-old man with Rendu-Osler-Weber disease, otherwise known as hemorrhagic teleangiectasia, in whom a spontaneous hemothorax occurred following the rupture of one of multiple pulmonary arteriovenous fistulae (PAVF). An emergency life-saving operation was performed which revealed the ruptured fistula lying just beneath the visceral pleura. This case demonstrates that patients in whom a pulmonary angiogram shows an arteriovenous fistula lying just beneath the visceral pleura should undergo prophylactic surgery to avoid a life-threatening emergency, whenever possible.

Adult↗

PubMed1993

Nephrosialidosis: ultrastructural and lectin histochemical study.

The neuropathological findings in a Japanese male with nephrosialidosis are reported. Clinically, coarse face, psychomotor retardation, macular cherry-red spot and proteinuria were noted at 1 year and 7 months. He was diagnosed to have nephrosialidosis on the basis of a deficiency of alpha-neuraminidase activity in both lymphocytes and cultured skin fibroblasts, and of severe glomerular and tubular involvement on renal biopsy. He died of multiple organ failure at 8 years and 6 months. There were numerous vacuoles and storage materials in visceral organs, particularly in the glomerular and tubular epithelial cells of the kidney and Kupffer cells as well as hepatocytes in the liver. Neuropathological examination revealed severe neuronal storage in the selected part of the central nervous system: lower motor neurons of the brain stem and spinal anterior horn cells, as well as neurons in the basal nucleus of Meynert. In the peripheral nervous system, sympathetic ganglia were severely affected. There was little or no neuronal storage in the basal ganglia, cerebral cortex or cerebellum, and demyelination was not found. Electron microscopic examination showed fine wavy multilamellar structures in the spinal anterior horn cells or Zebra body-like structures in the neurons of the Meynert's basal nucleus. Lectin histochemistry was positive for wheat germ agglutinin, Ricinus communis agglutinin-1 and peanut agglutinin within distended neurons. We conclude that the neuropathological feature in nephrosialidosis is not specific except for the selectiveness of the anatomical sites of involvement. It shares some aspects found in other types of sialidosis or galactosialidosis.

Brain↗