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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 307 records · Page 17Linked to original sources
PubMed1993

Sequence-tagged NotI sites of human chromosome 21: sequence analysis and mapping.

We isolated and analyzed 19 NotI site-containing clones specific for human chromosome 21. The overall process consisted of selective isolation of NotI site-containing clones from flow-sorted chromosome 21 libraries, selection of independent clones by their restriction patterns and nucleotide sequences, and assignment of the clones to chromosome 21. Sequence analysis showed that the regions around the NotI sites had features typical of CpG islands, such as extremely high GC content, high-frequency appearance of CpG dinucleotide sequences, and lack of methylation of these CpGs. PCR conditions for these extremely G + C-rich templates were optimized to establish these NotI sites as sequence-tagged sites.

Base Sequence↗
PubMed1993

Distribution, origin and plasticity of galanin-immunoreactivity in the rat carotid body.

The distribution, origin and plasticity of galanin immunoreactivity in the rat carotid body was examined using an indirect immunofluorescence method. Galanin-immunoreactive nerve fibers were observed around the blood vessels as well as around the clusters of glomus and sustentacular cells. A double-immunofluorescence method revealed the coexistence of galanin- and calcitonin gene-related peptide-immunoreactivities in these nerve fibers. In the jugular, petrosal and nodose ganglia which supply the sensory nerve fibers to the carotid body, subpopulations of neurons showed both galanin- and calcitonin gene-related peptide-immunoreactivities. In the superior cervical ganglion, a few neurons were immunoreactive for galanin but not calcitonin gene-related peptide. While the nerve fibers showing both galanin- and calcitonin gene-related peptide-immunoreactivities disappeared after transection of the carotid sinus nerve, many galanin-immunoreactive nerve fibers without calcitonin gene-related peptide-immunoreactivity appeared throughout the operated carotid body. In addition, galanin-immunoreactive glomus cells which were not observed in the normal carotid body, were apparent at one and three days after transection of the carotid sinus nerve. At seven days after the carotid sinus nerve transection, the galanin-immunoreactive glomus cells disappeared. In the superior cervical ganglion, the number of galanin-immunoreactive neurons increased from one day after transection of the carotid sinus nerve. Within three days after the carotid sinus nerve transection in combination with superior cervical ganglion-ectomy, all galanin-immunoreactive nerve fibers disappeared, while many galanin-immunoreactive glomus cells appeared in the operated carotid body. At seven days after this operation, the number of galanin-immunoreactive glomus cells decreased and a few galanin-immunoreactive nerve fibers with or without calcitonin gene-related peptide-immunoreactivities appeared. Transection of the vagus nerve had no effect on the number or distribution of galanin-immunoreactivity in the carotid body. Disappearance of galanin- and calcitonin gene-related peptide-immunoreactive nerve fibers after transection of the carotid sinus nerve suggests that the majority of those nerve fibers originate from petrosal neurons which colocalize galanin- and calcitonin gene-related peptide-immunoreactivity. In addition, the carotid sinus nerve transection may cause the acquisition of galanin-immunoreactivity in originally immunonegative glomus cells, and in nerve fibers which probably originate from the superior cervical ganglion.

Animals↗
PubMed1993

A NotI restriction map of the entire long arm of human chromosome 21.

A variety of maps of the human genome have been constructed, including cloned DNA maps. We have isolated 40 of the 42 NotI sites that exist on the long arm of human chromosome 21, as NotI linking clones and constructed a complete NotI restriction map spanning the entire region. This map, which provides the most reliable ordering and distance estimation in the region from a pericentromeric locus to the terminus, demonstrates the usefulness of linking clone mapping for analysing human chromosomes.

Animals↗
PubMed1993

How to see characteristics of structural parameters in QSAR analysis: descriptor mapping using neural networks.

In addition to its outstanding abilities in both classification and fitting, the neural network can also accurately predict the values of the untrained region. To rationalize this ability of prediction, the authors mathematically discussed the valid region of prediction. Based on such a background, the authors proposed "descriptor mapping" in the QSAR analysis, which visualizes the nonlinear dependencies between structural parameters. A variable of the linear multiple regression analysis in the QSAR study is supposed to be linear to the biological intensity and is independent of other variables. Analysis by the descriptor mapping method discloses the reality.

Anticarcinogenic Agents↗
PubMed1993

Expression of a rice homeobox gene causes altered morphology of transgenic plants.

We have isolated a cDNA clone encoding a homeobox sequence from rice. DNA sequence analysis of this clone, which was designated as Oryza sativa homeobox 1 (OSH1), and a genomic clone encoding the OSH1 sequence have shown that the OSH1 gene consists of five exons and encodes a polypeptide of 361 amino acid residues. Restriction fragment length polymorphism analysis has shown that OSH1 is a single-copy gene located near the phytochrome gene on chromosome 3. Introduction of the cloned OSH1 gene into rice resulted in altered leaf morphology, which was similar to that of the maize morphological mutant Knotted-1 (Kn1), indicating that OSH1 is a rice gene homologous to the maize Kn1 gene. RNA gel blot analysis has shown that the gene is primarily expressed in the shoot apices of young rice seedlings. This finding is supported by results of transformation experiments in which the 5' flanking region of the gene directed expression of a reporter gene in the shoot apex, particularly in stipules, of transgenic Arabidopsis. To elucidate the biological function of the OSH1 gene product, the coding region was introduced into Arabidopsis under the control of the cauliflower mosaic virus 35S promoter. Almost all transformants showed abnormal morphology. The typical phenotype was the formation of clumps of abundant vegetative and reproductive shoot apices containing meristems and leaf primordia, which did not form elongated shoots. Some transformants with a less severe phenotype formed elongated shoots but had abnormally shaped leaves and flowers with stunted sepals, petals, and stamens. The abnormal phenotypes were inherited, and the level of expression of the introduced OSH1 correlates with the severity of the phenotype. These findings indicate that the abnormal morphologies of the transgenic plants are caused by the expression of the OSH1 gene product and, therefore, that OSH1 is related to the plant development process.

Amino Acid Sequence↗
PubMed1993

Role of active oxygen, lipid peroxidation, and antioxidants in the pathogenesis of gastric mucosal injury induced by indomethacin in rats.

The roles of active oxygen, lipid peroxidation, and the antioxidative defence mechanism in gastric mucosal injury induced by treatment with indomethacin in rats were investigated. The total area of gastric erosions and concentration of lipid peroxides in the gastric mucosa increased with time after administration of indomethacin (20 mg/kg, orally). The alpha-tocopherol:total cholesterol ratio in serum was significantly decreased and the activity of glutathione peroxidase, an important enzyme to scavenger of lipid peroxides, was inhibited by the administration of indomethacin. Treatments with superoxide dismutase and catalase inhibited the increases in gastric mucosal erosions and lipid peroxides in the gastric mucosa, and the reduction of serum alpha-tocopherol. Treatment with these scavengers did not improve the decreased glutathione peroxidase activity. These findings suggest that active oxygen species and lipid peroxidation play an important part in the pathogenesis of gastric mucosal injury induced by indomethacin, and that the decreased glutathione peroxidase activity aggravated the injury due to accelerated accumulation of hydrogen peroxide and lipid peroxides in the gastric mucosal cell.

Animals↗
PubMed1993

Design and preparation of ethyl cellulose microcapsules of gadopentetate dimeglumine for neutron-capture therapy using the Wurster process.

Microcapsules of hygroscopic, highly water-soluble gadopentetate dimeglumine (Gd-DTPA-DM) for use in preliminary in vivo experiments for neutron-capture therapy were designed. They were prepared with such properties as a particle size small enough to be suspended and injected through a syringe, a negligible release of Gd-DTPA-DM, and a high drug content by means of the Wurster process, a spray coating method using a spouted bed with a draft tube. They were composed of lactose cores of 53-63 microm, an undercoat of ethyl cellulose (EC) and polyvinylpyrrolidone (PVP), a drug-layer of Gd-DTPA-DM, EC and PVP, a waterproof coat and a release-sustaining overcoat of EC and cholesterol (1:1), and a surface treated with hydrogenated egg lecithin. By curing at 110 degrees C for 30 min after mixing with 20% pulverized mannitol powder, the 20% overcoating suppressed the release of Gd-DTPA-DM from 75-106 microm microcapsules to less than 10% for the first 20 min, which was the period required to prepare a suspension, inject it and irradiate the neutron. The microcapsules could be used to confirm that the intracellular presence of Gd is not critical in gadolinium neutron-capture therapy.

Cellulose↗
PubMed1993

Purification and characterization of recombinant human macrophage colony-stimulating factor expressed in Chinese hamster ovary cells.

We expressed human macrophage colony-stimulating factor (M-CSF) in Chinese hamster ovary (CHO) cells by introducing an expression plasmid coding for a 554-amino-acid M-CSF precursor and dihydrofolate reductase (DHFR) gene, and by amplifying the sequence. A cell line was obtained that secreted approximately 200,000 units/ml after 6 days in culture. The expressed recombinant human M-CSF (rhM-CSF) primarily consisted of two molecular species, a main 80-90 kD M-CSF as a homodimer and a molecular form higher than 150 kD. Purification of a main rhM-CSF gave an apparently homogeneous protein disulfide-bonded from 42-kD subunits, but one of the purified rhM-CSFs was composed of two subunit species with molecular masses of 44 and 42 kD. These purified rhM-CSFs had substantially the same specific activity (1 to 4 x 10(7) units/mg protein). Deglycosylation experiments with the latter rhM-CSF using chemical (trifluoromethanesulfonic acid) and enzymatic methods found a terminal neuraminic acid in addition to N- and O-glycosylation, but the two subunit species did not coalesce into a single molecule.

Amino Acid Sequence↗
PubMed1993

Determination of alpha-tocopherol stereoisomers in biological specimens using chiral phase high-performance liquid chromatography.

The alpha-tocopherol stereoisomers in biological specimens were investigated using high-performance liquid chromatography. All-rac-alpha-Toc acetate was separated into four peaks (peak area ratio: 4:2:1:1) by Chiralpak OP(+)HPLC. 2R-isomers constituted the first peak and 2S-isomers were separated into three peaks (peak area ratio: 2:1:1). 2-Ambo-alpha-Toc acetate was completely separated into RRR- and SRR-alpha-Toc acetate by this method. The present HPLC method was used for the separation of all-rac-alpha-Toc in blood and tissues of rat. The analytical recoveries of RRR- and SRR-alpha-Toc acetate added to blood and tissues were 90.5-98.2% for RRR-alpha-Toc and 93.7-100.5% for SRR-alpha-Toc. The distribution of alpha-Toc stereoisomers in the blood and tissues from rats administered all-rac-alpha-Toc acetate was investigated by HPLC. The concentrations of the 2R-isomers in the blood and tissues were markedly higher than the concentrations of the 2S-isomers, and the levels of alpha-Toc stereoisomers showed marked differences between blood and tissues.

Animals↗
PubMed1993

Evaluation of the conjugate between N4-(4-carboxybutyryl)-1-beta-D-arabinofuranosylcytosine and chitosan as a macromolecular prodrug of 1-beta-D-arabinofuranosylcytosine.

The conjugate of N4-(4-carboxybutyryl)-1-beta-D-arabinofuranosylcytosine (glu-ara-C) with chitosan, named chi-glu-ara-C, was prepared and evaluated on its utility as a macromolecular prodrug. 1-beta-D-Arabinofuranosylcytosine (ara-C) was predominantly regenerated gradually from chi-glu-ara-C in 1/15 M phosphate buffer, pH 7.4, at 37 degrees C, and its amount after 7 d incubation was 56% (w/w). The antitumor effect was evaluated by an increase in the lifespan (ILS) of the mice bearing P388 leukemia at the single administration at 24 h after inoculation. Ara-C exhibited an ILS of 3.4% at a dose of 100 mg/kg, and the survival time was not significantly different from that of the control. However, chi-glu-ara-C showed an ILS of 60.7% at a dose of 88 mg eq ara-C/kg, and the survival time was significantly different from that of the control. Chitosan and chi-glu-ara-C were observed to cause the side effects judged from the body weight loss to a certain extent. However, chi-glu-ara-C was recognized to be useful because of its effectiveness.

Animals↗
PubMed1993

[Effect of extended thymectomy in myasthenia gravis of pure ocular type].

The effect of extended thymectomy in myasthenia gravis of pure ocular type was investigated in 13 patients, who were divided into the surgical group of nine and the conservative group of four. In the surgical group, the onset was at 47 +/- 20 years old. The preoperative duration of symptoms was 4 +/- 6 years. The age at the time of operation was 51 +/- 16 years old. Three patients had thymomas, including one malignant thymoma. Acetylcholine receptor antibody titer was over normal range with 34.0 +/- 49.7 nmol/l. No postoperative crisis occurred. The palliation rate of the surgical group was more higher through the whole period than that of the conservative group, and increased with progress of the course. The remission occurred in the surgical group, but did not in the conservative group. It took 7 months to improve the symptom in the surgical group, while 18 months in the conservative group. We conclude extended thymectomy is reasonable for patients with myasthenia gravis of pure ocular type.

Adult↗
PubMed1993

[Surgical treatment of elderly patients with primary lung cancer].

Fourteen patients with lung cancer over the age of 70 years had the standard operation with mediastinal lymph node dissection. Their postoperative complications and prognoses were compared with those of 47 patients under the age of 70 years with the same operation. The propriety of the standard operation with mediastinal lymph node dissection for lung cancer in elderly patients was studied. A program of respiratory training was arranged preoperatively for the patients. Preoperative complications was more common in elderly than in younger patients, but postoperative complications were less frequent. The prognosis in elderly patients was also satisfactory. We conclude that the standard operation with mediastinal lymph node dissection for lung cancer can be performed as well in elderly as in younger patients.

Adult↗
PubMed1993

[Cor triatriatum with situs inversus totalis: a case report of an infant].

Cor triatriatum associated with situs inversus is rare. A 6-month-old male who had cor triatriatum with atrial septal defect (ASD) and situs inversus totalis was successfully operated. Urgent surgical intervention was performed because of congestive cardiac failure despite drug therapy. The abnormal septum in the left atrium was resected and ASD was closed. His postoperative course has been uneventful.

Cardiac Catheterization↗
PubMed1993

[Physical mapping of human chromosomes with linking clones and jumping clones].

Physical maps facilitate the correlation of genetic linkage maps and actual genome structure, and contribute to the immediate access to disease genes in question. The introduction of pulsed-field gel electrophoresis (PFGE) made it possible to construct restriction maps in Mb order with rare-cutting enzymes. Linking clones and jumping clones are useful tools for constructing long-range and accurate maps. The linking clones are used to identify adjacent restriction fragments and the jumping clones are to identify neighboring restriction sites. The general strategy for physical mapping using these clones and our application to NotI restriction mapping of human chromosome 21 are described.

Animals↗
PubMed1993

[Clinical application of recombinant human SOD for the protection of ischemia reperfusion injury during open heart surgery].

We have applied recombinant human superoxide dismutase (RH-SOD) to prevent ischemia reperfusion injury in the patients who received open heart surgery. Twenty-four patients were divided into 2 groups; group A had no treatment as control and group B received bolus injection of RH-SOD (35,000 IU/kg) into cardiopulmonary bypass 5 minutes before reperfusion. Arterial and coronary sinus blood was collected to measure chemiluminescence (ChL) value, SOD activity, lactate and pyruvate level, and several parameters of myocardial oxygen metabolism after reperfusion. Arterio-venous difference of ChL value showed the tendency of less ChL generation of the heart in group B compared with those in group A. But no other parameters showed significant difference between the two groups. Our data suggested that this way of the administration of RH-SOD failed to improve the myocardial protection during open heart surgery. Further investigation, such as dose response study, might be required to determine whether RH-SOD possess beneficial effects or not in the clinical setting.

Heart Arrest, Induced↗