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Biomedical subjects

A Iida

Publications and source records attributed to A Iida.

At least 127 records · Page 7Linked to original sources
PubMed1991

Evidence That More than 90% of beta-Glucuronidase-Expressing Cells after Particle Bombardment Directly Receive the Foreign Gene in their Nucleus.

Plasmid DNA harboring the beta-glucuronidase (GUS) gene, coated on gold particles, was delivered into cultured tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells using a pneumatic particle gun. Cytological analyses of intracellular location of the introduced gold particles before and after GUS expression assay indicated that more than 90% of GUS-expressing cells after bombardment received a DNA-coated particle in their nucleus.

Journal Article↗
PubMed1991

Efficiency of particle-bombardment-mediated transformation is influenced by cell cycle stage in synchronized cultured cells of tobacco.

Plasmid DNA pB1221 harboring beta-glucuronidase gene was delivered to synchronized cultured tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells of different cell cycle stages by a pneumatic particle gun. The cells bombarded at M and G(2) phases gave 4 to 6 times higher transformation efficiency than those bombarded at the S and G(1) phases.

Journal Article↗
PubMed1991

Trichosporin-B-III, an alpha-aminoisobutyric acid-containing peptide, causes Ca(2+)-dependent catecholamine secretion from adrenal medullary chromaffin cells.

We examined the effect of trichosporin-B-III, an alpha-aminoisobutyric acid-containing antibiotic peptide consisting of 19 amino acid residues and a phenylalaninol, on catecholamine secretion from cultured bovine adrenal chromaffin cells. Incubation of the cells with trichosporin-B-III (3-20 microM) caused an increase in the secretion of catecholamines. The secretion induced by trichosporin-B-III at low concentrations (3 and 5 microM) was completely dependent on external Ca2+, whereas that induced by higher concentrations (10 and 20 microM) was partly independent of Ca2+. Trichosporin-B-III at low concentration (5 microM) did not increase the release of lactate dehydrogenase, a marker enzyme of cytoplasm, from the cells. In contrast, the peptide at higher concentration (10 microM) increased the release of the enzyme. Trichosporin-B-III also caused both 45Ca2+ influx into the cells and an increase in the intracellular free Ca2+ concentration. The increases in catecholamine secretion and 45Ca2+ influx behaved similarly in relation to trichosporin-B-III concentration (3-10 microM). The time courses of the increases in secretion, 45Ca2+ influx, and intracellular free Ca2+ concentration induced by trichosporin-B-III were also quite similar. Trichosporin-B-III-induced (at 5 microM) secretion was not affected by the elimination of Na+ from the incubation medium or by the addition of tetrodotoxin, a blocker of highly selective voltage-dependent Na+ channels, or hexamethonium, a blocker of nicotinic acetylcholine receptors. On the other hand, both diltiazem (2-200 microM) and nicardipine (1-200 microM), blockers of voltage-dependent Ca2+ channels, inhibited the secretion induced by trichosporin-B-III (5 microM) in a concentration-dependent manner. Trichosporin-B-III-induced (at 5 microM) secretion also was suppressed by the addition of Mn2+ (5 mM) to the medium. The diltiazem (20 microM) inhibition of trichosporin-B-III-induced (at 5 microM) secretion was reversed by increasing the external Ca2+ concentration. These results indicate that trichosporin-B-III causes the secretion of catecholamines from bovine adrenal chromaffin cells by two mechanisms, Ca2+ dependent and Ca2+ independent (only at high concentrations of trichosporin-B-III). Furthermore, these results strongly suggest that trichosporin-B-III, in Ca(2+)-dependent secretion, activates endogenous voltage-dependent Ca2+ channels, or itself forms the channels in the membranes, and induces Ca2+ influx into the cells.

Adrenal Medulla↗
PubMed1990

5-Formyldeoxyuridine: a new type of DNA damage induced by ionizing radiation and its mutagenicity to salmonella strain TA102.

An aqueous solution of calf thymus DNA was irradiated by 60Co gamma-rays and modified nucleosides produced in DNA were analyzed by high-pressure liquid chromatography coupled with a photodiode array UV detector. A new product with UV absorption maxima at 230 nm and 280 nm was observed. The structure of this compound was proposed to be 5-formyldeoxyuridine (f5dU) based on the mass spectrum of its trimethylsilyl derivative (M+, m/z472) and the structure was confirmed by chemical synthesis. The yield of f5dU (2.4/10(4) dT/krad) in DNA was of roughly the same order as that of 8-hydroxydeoxyguanosine and 5-hydroxymethyldeoxyuridine. Free f5dU was mutagenic to Salmonella typhimurium strain TA102: therefore f5dU incorporated into DNA may induce mutations.

Animals↗
PubMed1989

Spotted fever group rickettsia in dogs in Japan.

Prevalence of antibody against spotted fever group-rickettsia in dogs (14/134) from the northern part of Shikoku Island, where spotted fever group rickettsia infection in human is endemic, is significantly higher than that in dogs (4/189) from nonendemic areas.

Animals↗
PubMed1988

[Surgical treatment of metastatic lung cancer from colorectal cancers].

Based on conclusions obtained after the observation of 61 colorectal cancer patients with a lung metastasis, the resection of lung metastasis as a therapy was evaluated. Among these 61 patients, only 5 patients had been identified as having a lung metastasis at the time of resection of the primary lesion, whereas the other 56 patients developed the lung metastasis after the curative resection of the colorectal cancer. Only one patient with a synchronous lung metastasis and twelve patients (eleven with a solitary metastatic lesion and one with multiple metastatic lesions) with metachronous lung metastasis underwent removal of the lung metastasis. The three-year survival rate was 65.2% in the metachronous group.

Adult↗
PubMed1986

Gene transfer into intact plant cells by electroinjection through cell walls and membranes.

Tobacco mosaic virus (TMV) RNA was introduced directly into mesophyll cells of Nicotiana tabacum var. Samsun using electric-field pulses (electroinjection). The injected gene was successfully expressed in the recipient cells as judged by the assay for the virus coat protein using immunofluorescence and by the virus infectivity assay of the homogenate of the electroinjected cells for local lesions on tobacco leaves. As much as 50% of the cells that survived 24 days after electroinjection showed immunofluorescent specks.

Capsid↗
PubMed1986

[An ultrastructural study of the localization of alkaline phosphatase and Na-K ATPase in the labyrinth from the IUGR rat].

To elucidate the pathogenesis of intrauterine growth retardation (IUGR), the ischemic placentae produced by uterine artery and vein ligation were morphologically and histochemically investigated in rats. In the ischemic condition, fetal growth was remarkably retarded. The labyrinthi were atrophic and trophoblasts were degenerated ultrastructurally in association with mitochondrial swelling, increased microvesicles, dense bodies and fibrin deposition in the dilated intercellular spaces. Alkaline phosphatase and Na-K ATPase were localized on the plasma membrane in control rats. Na-K ATPase activity was observed in the basal side of cytotrophoblasts. However, the enzyme activities were decreased in the ischemic condition. The reaction products of horseradish peroxidase were present in the dilated intercellular spaces and increased cytoplasmic vesicles. These results suggest that in the ischemic condition, IUGR might be induced by the plasma membrane dysfunction following decreased enzyme activities and irregular distribution of horseradish peroxidase.

Alkaline Phosphatase↗
PubMed1986

[Surgical treatment of colon cancer].

The treatment of early colon cancer limited lamina propria mucosa is endoscopic polypectomy. If invasion into the submucosal layer is present, usual colectomy with regional lymph adenectomy is indicated. Colon cancer without distant metastasis is treated by colectomy with regional lymph adenectomy. Right hemicolectomy, transverse colectomy, left hemicolectomy, and sigmoidectomy are indicated according to the location of the cancer. Five years survival rate for curative resection in 96 personal cases was 80.8%. Palliative resection was available to prolong the survival time. Mean survival time after palliative resection was 14 months, but in unresectable case it was 4 months.

Colectomy↗
PubMed1985

A signal sequence mutant defective in export of ribose-binding protein and a corresponding pseudorevertant isolated without imposed selection.

Ribose-binding protein is exported to the periplasmic compartment of Escherichia coli by a process that involves proteolytic cleavage of an amino-terminal extension of amino acids from the precursor form of the protein. In a collection of mutants isolated as defective in the Rbs transport system, a strain was identified that contained only precursor ribose-binding protein, none of which was exported to its normal location in the periplasm. The mutated rbsB contained a base substitution that results in a change of leucine to a proline at position-17 in the signal sequence. A pseudorevertant of the mutant contained proteolytically processed, active ribose-binding protein in the periplasm. The pseudorevertant rbsB carried a second mutation: serine at position-15 in the signal sequence was changed to phenylalanine. Isolation of a signal sequence mutant and a corresponding pseudorevertant without specific selection or site-directed mutagenesis emphasizes the possibility of obtaining export mutants without the use of procedures that could bias or limit the range of mutations found. Explanation of the extreme phenotype of the mutant and the effective correction of that phenotype in the pseudorevertant requires extension of current notions of critical features of signal sequences.

Amino Acid Sequence↗
PubMed1984

Molecular cloning and characterization of genes required for ribose transport and utilization in Escherichia coli K-12.

We isolated spontaneous and transposon insertion mutants of Escherichia coli K-12 that were specifically defective in utilization or in high-affinity transport of D-ribose (or in both). Cotransduction studies located all of the mutations near ilv, at the same position as previously identified mutations causing defects in ribokinase ( rbsK ) or ribose transport ( rbsP ). Plasmids that complemented the rbs mutations were isolated from the collection of ColE1 hybrid plasmids constructed by Clarke and Carbon. Analysis of those plasmids as well as of fragments cloned into pBR322 and pACYC184 allowed definition of the rbs region. Products of rbs genes were identified by examination of the proteins produced in minicells containing various rbs plasmids. We identified four rbs genes: rbsB , which codes for the 29-kilodalton ribose-binding protein; rbsK , which codes for the 34-kilodalton ribokinase ; rbsA , which codes for a 50-kilodalton protein required for high-affinity transport; and rbsC , which codes for a 27-kilodalton protein likely to be a transport system component. Our studies showed that these genes are transcribed from a common promoter in the order rbsA rbsC rbsB rbsK . It appears that the high-affinity transport system for ribose consists of the three components, ribose-binding protein, the 50-kilodalton RbsA protein, and the 27-kilodalton RbsC protein, although a fourth, unidentified component could exist. Mutants defective in this transport system, but normal for ribokinase , are able to grow normally on high concentrations of the sugar, indicating that there is at least a second, low-affinity transport system for ribose in E. coli K-12.

Bacterial Proteins↗
PubMed1984

Contrast echocardiography in detection of portopulmonary venous anastomosis.

Portopulmonary venous anastomosis is a potential channel for systemic arterial embolization during embolization procedures for bleeding esophageal varices. To document the presence of such anastomoses, 15 patients with esophageal varices were studied by real-time contrast echocardiography combined with transhepatic cineportography. Cinefluorographic technique, which was applied for this purpose, occasionally failed to demonstrate the dynamic events in the left atrium because of rapid dilution of contrast medium. Echocardiography after the injection of dextrose solution into the gastric coronary vein allowed two-dimensional real-time images of contrast echoes in the left cardiac chambers. By combining these two methods, more reliable diagnostic information was obtained in five of the 15 patients studied.

Adult↗