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Biomedical subjects

T Horiuchi

Publications and source records attributed to T Horiuchi.

At least 487 records · Page 27Linked to original sources
PubMed1985

[UFT, UFTM, and UFTM-Dpc treatment of gastric cancer].

It became increasingly evident that UFTM chemotherapy, a combination of UFT and mitomycin C is one of the most recommendable therapy for advanced gastric cancer, especially for the treatment of Borrmann type 4 gastric cancer. Objective responses were achieved in 18 out of 26 (69.2%) patients with Borrmann type 4 gastric cancer. Moreover, UFTM-Dpc treatment, a combination therapy of UFTM plus D-penicillamine (suppressor of collagen synthesis), is proposed for the treatment of Borrmann type 4 gastric cancer from the point of view of collagen synthesis inhibition. It is likely that D-penicillamine might inhibit the peritoneal metastatic involvements, which is lethal to the patients finally.

Aged↗
PubMed1985

[Current problems in the surgical treatment of acquired heart disease].

Despite recent progress in surgical treatment for acquired heart disease, there still remain some problems to be solved. Recently, incidence of the aged and serious cases are increasing. In order to detect the limitation of surgical indication for these cases, a multivariate analysis for prediction of low cardiac output syndrome (LOS) after prosthetic valve replacement was performed. Variables with significant relationship to LOS were different from the types of disease and it seemed difficult to decide indication from single factor such as age or cardiac function alone. Mechanical assist for the postoperative failing heart was carried out for 45 cases. Of these 45, 3 cases underwent clinical application of partial artificial heart (PAH). Two cases weaned from PAH and there was one long-term survival. Duration of cardiac assist in one case who did not wean from PAH was as long as 70 days. Incidence of re-replacement of prosthetic valve due to malfunction was higher in recent 5 years when compared to that in former years. Incidence and type of malfunction of prosthetic valve were different according to the types of prosthesis. Survival and event-free rates in long-term follow-up period were markedly embellished by the types of prosthesis.

Aged↗
PubMed1984

Reduction by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a calmodulin antagonist, in the number of phorbol ester receptors in mouse skin.

A calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7), reduced the number of phorbol ester receptors in mouse skin in a dose- and time-dependent manner. The reduction occurred immediately after topical application of 30 mumoles of W-7, reaching a maximum of 86% after 5 min. Reduction in specific binding of 12-O-tetra-decanoylphorbol-13-acetate can explain the antitumor promoting activity of W-7 in mouse skin.

Animals↗
PubMed1984

Control of cell division by sex factor F in Escherichia coli. I. The 42.84-43.6 F segment couples cell division of the host bacteria with replication of plasmid DNA.

The F plasmid of Escherichia coli was used to study the genetic background of the control circuit in the bacteria that co-ordinates DNA replication and cell division of the host cells. When DNA replication of the F plasmid was blocked by growing cells carrying an amber-suppressible replication-defective F plasmid mutant under restrictive conditions, the cells continued to divide for about one generation until F plasmid was supposedly diluted to one copy per cell, and then they stopped dividing and formed non-septated filamentous cells. These observations suggest that completion of a round of replication is a necessary and sufficient condition of F DNA synthesis in the cell division of F+ bacteria; i.e. cell division of the F+ bacteria is coupled with DNA replication of the F plasmid. The observation that Giemsa-stainable materials in the filamentous cells were clustered in the center indicates that partitioning of chromosomal DNA (and presumably of F plasmid DNA) is also coupled with plasmid DNA replication. The function necessary for this coupling is carried by the 42.84-43.6 F (BamHI-PstI) segment, which is located outside the region essential for replication of the F plasmid. The nucleotide sequence demonstrates the existence of two open reading frames in this region, which encode polypeptides of 72 and 101 amino acids, respectively. These two reading frames are most likely to be transcribed as a single polycistronic message in the direction from the BamHI site at 42.84 F to the PstI site at 43.6 F. The expression of this "operon" is likely to be controlled by plasmid DNA replication.

Base Sequence↗
PubMed1984

Control of cell division by sex factor F in Escherichia coli. II. Identification of genes for inhibitor protein and trigger protein on the 42.84-43.6 F segment.

The genetic structure of the 42.84-43.6 F (BamHI-PstI) segment of the F plasmid, which contains all the F DNA sequences necessary for coupling cell division of F+ bacteria with plasmid DNA replication, was analyzed by isolating a series of amber mutants. Two cistrons were found in this region and they were designated letA and letD (an abbreviation for lethal mutation). The letA and letD cistrons were mapped on the 42.84-43.35 F (BamHI- XmaI ) segment and the 43.07-43.6 F (HincII-PstI) segment, respectively, and are presumed to correspond to the first (43.04-43.26 F) and second (43.26-43.57 F) open reading frames, respectively, which were found in this region by nucleotide sequencing. The letD gene product acts to inhibit cell division of the host bacteria and to induce prophages in lysogenic bacteria, whereas the letA gene product acts to suppress the activity of the letD gene product. Taking into consideration the fact that the 42.84-43.6 F segment carries all the F plasmid genes necessary for coupling cell division with plasmid DNA replication, and that the expression of the genes is likely to be controlled by plasmid DNA replication, we constructed the following hypothesis. Before completion of plasmid DNA replication, LetD protein acts to prevent cell division of the host bacteria. When plasmid DNA replication is completed, synthesis of LetA protein (and also LetD protein) takes place and the LetA protein synthesized acts to suppress the activity of LetD protein and make the cell ready for cell division. Actual cell division will take place when replication of both chromosomal and plasmid DNA is completed and the termination protein of the chromosome and the LetA protein of F plasmid are both synthesized. When cell division takes place LetA protein is consumed, and as a result LetD protein becomes active and prevents cell division until the next round of DNA replication is completed.

Bacteriophage lambda↗
PubMed1984

RNase H-defective mutants of Escherichia coli: a possible discriminatory role of RNase H in initiation of DNA replication.

Mutants of Escherichia coli completely deficient in RNase H activity were isolated by inserting transposon Tn3 into the structural gene for RNase H, rnh, and its promoter. These rnh- mutants exhibited the following phenotypes; (1) the mutants grew fairly normally, (2) rnh- cells could be transformed with ColE1 derivative plasmids, pBR322 and pML21, though the plasmids were relatively unstable, under non selective conditions, (3) rnh- mutations partially suppressed the temperature-sensitive phenotype of plasmid pSC301, a DNA replication initiation mutant derived from pSC101, (4) rnh- mutations suppressed the temperature-sensitive growth character of dnaAts mutant, (5) rnh- cells showed continued DNA synthesis in the presence of chloramphenicol (stable DNA replication). Based on these findings we propose a model for a role of RNase H in the initiation of chromosomal DNA replication. We suggest that two types of RNA primers for initiation of DNA replication are synthesized in a dnaA/oriC-dependent and -independent manner and that only the dnaA/oriC-dependent primer is involved in the normal DNA replication since the dnaA/oriC independent primer is selectively degraded by RNase H.

DNA Replication↗
PubMed1984

DNA sequence of an amber replication mutant indicates that a 29 kd protein is the product of the F plasmid replication gene.

DNA sequencing shows that the mutational alteration resulting from an amber-suppressible replication-defective mutation of F plasmid is a single base pair change from C:G to T:A which yields an amber codon in the coding frame for a 29 kd polypeptide located in the minimal replication region. We thus identified the gene indispensable for F DNA replication as the coding frame which encodes a 29 kd polypeptide. We will designate this gene repA.

Base Sequence↗
PubMed1984

Intercellular junctions in odontoblasts of the rat incisor studied with freeze-fracture.

The morphology and distribution of various types of intercellular junctions were investigated in young odontoblasts. Gap junctions were found between odontoblasts as well as between odontoblasts and fibroblasts in the dental pulp. The junctions between odontoblasts were larger and more numerous than those between odontoblast and fibroblast, suggesting that the former may play an important role in regulating cellular activity and the latter may provide a pathway of low electrical resistance between odontoblast and nerve fibres. Irregularly-shaped gap junctions appeared as small aggregations of particles associated with a particle-free area and may indicate that the junction might not yet have been completely assembled. Tight junctions were observed at the distal ends of the young odontoblasts, arranged to form small maculae or faciae occludentes rather than belt-like zonulae. It is therefore not likely that the junction contributes to barrier function in the young odontoblasts. Although structures resembling typical desmosome were recognizable, this type of junction in odontoblasts is properly termed a desmosome-like junction from its morphological peculiarities.

Animals↗
PubMed1984

Immunologic characterization of plasma glucagon components in a patient with malignant glucagonoma.

Plasma immunoreactive glucagon (IRG) components were analyzed by gel filtration on either a Bio-Gel P-30 or a Sephadex G-150 column (1.0 X 68 cm) in a 47-year-old male with biopsy-proven malignant glucagonoma. Plasma samples were obtained before and after 20 courses of streptozotocin treatment as well as after administration of a somatostatin-derivative (SRIF-D, 0.38 mg, subcutaneous), regular insulin (0.2 U/kg, intravenous), and secretin (2 U/kg, intravenous). The fractions from the columns were assayed for IRG by simultaneous radioimmunoassay with C-terminal (Unger 30 K) and N-terminal (OAL 196) antibodies to glucagon. Four IRG components were observed. The largest had a molecular weight of approximately 150,000 daltons and cross-reacted much more strongly with the N-terminal antibody than with the C-terminal. The second IRG component appeared to be about 9000 daltons and cross-reacted more strongly with the N-terminal antibody. The third and major IRG component comprised 51.8% to 88.1% of the total IRG as measured with C-terminal antibody, corresponded in molecular weight to synthetic 3500 dalton glucagon, and reacted roughly equally with each of the two antibodies. The fourth IRG component cross-reacted only with N-terminal antibody and appeared to be smaller than 3500 daltons. The plasma IRG level decreased from 8829 pg/mL to 1421 pg/mL (averages of five consecutive determinations) after 20 courses of treatment with streptozotocin with significant clinical improvement. A marked (74%) but transient decrease in plasma IRG was observed after the SRIF-D injection, whereas secretion and insulin caused increases in plasma IRG level of 53% and 22%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma, Islet Cell↗
PubMed1984

Sensitive induction of chromosome aberrations in the in vivo liver cells of rats by N-nitrosodiethylamine.

The in vivo induction of chromosome aberrations has been studied in the liver cells of rats exposed to N-nitrosodiethylamine (DEN). Rats were treated with DEN before or after partial hepatectomy. For chromosome analysis, liver cells were isolated by a collagenase digesting procedure. In both treatment schedules, DEN caused significant and dose-dependent chromosome structural aberrations at dose levels as low as 0.5-4.0 mg/kg which are comparable to the range employed in lifetime carcinogenicity tests. Repeated exposures to DEN increased the rates of aberrations. By the procedure described above, detection of clastogenic activities of other hepatocarcinogens will be possible.

Animals↗
PubMed1984

Ex vivo preclinical evaluation of membrane plasma separators.

Four different types of hollow-fiber membrane plasma separators, constructed of cellulose acetate, polyvinyl alcohol, polyethylene, and polymethylmethacrylate membranes, were evaluated in ex vivo dog perfusions under conditions simulating their clinical use. An arteriovenous (A-V) fistula constructed in the dogs for blood access enabled repeated access to be achieved without surgical intervention. All modules produced transient leukopenia and a reduction of platelet counts. The polymethylmethacrylate module showed minimum reductions of white blood cell counts and CH50. The early leukocyte count reduction in membrane plasmapheresis is most likely related to the magnitude of complement activation by the membrane, as is seen with hemodialysis.

Animals↗
PubMed1984

Nucleotide sequence of the phoS gene, the structural gene for the phosphate-binding protein of Escherichia coli.

phoS is the structural gene for the phosphate-binding protein, which is localized in periplasm and involved in active transport of phosphate in Escherichia coli. It is also a negative regulatory gene for the pho regulon, and the gene expression is inducible by phosphate starvation. The complete nucleotide sequence of the phoS gene was determined by the method of Maxam and Gilbert (A. M. Maxam and W. Gilbert, Methods Enzymol. 65:499-560, 1980). The amino acid sequences at the amino termini of the pre-PhoS and PhoS proteins and at the carboxy terminus of the PhoS protein were determined by using the purified proteins. Furthermore, the amino acid sequence of enzymatically digested peptide fragments of the PhoS protein was determined. The combined data established the nucleotide sequence of the coding region and the amino acid sequence of the pre-PhoS and the PhoS proteins. The pre-PhoS protein contains an extension of peptide composed of 25 amino acid residues at the amino terminus of the PhoS protein, which has the general characteristics of a signal peptide. The mature PhoS protein is composed of 321 amino acid residues, with a calculated molecular weight of 34,422, and lacks the disulfide bond and methionine. The regulatory region of phoS contains a characteristic Shine-Dalgarno sequence at an appropriate position preceding the translational initiation site, as well as three possible Pribnow boxes and one -35 sequence. the nucleotide sequence of the regulatory region of phoS was compared with those of phoA and phoE, the genes constituting the pho regulon.

Amino Acid Sequence↗