[A case of pneumatosis cystoides intestinalis associated with pulmonary fibrosis].
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
K Ohyama
Publications and source records attributed to K Ohyama.
Active transcription of the pseudogene for subunit 7 of the NADH dehydrogenase in Marchantia polymorpha mitochondria.
A pseudogene, psi nad7, which has significant sequence similarity (66.7% amino acid identity) with the bovine nuclear gene for a 49 kDa subunit of the NADH dehydrogenase (NADH:ubiquinone oxidoreductase, EC 1.6.99.3), has been identified on the mitochondrial genome of the liverwort Marchantia polymorpha. The predicted coding region, which includes six termination codons, is actively transcribed into RNA molecules of 16 and 9.6 kb in length, but RNA splicing products were not detected in the liverwort mitochondria. Genomic DNA blot analysis and RNA blot analysis using poly(A)+ RNA suggest that a structurally related nuclear gene encodes the mitochondrial ND7 polypeptide. These results imply that this psi nad7 is a relic of a gene transfer event from the mitochondrial genome into the nuclear genome during mitochondrial evolution in M. polymorpha.
Amino Acid Sequence↗
Mutagenesis and the molecular modeling of the rat angiotensin II receptor (AT1).
The molecular interaction involved in the ligand binding of the rat angiotensin II receptor (AT1A) was studied by site-directed mutagenesis and receptor model building. The three-dimensional structure of AT1A was constructed on the basis of a multiple amino acid sequence alignment of seven transmembrane domain receptors and angiotensin II receptors and after the beta 2 adrenergic receptor model built on the template of the bacteriorhodopsin structure. These data indicated that there are conserved residues that are actively involved in the receptor-ligand interaction. Eleven conserved residues in AT1, His166, Arg167, Glu173, His183, Glu185, Lys199, Trp253, His256, Phe259, Thr260, and Asp263, were targeted individually for site-directed mutation to Ala. Using COS-7 cells transiently expressing these mutated receptors, we found that the binding of angiotensin II was not affected in three of the mutations in the second extracellular loop, whereas the ligand binding affinity was greatly reduced in mutants Lys199-->Ala, Trp253-->Ala, Phe259-->Ala, Asp263-->Ala, and Arg167-->Ala. These amino acid residues appeared to provide binding sites for Ang II. The molecular modeling provided useful structural information for the peptide hormone receptor AT1A. Binding of EXP985, a nonpeptide angiotensin II antagonist, was found to be involved with Arg167 but not Lys199.
Amino Acid Sequence↗
Disulfide bridges in extracellular domains of angiotensin II receptor type IA.
Angiotensin II receptor type IA (AT1A) has a cysteine (Cys) residue in each of four extracellular domains, and these Cys residues are believed to form two disulfide bridges. However, the question as to which pairs of Cys residues form disulfide bridges have not been experimentally determined. We constructed four mutants of rat AT1A, in which extracellular Cys residues were individually replaced by glycine (mutant C-1, C-2, C-3 and C-4). Further, we constructed two double mutants, in which two extracellular Cys residues were simultaneously substituted for by glycine. The binding affinity for angiotensin II in a double mutant C-1 + 4 (Cys18,274Gly) was similar to that in individually substituted mutants (C-1, C-2, C-3 and C-4) whereas the ligand binding of a double mutant C-2 + 4 (Cys101,274Gly) was completely abolished. The bindings of the non-peptide AT1A antagonist [125I]EXP-985 to mutants C-1, C-4 and C-1 + 4 were only slightly reduced whereas in mutant C-2, C-3 and C-2 + 4 the specific binding for [125I]EXP-985 was completely abolished. These results suggest that disulfide bridges in AT1A are formed between Cys18 and Cys274, and between Cys101 and Cys180, and the latter disulfide bond is essential for the binding of the non-peptidic antagonists [125I]EXP-985 or losartan.
Angiotensin II↗
Migration of dopaminergic neurons in the embryonic mesencephalon of mice.
Migration of dopamine (DA)-containing neurons and its guiding cues were histologically examined in the embryonic mesencephalon of normal mice. Cells immunoreactive (ir) for tyrosine hydroxylase (TH), a DA-synthesizing enzyme, were first detected on embryonic day 10 (E10) in the medio-basal part of the mesencephalon and were distributed throughout the entire length of the ventral mesencephalic wall at E12. By E14, TH-ir cells were located laterally along the ventral pial surface to form the primordia of the substantia nigra. Experiments with a single injection of bromodeoxyuridine, a thymidine analog, demonstrated that cells generated in the ventricular surface of the ventral mesencephalon at E11 migrated ventrally and then moved laterally to form the substantia nigra and the ventral tegmental area. Electron microscopic examination of the ventral mesencephalon of E12 mice disclosed that in the dorsal part ventrally migrating immature neurons made close contacts with the processes of radial glial cells. The expression of tenascin was transiently seen on radial glial processes between E10 and E13 coincident with the period of the ventral migration of mesencephalic DA neurons. By double immunostaining of E13 mesencephalon, ventrally migrating TH-ir cells were seen to be apposed to tenascin-bearing radial glial processes. On the other hand, laterally migrating neurons in the basal part of the mesencephalon were observed by electron microscopy to contact with tangentially arranged nerve fibers which were immunopositive for the 160 kDa neurofilament polypeptide at the light microscopic level from E10. Double immunostaining of E13 mesencephalon demonstrated that laterally migrating TH-ir cells were intermingled among neurofilament-ir fiber bundles. The cells of origin of the tangential nerve fibers were detected in the lateral part of the mesencephalon, when a fluorescent dye, 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) was injected into the basal part of the mesencephalon of fixed E12 mice. The present results suggest that guiding cues of the radial migration of mesencephalic DA neurons represent processes of radial glial cells which express tenascin. On the other hand, tangentially arranged nerve fibers originating from the lateral part of the mesencephalon may provide a scaffolding along which the mesencephalic DA neurons subsequently migrate laterally to form the ventral tegmental area and the substantia nigra.
Animals↗
Cloning, expression and regulation of angiotensin II receptors.
Complementary DNAs for angiotensin II type 1 receptor isoforms AT1A and AT1B were cloned by expression cloning from bovine adrenal and rat vascular smooth muscles. Human AT1 receptor was also cloned. Seven transmembrane structures emerged. The AT1 type receptor interacted with more than one type of G-proteins. The ligand binding site of AT1 involving Arg167, Lys199, and Asp263 has been identified by site directed mutagenesis. The regulation of the receptors occur at many stages. The isoform, AT2, was also expression cloned from rat pheochromocytoma cells. Although its ligand binding is not affected by stable GTP analogs, it is a seven transmembrane domain receptor. It mediates the modulations of phosphotyrosine phosphatase by angiotensin II and AT2 specific CGP42112A. The modulation was abolished by pertussis toxin. Thus, AT2 belongs to a new class of angiotensin receptors with unique signalling and regulatory mechanisms. AT1 mediates cellular growth. Interestingly, AT2 expression is inversely related to the mitogenic activity of cells.
Amino Acid Sequence↗
Presence of Vicia graminea lectin- or Vicia unijuga lectin-binding (Vgu) glycoproteins, Vgu glycoproteins with Thomsen-Friedenreich (T) activity and T-active glycoproteins in human meconium.
Perchloric acid-soluble fraction prepared from a mixture of meconiums of 22 newborn babies was subjected to a systematic affinity chromatography using Vicia unijuga lectin-Cellulofine column and Arachis hypogaea lectin-Agarose column and separated into four fractions, Vgu glycoprotein, Vgu glycoprotein with T activity, T-active glycoprotein and another glycoprotein fractions. HPLC analysis showed that the first fraction contained three glycoproteins with molecular weight (Mw) of about 19,400 kDa, 5500 kDa and 1900 kDa, the second fraction consisted of two glycoproteins with Mw of about 460 kDa and 150 kDa and the third fraction composed of several glycoproteins including the main glycoprotein with Mw of about 11,700 kDa.
Amino Acid Sequence↗
Construction of an equalized cDNA library from Arabidopsis thaliana.
Using a kinetic approach, a cDNA library composed of almost equal representations of all genes expressed in the aerial parts of 2-week-old Arabidopsis was constructed. A cDNA was synthesized with an oligo dT primer containing a Notl site. A linker containing the nucleotide sequence of Sse8387I which recognizes octanucleotides was added at the ends of the synthesized cDNA. The cDNA was amplified by the polymerase chain reaction (PCR), denatured, and reassociated under modified conditions. Thereafter, the remaining single-stranded DNA was converted to double-stranded DNA and amplified by PCR. These equalization steps were repeated three times and the products were cloned unidirectionally into a plasmid vector. Equalization was evaluated by colony hybridization and DNA sequencing. This approach will be applicable to construct a cDNA library suitable for subtraction, differential screening, and expression screening, especially for mRNA species present at very low concentrations in a few cells of a specific tissue.
Arabidopsis↗
Effects of growth hormone and insulin-like growth factor I on testosterone secretion in premature male rats.
Present study was planned to clarify the effects of GH and insulin-like growth factor I (IGF-I) on testosterone secretion using premature male rats. Forty rats were divided four groups. GH, IGF-I, both of them or normal saline solution as control were subcutaneously administered to the rats of each group for seven days from 3-week to 4-week of age. After the treatment, six of each group were used to human chorionic gonadotropin (hCG) loading and four to Leydig cell preparation. Serum testosterone responses to hCG loading were significantly higher in 4-week-old rats treated with GH and/or IGF-I for 1 week than in control rats. However, the responses were similar among three treated groups (GH, IGF-I and both). After one-week treatment with GH and/or IGF-I, isolated Leydig cells were prepared from testes of 4-week-old rats and testosterone production by the stimulation of hCG was examined. Amounts of testosterone production stimulated by hCG were significantly greater in the treated rats than in control rats. These findings suggest that GH mediated by IGF-I promotes the testicular responsiveness to gonadotropin on testosterone production in premature rats.
Analysis of Variance↗
[Subdural abscess following chronic subdural hematoma].
This is a report of subdural abscess following chronic subdural hematoma. An 86-year-old male was admitted to our hospital due to drowsiness and left hemiparesis. He had been suffering from a spike fever which originated during chronic cholecystitis and cholelithiasis and which had continued since 2 years prior to admission. On admission, CT scans revealed right chronic subdural hematoma, and the collection of a few old hematomas was suspected in the left subdural space. An emergency removal of the right hematoma was carried out by using right single burr hole. It was found that the old hematoma accompanied a yellow-white abscess in the subdural space. Escherichia coli were detected from a bacterial culture of the abscess. Postoperative enhanced MRI clearly showed the capsule of the right subdural abscess, and the left chronic subdural hematoma. Removal of the left hematoma was performed by using a left single burr hole. But the abscess did not exist in the left subdural space, and only old hematomas had collected there. The bacterial culture of the left old hematoma was negative. Escherichia coli might be implanted on the capsule of the right chronic subdural hematoma by bacteremia derived from chronic cholecystitis. It was considered that the formation of the subdural abscess might have developed through the deterioration of the immunological function under the influence of senility.
Aged↗
Expression of trkC in a mouse osteoblastic cell line and its response to neurotrophin-3.
In a cultured osteoblastic cell line, MC3T3-E1 derived from newborn mouse calvaria, the mRNA encoding TRKC, which is the receptor molecule of neurotrophin-3 (NT-3), was detected by the polymerase chain reaction (PCR) method. The mRNAs of the normal type and one alternative form (C14) were highly expressed in the exponential growth phase of MC3T3-E1 cells and decreased as the cells reached the differentiation stage. NT-3, but not nerve growth factor (NGF), stimulated the proliferation of MC3T3-E1 cells in a dose-dependent manner. NT-3 also stimulated calcium incorporation through the surface of MC3T3-E1 cells, indicating the association of NT-3 and its receptor on the cell surface.
Animals↗
Role of carboxyl tail of the rat angiotensin II type 1A receptor in agonist-induced internalization of the receptor.
Binding of angiotensin II (Ang II) to its receptor type 1A (AT1A) is known to trigger its internalization. We studied the role of cytosolic segments of AT1A in the internalization, and obtained results indicating a functional role of the cytosolic carboxyl terminal tail of AT1A in the internalization. Deletion of 50 amino acids from the carboxyl terminus abolished the receptor internalization. Deletion mutants lacking 13 and 32 amino acid residues in the carboxyl terminal cytosolic region were internalized to the same extent as wild type AT1A; however, internalization of a mutant lacking the last 42 residues was partially suppressed. Thus, residues 310 through 327 were shown to be essential for the internalization. We propose that a short domain in the cytoplasmic tail (residues 310 to 327) may play a dominant role in the agonist-induced receptor internalization of AT1A. Our results also suggest that the molecular determinants of the AT1A receptor involved in receptor internalization are distinct from those participating in the desensitization process.
Amino Acid Sequence↗
Genetic analysis of HIV-1 during rapid progression to AIDS in an apparently healthy man.
We encountered a case of HIV-1 infection in a previously healthy man, which was characterized by rapid progression to AIDS and death within 7 months in association with high levels of antigenemia throughout the clinical course and no humoral immune response for at least 6 months. Genetic changes of the third variable domain (V3) of the envelope gene of HIV-1 in serum samples were analyzed at four time points during his rapid clinical course. The nucleotide changes were confined to a maximum of three substitutions among 105 nucleotides of the V3 region. A major population of the viral clones in this patient showed one amino acid substitution from aspartic acid (a negatively charged amino acid) to lysine (a positively charged amino acid) at position 30 from the first cysteine of the V3 loop. This substitution was thought to be associated with phenotypic changes, and viruses with this sequence in the V3 region had a strong syncytium-inducing ability in MT-4 cells. It appears that the lack of a humoral immune response accelerated disease progression in our patient and a genetic change that appeared to produce a phenotypic change occurred at an early stage of the disease.
Acquired Immunodeficiency Syndrome↗
Cloning, expression and regulation of angiotensin II receptors.
Angiotensin II isoform 1 (AT1) receptor cDNAs were cloned by expression cloning from bovine adrenal and rat vascular smooth muscles. Human AT1 receptor was also cloned. Seven transmembrane structures emerged. A single type of receptor seems to interact with more than one type of G-protein. AT1 consists of subtypes AT1A and AT1B, and the regulation of the receptors occurs at many stages. The isoform AT2 was also expression cloned from rat pheochromocytoma cells. Although its ligand binding is not affected by GTP analogs, it is a seven transmembrane domain receptor. It mediates the inhibition of phosphotyrosine phosphatase by angiotensin II and AT2 specific CGP42112A; the inhibition was abolished by pertussis toxin. Thus, AT2 belongs to a new class of angiotensin receptors with unique signalling and regulatory mechanisms.
Amino Acid Sequence↗
Angiotensin II receptors: cloning and expression.
To identify the mechanisms of action of isoforms angiotensin II receptors (AT1A, AT1B, and AT2) and to overcome the difficulties encountered in attempts to purify the receptors, we have expression-cloned their cDNAs from bovine and rat sources and isolated human cDNA and rat and human genomic DNA. The AT1A and AT1B cDNAs were found to encode respective receptor proteins with 359 amino acid residues, whereas, AT2 encodes a 363 amino acid residue receptor protein. Both AT1 and AT2 were found to conform with the seven transmembrane receptor structural motif, but showed only 32% amino acid residue identity to each other. The AT1 receptor was shown to be coupled to, at least, three different G proteins activating phospholipase C, inhibiting adenylyl cyclase and opening an L-type Ca(2+)-channel, whereas, AT2 was found to inhibit a phosphotyrosine phosphatase activity without affecting guanylyl cyclase by a pertussis-toxin-sensitive, presumably G-protein-mediated mechanism.
Amino Acid Sequence↗
Cyclin E enhances P53-mediated transactivation.
Plasmids expressing G1 and G2 cyclins were introduced into the Saos-2 cell system monitoring p53-mediated transactivation [(1993) Oncogene 8, 543]. Cyclin E, but not other cyclins, enhanced the p53-mediated transactivation about 2-fold. Co-transfection of a CDK2 expression plasmid caused a 30% increase in the extent of the p53-mediated transactivation. Moreover, the transfected p53 protein became phosphorylated coordinately with the enhanced transactivation. The close correlation between transactivation and p53 phosphorylation suggests that phosphorylation is involved in positive regulation for the transactivation by p53.
Cells, Cultured↗
Isolation and influenza virus receptor activity of glycophorins B, C and D from human erythrocyte membranes.
(1) Glycophorins (GPs) AM, AN, B, C and D were each isolated into a high state of purity from human erythrocyte membranes by a combination of lithium diiodosalicylate (LIS)-phenol extraction, gel-filtration with Bio-Gel A1.5m and HPLC with LiChrospher 1000 TMAE. (2) GPs-B, -C and -D reacted with influenza A and B viruses as well as GPs-AM and -AN and the order of reactivities against two viruses of the glycophorins was as follows: GP-B > GP-C > GP-AM = GP-AN >> GP-D for the former virus and GP-C > GP-B > GP-AM = GP-AN >> GP-D for the latter virus.
Amino Acids↗
Group I introns in the liverwort mitochondrial genome: the gene coding for subunit 1 of cytochrome oxidase shares five intron positions with its fungal counterparts.
The complete nucleotide sequence of the mitochondrial DNA (mtDNA) from a liverwort, Marchantia polymorpha, contains thirty-two introns. Twenty-five of these introns possess the characteristic secondary structures and consensus sequences of group II introns. The remaining seven are group I introns, six of which happen to interrupt the gene coding for subunit 1 of cytochrome oxidase (cox1). Interestingly, the insertion sites of one group II and four group I introns in the cox1 gene coincide with those of the respective fungal mitochondrial interns. Moreover, comparison of the four group I introns with their fungal counterparts shows that group I introns inserted at identical genomic sites in different organisms are indeed related to one another, in terms of the peptide sequences generated from the complete or fragmental ORFs encoded by these introns. At the same time, the liverwort introns turned out to be more divergent from their fungal cognates than the latter are from one another. We therefore conclude that vertical transmission from a common ancestor organism is the simplest explanation for the presence of cognate introns in liverwort and fungal mitochondrial genomes.
Amino Acid Sequence↗