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Biomedical subjects

R Ito

Publications and source records attributed to R Ito.

At least 127 records · Page 7Linked to original sources
PubMed1986

RNA polymerase II transcription terminates at a specific DNA sequence in a HeLa cell-free reaction.

Recently, we identified a specific DNA sequence from the gastrin gene that regulates RNA polymerase II transcription termination in vivo. In the studies presented here, we examined the processing and termination activity of this sequence in vitro. When present in an in vitro synthesized RNA, this sequence (U9A2U5AU4AU4AU5) does not serve as an RNA processing signal on incubation with HeLa whole-cell extract. However, transcription of template DNA in HeLa whole-cell extract does terminate near the 5' end of this sequence. Nuclease S1 and exonuclease VII mapping of the 3' region of the in vitro synthesized RNAs confirm these results. The termination activity of the sequence A9T2A5TA4TA4TA5 is independent of the distance from the promoter and of the nature of the DNA template (linear vs. circular). The termination activity of the sequence shows a strong orientation dependence. These results strongly suggest that the termination activity of this cis-acting element is modulated by a trans-acting cellular factor. The unique structural feature of this sequence, a 10.5-base-pair inverted repeat, may determine the specificity of interaction of the trans-acting factor with the cis-acting element, resulting in accurate termination of transcription.

Adenine Nucleotides↗
PubMed1986

A specific DNA sequence controls termination of transcription in the gastrin gene.

We located and characterized a downstream transcriptional regulatory element in the human gastrin gene by transferring the gastrin gene 3' fragment, from which the polyadenylation signal sequence was deleted, into the shuttle vector pSCAT10 at a site located immediately downstream from the chloramphenicol acetyltransferase (CAT) gene and upstream from the simian virus 40 polyadenylation region. Study of CAT RNA derived from the hybrid plasmids, indicated regulation of transcription on the gastrin gene fragment. Analysis of deletion mutants generated from the 5' region of the fragment by CAT assay and by S1 nuclease mapping of mRNAs indicated the possible involvement of an oligothymidylate-rich sequence in transcription regulation. Mapping of gastrin gene RNA 3' ends to the 5' side proximal to the oligothymidylate-rich sequence clearly demonstrated that this sequence is a transcriptional terminator element. This unique sequence, interspersed with one or two adenines, which also functions in an orientation-dependent manner, is located 192 nucleotides downstream from the gastrin gene polyadenylation site, and serves as a transcriptional termination signal.

Acetyltransferases↗
PubMed1986

A new expression of pharmacological activity, ET63.

We studied the response time of drugs in relation to the feedback mechanism in animals. The time from drug administration to onset of loss and recovery of righting reflex or death by hexobarbital in mice were measured at several dose levels and it was demonstrate that in every case the time (t)- response rate (R) function could be expressed as: (formula: see text) These parameters could be obtain by use of only a small number of animals at every dose level. The result suggests that the pharmacological activity of not only pure drugs but also of commercial chemicals with fixed standard of purity and concentrations may be expressed by the parameter t63 transposed as ET63. t63: time when cummulative response rate reaches 63%. t1: latency.

Animals↗
PubMed1985

Expression of srnB gene of F plasmid by altered RNA polymerase in Escherichia coli.

Degradation of otherwise stable rRNA and tRNA takes place in the presence of rifampin, dependent on the F plasmid srnB gene. We have reported that a protein newly synthesized in the presence of rifampin might be a product of the srnB gene required for stable RNA degradation (Ito, R. and Ohnishi, Y. (1983) Biochim. Biophys. Acta 739, 27-34). Here we have further studied the mechanism of srnB expression. Among eighteen mutants with altered RNA polymerase, two (TJ2470 (rpoC4) and TJ302 (rpoC56)) showed RNA degradation at high temperature (42 degrees C) when the srnB gene was present. Labeling proteins at 42 degrees C in strain TJ2470 indicated that a protein of molecular weight 12 000 was a product of the srnB gene, and that expression of the srnB gene provoked RNA degradation. Using plasmid pTK4, in which the srnB gene is inserted downstream of the promoter of lacZ, lac promoter-dependent expression of the srnB gene, with production of the putative protein product, also induced RNA degradation at 42 degrees C, with no requirement for added rifampin or altered RNA polymerase. RNA degradation in these conditions was quite similar to that in the case of the addition of rifampin; e.g., it showed some responses to Mg2+, temperature and RNAase I content of the cells. Expression of the srnB gene dependent on lac promoter was also observed in minicells. Thus, it is inferred that the srnB gene is probably repressed under normal conditions with its own promoter; its expression initiates RNA turnover.

Bacterial Proteins↗
PubMed1985

The Technicon RA-1000 evaluated for measuring sodium, potassium, chloride, and carbon dioxide.

We evaluated the Technicon RA-1000 "random-access" analyzer for the measurements of sodium, potassium, and carbon dioxide by an indirect potentiometric method (ion-selective electrode) and for chloride by a colorimetric method (mercuric thiocyanate). For various concentrations of control materials the total precision (CV) ranged from 0.9 to 1.2% for sodium, 1.1 to 1.3% for potassium, 1.0 to 1.2% for chloride, and 2.8 to 3.8% for carbon dioxide. The system demonstrated acceptable performance in linearity and carryover. Patients' results from the RA-1000 correlated well with those from the Beckman ASTRA-8. In a study on potential interferences, we found that high concentrations of salicylate and bromide significantly affected measurements of carbon dioxide and chloride, respectively. The RA-1000 requires only 30 microL of sample for all four tests and it offers a high throughout (30 specimens analyzed for the four tests in 25 min). This precise, easy-to-use, random-access analyzer requires minimal maintenance.

Autoanalysis↗
PubMed1985

[Clinical evaluation of sisomicin following intravenous drip infusion in respiratory tract infections].

The efficacy, safety and utility of sisomicin (SISO) followed intravenous infusion were evaluated in 35 cases with various respiratory infections. For many cases, SISO was given at a daily dosage of 100 mg, and a single dose was infused over about 1 hour. Clinical efficacy was evaluable in 28 cases including pneumonia (14 cases), bronchitis (8 cases), bronchiectasis (4 cases), pulmonary suppuration (1 case) and pulmonary abscess plus pyothorax (1 case). Almost cases had diagnosis of serious infection associated with various diseases. Clinical efficacy was evaluated as "excellent" in 2 cases, "good" in 15 cases, "fair" in 5 cases and "poor" in 6 cases, and efficacy rate in total case was 60.7%. Efficacy rate stratified by disease was calculated as 57.1% in pneumonia, 87.5% in bronchitis, 50.0% in bronchiectasis. Responses against pulmonary suppuration or pulmonary abscess with pyothorax were little or not. Bacteriologically, organisms isolated from sputum cleared in 7 out of 15 evaluable cases, thus the responses rate was 46.7%. Adverse reaction probably due to treatment observed in 2 cases with hepatic dysfunction. Blood levels of SISO at the end of infusion were ranged from 2.1 to 6.4 micrograms/ml, and no tendency of accumulation in blood after repeated infusion was showed.

Adolescent↗
PubMed1984

Development of the axon cap neuropil of the Mauthner cell in the goldfish.

Development of the axon cap neuropil of the Mauthner neuron in post-hatching larval goldfish brains was observed electron-microscopically. The axonal initial segment of newly hatched (day-4) larvae is completely covered with synaptic terminals containing clear spherical synaptic vesicles. Profiles of thin terminal axons, the spiral fibers, containing similar synaptic vesicles, rapidly increase in number around the initial segment and form glomerular neuropil similar to the central core of the adult axon cap by day 7. Three types of synapses are formed in the core neuropil. Bouton-type synapses contacting the initial segment are most abundant in day-4 to -14 larvae; they decrease thereafter and are rare on the distal half of the initial segment of day-40 larvae. Asymmetric axo-axonic synapses are commonly observed between spiral fibers in the core neuropil of day-7 to -19 larvae, but become fewer by day 40. Unique symmetrical axo-axonic synapses showing accumulation of synaptic vesicles on either side of apposed membrane thickenings first appear in day-14 core neuropil, gradually increase in number, and become the predominant type in day-40 core neuropil. Thick myelinated axons, which lose their myelin sheaths in the glial cap cell layer, start to penetrate into the axon cap on day 10. They gradually increase in number and form the peripheral part of the axon cap together with the cap dendrites, which finally grow into the axon cap from the axon hillock region of the Mauthner cell by day 40.

Age Factors↗
PubMed1984

Structural analysis of the gene encoding human gastrin: the large intron contains an Alu sequence.

We have isolated a human gastrin gene from a genomic library by employing a human gastrin cDNA clone as a hybridization probe. The total length of the gene is approximately 4.0 kilobase pairs, and the gene is separated into three exons and two introns. A 130-base-pair intron interrupts the coding region and a 3.0-kilobase-pair intron is located in the 5' untranslated region. Nucleotide sequence analysis showed that all of the exon-intron boundaries follow the A-G/G-T consensus sequences. A putative transcription initiation site is assigned to the adenine 60 nucleotides upstream from the exon-intron junction on the basis of S1 nuclease protection mapping. A possible "TATA" equivalent sequence T-T-A-T-A-A is located 28 base pairs upstream from the transcription initiation site. A "CAT box" sequence, C-A-T-T, is located 99 nucleotides upstream of the transcription initiation site. A poly(A)-addition signal, A-A-U-A-A-A, is located 80 base pairs downstream from the termination codon. Comparison of the nucleotide sequences of the human cDNA and the genomic clone revealed that the aspartic acid codon at position 71 of preprogastrin is interrupted by the small intron (130 base pairs). The 3' region of the large intron contains a sequence of 300 nucleotides that is flanked by 15-nucleotide direct repeats. This sequence exhibits a striking homology to the human Alu-type sequence.

Amino Acid Sequence↗
PubMed1984

[Biology of cancer cell-stroma interaction in carcinogenesis and cancer progression].

Cancer cells are dependent on physical and chemical supports of stroma no less than non-cancerous cells and tissues are. The role of stroma should, therefore, be important in genesis and progression of cancers growing in vivo. But this aspect underlying carcinogenesis and manifestation of human cancers has long been neglected or attracted less attention in the investigations of oncology. Focusing particular attention on parenchyma-stromal interaction in gastrointestinal mucosa, the authors have found that, quite unexpectedly, in normal gastric as well as intestinal mucosa of all the animal species so for studied, vascularity is always poorly developed in the generative cell zones. Cross-sectional area of vascular bed is markedly reduced in this zone. Application of Hagen-Poiseulle law revealed that the reduced total cross-sectional area, resulting in a rapid drop in hydrostatic pressure, creates here a situation particularly favorable for proliferating cell population. Since the transport of water soluble material together with tissue fluid through the capillary wall is driven by the hydrostatic pressure, the generative cell zones are found to be present at the site where the turnover of the material is the most active. Before the zone of the rapid pressure drop, there appears zone of relatively high intravascular hydrostatic pressure, where secretory function seems to be facilitated. This zone, as is well known, corresponds to glandular portion of the mucosa. After the zone of the rapid pressure drop (in surface of the mucosa), zone of a low intravascular hydrostatic pressure appears, where absorptive function is to be facilitated. Within such zones, in gastric mucosa surface epithelium and in intestinal mucosa absorptive villi cells are located. It is likely that architecture of gastrointestinal epithelium and vascular pattern in the stroma is closely correlated and that the former is determined, at least partly, by the latter. When human gastric mucosa shows intestinal metaplasia, the vascular pattern is always of the type of intestine. Investigating causal relationship of the changes in vascular pattern and epithelial metaplasia, we found that, in human gastric mucosa, vascular architecture began to shift to the intestinal pattern, though not complete, when incipient changes of chronic gastritis became manifest. This is peculiar to human gastric mucosa and thought to be species specific characteristics of mucosal stroma in human stomach.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma, Mucinous↗
PubMed1984

Chemical and clinical evaluation of the random access analyzer "RA-1000".

In the RA-1000, a random-access discrete analyzer, an inert fluorocarbon fluid is used to prevent interaction and carryover. Production-model instruments were evaluated in two laboratories with respect to determination of glucose, creatinine, total protein, inorganic phosphorus, cholesterol, alkaline phosphatase, lactate dehydrogenase, creatine kinase, gamma-glutamyltransferase, and aspartate and alanine aminotransferases. Within-run, among-run, and day-to-day (for 15 days) precision was assessed, and results were correlated with those obtained by the methods routinely in use in our departments. Precision was excellent, correlation acceptable.

Autoanalysis↗
PubMed1983

The roles of RNA polymerase and RNAase I in stable RNA degradation in Escherichia coli carrying the srnB+ gene.

In Escherichia coli cells carrying the srnB+ gene of the F plasmid, rifampin, added at 42 degrees C, induces the extensive rapid degradation of the usually stable cellular RNA (Ohnishi, Y., (1975) Science 187, 257-258; Ohnishi, Y., Iguma, H., Ono, T., Nagaishi, H. and Clark, A.J. (1977) J. Bacteriol. 132, 784-789). We have studied further the necessity for rifampin and for high temperature in this degradation. Streptolydigin, another inhibitor of RNA polymerase, did not induce the RNA degradation. Moreover, the stable RNA of some strains in which RNA polymerase is temperature-sensitive did not degrade at the restrictive temperature in the absence of rifampin. These data suggest that rifampin has an essential role in the RNA degradation, possibly by the modification of RNA polymerase function. A protein (Mr 12 000) newly synthesized at 42 degrees C in the presence of rifampin appeared to be the product of the srnB+ gene that promoted the RNA degradation. In a mutant deficient in RNAase I, the extent of the RNA degradation induced by rifampin was greatly reduced. RNAase activity of cell-free crude extract from the RNA-degraded cells was temperature-dependent. The RNAase was purified as RNAase I in DEAE-cellulose column chromatography and Sephadex G-100 gel filtration. Both in vivo and with purified RNAase I, a shift of the incubation mixture from 42 to 30 degrees C, or the addition of Mg2+ ions, stopped the RNA degradation. Thus, an effect on RNA polymerase seems to initiate the expression of the srnB+ gene and the activation of RNAase I, which is then responsible for the RNA degradation of E. coli cells carrying the srnB+ gene.

DNA-Directed RNA Polymerases↗
PubMed1983

Assaying plasma prekallikrein (PPK) by a chromogenic based method: analytical considerations and reference values in healthy adults, the pregnant woman, and the neonate.

Analytical assays that measure the amidolytic activity of plasma kallikrein (PK) must overcome the problem of anti-kallikrein inhibition during the activation of PPK to PK. We resolved this problem by exposure of plasma to 50 mg/L dextran sulfate in acetone/water (35/65, vol/vol) at 0 degrees C for 15 minutes. PK activity was assayed using the chromogenic substrate, S-2302 (KABI). A centrifugal analyzer (CentrifiChem) was used to monitor the change in absorbance at 405 nm and 37 degrees C. The assay was linear to a value 3 times that found in normal human plasma. The specificity of the substrate for PK was demonstrated by using plasma deficient in PPK (Fletcher trait) diluted with normal human pooled plasma (NHPP). Day-to-day analytical variation was 2.4% for NHPP having a mean value of 85.9 mukat/L (n = 26). Using our amidolytic method, we determined PPK values in 50 healthy adults, 80 pregnant women during each trimester of gestation, and 151 neonates (cord blood specimens). The middle 95% reference interval for the adults was 54.0 - 118.8 mukat/L, for pregnant women at first trimester: 59.0 - 129.0, second trimester: 72.3 - 161.5, third trimester: 75.6 - 152.4, day of labor: 67.7 - 144.9, and 1-9 weeks postpartum: 69.4 - 151.0 mukat/L, and for the neonate: 11.5 - 44.9 mukat/L. We observed that women on oral contraceptives had significantly greater PPK values than those not on oral contraceptives. Intra-individual variation of PPK values was relatively low in non-pregnant women with the day-to-day coefficient of variation being 4.1 - 6.1% in 5 subjects monitored over a 30 day period. The high value of inter-individual/intra-individual ratio was appreciated in pregnant women in that the PPK value observed during the first trimester was a means to predict the value approaching term. The mean PPK value during the first trimester was 105.1% of the mean seen in non-pregnant women while the mean PPK value nearing term was 130.1% of that value.

Adult↗
PubMed1983

A two-generation study of human sex-ratio variation.

We report here the first vertical population study of human sex-ratio variation. Sex-ratio data for 2 generations from Akita, Japan, have been analyzed. Parental age, birth order, sequences of the sexes at birth, and generations have no statistically significant effect on sex ratio. There is a slight excess of males at birth, as is typical for human sex-ratio studies. There is evidence of sex-ratio-dependent family planning. An analysis of vertical transmission of sex-ratio modifying factors that excludes effects of birth order in both the parental and offspring generations has detected a marginally significant paternal effect. Genetic variability of the sex ratio, if present at all, is of a very minor magnitude.

Adult↗