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Biomedical subjects

T Enomoto

Publications and source records attributed to T Enomoto.

At least 325 records · Page 18Linked to original sources
PubMed1983

[Intracranial arachnoid cyst and porencephaly of the middle fossa--its clinical and neuroradiological study].

We reported four cases with well demarkated low density area in the middle cranial fossa, which was not enhanced with contrast medium and had the same absorption coefficient as the CSF. The operations and histological examinations revealed that two cases were arachnoid cysts and the others were porencephalic cysts. The clinicoradiological differential clues are listed below. 1) The porencephaly has intimate relation with focal neurological signs. 2) The thinning and bulging of the temporal bone are not a specific finding of an arachnoid cyst. Hemicranial atrophy, elevation of minor sphenoid wing and dilatation of paranasal sinuses in addition to focal bulging and thinning are indicative of porencephalic cyst. 3) Hemiatrophy of the brain and dilatation of the lateral ventricle on CT as well as the absorption coefficient of the brain surface facing the cyst are important finding of the porencephaly in differentiation. 4) The investigation of CSF dynamic is by no means helpful in differentiation between arachnoid cyst and porencephaly except intraarachnoid cyst. 5) The horizontal portion of the middle cerebral artery is not elevated in both two porencephalic cases. One of them showed a slight shift of anterior cerebral artery toward the affected side. An obstruction of the vessel is an important finding in porencephaly. 6) The electroencephalography can clearly demonstrate a porencephalic cyst as a localized slow focus, whereas it is not so remarkable in an arachnoid cyst.

Adult↗
PubMed1982

Adenovirus DNA replication in vitro: identification of a host factor that stimulates synthesis of the preterminal protein-dCMP complex.

A protein factor that participates in the formation of a covalent complex between the 80,000-dalton precursor of the adenovirus (Ad) terminal protein (pTP) and 5'-dCMP has been isolated and characterized. This 47,000-dalton protein, isolated from nuclear extracts of uninfected HeLa cells, has been designated nuclear factor I. It is free of detectable DNA polymerase alpha, beta, and gamma activities. In the presence of Ad DNA-prot, the Ad-protein fraction (containing the pTP and the Ad-associated DNA polymerase), ATP, Mg2+, and dCTP, nuclear factor I stimulates formation of the pTP-dCMP complex. Addition of the Ad DNA binding protein (Ad DBP) renders the formation of the pTP-dCMP complex completely dependent on the addition of nuclear factor I. When Ad DNA-prot is replaced with phi X174 single-stranded circular DNA, pTP-dCMP complex formation requires only the Ad-protein fraction; Ad DBP and ATP are inhibitory and nuclear factor I has no effect on this reaction. This suggests that the initiation reaction observed with Ad DNA-prot in the absence of Ad DBP occurs at single-stranded DNA sites. In the presence of Ad DBP, these sites are blocked thus creating a requirement for nuclear factor I in pTP-dCMP complex formation.

Adenoviruses, Human↗
PubMed1982

Adenoviral protein-primed initiation of DNA chains in vitro.

The initiation of DNA chains by the 80-kilodalton form of the adenovirus terminal protein has been studied. This protein, which can be covalently linked to dCMP, is isolated complexed to a 140-kilodalton protein possessing DNA polymerase activity. In the presence of adenovirus DNA-protein, the formation of the 80-kilodalton protein-dCMP complex requires the addition of ATP and nuclear extract from uninfected cells in addition to Mg2+ and dCTP. When single-stranded DNA is used in place of the adenovirus DNA-protein, the formation of the 80-kilodalton protein-dCMP complex occurs in the absence of ATP and nuclear extract. In the presence of the four dNTPs, the complex yields DNA chains of various sizes between 100 and 300 nucleotides. The products formed with bacteriophage phi X174 single-stranded circular DNA as the template are site specific, predominantly derived from the sequences between nucleotides 2363 and 2977 and between nucleotides 3760 and 4206. These small dNA chains are blocked at their 5' ends with the 80-kilodalton protein but possess free 3'-OH ends that are susceptible to degradation by exonuclease III and can be elongated to replicative form II products with DNA polymerase I of Escherichia coli or eukaryotic DNA polymerase beta preparations. A protein priming model explaining the different requirements for initiation with adenovirus DNA-protein and with phi X174 DNA is presented.

Adenoviruses, Human↗
PubMed1982

Effect of progesterone and FSH on testes of immature chickens.

The effect of progesterone (P), estradiol benzoate (EB) plus P, and FSH on the testicular weight, macromolecular content, and incorporation of 3H-leucine, 3H-uridine and 3H-thymidine into macromolecules was examined in the testes of immature chickens. Not P alone but EB plus P lowered the testicular weight, and content of protein and RNA in the tissues, whereas FSH brought about an increase in the weight, and content of the two macromolecular elements. The DNA content was not affected by any hormones used. P, EB plus P and FSH brought about a decrease in the incorporation of radioactive leucine, uridine and thymidine into the macromolecules in the testes, with the exception of no change in the incorporation of 3H-uridine after EB plus P treatment and 3H-thymidine after FSH treatment. These results suggest that P, alone or in combination with estrogen, and FSH cause several changes in metabolic activity in the testes of immature chickens.

Animals↗
PubMed1981

A system of DNA replication in HeLa nuclei treated with inhibitors of protein synthesis.

An in vitro DNA synthesizing system consisting os isolated nuclei from HeLa cells which had been treated with inhibitors of protein synthesis was investigated. Treatment with both 30 microgram/ml cycloheximide and 10 microgram/ml puromycin of S-phase cells reduced the rate of DNA synthesis immediately; however, the overall DNA synthesis continued for up to 4 h with a diminished rate and then ceased. In the nuclei which were isolated from the cells which had been incubated with these drugs for 6 h, little incorporation of [3H]TTP into acid-insoluble materials was observed. Addition of cytosol prepared from cells actively synthesizing DNA induced the incorporation of [3H]TTP in these nuclei, while little induction was observed by the addition of cytosol prepared from drug-treated cells in spite of the fact that the latter cytosol stimulated DNA synthesis in isolated nuclei from non-treated cells. The induced DNA synthesis was shown to require Mg2+, all four deoxyribonucleoside triphosphates and ATP, and to proceed discontinuously. The activity inducing DNA synthesis in drug-treated nuclei fluctuated with the phases in a cell cycle and it was not ascribed solely to DNA polymerase alpha nor to DNA ligase.

Cell Nucleus↗
PubMed1981

Suspected intraaqueductal perinatal hemorrhage in congenital hydrocephalus.

A 8-day-old boy with congenital hydrocephalus was given a shunt operation. Computed tomography (CT) revealed marked internal hydrocephalus and a high density area about the aqueduct of Sylvius, in the fourth ventricle and perhaps partly in the third ventricle which was completely absorbed one month later. Later conray ventriculography demonstrated aqueductal obstruction. Neuroradiologically there was neither neoplastic nor vascular lesion. The patient achieved almost normal motor and mental development at 9 months of age. The cephalopelvic discrepancy and vacuum extraction are thought to be the most likely caused of the hemorrhage. The site of hemorrhage was quite unusual as a neonatal intraventricular hemorrhage.

Cerebral Hemorrhage↗
PubMed1981

Adenovirus DNA replication in vitro: purification of the terminal protein in a functional form.

The 80,000-dalton form of the adenovirus (Ad) terminal protein (pTP) has been purified from Ad-infected HeLa cells. pTP was assayed by its ability to form a covalent complex with dCMP. The protein copurified with an activity that is essential for in vitro Ad DNA replication (Ad protein activity) as well as with a DNA polymerase activity that was distinguished from those of HeLa cell DNA polymerases alpha, beta, and gamma. The Ad protein-associated DNA polymerase activity was detected with activated DNA but not with poly(rA).oligo(dT) as template and was insensitive to aphidicolin and sensitive to N-ethylmaleimide. The Ad protein, DNA polymerase, and pTP-dCMP complex-forming activities sedimented in a glycerol gradient as a single peak with an apparent molecular size of 180,000 daltons. NaDodSO4/polyacrylamide gel analysis of the glycerol gradient fraction showed major bands of 80,000 and 140,000 daltons. The 80,000-dalton band was identified as pTP by comparison of its tryptic peptide map with that of the 55,000-dalton form of the terminal protein, which was purified from Ad virions.

Adenoviruses, Human↗
PubMed1981

Replication of adenovirus DNA-protein complex with purified proteins.

A protein fraction isolated from the cytosol of adenovirus-infected HeLa cells, which contained DNA polymerase alpha, catalyzed adenoviral DNA replication in the presence of adenovirus DNA binding protein, eukaryotic DNA polymerase beta, ATP, all four dNTPs, and MgCl2. DNA replication started at either end of exogenously added adenoviral DNA and was totally dependent on the presence of terminal 55,000-dalton proteins on the DNA template. The replicaton of adenovirus DNA in the system was sensitive to aphidicolin and retained nearly all the properties of DNA replication that occur in vivo or in vitro with crude extracts. The 5'-ends of the newly synthesized adenovirus DNA strands were covalently linked to an 80,000-dalton protein linked to dCMP. DNA synthesized with purified proteins was only 25-50+ the length of parental viral strands. Addition of cytosol extracts from uninfected HeLa cells to reaction mixtures containing purified proteins gave full-length adenoviral DNA strands.

Adenoviruses, Human↗
PubMed1981

Tumor promoters cause a rapid and reversible inhibition of the formation and maintenance of electrical cell coupling in culture.

The effect of tumor promoters on electrical coupling between human FL cells was investigated with a microelectrode technique. When a low concentration (100 ng/ml) of 12-O-tetradecanoylphorbol 13-acetate (TPA) was added to culture medium, only 6% of the cells showed electrical coupling after 5 hr, whereas in control medium more than 90% of the cells were coupled. In the presence of TPA, cell coupling remained suppressed for at least another 19 hr. When TPA was washed out from the culture medium, the cells commenced electrical coupling: 90% of the cells were coupled within 4 hr of the removal of TPA, a rate very similar to that of nontreated control cells. Therefore, TPA-mediated inhibition of cell coupling is reversible. When TPA was added to a culture in which more than 90% of the cells had already established electrical coupling, the percentage of coupled cells decreased to 6% within 8 hr, indicating that TPA can also diminish already established cell coupling. Inhibition of cell coupling also was achieved with other mouse skin tumor promoters--phorbol 12,13-didecanoate, ingenol dibenzoate, and mezerein--whereas nonpromoting derivatives--phorbol and 4 alpha-phorbol 12,13-didecanoate-showed no effect. None of these compounds changed the membrane potential, membrane resistance, or growth rate of FL cells. Thus, it appears that TPA and structurally-related tumor promoters specifically disturb the formation or function, or both, of cell-cell junctions, without significantly affecting the general properties of the surface membrane or the growth of FL cells.

Cell Division↗
PubMed1981

ATP requirement for the processes of DNA replication in isolated HeLa cell nuclei.

The ATP requirement for two steps of DNA replication, the synthesis and subsequent joining of Okazaki fragments, was investigated by using isolated HeLa cell nuclei. Among adenine nucleotides tested, high levels of dATP and ADP stimulated DNA synthesis. In the presence of high levels of ATP, the addition of high levels of dATP or ADP resulted in about 70% inhibition of DNa synthesis. The optimal concentration of ATP for the stimulation of DNA synthesis varied depending on the magnesium ion concentration. When the molar ratio of magnesium ion to ATP was approximately 1, maximal stimulation was attained. Product analysis by sedimentation in an alkaline sucrose gradient revealed that both Okazaki fragments and high molecular weight DNA were synthesized in the presence of high levels of ATP, whereas in the case of dATP and ADP, little high molecular weight DNA was synthesized. The ability to synthesize high molecular weight DNA was restored to nuclei by adding low levels of ATP in the presence of high levels of ADP but not of dATP.

Adenine Nucleotides↗
PubMed1981

Computed tomography in von Recklinghausen's disease.

Though we knew it would be difficult to predict whether a child having von Recklinghausen's disease would develop a central nervous system lesion in the future, we tried to find a clue to this question in our study, by comparing computed tomography (CT) findings of 18 children with those of 21 adults. 55% of the children and 85% of the adults showed abnormal findings on CT. The most common finding was mild ventricular dilatation without periventricular hypodensity. Some of them showed ventricular stasis without block on radioisotope cisternography.

Adolescent↗