Biomedical subjects
Publications and source records attributed to C Nakayama.
A continuous spectrophotometric assay for thymidine phosphorylase has been developed and used to analyze the substrate properties of a number of 5-substituted 2'-deoxyuridines. A QSAR was found which relates the catalytic efficiency for various substrates to a single variable, the inductive field constant F.
A young male patient with adrenoleukodystrophy progressed from the frontal to the parieto-occipital region was reported. The spreading pattern of the brain lesion in this patient was confirmed by a serial examination of Technetium scintigrams and the neuropathological findings. The high uptake area of the isotope in the scintigrams seemed to represent the active demyelinating and infiltrative-reactive process in the white matter. A chemical analysis of the frozen white matter tissue of the patient revealed the existence of long chain fatty acids mor than C 22 in cholesteryl esters and gangliosides. It is suggested by this case that the demyelination process can start in the frontal white matter also in adrenoleukodystrophy as well as in Schilder's disease.
DNA dependent RNA polymerase II was purified to approximately 8300 fold from sonicated nuclear extract of cherry salmon (Onchorhynchus masou) liver by the following purification steps: polyethylene glycol treatment, DEAE=Sephadex A-25 column chromatography, heparin-Sepharose column chromatography, and affinity chromatography on DNA-cellulose. Final preparation of this enzyme has a specific activity of 157 nmole UMP incorporation into RNA per mg of protein per 10 min at 25 degrees. RNA polymerase I was also purified to approx. 3800 fold in a similar manner. Its specific activity was calculated as 26.2 nmole/mg/10 min. Utilization of various UTPs of these enzymes was studied by substitution experiments under the condition of limited synthesis. 5-Methyl UTP (rTTP) could be utilized by the RNA polymerase I 1.7 fold more efficiently compared with UTP. In contrast, the RNA polymerase II recognized rTTP as a substrate as efficiently as UTP. Similar experiments using other alkyl UTPs have been performed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Several 5-alkyl derivatives of 1-beta-d-arabinofuranosyluracil (araU) were tested for antiherpesviral activity and inhibitory action on cell growth in human embryonic lung fibroblasts. 1-beta-d-Arabinofuranosylcytosine, 9-beta-d-arabinofuranosyladenine, and 5-iododeoxyuridine (IUdR) were included as reference materials. Among the 5-alkyl derivatives of araU, arabinosylthymine was the most active, followed by 5-ethyl- and 5-propyl-araU. 5-Ethyl-araU was as active as IUdR and more active than 9-beta-d-arabinofuranosyladenine against herpes simplex virus (HSV) type 1 and did not inhibit cell growth at a concentration as high as 1,000 mug/ml. 5-Butyl- and 5-methoxymethyl-araU, as well as araU, exhibited relatively low activity. The araU derivatives tested were as active against HSV WT-34, an isolate from a patient with keratitis, as against HSV type 1. Against an IUdR-resistant isolate, HSV WT-20, arabinosylthymine was less inhibitory than IUdR. Deoxyribonucleic acid synthesis in HSV type 1-infected cells was markedly inhibited by arabinosylthymine, IUdR, and 5-ethyl-araU, whereas cellular deoxyribonucleic acid synthesis in uninfected cells was significantly inhibited by IUdR but not by arabinosylthymine or 5-ethyl-araU.
Non-infected urine samples of twenty six preoperative bladder cancers were examined by urinary CEA radioimmunoassay and exfoliative cytology. There were 65% of urinary CEA positivity and 58% of cytological positivity (class III, IV, V). CEA measurements were positive in 8 of 11 negative cytology cases (class I and II). Exfoliative cytological examination failed to detect most of well differentiated transitional cell carcinomas, while urinary CEA study detected 4 of 6 such cases. Combination of both urinary CEA measurement and cytology resulted in 85% of positivity. Therefore we recommend routine use of this combination as a screening system of bladder cancer.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This report deals with the test of a series of 5-halogenated derivatives of ara-UTP for the inhibition of DNA polymerase gamma and viral reverse transcriptase. The compounds newly synthesized and tested were; ara5-FUTP, ara5-C1UTP, ara5-BrUTP and ara5-IUTP. The results were: 1) All these compounds were inhibitory to DNA polymerase gamma and reverse transcriptase. The mode of inhibitions was, in all cases, competitive against dTTP. 2) Ki values for these inhibitors with DNA polymerase gamma were lower than those with reverse transcriptase. 3) Ara5-ClUTP was less inhibitory to reverse transcriptase than other derivatives.
This is the first report dealing with the effect of 1-beta-D-arabinofuranosylthymine 5'-triphosphate (araTTP), synthesized by a new method, on eukaryotic DNA polymerase [EC 2.7.7.7]. AraTTP was tested for the inhibition of DNA synthesis in vitro using highly purified mouse myeloma DNA polymerase alpha in comparison with 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (araCTP). AraTTP was found to inhibit competitively the incorporation of [3H]dTTP into DNA and non-competitively the incorporation of [3H]dCTP, while the mode of the inhibition by araCTP was non-competitive with respect to dTTP and competitive with respect to dCTP. Neither araTTP nor araCTP was utilized as a substrate in place of dTTP or dCTP in DNA synthesis by DNA polymerase alpha.
Urine CEA levels of sixty six cystectomy patients with urinary tract reconstruction using the small or large bowel was evaluated. Most of them had abnormally high CEA levels regardless of bladder tumor recurrence. Ileal conduit cases showed higher CEA levels than those of colocystoplasty cases. We think this is probably due to difference of mucosal surface areas rather than of original location of the resected specimens, for the small bowel contains much wider mucosal surface in a length unit.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.