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Biomedical subjects

T Andoh

Publications and source records attributed to T Andoh.

At least 109 records · Page 6Linked to original sources
PubMed1997

[A case of mediastinal liposarcoma surgically removed by bilateral thoracotomy].

A rare case of mediastinal liposarcoma was experienced at our institute. A 64-year-old male patient was accidentally found by chest X-ray photo. The tumor was so gigantic and seemed to involve the descending aorta, therefore, it was removed through bilateral thoracotomy. It was well encapsulated and its malignancy resides in that of low grade to be completely removed. The patient is expected to acquire long term survival.

Humans↗
PubMed1997

[Clinical application of 31P-chemical shift image using 31P-volume coil to Moyamoya disease].

31P-MRS and 31P-Chemical Shift Image(CSI) using volume coil were applied to Moyamoya disease of 14 cases, data of which were compared with clinical manifestations and neuroimagings. In four asymptomatic cases, signal intensity of both total P and total ATP was almost equal in each voxel, but in other cases, both signal intensity of the lesion was relatively decreased, compared with non-lesion. Especially, signal intensity of total P and total ATP in ischemic lesion was significantly decreased. This showed that 31P-CSI is able to demonstrate cerebral ischemic lesion not detected by CT and MRI. We have reported on Moyamoya disease that 31P-MRS comparatively correlates to cerebral blood flow and 31P-CSI demonstrates ischemic lesion as not detected by CT and MRI less invasively.

Cerebrovascular Circulation↗
PubMed1997

[Inhibitors of DNA topoisomerases].

DNA topoisomerases are enzymes regulating the conformational state of DNA in every aspect of genetic processes by catalyzing transient cleavage and religation of DNA strands. The enzymes are targets of some of the important anticancer drugs. Many candidates of anticancer drugs are being screened via inhibition of the enzymes. In the present review, I discuss the role of DNA topoisomerases in genetic processes in mammalian cells, characteristics and mode of action of topoisomerase inhibitors, and resistance of tumor cells to the anticancer drugs.

Animals↗
PubMed1996

Effects of DNA topoisomerase inhibitors on nonhomologous and homologous recombination in mammalian cells.

To study the involvement of DNA topoisomerases in recombination in mammalian cells, we used gene transfer assays to examine the effects of DNA topoisomerase inhibitors on nonhomologous (illegitimate) and homologous recombination. The assays were performed by transfecting adenine phosphoribosyltransferase-deficient (APRT-) CHO cells with plasmids carrying the wild-type or mutant aprt genes and by treating the cells with the inhibitors, followed by subsequent cultivation to select for APRT-positive (APRT+) colonies. Treatments with DNA topoisomerase II inhibitors such as VP-16, VM-26, ICRF-193 resulted in a 3- to 5-fold stimulation of integration of both closed-circular and linearized plasmids carrying the wild-type aprt gene into the recipient genome through nonhomologous recombination. The same treatments also increased 6- to 9-fold and 3-fold the number of APRT+ recombinant colonies that were generated by cotransfecting two closed-circular plasmids with nonoverlapping defective aprt genes and their linearized equivalents, respectively. However, this cotransfection assay involved intrinsically nonhomologous recombination processes; normalization of the frequencies by dividing them with those of the above nonhomologous recombination revealed 2-fold enhancement of homologous recombination events between the circular mutant genes but not between the linear ones. In contrast, DNA topoisomerase I inhibitor, camptothecin, showed no such effect on either recombination. From these results, we discuss the function of DNA topoisomerases on recombination in mammalian cells.

Adenine Phosphoribosyltransferase↗
PubMed1996

Expression of tachykinin NK1 receptor mRNA in dorsal root ganglia of the mouse.

We examined whether mRNA coding for tachykinin NK1 receptor is expressed in the dorsal root ganglion (DRG) of the mouse, using reverse transcription-polymerase chain reaction (RT-PCR). Both the RT-PCR of the total RNA from the DRGs using four pairs of primers and the digestion of these products with the restriction enzymes gave bands with the predicted length. Further amplification (nested PCR) of part of one PCR product also gave a band with the predicted length. Southern blot hybridization of RT-PCR products of total RNA from the DRG and several CNS regions revealed that the expression level of NK1 receptor mRNA in the DRG was similar to the cerebellum and less than the olfactory bulb, cerebral cortex, medulla oblongata and spinal cord. The present results suggest that NK1 receptor mRNA is expressed in the mouse DRG, although the level is relatively low.

Animals↗
PubMed1996

[Plasma interleukin-10 levels in Kawasaki disease].

Time course of interleukin-10 (IL-10) in plasma of patients with Kawasaki disease was measured. The results are as follow: (1) IL-10 concentration in plasma of patients in acute phase of Kawasaki disease (median 37.8 pg/ml) was high, compared with that in convalescent phase (5.77 pg/ml) or that of control children (10.2 pg/ml). (2) From the examination of IL-10 concentration in plasma collected by following its time course, it was revealed that most of cases with this disease showed transiently high figure in the acute phase, then the figure diminished promptly afterwards.

Acute-Phase Reaction↗
PubMed1996

[Methodological study of hemodynamic analysis of lung mass by contrast enhanced dynamic CT].

We investigated a method of analyzing the hemodynamics of the lung mass by contrast enhanced dynamic computed tomography (dynamic CT) to determine the difference in vascular supply between the pulmonary artery and bronchial artery using an experimental model. Our experimental model consisted of two injectors connected to two tubes, representing the pulmonary artery and bronchial artery, which were further connected to a chamber representing the lung mass. Following infusion of contrast medium into each tube with some delay time, dynamic CT scans were performed to obtain time density curves of the two tubes and the chamber. Using the time-density curve of contrast passage, flow rates from the two tubes into the chamber were calculated by the curve fitting method. Calculated values correlated well with the adopted flow rates of fluid from the injectors (r = 0.893) in the experiment. The results indicate our method of individually measuring flow rates of dual-input blood flow, i.e., from the pulmonary artery and bronchial artery, into the lung mass is applicable clinically to determine blood flow by the two arteries supplying the lung mass.

Animals↗
PubMed1996

[Assessment of thalamic regional cerebral blood flow in patients with cerebrovascular disease].

The thalamus is believed to play an integrative role in the central nervous system. In the present study, thalamic rCBF was measured in 65 CVD patients and 15 normal volunteers by stable Xe/CT scanning. ROIs were chosen in the thalamic slice at a level 5cm over the OM line, and mean CBF was 7 cm over the OM line. The clinical factors focused on in multiple regression analysis were: age (A), sex (Se), stage from onset (St), lesion side (Sd); unilaterality or bilaterality, size (Sz) thalamic lesion (Tl). GCS (G), HDS-R (H); Hasegawa dementia score (revised), symptoms (Ss) such as anxiety, dizziness, head-headed feeling and headache, and neurological deficits (N). Each factor was graded and scored. Statistically, there was a significant correlation between thalamic rCBF (Y) and mean CBF (X) in the less affected hemisphere: Y = 1.82X + 2.2, r = 0.801, p < 0.001, n = 65. Multiple regression analysis of the thalamic rCBF revealed that the Sz factor was significant (p < 0.0001) on the lesion side: Y = 76.7-10.2Sz, r = 0.644, p < 0.001, n = 51, while the Se, Sd and St factors were significant (p < 0.005) on the less affected side: Y = 71.9 + 9.7Se-6.8Sd-5.0St, R = 0.585, p < 0.001, n = 65. The thalamic index (X), an indicator of thalamic atrophy, and thalamic rCBF were significantly correlated: Y = 28.7X + 10.2, r = 0.386, p < 0.001, n = 80. In conclusion, thalamic rCBF appeared to reflect the degree of organic changes and time course in the cerebral hemisphere, because factors such as size, sex and stage were statistically significant.

Cerebral Infarction↗
PubMed1996

Reduced expression of DNA topoisomerase II confers resistance to etoposide (VP-16) in small cell lung cancer cell lines established from a refractory tumor of a patient and by in vitro selection.

Cell lines, LC-5 and LC-172, were established from tumors of a small cell lung cancer patient prior to and after combination chemotherapy including etoposide (VP-16), when drug-resistant tumors developed in relapse. A VP-16-resistant cell line, LC-172/VP, was selected from the LC-172 cells in culture in multiple steps with VP-16. LC-172 cells were 3.5-fold resistant to VP-16 in growth inhibition, and 3.3-fold resistant to adriamycin as compared with LC-5 cells. LC-172/VP cells showed large differences in cross-resistance to topoisomerase II-targeting drugs such as VP-16, 200-fold, adriamycin, 10-fold, and MST-16, 4.3-fold; the cells were moderately refractory, 5.5-fold, to vincristine. VP-16 accumulation in the cells was similar in three cell lines. Topoisomerase II unknotting activity was reduced 7- to 10-fold in LC-172/VP and 1.5- to 2-fold in LC-172 cells compared with LC-5 cells, while relaxing activity of topoisomerase I appeared to be unchanged. Topoisomerase II protein was also reduced 5- to 10-fold in LC-172/VP and marginally so in LC-172 cells. Topoisomerase II alpha and II beta were each reduced 10-fold and 2-fold, respectively, in LC-172/VP cells, while they were both slightly decreased (-1.5-fold), respectively, in LC-172 cells compared with LC-5 cells. No apparent alteration in ATP requirement for catalytic activity and in sensitivity to VP-16 was observed for topoisomerase II from the three cell lines. Taken together, these results suggested that resistance to VP-16 in LC-172 and LC-172/VP is associated with a quantitative reduction in expression of topoisomerase II alpha of the parental type.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

[Circulating interleukin-4 levels in acute phase Kawasaki disease].

We have measured the plasma levels of IL-4 in patients with Kawasaki disease, serially. The results were as follows: The plasma levels of IL-4 from patients with Kawasaki disease in acute phase (median 17 pg/ml) were significantly higher than those from the patients in convalescent phase (median 1.96 pg/ ml, p = 0.001) or from control children (median 7.64 pg/ml, p = 0.001). These findings imply that Th2 (or Tho) cells may be vigorously stimulated at an acute phase of this disease, and that IL-4 produced by these cells may possibly modulate the pathological conditions of this disease.

Acute Disease↗
PubMed1995

High affinity interaction of mammalian DNA topoisomerase I with short single- and double-stranded oligonucleotides.

The interaction of DNA topoisomerase I (topo I) with a set of single- and double-stranded oligonucleotides containing 5-27 mononucleotides was investigated. All single- and double-stranded oligonucleotides were found to inhibit competitively the supercoiled DNA relaxation reaction catalyzed by topo I. The enzyme affinity for specific sequence pentanucleotides of the scissile (GACTT, Ki = 2 microM) and non-cleaved chain (AAGTC, Ki = 110 microM) is about 2-4 orders of magnitude higher than that for non-specific oligonucleotides. This specific sequence affinity increases in several cases; lengthening of single-stranded oligonucleotides, formation of stable duplexes between complementary oligonucleotides and preincubation of the enzyme with ligands before addition of supercoiled DNA. We assume that oligonucleotides having a high affinity to the enzyme can offer a unique opportunity for rational design of topoisomerase-targeting drugs.

Base Sequence↗
PubMed1995

Human immunodeficiency virus type 1 reverse transcriptase: enhancement of activity by interaction with cellular topoisomerase I.

A number of studies have suggested that topoisomerase I (topo I) activity may be important in human immunodeficiency virus type 1 (HIV-1) replication. Specifically it has been reported that purified virus particles have topo I activity and that inhibitors of this enzyme can inhibit virus replication in vitro. We have investigated a possible association of HIV-1 gag proteins with topo I activity. We found that whereas the gag-encoded proteins by themselves do not have activity, the nucleocapsid protein p15 can interact with and enhance the activity of cellular topo I. Furthermore it could be demonstrated that topo I markedly enhanced HIV-1 reverse transcriptase activity in vitro and that this could be inhibited by the topo I-specific inhibitor camptothecin. The findings suggest that cellular topo I plays an important role in the reverse transcription of HIV-1 RNA and that the recruitment of this enzyme may be an important step in virus replication.

Base Sequence↗
PubMed1995

DNA topoisomerase II is the molecular target of bisdioxopiperazine derivatives ICRF-159 and ICRF-193 in Saccharomyces cerevisiae.

Bisdioxopiperazines such as ICRF-159 and ICRF-193 have been shown to inhibit DNA topoisomerase II. To determine the molecular target of these compounds in vivo, we utilized a yeast genetic system in which the topoisomerase II activity can be modulated. To reduce topoisomerase II activity, we used top2-1 mutant yeast cells that have normal DNA topoisomerase II activity at 25 degrees C but greatly reduced enzyme activity at 30 degrees C, a temperature that is semipermissive for growth. At 25 degrees C top2-1 cells are as sensitive to the ICRF compounds as the wild-type strain; at 30 degrees C the cells became hypersensitive to these agents. In contrast, top2-1 strains become very resistant to the class of topoisomerase II inhibitors such as amsacrine and etoposide, which stabilize the covalent enzyme-DNA intermediate of the enzyme reaction. Overexpression of topoisomerase II from a plasmid-born TOP2 gene results in lower susceptibility to ICRF compounds and higher susceptibility to amsacrine than the parental strain exhibits. These results support the hypothesis that the main cellular target of ICRF compounds is DNA topoisomerase II, and that these compounds, unlike amsacrine and etoposide, inhibit topoisomerase II activity without stabilizing an enzyme-DNA covalent complex.

Amsacrine↗
PubMed1995

Paresthesia induced by cutaneous infection with herpes simplex virus in rats.

To assess the effects of herpetic infection on somatic sensations, herpes simplex virus type-1 was inoculated into the unilateral hind paw of the rat and its behavioral responses to noxious pressure and tactile stimulation were examined. Herpetic infection significantly increased the nociceptive threshold of the treated hind paw with a delay around 4 days. The increase in the nociceptive threshold continued at least until post-inoculation day 21 and was larger at night than in the morning. Any alterations in tactile responses were not observed during this period. Herpetic DNA was detected by polymerase chain reaction in the inoculated skin, but not in the dorsal root ganglia on the inoculated side, on the next day after inoculation. But on the following days it was detected in the dorsal root ganglia, but not in the skin. These results suggest that herpetic infection of the dorsal root ganglion produces paresthesia as a functional abnormality of the sensory neurons in rats.

Animals↗
PubMed1995

Synthesis of simian virus 40 C-family catenated dimers in vivo in the presence of ICRF-193.

The effect of ICRF-193, a non-cleavable, complex-stabilizing type of topoisomerase II inhibitor, on SV40 DNA replication in vivo was examined. As analyzed by one and two-dimensional gel electrophoresis, C-family catenated dimers, each composed of two intertwined, covalently closed SV40 DNAs, were mainly synthesized in the presence of the drug. On removal of the drug these C-family dimers were segregated into monomers. These results indicate that topoisomerase II is required for the segregation of replicated daughter molecules, but it is not absolutely required for the replication of DNA molecules up to the C-family dimers.

DNA Replication↗
PubMed1995

Establishment and characterization of human gastric and colonic xenograft lines resistant to CPT-11 (a new derivative of camptothecin).

CPT-11-resistant human gastric and colonic xenograft lines were established by direct intratumoral injection of CPT-11 into subcutaneous SC-1-NU and CC-2-NU tumors in nude mice once a week for 10 months. The resistance of these xenograft lines to CPT-11 was confirmed by growth inhibition rate, to be 36.3% and 45.4%, respectively, compared to each parent cell line. DNA topoisomerase I activity of the nuclear extracts of SC-1-NU/CPT-11 and CC-2-NU/CPT-11, as assayed by relaxation of supercoiled DNA Col-E1, was significantly less than those of the parent lines. The cellular levels of topoisomerase I in those resistant lines measured by Western blot analysis were 0.57- and 0.79-fold lower than those of the parental lines, respectively. However, the activity of DNA topoisomerase II of those resistant cell lines assayed by decatenation of kinetoplast DNA was higher than that of the parental lines and the cellular levels of topoisomerase II in the resistant lines measured by Western blot analysis were 10.8- and 8.1-fold higher than those of the parent lines. Intracellular accumulation of CPT-11 in CPT-11-resistant tumors was not changed as compared to that of the parental lines, but hydrolysis of CPT-11 to more active SN-38 was reduced in the resistant tumors.

Animals↗