Biomedical subjects

T Andoh

Publications and source records attributed to T Andoh.

At least 91 records · Page 5Linked to original sources

PubMed1997

Interaction of the DNA topoisomerase II catalytic inhibitor meso-2,3-bis(3,5-dioxopiperazine-1-yl)butane (ICRF-193), a bisdioxopiperazine derivative, with the conserved region(s) of eukaryotic but not prokaryotic enzyme.

ICRF-193 [meso-2,3-bis(3,5-dioxopiperazine-1-yl)butane], a bisdioxopiperazine compound, has been shown to be a catalytic inhibitor of DNA topoisomerase II by stabilizing the enzyme in the form of a closed "protein clamp," an intermediate form in the catalytic cycle (Roca et al., Proc Natl Acad Sci USA 91: 1781-1785, 1994). In view of its usefulness as a probe in the functional analysis of the enzyme, we tried further to define the domain(s) of the enzyme interacting with the drug by examining its inhibitory activity on type II topoisomerases from various species of eukaryotes and prokaryotes. ICRF-193 inhibited the enzyme from yeast, fly, frog, plant, and mammals at IC50 values in the range of 1-13 microM. Experiments using fission yeast truncated mutant type II enzyme lacking both amino-terminal 74 amino acids and carboxy-terminal 265 amino acids revealed that ICRF-193 interacts with the 125 kDa "core" polypeptide of the enzyme. In contrast, prokaryotic type II enzymes, Escherichia coli DNA gyrase, topo IV, and phage T4 topo, were not affected by the drug. From these results, the domain(s) common to eukaryotic but not to prokaryotic type II enzymes interacting with ICRF-193 was speculated.

Amino Acid Sequence↗

PubMed1997

Nociceptin gene expression in rat dorsal root ganglia induced by peripheral inflammation.

Nociceptin has been suggested to be involved in nociceptive processing in the spinal dorsal horn. To investigate whether the biosynthesis of nociceptin is altered in animals with nociceptive hypersensitivity, we examined effects of peripheral inflammation on the expression of prepronociceptin mRNA, especially in the dorsal root ganglion of the rat. Although little or no expression of prepronociceptin mRNA was observed in the dorsal root ganglia of naive animals, carrageenan-elicited inflammation markedly induced its expression, peaking within 30 min, a time when nociceptive hypersensitivity was not yet apparent. The results suggest that peripheral inflammation induced nociceptin expression in primary sensory neurons, which may be associated with the production of nociceptive hypersensitivity.

Animals↗

PubMed1997

Quantitative determination of endogenous nitric oxide in the mouse skin in vivo by microdialysis.

We have developed a subcutaneous microdialysis system for the determination of nitric oxide (NO) concentration in the skin. The skin was microdialyzed using a degassed solution containing 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide and the perfusate was reacted on-line with Griess' reagent. This method could reveal NO production following intradermal injection of bradykinin (10-100 nmol/site) in mice. The increase in cutaneous NO after bradykinin (100 nmol/site) was dose dependently suppressed by the NO synthase inhibitor. NG-nitro-L-arginine methyl ester, and the bradykinin B, receptor antagonist, D-Arg-[Hyp3, Thi5.8, D-Phe7]-bradykinin. This system may be useful for pharmacological and physiological experiments on the role of NO in the skin.

Animals↗

PubMed1997

Overcoming CPT-11 resistance by using a biscoclaurine alkaloid, cepharanthine, to modulate plasma trans-membrane potential.

Irinotecan, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin, (CPT-11) resistance was overcome by using a biscoclaurine alkaloid, cepharanthine, in CPT-11- and multidrug-resistant 50MT-1 cells. 50MT-1 cells were established from a mouse breast-cancer cell line, FM3A, by subjecting the cells to a low dose of CPT-11 continuously. 50MT-1 cells exhibited resistance to CPT-11 (40-fold in colony-formation assay) and to other drugs such as doxorubicin (11.7-fold) and etoposide (VP-16) (16.8-fold). The plasma trans-membrane potential was lower in 50MT-1 cells than in FM3A cells, although there were no differences in expressions of P-glycoprotein and of DNA topoisomerase-I and -II proteins. The lower membrane potential in 50MT-1 cells was augmented by co-treatment with a non-toxic dose of cepharanthine. CPT-11 resistance in 50MT-1 cells was overcome (5.0- to 1.4-fold, 6-hr exposure) by the co-treatment with cepharanthine through increasing intracellular accumulation of CPT-11. Resistance to doxorubicin and VP-16 was also overcome by cepharanthine treatment (2.5- to 0.69-fold and 4.2- to 1.4-fold respectively). We conclude that the modification of plasma trans-membrane potential by cepharanthine should be effective in overcoming CPT-11 and multidrug resistance in 50MT-1 cells.

Alkaloids↗

PubMed1997

DNA topoisomerase II as the cellular target of a novel antitumor agent ICRF-193, a bisdioxopiperazine derivative, in Xenopus egg extract.

We have investigated the molecular target of an antitumor agent ICRF-193, a bisdioxopiperazine derivative, in in vitro chromosome condensation system of Xenopus egg extract (XEE), where DNA topoisomerase II was previously demonstrated to play a crucial role. Demembranated Xenopus sperm head chromatin is converted to metaphase chromosome-like structure in XEE in two steps, i.e., swelling of the chromatin followed by condensation of chromosome. When ICRF-193 was added to the reaction, swelling of the chromatin was not affected but chromosome condensation was completely blocked. This blockade was reversed by exogenous supplement of calf thymus topoisomerase II, which was in turn neutralized by anti-topoisomerase II monoclonal antibody. These results demonstrate that topoisomerase II is the molecular target of the drug ICRF-193.

Animals↗

PubMed1997

High affinity interaction of mouse DNA topoisomerase I with di- and trinucleotides corresponding to specific sequences of supercoiled DNA cleaved chain.

Recently mouse DNA topoisomerase I (topo) was shown to possess high affinity for a single-stranded AAGACTTAG nonanucleotide (K(i) = 2.0 microM) corresponding to the scissile strand of the minimal DNA duplex, which is necessary for cleavage of supercoiled DNA. In order to determine the most important part of the above sequence for the DNA recognition by topo, the interactions of the enzyme with a set of extremely short (2-5 nucleotides in length) oligonucleotides corresponding to different parts of the nonanucleotide have been investigated. The affinities of different oligonucleotides corresponding to the CTTAG part of the sequence (K(i) = 0.13-0.92 mM) were shown to be significantly lower than that for the AAGA tetranucleotide (K(i) = 9.0 microM). Topo effectively recognized even short oligonucleotides containing only two or three bases (AGA and pAG, K(i) = 20 and 50 microM). We suppose that oligonucleotides having a high afffinity to the enzyme can offer a unique opportunity for the rational design of topoisomerase-targeting drugs.

Animals↗

PubMed1997

ICRF-193, a catalytic inhibitor of DNA topoisomerase II, delays the cell cycle progression from metaphase, but not from anaphase to the G1 phase in mammalian cells.

We have shown previously that ICRF-193, a catalytic inhibitor of DNA topoisomerase II (topo II), delays cell cycle progression in HeLa S3 cells. We report here that the delay of the transition in M phase is observed when HeLa S3 cells were treated with ICRF-193 during metaphase, but not thereafter. ICRF-193 also delayed the degradation of cyclin B in the transition from M to G1 phase, while in Chinese hamster ovary (CHO) cells the drug did not delay the progression in M phase. Since HeLa S3 and CHO cells are 'stringent' and 'relaxed' in mitotic control, respectively, it is suggested that under topo II inhibition, the M phase checkpoint operates through an inability for chromosome segregation.

Anaphase↗

PubMed1997

Disorder of bile acid metabolism in children with short bowel syndrome.

The profile of fecal bile acids was examined in 13 children with short bowel syndrome; 7 of the 13 did not have diarrhea and the other 6 had intractable diarrhea. In children without diarrhea, no severe fat malabsorption was recognized, and the content of total bile acids in the feces was within the normal range or slightly higher. The ratio of primary to total bile acids showed various patterns. In children with intractable diarrhea, in contrast, fat malabsorption was observed and the fecal content of total bile acids in these patients was more than ten times higher than that of the control group, primary bile acids accounting for more than 95% of the total bile acids and taurine- or glycine-conjugated bile acids for 10%. In the children with intractable diarrhea, the values for the D-xylose absorption test were lower than the normal range. These results suggested that, in children with short bowel syndrome with diarrhea, the loss of bile acids was strongly associated with a decrease in the actual absorptive surface area of the residual small intestine, and the growth of the normal bacterial flora was disturbed in the residual intestine. Some children with or without diarrhea also had hyper bile acidemia. Ursodeoxycholic acid was not effective for the treatment of hyper bile acidemia or fat malabsorption.

Adolescent↗

PubMed1997

The relationship between moyamoya disease and bacterial infection.

To examine the relationship between Moyamoya disease and bacterial infections, authors studied the serum of 85 cases of Moyamoya disease and the influence of Propionibacterium acnes (P. acnes) infection on intracranial arteries in rats. The serum levels of P. acnes antibody, IgM, transferrin (Tf), alpha 2-macroglobulin (alpha 2M) were significantly higher in Moyamoya disease than in normal volunteers. Moyamoya-like changes of the intracranial internal carotid arteries were histopathologically demonstrated in P. acnes infectious rats. These findings suggest that P. acnes and immunological factors might play a role in the pathogenesis of Moyamoya disease.

Adolescent↗

PubMed1997

Studies on cytomegalovirus and Epstein-Barr virus infection in moyamoya disease.

In this study, measurement of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) viral antibody titers and analysis of both viral genomic sequences using polymerase chain reaction (PCR) were performed to clarify the correlation of viral infection and Moyamoya disease. Serum samples were obtained from 64 patients with Moyamoya disease. The ages ranged from 5 to 66 years, with a mean age of 35.1 years. There were 23 males and 41 females. The serum antibody titers to CMV and EBV were measured by means of compliment fixation test and fluorescent antibody method respectively. Those titers of the patients were compared with those of 13 patients of atherosclerotic internal carotid occlusion and 34 normal volunteers. On the other hand, CMV and EBV genomic sequence using PCR, which was utilized with specific primer pairs, were performed in 22 patients of Moyamoya disease and ten normal volunteers. The following results were obtained; The antibody titer of EBV in Moyamoya disease was significantly higher than that in controls. However, no significant difference of antibody titer against CMV was detected. In EBV DNA analysis by use of PCR, EBV DNA was proved in 15 out of 20 patients with Moyamoya disease and four out of nine normal controls. Namely, EBV DNA was seen more frequently in patients with Moyamoya disease, compared with normal controls. In inverse, CMV DNA was not seen in patients with Moyamoya disease nor normal controls. In conclusion, the antibody titer of EBV revealed high levels in Moyamoya disease and EBV DNA was also detected more frequently in patients with Moyamoya disease. These results suggested a possibility that EBV infection might be involved in the pathogenesis of Moyamoya disease.

Adolescent↗

PubMed1997

Absorption, distribution, metabolism and excretion of a new, 14C-labelled oxazolidinone MAO-A inhibitor in rat and dog.

1. After oral administration of 14C-labelled (5R)-3-[2-((1S)-3-cyano-1-hydroxypropyl)benzothiazol-6-yl]-5-metho xymethyl -2-oxazolidinone (E2011) at a dose of 1 mg/kg, the blood level of radioactivity reached a maximum concentration (Cmax) of 0.545 microgram eq./ml after 0.25 h in the rat and of 0.900 microgram eq./ml after 0.5 h in the dog. In dog plasma, Cmax for radioactivity and unchanged E2011 were 0.862 microgram eq./ml and 0.650 microgram/ml respectively with corresponding Tmax (time at Cmax) of 0.75 and 0.25 h. The unchanged drug in dog plasma was below the detection limit (5 ng/ml plasma) after 24 h. 2. The tissue levels of radioactivity were measured at 0.25 (Tmax), 6, 24, and 168 h after administration to the rat and at 0.5 (Tmax), 24, and 168 h in the dog. The radioactivity was distributed in all tissues examined at Tmax in the rat and dog. The radioactivity levels of the cerebral cortex in the rat and dog were 26 and 36% of the plasma level at Tmax. The radioactivity in tissues decreased at almost the same rate as that in plasma. Plasma protein binding of the unchanged drug in the rat in vitro were about 70% in the range of 0.1-10 micrograms/ml, and those in the dog were about 45% in the same concentration range. 3. Cumulative excretion of radioactivity in the rat was 74.5% in urine and 22.5% in faeces after 7 days. In the dog, 55.5 and 36.5% of the radioactivity administered were excreted in urine and faeces respectively after 7 days. The biliary excretion of radioactivity in the cannulated rat was 23.0% within 48 h. 4. In tlc analysis of plasma and tissues of the rat and dog, the radioactivity for the unchanged drug was much higher than metabolites. In tlc analysis of urine, the same metabolites were detected in the rat and dog, and the radioactivity of a metabolite, IM1, was the highest in the both animals. Eight metabolites were detected in the plasma, tissues and excreta of the rat, and four metabolites in the dog. 5. In conclusion, the absorption, distribution, metabolism and excretion of 14C-labelled E2011 in the rat and dog have been established, and only minor differences were observed between these species.

Absorption↗

PubMed1997

Volatile anaesthetic effects on calcium conductance of planar lipid bilayers formed with synthetic lipids or extracted lipids from sarcoplasmic reticulum.

Volatile anaesthetics are known to increase leakage of calcium from the light fraction of skeletal sarcoplasmic reticulum (L-SR) which has no calcium release channels. To explore the role of the lipid environment, we have examined the effect of volatile anaesthetics on calcium conductance (gCa) of lipid membranes. Planar lipid bilayers were formed with a mixture of synthetic phospholipids and cholesterol, resembling the composition of SR membranes, or with lipids extracted from skeletal L-SR, gCa was estimated by calculating the calcium transference number (tCa) using diffusion potential measurements. Membranes formed with L-SR-extracted lipids had a higher gCa than membranes formed with synthetic lipids. Volatile anaesthetics increased total conductance and gCa in a dose-dependent manner, but did not affect tCa or membrane specific capacitance. In membranes formed with L-SR-extracted lipids, isoflurane induced the largest increase in gCa (1260 (SEM 304) % increase, n = 4, 0.94 mmol litre-1), followed by enflurane (264 (75)%, n = 5, 1.88 mmol litre-1) and halothane (53 (33)%, n = 5; 1.54 mmol litre-1). In membranes formed with synthetic lipids, volatile anaesthetic-induced increases in gCa followed the same trend but were larger. Volatile anaesthetics increased gCa without changing the ionic selectivity of membranes. However, the magnitude of the increase in gCa in the presence of volatile anaesthetics cannot account for the previously observed calcium leakage from L-SR vesicles. Therefore, the volatile anaesthetic-induced increase in calcium leakage in L-SR vesicles must be mediated via other pathways involving membrane proteins.

Anesthetics, Inhalation↗

PubMed1997

Differential effects of thiopental on neuronal nicotinic acetylcholine receptors and P2X purinergic receptors in PC12 cells.

BACKGROUND: PC12 cells, derived from rat pheochromocytoma, express neuronal nicotinic acetylcholine receptors (nAchRs) and P2X purinergic receptors, both of which resemble the receptors in postganglionic sympathetic neurons. The former is the established and the latter is the putative receptor to mediate fast synaptic transmission. The authors investigated effects of thiopental on these two ligand-gated ion channels. METHODS: Whole cell currents were recorded in PC12 cells without treatment of nerve growth factor, using conventional whole cell patch clamp technique. Nicotine or adenosine triphosphate (ATP) 30 microM was applied for 4-5 s in the absence or presence of thiopental 3-300 microM. RESULTS: Nicotine induced the rapidly decaying inward current at -60 mV, which exhibited the characteristics of the neuronal nAchR-mediated current. Thiopental inhibited the nicotine-induced inward current and accelerated the current decay in a dose-dependent manner, resulting in the greater effects on the steady current than the peak current. IC50s for the peak and steady current were 56.7 and 7.4 microM, when the anesthetic was coapplied with nicotine. Thiopental's inhibition was not associated with a change in the reversal potential and was voltage-independent at membrane potential of -30 to -70 mV. Most of thiopental's effects seemed to require channel opening. In contrast to the nicotine-induced current, thiopental had little effect on the current elicited by ATP. CONCLUSIONS: Thiopental, whose reported EC50 for general anesthesia is 25 microM, inhibited the neuronal nAchR-mediated current but not the P2X receptor-mediated response in PC12 cells at clinically relevant concentrations. Inhibition may result in suppression of synaptic transmission in sympathetic ganglia.

Adenosine Triphosphate↗

PubMed1997

Effects of ICRF-193, a catalytic inhibitor of DNA topoisomerase II, on sister chromatid exchange.

To investigate whether mammalian DNA topoisomerase II is directly involved in recombination events, the effects of ICRF-193, a specific catalytic inhibitor on sister chromatid exchange (SCE), were examined in MR-6 cells. ICRF-193 only slightly elevated SCE formation after 3 or 44 h treatments, while VP-16, a cleavable complex forming type of topoisomerase II inhibitor, caused significant enhancement. ICRF-193 had no effect on N-methyl-N'-nitro-N-nitrosoguanidine-induced SCE formation. It would thus appear that the inhibition of topoisomerase II does not affect recombinational repair, and that topoisomerase II inhibitors such as VP-16 and 4'-(9-acridinyl amino) methane sulfon-m-anisidide induce SCE through production of DNA strand breaks, rather than by inhibiting the enzyme activity.

Antineoplastic Agents, Phytogenic↗

PubMed1997

High levels of circulating interleukin-4 and interleukin-10 in Kawasaki disease.

For analysis of the cytokine network in Kawasaki disease (KD), we measured over time the plasma levels of interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 in patients with KD. Fifteen patients with KD were studied. Eight healthy children were selected as control subjects. Circulating IFN-gamma levels were measured by immunoradiometric assay, and IL-4 and IL-10 levels were measured by enzyme-linked immunosorbent assay. The results were as follows: (1) The plasma levels of IFN-gamma in KD patients in the acute phase were significantly higher than the levels of patients in the convalescent phase (p < 0.05) and those of the control children (p < 0.05). (2) The plasma levels of IL-4 in the KD patients in the acute phase were significantly higher than the levels of the patients in the convalescent phase (p = 0.001) and those of the control children (p = 0.001). (3) The plasma levels of IL-10 in the KD patients in the acute phase were significantly higher than the levels of the patients in the convalescent phase (p < 0.03) and those of the control children (p < 0.005). (4) The investigation of the relationship between the IL-4 and IFN-gamma levels during the acute phase of KD demonstrated a significant reciprocal relationship (p < 0.05). (5) There was no significant relationship between the IL-4 and IL-10 levels during the acute phase. However, plasma IL-10 levels were low in the patients with high levels of plasma IL-4, and the patients with high levels of IL-10 revealed low levels of plasma IL-4. The above results suggested that a variety of patterns of cytokine production was present in the acute phase of this disease, and that the key cytokine, which might regulate the cytokine network, was IL-4.

Case-Control Studies↗

PubMed1997

Analysis of dissociated single neurons by simple and semi-quantitative RT-PCR (reverse transcription and polymerase chain reaction).

We have developed a simple and semi-quantitative method for mRNA determination in single cells using the reverse transcription and polymerase chain reaction (RT-PCR). The distinct features of this method are the highly efficient RNA harvest from whole dissociated cells and the ability to perform all RT procedures in one tube that allowed semi-quantitative determination of mRNA in dissociated cells. This method revealed that histamine H1-receptor mRNA was highly expressed in 5/28 small and 1/26 large dorsal root ganglion neurons of the mouse.

Animals↗

PubMed1997

Clinical analysis of recurrent subarachnoid hemorrhage after neck clipping surgery.

The clinical features of recurrent subarachnoid hemorrhage (SAH) after neck clipping surgery were investigated in a series of 1,436 consecutive patients treated between 1980 and 1994, and seven patients treated prior to 1980. Recurrent SAH occurred within 1 month in seven patients and between 1.5 and 20 years in 20 patients (mean interval 9.2 years) from the first surgery. The patients were aged from 31 to 76 years (mean 49.8 years) at the first SAH. There were 19 females and eight males. Recurrent SAH occurred at the same site as the prior aneurysms in 12 cases, at an infundibular dilatation in three cases, de novo aneurysms in nine cases, untreated multiple aneurysms in two cases, and unknown in one case. The main causes for early recurrent SAH were incomplete clipping or untreated multiple aneurysms, whereas late recurrent SAH was due to de novo aneurysms, untreated multiple aneurysms, or regrowth aneurysm at the prior site. The outcomes of late recurrent SAH were good in eight cases, moderate disability in two, severe disability in three, and dead in seven, whereas most cases of early recurrent SAH resulted in poor outcome. Immediate postoperative angiography is desirable in cases with incomplete clipping, because early recurrent SAH resulted in poor outcomes. De novo or regrowth aneurysms caused late recurrent SAH, so follow-up angiography is strongly recommended for young patients, even if complete clipping was achieved.

Adult↗

PubMed1997

The sex differences in cord-blood cholesterol and fatty-acid levels among Japanese fetuses.

We examined serum cholesterol and fatty-acid levels of cord blood and maternal blood samples collected from 193 Japanese fetuses and their mothers. Our study, which is the largest study of this kind ever conducted in Japan, is the first Japanese study reporting that total, high density lipoprotein (HDL) and non-HDL cholesterol levels in females were statistically significantly higher than those in males; the sex differences of total, HDL and non-HDL cholesterol levels were 8.5 mg/dl (P = 0.002), 4.5 mg/dl (P = 0.004) and 4.1 mg/dl (P = 0.045), respectively. The sex difference of total cholesterol was attributable to both HDL and non-HDL cholesterol. The sex of fetuses didn't show evident differences in cholesterol levels in maternal sera. Fatty-acid levels in cord blood were also higher in female fetuses than in male fetuses. However, none of the differences except for monoene fatty acids were statistically significant. Further investigations seem warranted to elucidate the mechanisms involved in our results.

Adult↗