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K Ohtani

Publications and source records attributed to K Ohtani.

At least 199 records · Page 11Linked to original sources
PubMed1990

[Effects of gonadotropin on the growth of malignant ovarian neoplasms assessed by subrenal capsule assay].

In the present study 18 cases of malignant ovarian neoplasm were studied to determine the possible role of sex steroid hormones and gonadotropins on tumor development. Twelve cases of serous cystadenocarcinoma, 2 of mucinous cystadenocarcinoma, 2 of endometrioid carcinoma, one malignant Brenner tumor, and one yolk sac tumor were examined with respect to their response to estradiol (E2), [D-Ser(But)6]-LHRH (1-9) nonapeptide-etylamide (Buserelin), human menopausal gonadotropin (HMG), RU 38486 (RU), and pure FSH by subrenal capsule assay (SRCA). Also 125I-FSH binding assay and the protein kinase C (CK) activity were studied in vitro. The results showed; 1) Seventy-three% cases showed a significant increase (p less than 0.05) in size due to SRCA. 2) In the FSH, HMG, and Buserelin treated groups, the size of xenografts increased (p less than 0.05) and the highest response was obtained with FSH. 3) Ninety-one% of cases demonstrated in vitro FSH specific binding which was significantly higher (p less than 0.05) in the cases which responded to gonadotropins in SRCA (42,288 +/- 25,454 vs 6,980 +/- 1,952, mean +/- SD, cpm/mg tissue). 4) CK activity was increased significantly (p less than 0.05) by gonadotropin (204.5 +/- 2.4 vs 363.9 +/- 7.2, mean +/- SD, cpm/mg tissue). These results suggest that gonadotropins possibly play a role in prompting the tumorigenesis of the malignant ovarian neoplasms through specific receptors and this mechanism may modify the CK system in malignant ovarian neoplasms.

Adenocarcinoma↗
PubMed1990

Antitumor activity of T-2 toxin-conjugated monoclonal antibody to murine thymoma.

T-2 toxin (T-2(4)), one of the trichothecene mycotoxins produced by various gerera of Fusarium spp., is a potent inhibitor to the syntheses of protein and DNA in mammalian cells. The selective cytotoxicity of T-2 toxin-conjugated anti-EL-4 monoclonal antibodies (T-2-mAb) was investigated against murine thymoma EL-4 cells in vitro and in vivo systems. At first T-2 was converted to T-2 hemiglutarate by glutaric anhydride. Then T-2 hemiglutarate was activated to 3-[4-(N-succinimidoxycarbonyl)-butyryl]-T-2 (T-2-G-OSu) by N-hydroxysuccinimide. Thus obtained T-2-G-OSu was conjugated with mAb specific for EL-4 cells. The T-2-mAb markedly inhibited the proliferation of cultured EL-4 cells, but no such cytotoxic effect was observed against irrelevant SP2/0 cells. The cytotoxicity of T-2-conjugated normal gamma globulin (T-2-nGG) against EL-4 cells was far less than that of the above T-2-mAb. Ammonium chloride and monensin, inhibitors of lysosomal enzymes, enhanced the cytotoxicity of T-2-mAb. The presence of both 2-deoxyglucose together with sodium azide, inhibitors of energy-dependent reaction, reduced the cytotoxicity of T-2-mAb. Therefore, the selective binding to the target cells followed by an energy-dependent endocytosis and an intracellular liberation of T-2 by hydrolysis may account for the cytotoxicity of the T-2-mAb. In mice pre-transplanted with EL-4 cells, T-2-mAb increased the mean survival time (MST) with a direct dosage dependence.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Cell line-dependent response of the enhancer element of simian virus 40 to transactivator p40tax encoded by human T-cell leukemia virus type I.

The trans-acting transcriptional factor p40tax of human T-cell leukemia virus type I (HTLV-I) can activate expression not only of its own viral genes but also of other viral and cellular genes. We examined the cis-acting sequences in the simian virus 40 (SV40) enhancer required for its activation by HTLV-I p40tax. Experiments with chloramphenicol acetyltransferase constructs bearing the SV40 enhancer elements revealed that p40tax-dependent transactivation of the SV40 enhancer is mediated through the C element that contains the typical sequence for binding of a nuclear factor NF-kappa B. Activation of the C element by p40tax was seen in a limited set of cell lines as was also seen with the whole enhancer of SV40. Binding of NF-kappa B or NF-kappa B-like factor to the SV40 C element increased when p40tax was expressed. The fact that HTLV-I p40tax utilizes a cellular regulatory mechanism to transactivate the SV40 enhancer in a cell-dependent manner may have implications for the pathogenesis of adult T-cell leukemia.

Base Sequence↗
PubMed1989

Differential activation of the 21-base-pair enhancer element of human T-cell leukemia virus type I by its own trans-activator and cyclic AMP.

A transcriptional trans-acting factor p40tax of human T-cell leukemia virus type I (HTLV-I) functions as an inducer for expression of HTLV-I provirus via activation of the enhancer in the long terminal repeat of HTLV-I. In addition to p40tax and a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, we report here that forskolin, an activator of adenyl cyclase, also induces function of the HTLV-I enhancer. Experiments with mutants of the HTLV-I enhancer revealed that TPA-induced activation was not mediated by solely a 21-base-pair (bp) sequence that is repeated three times in the enhancer, whereas the 21-bp enhancer element can act as a sufficient cis-acting sequence for activation by both p40tax and forskolin. In addition, we found that nuclear factor(s) like the cyclic AMP-responsive element (CRE) binding factor could bind to the HTLV-I 21-bp enhancer element. However, a difference was found in sequences required for activation by p40tax and forskolin. A CRE related sequence present in the 21-bp enhancer element was enough for forskolin-induced activation. On the other hand, p40tax required a much longer sequence that is overlapping but not identical to the CRE related sequence, suggesting that the forskolin-induced cyclic AMP pathway may be partly involved in, but not sufficient for p40tax-mediating trans-activation of the HTLV-I enhancer.

Base Composition↗
PubMed1989

Electroporation: application to human lymphoid cell lines for stable introduction of a transactivator gene of human T-cell leukemia virus type I.

Conditions were developed for stable introduction of foreign DNA into human lymphoid cell lines by electroporation. To introduce stably the p40 gene of human T-cell leukemia virus type I (HTLV-I) into the human lymphoid cell line Jurkat, the p40 expressing plasmid, pMAXRHneo-1, which carries the neo resistant gene, was transfected into Jurkat cells at a voltage of 2500 V and capacitance of 21.7 microF, and stable transformants were screened for neo (G418) resistance. The frequency of transformants was more than one per 2 x 10(5) cells used initially. Clones that were resistant to G418 were shown to have the p40 gene integrated into the host genome and to express mRNA and protein from the introduced plasmid. Expression of p40 in the transformed Jurkat cells was also confirmed by testing the trans-activating effect of HTLV-I enhancer by p40. High frequencies of stable transformations of 10(-4) to 10(-6) were also reproducibly obtained by electroporation of the human T cell lines HSB-2 and TALL-1, a human B cell line Raji, a human monocytic cell line U937, and a human erythroleukemia cell line K562. These results demonstrate that electroporation is a very efficient method for introducing foreign DNA into human lymphoid cell lines.

Blotting, Northern↗
PubMed1989

Emergence of large plaque-producing clones of human immunodeficiency virus (HIV) in vitro.

Large plaque-inducing clones were obtained from small plaque-inducing parental clones of human immunodeficiency virus (HIV) by the plaque-cloning method. The cloned HIVs that formed large and small plaques were studied as follows: 1) infectivity was determined by the ratio of plaque-forming units (PFU) to reverse transcriptase (RT) activity; 2) viral growth was assessed by the amount (RT activity) of virus after infection; and 3) HIV long terminal repeat (LTR)-linked gene expression of the viruses was measured by chloramphenicol acetyltransferase (CAT) assay using persistently infected MOLT-4 cells. Results showed that clones producing large plaques showed similar or slightly lower infectivity but higher virus production, faster viral growth, and higher gene expression activity than clones producing small plaques. These analyses revealed that clones producing large plaques could replicate more rapidly than those producing small plaques. Restriction enzyme map analysis of these cloned viruses showed that they were also genetically different. These results suggest that the changes in the biological features observed here might be due to mutation during the cloning procedure.

DNA, Viral↗
PubMed1989

Functional mapping of the activity of the R region in the human T-cell leukemia virus type I long terminal repeat to increase gene expression.

We previously demonstrated the activity of the R fragment in the long terminal repeat of human T-cell leukemia virus type I for elevation of the level of gene expression. In this study, the fragment was deleted with BAL31 nuclease to determine its functional domain. Series of the shortened R fragments were linked to the simian virus 40 promoter unit, which regulated expression of a reporter gene. Examination with the R fragments deleted from the 5' and 3' ends showed that borders of the functional domain were mapped within nucleotide positions 458 to 473 for the 5' end and nucleotide positions 559 to 594 for the 3' end, respectively. Thus we conclude that a 136-base-pair fragment corresponding to the second half of the R region was sufficient to allow elevation of the level of gene expression.

Base Sequence↗
PubMed1989

A sensitive enzyme-linked immunosorbent assay of ochratoxin A based on monoclonal antibodies.

We prepared seven monoclonal antibodies (mAbs, OTA.1, 2, 3, 4, 5, 6 and 7) which were reacted with ochratoxin A (OTA), and have developed a specific and highly sensitive enzyme-linked immunosorbent assay (ELISA) for detection of OTA. The mAbs, OTA.1, 3, 4, 5 and 7, specifically reacted with OTA but much less with its analogs, ochratoxin B (OTB, about 1% of OTA) and ochratoxin alpha (OT alpha, less than 0.1% of OTA). One of the mAbs, OTA.2, equally reacted with OTA and OTB but hardly at all with (4R)-4-hydroxyochratoxin A or OT alpha (less than 0.1% of OTA). All of the mAbs reacted with ochratoxin C. None of the mAbs reacted with coumarin, 4-hydroxycoumarin or L-beta-phenylalanine. In the competitive ELISA with OTA.1 and OTA.7, the lowest detectable amount of standard OTA in solution was 50 pg/ml (2.5 pg per assay). This assay was applied for the quantitation of OTA added to chicken meat, wheat flour, porcine plasma and bovine serum. With minimal sample preparation, reliable and reproducible determinations were possible when concentrations of OTA were higher than 0.1-1 ng/g.

Animals↗
PubMed1989

Detection of HTLV-I genome in seronegative infants born to HTLV-I seropositive mothers by polymerase chain reaction.

We applied the polymerase chain reaction (PCR) method to detect gag, env and pX sequences of human T cell leukemia virus type I (HTLV-I) provirus in peripheral blood lymphocytes of seronegative infants born to HTLV-I seropositive mothers. Out of 22, five subjects were found to contain the HTLV-I provirus genome. Two of the five cases were judged to be negative for not only anti-HTLV-I antibodies but also the viral antigens on cultivated lymphocytes by the conventional antibody/antigen detection methods. These results indicate that PCR is of great use as a simple and highly sensitive method detect HTLV-I infection.

Adult↗
PubMed1989

Activation of endogenous c-fos proto-oncogene expression by human T-cell leukemia virus type I-encoded p40tax protein in the human T-cell line, Jurkat.

We examined the ability of the trans-acting factor p40tax of human T-cell leukemia virus type I (HTLV-I), which is thought to be a crucial molecule in T-cell transformation by HTLV-I, to activate expression of a set of endogenous cellular genes related to T-cell proliferation. For this purpose we established a subclone (JPX-9) of Jurkat cells that was stably transfected with an expression plasmid containing the p40tax gene, whose expression is definitely dependent on heavy-metal ions. Expression of the interleukin-2 receptor alpha chain in JPX-9 cells was induced in response to the induction of p40tax expression, as has been demonstrated by others in transient transfection experiments with Jurkat cells. In addition, we found that significant enhancement of expression of the nuclear proto-oncogene c-fos was closely associated with expression of p40tax. Continous enhancement in the level of c-fos mRNA was observed in the presence of p40tax. In contrast, mRNA levels of other nuclear proto-oncogenes (c-myc, c-myb, and c-jun) were not appreciably effected by the expression of p40tax. These results suggest that (i) in addition to the interleukin-2-interleukin-2 receptor system, cellular genes such as c-fos, which regulate normal T-cell growth, are also activated directly or indirectly by p40tax and (ii) p40tax-induced modulation of gene expression plays a crucial role in T-cell transformation by HTLV-I.

Blotting, Northern↗
PubMed1989

Cerebral palsy in Tottori, Japan. Benefits and risks of progress in perinatal medicine.

From the changing incidence of cerebral palsy (CP) in the Tottori joint study, the absolute number of saved non-CP babies in the period 1955-1984 in the whole of Japan was calculated as about 33,000. The significant decrease of the incidence in the period 1955-1980 was mainly related to the advances made in perinatal medicine. In contrast, the recent reincrease is attributable to low-birth-weight CP. As for the risk factors for quadriplegia or double hemiplegia of CP, maternal toxemia, low Apgar scores and neonatal abnormal signs were important. Diplegia and paraplegia were significantly correlated with low birth weight. Among the babies weighing below 2,000 g, there was a more than 40-fold increased risk of CP compared with that in the general population. As for the risk for low-birth-weight diplegic CP, the number of abnormal signs in the neonatal period is correlated with the brain damage. The next step in preventing perinatal brain damage might be to give more attention to fetal deprivation and to well-balanced and sensible neonatal care of risk babies.

Cerebral Palsy↗
PubMed1989

Reticuloendothelial system-activating polysaccharides from rhizomes of Panax japonicus. I. Tochibanan-A and -B.

From rhizomes of Panax japonicus (Araliaceae), two polysaccharides named tochibanan-A and -B, which show reticuloendothelial-potentiating activity in the carbon clearance test in mice, were isolated. The structure of tochibanan-A (molecular mass: 23,000) was elucidated as a linear beta-1,4-D-galactan. Tochibanan-B (molecular mass: 40,000) consists of D-galactose (87.1%), L-arabinose, D-glucose and D-galacturonic acid and has a beta-D-(1----4)-linked galactopyranosyl backbone possessing GalA-(1----6)-Gal, Ara-(1----5)-Ara, Gal, and Glc side chains. The structure around the branching points and the repeating unit were investigated and a possible structure of tochibanan-B is proposed.

Animals↗
PubMed1989

[Effects of levocarnitine chloride (LC-80) on hemodynamics and myocardial metabolism in anesthetized open-chest dogs under normoxic or hypoxic conditions].

The effects of LC-80, infused intravenously at a rate of 10 mg/kg/min for 30 min, on hemodynamics and myocardial metabolism were investigated in anesthetized open-chest dog preparations under a normal oxygen tension of arterial blood (PaO2) ranging from 100 to 120 mmHg or low PaO2 ranging from 40 to 50 mmHg. (1) Normal PaO2 + High free fatty acidemia (HFFA): HFFA was produced by the intravenous infusion of Intralipid at a rate of 0.1 ml/kg/min after the rapid intravenous injection of 500 U/kg of heparin. Under this experimental condition, no significant changes in hemodynamics and myocardial metabolism were observed in both the LC-80 treated group and control group. (2) Low PaO2 + HFFA: Under this condition, there was no significant difference in hemodynamics between the LC-80 treated group and the control group, and the myocardial function in both groups tended to decrease. However, the increase in the coronary flow of the LC-80 treated group tended to be slight as compared with that of the control group. On the other hand, the decrease in the arterio-coronary venous difference of lactate was significantly less in the LC-80 treated group as compared to that in the control group. Furthermore, the reduction in myocardial redox potential (delta Eh) of the LC-80 treated group tended to be slight as compared with that of the control group. (3) Low PaO2 + HFFA + stress load: The hemodynamic responses (heart rate, left ventricular pressure, max dP/dt and cardiac work) to isoproterenol-induced stress were slightly but not significantly better in the LC-80 treated group than in the control group. While myocardial lactate production and the reduction of delta Eh in both groups became more prominent under this experimental condition, their degrees were apparently less in the LC-80 treated group as compared to those in the control group. These results suggest that LC-80 may have an improving effect on the anaerobic myocardial metabolism under anaerobic conditions such as hypoxia or stress load.

Animals↗
PubMed1989

[Percutaneous aortic valvuloplasty in the aged using the antegrade or retrograde method: a report of two cases].

Acquired calcified aortic stenosis in elderly patients successfully resolved after percutaneous aortic valvuloplasty (PAV) using the antegrade or retrograde method. The effectiveness and complications of these two methods were compared. A 79-year-old man who had acute myocardial infarction and pulmonary emphysema underwent aortic valvuloplasty using Medi-Tech balloons, 15 mm and 20 mm in diameter, via the brachial artery route. This caused a reduction of the peak and mean aortic valve pressure gradients, from 56 to 30 and from 59 to 35 mmHg, respectively and an increase in the valve area from 0.6 to 0.8 cm2. However, cardiac tamponade developed due to penetration of the left ventricular wall by the guide wire. A 73-year-old man who had transient cerebral ischemia and pulmonary emphysema underwent valvuloplasty by the Inoue's balloon technique (inflated up to 19 mm) via the saphenous vein. This resulted in a reduction of the peak and mean pressure gradients from 35 to 15 and from 39 to 15 mmHg respectively, a month thereafter. There were no complications. To our knowledge, these are the first two reported cases of acquired aortic stenosis which were relieved by percutaneous aortic valvuloplasty in Japan.

Aged↗
PubMed1989

[Percutaneous transvenous mitral valvuloplasty: short-term effects and complications].

Percutaneous transvenous mitral valvuloplasty (PTMV) using the Inoue balloon was performed in 18 patients with symptomatic mitral stenosis. They were seven men and 11 women, ranging in age from 38 to 77 years (mean 59 +/- 10 years). Among them, 13 were categorized as NYHA class II; four as class III; and one as class IV. As a result, the symptoms of 14 patients markedly improved. Survey by means of right and left heart catheterization and echocardiography before and after PTMV demonstrated significant improvement in test values; (1) a decrease in the mean mitral gradient from 8.5 +/- 3.3 to 4.8 +/- 2.0 mmHg (p less than 0.01), (2) an increase in the mean diastolic descent rate of the mitral valve from 17.6 +/- 8.3 to 25.1 +/- 8.1 mm/sec. (p less than 0.01), and (3) an increase in the mean mitral valve area from 1.3 +/- 0.5 to 1.7 +/- 0.5 cm2 (p less than 0.01). Bicycle ergometer stress test performed on the 13 patients before and after PTMV revealed a significant decrease in the mean pulmonary arterial pressure from 24 +/- 5 to 18 +/- 5 mmHg (p less than 0.01) at rest, and from 49 +/- 9 to 42 +/- 7 mmHg (p less than 0.05) after exercise. The degree of mitral regurgitation increased after PTMV in six patients, in three of whom it was severe. The severity was evidenced by a significant increase in the ratio of the mean balloon diameter to body surface area as compared with the data of the other 15 patients (20.6 +/- 2.2 to 18.0 +/- 1.4 mm/m2; p less than 0.05), the presence of a localized sclerosis of the mitral valve as demonstrated by two-dimensional echocardiography, and prolapse of the mitral valve as shown by a left atriogram. These early results indicated that PTMV using the Inoue balloon is an effective treatment for symptomatic patients with mitral stenosis unless severe mitral regurgitation develops. This complication may be partially due to the selection of an inappropriate balloon diameter, and due to co-existing myxomatous degeneration and localized sclerotic changes of the mitral valve.

Adult↗
PubMed1988

[A study of progestin, glucocorticoid binding and glycogen content in rat endometrium before and after implantation: effect of antiprogesterone RU-38486].

Pregnant rats were injected with 3H RU38486 into the uterine cavity on day 2, 4, 5 and 8 of pregnancy. Before implantation, the saturable RU binding increased significantly (day 2 vs. 4; 30.0 +/- 2.3 vs. 640.0 +/- 17.9 dpm/g, p less than 0.001). After implantation, the binding became higher at the nidation site (implantation vs. non-implantation site; 1156.1 +/- 237.1 vs. 595.0 +/- 24.3, p less than 0.001, day 5). The dexamethasone suppressive RU binding, on the other hand, showed no significant increase during day 4, 5 and 8. Daily administration of RU38486 during day 4 and 8 caused failure to implant or to develop normal conceptus. The endometrium in these RU treated animals was stained for tissue glycogen and studied light microscopically. The tissue glycogen content appeared to be markedly decreased in RU treated animals but only at the site of implantation. The decrease was observed in both decidua and trophoblasts but not in myometrium or decidual epithelium. The present results indicate; (1) In rats, endometrial progesterone binding increases prior to implantation. (2) After implantation, the nidation site further increases its saturable progesterone uptake compared to the non-implantation site. (3) When normal process of implantation is inhibited by RU38486 administration, there occurs a decrease in the glycogen synthesis at the nidation site, including decidua and trophoblasts.

Animals↗
PubMed1988

Specific receptors for thromboxane A2 in cultured vascular smooth muscle cells of rat aorta.

The specific binding site for thromboxane A2 (TXA2) was studied in cultured vascular smooth muscle cells (VSMC) of the rat aorta. [3H]SQ29,548, a potent and selective TXA2 receptor antagonist, displayed high-affinity and specificity, as well as saturable and displaceable binding to rat VSMC in culture. Scatchard analysis of equilibrium binding at 24 degrees C revealed a single class of binding sites with a Kd of 1.7 nM and a Bmax of 8.0 fmol/10(6) cells. A series of TXA2 receptor antagonists completely suppressed [3H]SQ29,548 binding to rat VSMC, and the rank order of their inhibitory potencies (Ki) correlated well with the potencies for suppression of the U46619-induced contraction of rat thoracic aorta. These results suggest that specific binding sites for [3H]SQ29,548 represent the TXA2 receptor in rat VSMC.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗