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T Ohno

Publications and source records attributed to T Ohno.

At least 541 records · Page 30Linked to original sources
PubMed1991

Correlation between nucleolar organizer region score and bromodeoxyuridine labeling index in C6 glioma cell line.

Correlation between the mean number of nucleolar organizer region-associated argyrophilic proteins (AgNORs) per cell and BrdU labeling index (LI), the percentage of S-phase cells, was investigated in vitro using rat C6 glioma cells under several different conditions such as increased concentration of fetal calf serum (FCS) in a stepwise manner in medium. In addition, the effect of dibutyryladenosine cyclic monophosphate (d-cAMP) on the mean number of AgNORs and the BrdU LI was examined. C6 glioma cells cultured with no FCS showed 5.1% BrdU LI and 3.46 AgNOR score. BrdU LI and AgNOR score of the cells cultured with 1% FCS were 26.5% and 6.25, respectively. Those with 5% FCS were 44.7% and 8.41, with 10% FCS; 49.8% and 10.85, and with 20% FCS; 48.4% and 10.64. Treatment of d-cAMP with 10% FCS induced morphological differentiation and reduced BrdU LI (9.4%) and AgNORs score (4.90), compared with C6 cells cultured in medium containing 10% FCS without d-cAMP. Thus, the BrdU LI and AgNOR score of the C6 cells cultured under several different concentration of FCS were shown to be well linearly related (r = 0.97) and both values were decreased with morphological alteration of C6 glioma cells in the presence of 1 mM d-cAMP.

Animals↗
PubMed1991

Silver-stained nucleolar organizer proteins in chondrosarcoma.

Silver-stained nucleolar proteins (AgNORs) were counted in primary chondrosarcomas of three histologic grades and in metastatic chondrosarcomatous lesions in the lung. The AgNOR numbers of neoplastic cells in primary tumors increased stepwise from grade 1 (4.42 +/- 1.11) through grade 2 (4.94 +/- 1.31) to grade 3 (6.97 +/- 1.10). There was a significant difference in AgNOR numbers between grade 3 and both grades 1 and 2 (p less than 0.001). Furthermore, the mean number of AgNORs in metastatic lesions (9.75 +/- 0.83) was significantly higher than that in primary sites (p less than 0.001). The number of AgNORs therefore reflects the grade of the chondrosarcoma. The results in the present study indicate that silver colloid staining is a useful technique for determining the histologic grade and evaluating the proliferative activity of chondrosarcomas.

Antigens, Nuclear↗
PubMed1991

Physiological significance of fatty acid elongation system in adrenoleukodystrophy.

We studied the metabolism of radioactive fatty acids in cultured skin fibroblasts from patients with adrenoleukodystrophy (ALD) and Zellweger syndrome (ZS) to clarify the physiological significance of the fatty acid elongation system in the accumulation of very long chain fatty acids (VLFA) in ALD. A substantial amount of radioactive C26:0 was synthesized from [18-14C]stearic acid by ALD and ZS fibroblasts, whereas radioactive C26:0 was not detected in control fibroblasts. Kinetic studies demonstrated that the production of radioactive C24:0 and C26:0 in ALD fibroblasts is higher than that of ZS fibroblasts, which suggests that the fatty acid elongation activity plays an important role for the accumulation of VLFA in ALD, in addition to the decreased VLFA oxidation activities. The addition of monounsaturated fatty acids including oleic acid and erucic acid specifically lowered the formation rate of VLFA without any significant effect on degradation activities of VLFA both in ALD and control fibroblasts. The results suggest that the mechanism of decrease of VLFA by administration of monounsaturated fatty acids is based on the inhibition of fatty acid elongation activity.

Adrenoleukodystrophy↗
PubMed1991

Proliferative assessment of GFAP-positive and GFAP-negative glioma cells by nucleolar organizer region staining.

The proliferative potential of two types of tumor cells that did or did not express glial fibrillary acidic protein (GFAP) in 19 cases of high-grade gliomas, including nine anaplastic astrocytomas (WHO criteria, grade 3) and 10 glioblastoma multiforme (grade 4), was investigated by a combined staining technique, one-step silver colloid method for nucleolar organizer region-associated argyrophilic protein (Ag-NOR) and immunocytochemistry for GFAP. The mean numbers of Ag-NORs in GFAP-positive cells and GFAP-negative cells of high-grade gliomas were 2.68 and 3.74, respectively. The value of GFAP-negative cells was significantly greater than that of GFAP-positive cells (p less than 0.01). Our results show that, by means of the immunocytochemistry for GFAP, tumor cells in human high-grade gliomas can be divided into two groups expressing GFAP or not, and that the mean number of Ag-NORs of GFAP-negative cells is more representative of the degree of histological malignancy than that of positive cells. It is considered that the proliferative assessment of GFAP-negative tumor cells in high-grade gliomas by combined staining of Ag-NOR silver staining and GFAP immunocytochemistry is useful for understanding the histological malignancy of high-grade gliomas.

Astrocytoma↗
PubMed1991

Interference in the radioimmunoassay of gastric prostaglandins by cimetidine, a histamine H2 blocker.

The present study was undertaken to assess whether cimetidine alters the levels of endogenous prostaglandin (PG) E2 and 6-keto-PGF1 alpha in the rat stomach. When cimetidine was mixed in vitro with a suspension of dextran-coated charcoal, to which [3H]-PGE2 had been adsorbed, levels of free [3H]-PGE2 were increased by cimetidine at concentrations above 1.0 mM, because of preferable adsorption of this blocker to the charcoal. Dextran-coated charcoal is used for the separation of antibody-bound [3H]-PGs from the free labelled compounds in the radioimmunoassay of PGs. Addition of cimetidine to standard solutions of PGE2 shifted the PGE2 calibration curve upward. Thus, when PGs in cimetidine-containing samples were quantitated by reference to the normal calibration curve, the assessed levels of PG were lower than the actual levels. Removal of cimetidine from the assay samples was successfully achieved by use of SEP-PAK C18 columns. Rats were injected intraperitoneally with 100 mg/kg of cimetidine only once or with 20 mg/kg twice daily for 7 days. Using this cleaning method, we found that both the basal levels of PGE2 and 6-keto-PGF1 alpha and those levels increased by intragastric administration of 1.0 M NaCl solution did not differ between rats treated with cimetidine and those treated with vehicle. It can be, therefore, concluded that cimetidine does not affect the gastric PG production.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Stimulation of the caudate nucleus induces contraversive saccadic eye movements as well as head turning in the cat.

The effects of stimulation of the caudate nucleus were investigated in alert cats, with special reference to the induction of eye and head movements. Stimulation of caudal portions of the caudate nucleus on one side with trains of current pulses induced gaze shifts towards the contralateral side. When the head of the animal was restrained, the majority of evoked eye movements were single conjugate saccades. The amplitude and direction of the evoked saccade varied depending on the initial eye position. The amplitude of the horizontal component tended to be larger for saccades initiated from more ipsilateral positions, and became gradually smaller as the initial eye position shifted to the contralateral side. If the eye was far into the contralateral positions, no saccades were induced. Furthermore, the saccades tended to have a downward component when the eye was initially focused upward, and an upward component when the eye was focused downward. When the head was made free to move, the same stimulation induced a sequence of contraversive staircase gaze shifts composed of coordinated eye and head movements. The eye movements in the orbit resembled nystagmus, consisting of contraversive saccades followed by reverse compensatory movements. The head turning, though smooth and continuous, was also suggested to consist of a series of movements coupled with saccadic eye movements. This study indicates a potential role of the caudate nucleus in the control of orienting reflexes.

Animals↗
PubMed1991

Shaking HIV-1 infected cells indicates novel behavior of MN strain.

The shaking method of harvesting human immunodeficiency virus type 1 (HIV-1) is a powerful method of obtaining high titer, highly infective virus solutions. In this method infected cells are suspended in a small volume of liquid and the mixture is shaken. Viral infectivity, measured by tissue culture infective dose (TCID50) studies, rises faster than virus titer, as measured by reverse transcriptase levels. It is postulated that this disproportionate increase in infectivity results from improved infectivity for the virus particles obtained from shaking the infected cells. Of the five strains of HIV-1 studied (IIIB, AL1212, 906, RJ4029, and MN), one strain, MN, behaved differently than the others. Upon shaking, its virus titer increased 18-fold, as opposed to the 5-10 fold increase demonstrated by the other strains. These results may indicate that MN virions are retained more on the surface of the infected cells, rather than budding off into the surrounding medium, than other HIV-1 strains. In support of this theory it was found that ratios of immunofluorescence assay scores to reverse transcriptase levels were higher for MN than for other strains.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Cytological characteristics of human glioma-infiltrating lymphocytes stimulated with recombinant interleukin 2 and an anti-CD3 antibody.

Tumor-infiltrating lymphocytes (TIL) were generated from 10 glioma specimens by using recombinant interleukin-2 and an anti-CD3 antibody (CD3 + TILs). We obtained more than 1 x 10(9) cells in 5 cases, more than 5 x 10(8) cells in 2 cases, and about 1 x 10(8) cells in 3 cases during three weeks of incubation from small specimens ranging in weight from 0.5 to 2.0 g. In 4 cases, TILs were expanded following stimulation with only rIL-2 (CD3-TILs). The growth rate of CD3-TILs was less than that of CD3 + TILs. Cytotoxicity of CD3 + TILs was lower than that of lymphokine-activated killer (LAK) cells in a standard 4h 51Cr release assay. Cold target inhibition was undertaken in three cases and specific cytotoxicity could be shown in only one case. CD3 + TILs mainly consisted of CD3-positive cells, ranging from 63.2 to 99.9%. The ratio of CD4-positive cells to CD8-positive cells was not constant. The expression of Leu 7 and CD16 was low. The present study did not confirm previous findings that TILs were more tumor-selective and potent than LAK cells. Furthermore, the results on in vitro antitumor activity of those cells were not necessarily consistent with the results on their clinical activity. Further careful work is necessary on the preparation of immunocytes and the subsequent adoptive immunotherapy.

Adult↗
PubMed1991

Kinetics of adenosine triphosphate hydrolysis by shortening myofibrils from rabbit psoas muscle.

1. Using a solenoid-operated mixing device, time-resolved measurements were made of shortening and accompanying ATP hydrolysis at 20 degrees C by myofibrils prepared from rabbit psoas muscle. 2. The extent of ATP hydrolysis was determined by an improved Malachite Green method for determination of inorganic phosphate (Pi) in the presence of a large excess of ATP. For the measurement of the change in sarcomere length by phase contrast microscopy, shortening was terminated without delay and artifact by a mixture of 0.2 M-acetate (pH 4.6) and 1.25% (v/v) glutaraldehyde. 3. The shortening velocity per half-sarcomere was 10 microns s-1 in 25 mM-KCl for sarcomere lengths above 1.4 microns, and at least 12 microns s-1 in 150 mM-KCl for sarcomere lengths above 1.7 microns. During this rapid shortening, there was no significant ATP turnover by cross-bridges (upper 95% confidence limit: 0.14 mol (mol of myosin head)-1 in 25 mM-KCl; 0.12 mol mol-1 in KCl solutions greater than or equal to 100 mM). 4. When the sarcomeres shortened below 1.7 microns in KCl concentrations greater than 100 mM or below 1.4 microns in 25 mM-KCl, there was a transient acceleration of ATP hydrolysis (delayed ATP hydrolysis), which was then followed by a steady slow hydrolysis. 5. The magnitudes (+/- estimated standard deviation) of delayed ATP hydrolysis by myofibrils of initial sarcomere length 2.4 microns were 0.42 +/- 0.19, 0.31 +/- 0.10 and 0.17 +/- 0.09 mol (mol myosin head)-1 in 25 mM, 100 mM and 150 mM-KCl, respectively. For myofibrils of sarcomere length 2.0 microns, however, it decreased to 0.24 +/- 0.10 mol mol-1 in 25 mM-KCl or to an insignificant level in 150 mM-KCl. 6. These results indicate that most of the ATP hydrolysis products remain bound to cross-bridges during rapid shortening, and that when the force opposing shortening increases, a proportion of cross-bridges rapidly dissociate the products and enter the next ATP cycle, which diminishes with the decrease in shortening distance as well as the increase in ionic strength. Such behaviour of the cross-bridge is probably a manifestation of its energetic and kinetic properties in the state with bound ADP and Pi interacting with actin filaments at zero load and at a transition from zero to non-zero loads.

Adenosine Triphosphate↗
PubMed1991

Specific cessation of minus-strand RNA accumulation at an early stage of tobacco mosaic virus infection.

The time course of accumulation of viral plus-strand RNAs (genomic RNA and subgenomic mRNA for the coat protein) and minus-strand RNA in tobacco protoplasts synchronously infected with tobacco mosaic virus (TMV) RNA was examined. In protoplasts infected with the wild-type TMV L RNA, the plus and minus strands accumulated differently not only in quantity but also in the outline of kinetics. The time courses of accumulation of the genomic RNA and coat protein mRNA were similar: they became detectable at 2 or 4 h postinoculation (p.i.), and their accumulation increased until 14 to 18 h p.i. The accumulation rate reached the maximum at about 4 h p.i. and then gradually decreased. In contrast, accumulation of the minus-strand RNA ceased at 6 to 8 h p.i., at which time the plus-strand accumulation was already about 100 times greater and still continued vigorously. This specific halt of minus-strand accumulation was not caused exclusively by encapsidation of the genomic RNA, because a similar halt was observed upon infection with a deletion mutant that lacks the 30K and coat protein genes. Upon infection with a mutant that could not produce the 130K protein (one of the two proteins that are thought to be involved in viral RNA replication), the accumulation levels of both plus and minus strands were lower than that of the parental wild-type virus. Given these observations, possible mechanisms of TMV replication are discussed.

Cell Transformation, Viral↗
PubMed1991

Mouse DNA primase plays the principal role in determination of permissiveness for polyomavirus DNA replication.

We have investigated the species-specific replication of polyomavirus DNA in the cell-free system that was established previously (Y. Murakami, T. Eki, M. Yamada, C. Prives, and J. Hurwitz, Proc. Natl. Acad. Sci. USA 83:6347-6351, 1986). Extracts from various species of cells supported polyomavirus DNA replication in a species-specific manner that was consistent with the host range specificity of polyomavirus; extracts prepared from mouse and hamster cells were active, whereas extracts prepared from human, monkey, and insect cells were inactive. The addition of DNA polymerase alpha-primase purified from mouse cells induced the replication of polyomavirus DNA in a cell-free system containing polyomavirus large tumor antigen and nonpermissive cell extracts, such as human and insect cell extracts. Isolated mouse DNA primase alone also induced polyomavirus DNA replication in human cell extracts but not in insect cell extracts, indicating that mouse DNA primase plays the principal role in determining permissiveness for polyomavirus DNA replication.

Animals↗
PubMed1991

Effects of prolactin on fertilization and cleavage of human oocytes.

The effects of PRL on fertilization and cleavage of human oocytes and subsequent pregnancy were studied. Forty-five patients (47 cycles) with euprolactinemic normal menstrual cycles undergoing in vitro fertilization (IVF) for the treatment of tubal infertility were selected for this study. The patients were divided into three groups dependent upon their mean serum PRL concentrations for the 3 days prior to oocyte retrieval; hypoprolactinemic (less than 10 micrograms/l), euprolactinemic (10-30 micrograms/l) and hyperprolactinemic cycles (greater than or equal to 30 micrograms/l). Multiple follicular development was induced with hMG, and 10 patients were randomized to receive bromocriptine beginning with the previous menstrual cycle. In the hypoprolactinemic cycle group, the fertilization rate was significantly lower than in the hyperprolactinemic cycle group, and the cleavage rate was significantly lower than in the other groups. The fertilization rates and the cleavage rates in the hyperprolactinemic cycle group were higher than those in the euprolactinemic cycle group; however, these differences were not statistically significant. While the pregnancy rates in the euprolactinemic cycle group were higher than in the other two groups, the numbers were too small for meaningful statistical comparison. The present study demonstrates that below normal concentrations of PRL have deleterious effects on IVF outcome. These data suggest that PRL may play a beneficial stimulatory role in oocyte maturation and the acquisition of developmental capacity.

Adult↗
PubMed1991

Studies on cardiotonic agents. VI. Synthesis of novel 4,5-dihydro-3(2H)-pyridazinone derivatives carrying some benzoheterocycles at the 6-position.

Several benzothiazolyl, imidazobenzothiazolyl, benzothienyl, benzothienopyrimidinyl and quinazolinyl 4,5-dihydro-3(2H)-pyridazinones were synthesized and examined for cardiotonic activity in anesthetized dogs after i.v. administration. Among them, 4-methylamino-7-(2,3,4,5-tetrahydro-5-methyl-3-oxo-6- pyridazinyl)quinazoline (36) showed potent and long-lasting inotropic activity (relative potency = 2.11, milrinone = 1). The activity of 36 was more potent than indolidan (2) (relative potency = 1.53) which is one of the most potent inotropic agents to date.

Animals↗
PubMed1991

Studies on cardiotonic agents. V. Synthesis of 1-(6,7-dimethoxy-4-quinazolinyl)piperidine derivatives carrying various 5-membered heterocyclic rings at the 4-position.

A series of 1-(6,7-dimethoxy-4-quinazolinyl)piperidines carrying various 5-membered heterocycles at the 4-position was synthesized and examined for cardiotonic activity in anesthesized dogs. The (4-oxo-2-thioxo-3-imidazolindinyl)amino derivatives showed the most potent inotropic activity. Marked loss of activity was observed in the 2,4-dihydro-3-thioxo-3H-1,2,4-triazolyl, the 2,4-dihydro-3-oxo-3H-pyrazolyl and the (2,3-dihydro-2-thioxo-3H-1,3,4-thiadiazol-5-yl)amino derivatives. The synthesis and structure-activity relationships are discussed.

Animals↗
PubMed1991

Studies on cardiotonic agents. VII. Potent cardiotonic agent KF15232 with myofibrillar Ca2+ sensitizing effect.

A series of novel 4,5-dihydro-5-methyl-6-(2 or 4-substituted 7-quinazolinyl)-3(2H)-pyridazinones was synthesized and examined for cardiotonic activity in anesthetized dogs. The 4-substituted aminoquinazolines generally showed potent and long-lasting inotropic activity. Fall in the activity was observed on the introduction of substituent at the 2-position of the quinazoline ring. The 3-substituted 4 (3H)-quinazolinimines generally exhibited weak activity. Ca2+ sensitizing effect of the 4-substituted amino derivatives was also examined in chemically skinned fiber from papillary muscle of guinea pig. The alkylamino derivatives exhibited small sensitizing effect, while the benzylamino derivatives exhibited large effect. Among them, KF15232 (Ix) was found to have the most potent cardiotonic and Ca2+ sensitizing activities.

Animals↗
PubMed1991

Difference in pressor responses to NG-monomethyl-L-arginine between conscious and anesthetized rats.

NG-Monomethyl-L-arginine (L-NMMA; 0.1-10 mg/kg, i.v.), a selective inhibitor of nitric oxide (NO) synthesis derived from L-arginine, elicited a greater increase in blood pressure in urethane/alpha-chloralose- and pentobarbital-anesthetized rats than in conscious Wistar rats. The pressor response to phenylephrine was almost equivalent in both conscious and anesthetized rats. These findings suggest that the experimental conditions (anesthetized or conscious) modify the spontaneously released NO's contribution to blood pressure regulation in vivo.

Anesthetics↗