Search PubMed⌕ Search

Biomedical subjects

H Ohmori

Publications and source records attributed to H Ohmori.

At least 361 records · Page 20Linked to original sources
PubMed1982

[Endogenous androgen levels of human prostatic tissues].

Endogenous androgen levels of prostatic tissues in patients with benign prostatic hypertrophy (BPH) and untreated prostatic cancer (PC) were determined by radioimmunoassay using sephadex LH-20 column chromatography. By this assay procedure, it was possible to measure tissue androgen levels with only 30 approximately 40 mg weight of tissues. In BPH (n=20) the concentrations of steroids (mean +/- standard deviation, ng/g. tissue weight) were 5 alpha-androstane 3 alpha, 17 beta diol (A-diol), 2.31 +/- 1.29; dihydrotestosterone (DHT), 4.97 +/- 2.17; testosterone (T), 0.62 +/- 0.33. In PC (n=17) the concentrations were 5.51 +/- 3.23; 3.94 +/- 3.16; and 0.93 +/- 0.38; respectively. The concentrations of DHT were raised and the levels of A-diol were reduced significantly (P less than 0.01) in BPH compared with PC. Tissue DHT levels of PC were variable, but they could be classified in to two groups. One was below 2 ng levels (n=8) similar to those of non-androgen target tissues and the other was over 2 ng (n=19). The relationships between histological differentiation and tissue DHT levels in prostatic cancer were examined. In poorly differentiated cancer (n=4), DHT levels were low in all cases, furthermore even in well differentiated ones there were 4 cases with levels below 2 ng. Thus, the measurement of endogenous DHT levels of prostatic tissues was considered to be valuable for the judgment of androgen dependency in prostatic cancer.

Aged↗
PubMed1982

Mechanism of augmentation of the antibody response in vitro by 2-mercaptoethanol in murine lymphocytes. I. 2-Mercaptoethanol-induced stimulation of the uptake of cystine, an essential amino acid.

The mechanism of augmentation of the primary antibody response in vitro by 2-mercaptoethanol (2-ME) was investigated. By using cystine-free RPMI 1640 medium, it was demonstrated that cyst(e)ine was absolutely required for eliciting the following murine lymphocyte reactions: antibody response to sheep erythrocytes, proliferative response to concanavalin A or lipopolysaccharide (LPS), and polyclonal antibody response induced by LPS. The maximal antibody response was attained with 2.5-5 mM cysteine or half-cystine. The serial feeding of fresh cysteine markedly amplified its capacity to support antibody response particularly when cysteine concentration was suboptimal. Such an effect was not observed in the serial addition of cystine. On the other hand, the dose-response curve of cystine was dramatically shifted to lower concentrations by the addition of 2-ME (1 x 10(-5) M), which alone could not elicit the antibody response in the absence of cystine, nor could it augment furthermore the maximal response induced by 2.5 mM half-cystine. Commercially available RPMI 1640 medium contains 0.41 mM half-cystine, which proved to be a suboptimal concentration for eliciting the maximal response. 35S-cystine was incorporated into murine lymphocytes five to six times more slowly than 35S-cysteine. The rate of cystine uptake, however, was accelerated by 2.5-fold in the presence of 1 x 10(-5) M 2-ME. A close correlation was observed between dose-response profiles of 2-ME in augmenting the antibody response and the stimulation of cystine uptake. These results strongly suggest that one of the roles of 2-ME in augmenting the antibody response in vitro is to facilitate the use of cystine contained in RPMI 1640 medium only at a suboptimal concentration.

Amino Acids, Essential↗
PubMed1982

A mechanism of the augmentation of antibody response in vitro by 2-mercaptoethanol: facilitation of cystine uptake in murine lymphocytes.

The mechanism of augmentation of antibody response in vitro by 2-mercaptoethanol (2-ME) was investigated. By employing cystine-free RPMI-1640 medium, it was demonstrated that cystine was absolutely required for eliciting the in vitro antibody response in murine lymphocytes. The augmentation by 2-ME was completely dependent on the presence of cystine. Maximal response was reached when cysteine or cystine (as half cystine) was added at 2.5 mM where 2-ME did not further enhanced the response. The serial feeding of cysteine, but not of cystine, amplified its potentiating activity at lower concentrations (less than or equal to 1 mM). The addition of 10(-5) M 2-ME to cystine shifted the dose-response curve to lower concentrations by about one order of magnitude. It was found that 35S-cystine was incorporated into lymphocytes one fifth more slowly than 35S-cysteine. Cystine uptake was accelerated by about 2.5-fold in the presence of 10(-5) M 2-ME. These data suggest that one of the roles of 2-ME in augmenting antibody response in vitro is to facilitate the uptake of cystine which is contained in RPMI-1640 medium and which is utilized less efficiently than cysteine.

Animals↗
PubMed1982

Development of post-tetanic potentiation at identified inhibitory and excitatory synapses in Aplysia.

1. The development of post-tetanic potentiation (p.t.p.) was studied at three identified synapses in the abdominal ganglion of Aplysia californica. They are (1) the excitatory synapse made onto R(15) by an axon in the right connective (RC(1)-R(15)), (2) the inhibitory synapse made by L(10) onto one of its follower cells in the rostral quadrant of the left abdominal ganglion (L(10)-LUQC), and (3) the excitatory synapse made by L(10) onto RB cells (L(10)-RB). Animals examined ranged from stage 11 juveniles weighing 2 mg to stage 13 adults weighing 300 g.2. Despite a marked decrease of the input resistance (34-fold) and a marked increase in the capacitance of the cells of the LUQC, the amplitude of i.p.s.p. measured at 50 mV more negative than its reversal potential decreases only 4-fold, between juvenile animals (25-65 mg) and adult animals (100 g). This suggests a marked increase in the synaptic current. A similar discrepancy in the extent of decrease between the input resistance and e.p.s.p. amplitude was found in the RC(1)-R(15) synapse during development.3. The amount of p.t.p., after tetanization at 5 Hz for 30 sec, increased with development. At the excitatory RC(1)-R(15) synapse, p.t.p. (defined as the percent of the maximal post-tetanus p.s.p. over the control p.s.p.) increased from 135+/-11% (mean+/-s.d., n = 7) to 334+/-72% (n = 10). At the inhibitory L(10)-LUQC synapse, p.t.p. increased from 99+/-11% (n = 6) to 276+/-58% (n = 7).4. At both types of synapses, the time course of p.t.p. decay was measured by fitting a single exponential function, showing no systematic developmental change in the time constant of p.t.p. decay from the time p.t.p. was first measured onwards. The time constant was 129+/-52 sec (n = 39) for RC(1)-R(15), and 45+/-7 sec (n = 20) for L(10)-LUQC.5. Divergent connexions made by the same presynaptic neurone L(10) on the inhibitory follower cells (L(10)-LUQC) and on the excitatory cells (L(10)-RB) showed the same amount of potentiation in the same animal after an L(10) tetanus. Convergent connexions onto the RB cells from the axon in the right connective and from L(10) produced completely independent potentiation. These results provide an independent support for the well established finding that p.t.p. results exclusively from presynaptic changes.6. At each of these several synapses which show robust p.t.p. in adult animals, p.t.p. appears as a late step in their development. There is thus a discrete and considerable interval of time between the establishment of functional connexions and the emergence of synaptic plasticity in these excitatory and inhibitory synapses in Aplysia.

Aging↗
PubMed1982

Studies of calcium channels in rat clonal pituitary cells with patch electrode voltage clamp.

1. The properties of the Ca channel in tissue cultured clonal cells (GH(3)) isolated from a rat anterior pituitary tumour were studied with the patch electrode voltage-clamp technique.2. To isolate the current through the Ca channel, the currents through the Na channel, the delayed K channel and the Ca(2+) induced K channel were minimized by replacing the external Na(+) with TEA(+) and adding EGTA to the K-free solution inside the patch electrode.3. The selectivity ratios through the Ca channel with different cations were 2.7 (Ba(2+)):1.6 (Sr(2+)):1.0 (Ca(2+)) and the m(2) form of the activation kinetics and the relationships between the time constant and the membrane potential were common to the three divalent cations.4. The amplitude of the Ba(2+) current increased linearly with [Ba(2+)](o) up to 25 mM and thereafter tended to show saturation.5. The current-voltage relation showed a positive shift along the voltage axis as [Ba(2+)](o) increased, probably due to the screening effect of Ba(2+) on the negative surface charges.6. The time constant of activation as a function of the membrane potential showed a parallel shift as [Ba(2+)](o) was increased, suggesting that the activation kinetics were independent of the permeant ion concentration.7. The time constant of the tail current was consistent with m(2) kinetics for opening and closing of the Ca channel.8. The extrapolated ;instantaneous' tail current rapidly increased as the activating membrane potential became more positive and reached an apparent saturation at membrane potentials substantially more positive than the potential that gave the maximum peak inward current, and suggested that the single channel has a sigmoidal current-voltage relationship.9. The power density spectrum obtained during the steady-state inward Ba(2+) current had a cut-off frequency which was nearly voltage independent; this is expected if the fluctuation of the current originates from m(2) activation kinetics.10. The results of noise analysis suggest that the amplitude of the single Ca channel current was about 0.2 pA at 25 mM-Ba(2+) and 0.7 pA at 100 mM-Ba(2+) for membrane potentials in the vicinity of the maximum inward current.

Animals↗
PubMed1982

Effects of steroid sex hormones and adriamycin on human bladder cancer cells in culture.

The effects of steroid sex hormones on the established cell lines derived from human urinary bladder cancer, T24, and from human transitional cell cancer of the urinary tract, 253J, were examined using the colony formation method. Of the seven kinds of steroid hormones tested, estradiol-17 beta was intensively cytotoxic for both cells. The cytotoxic effect was depended on the dose and time of treatment. The combined effect of Adriamycin and estradiol-17 beta on T24 cells could be recognized at low concentrations of Adriamycin (less than or equal to 10(-3) micrograms/ml) after exposure for 24 h.

Aged↗
PubMed1982

[Clinical effect of UFT on bladder cancer].

UFT (a mixture of futraful and uracil) was administered orally to 15 cases of recurrent and superficial bladder cancer principally for more than 4 weeks at the doses of 300 or 600 mg per day. The result was evaluated by Koyama-Saito's response criteria. Of 14 evaluable cases, complete remission was noted in 5. Two cases of advanced bladder cancer were treated with UFT combined with irradiation therapy, and one case was found that cancer cells degenerated severely in the primary lesion pathologically. Another case was recognized that lung metastasis disappeared completely. As the side effects, anorexia occurred in 2 cases with 600 mg per day and 1 case with 300 mg, but it was not so severe to terminate UFT therapy. From above-mentioned results, UFT seems to be a useful drug for the treatment of bladder cancers.

Aged↗
PubMed1982

A novel oxidative degradation of N-nitrosamine via electron transfer.

Anodic oxidation of N-nitrosamines derived from various secondary amines has been investigated by cyclic voltammetry and controlled-potential electrolysis at a glassy carbon electrode in acetonitrile. The nitrosamines give one, two, or three irreversible anodic peaks, depending upon the structure of the parent secondary amines. Electrolysis of simple dialkylnitrosamines gave the corresponding nitramines with coulometric n-values between 1 and 1.5, together with beta-ketonitrosamines in which the carbonyl group is on the same side as the nitroso-oxygen atom. With N-nitrosopiperidine (derived from a cyclic amine), N-nitropiperidine was formed in the same way, but the beta-oxidized nitrosamine was not detected in the solution from electrolysis. Added water (ca. 1%) in acetonitrile had essentially no effect on the electrochemistry of simple dialkylnitrosamines, whereas the first anodic peak of N-nitrosopiperidine was increased and the formation of N-nitropiperidine was inhibited in the macroscale electrolysis. In deoxygenated acetonitrile, the first anodic peaks of all the nitrosamines examined were enhanced and the other anodic peaks became obscure. Macroscale electroysis gave neither the nitramines nor the beta-ketonitrosamines and the coulometric n-value increased. It is suggested that unidentified oxidation processes produce electroactive species whose further oxidation results in various degradation products.

Nitrosamines↗
PubMed1982

SA96: an immunopharmacological profile in vitro.

We have screened from various thiol compounds SA96 (2-mercapto-2-methylpropanolyl-L-cysteine) as a stimulant of LPS-induced proliferative response of murine lymphocytes, and the immunopharmacological profile of this compound was studied in vitro. SA96, only at 10(-3) M concentration, caused 3H-thymidine (3H-TdR)uptake in the presence of foetal calf serum (FCS). The effects of SA96 on the proliferative response to mitogens were biphasic. The uptake 3H-TdR induced by Con A or LPS was suppressed in a dose-dependent manner below 10(-4) M, but was enhanced at 10(-3) M in the case of LPS. The response to Con A was recovered from the suppression at 10(-3) M, but did not exceed the control level. Some experiments suggested that cysteine moiety might importantly contribute to the proliferative response caused by SA96. SA96 enhanced the PFC response to SRBC in vitro at 10(-5) approximately 10(-4) M (nonmitogenic doses), but markedly inhibited the elevated response in the presence of 2-mercaptoethanol (2-ME). On the other hand, PFC response to DNP-Ficoll )a T-independent antigen) was augmented by SA96 irrespective of the presence of 2-ME. These findings suggest that SA96, a thiol compound, may be useful as an immunomodulator like levamisole.

Animals↗
PubMed1981

Development of intrinsic burst generation in identified neuron R15 of Aplysia.

The development of endogenous bursting pattern of identified neuron R15 of Aplysia was studied, in animals ranging from juveniles weighing 27 mg to adult animals weighing 350 g. In the youngest animals studied, R15 only fires irregularly, somewhat later it begins firing in brief bursts, and only in early adulthood does its characteristic burst firing pattern.

Action Potentials↗
PubMed1981

Emergence of posttetanic potentiation as a distinct phase in the differentiation of an identified synapse in Aplysia.

The developmental time course of posttetanic potentiation was studied at an identified chemical synapse. In stage 11 juveniles (3 weeks after metamorphosis), the synaptic connections made by cholinergic neuron L10 onto postsynaptic neurons L2 to L6 were present but showed no posttetanic potentiation. In stage 13 adults (12 weeks after metamorphosis), the same tetanus resulted in an increase of 300 percent in the synaptic potential. A similar pattern was observed at two other identified synapses in the abdominal ganglion. Thus, the initial steps in synapse formation do not include the expression of this plastic capability. Rather, at least 10 weeks is required between the onset of synaptic function and the final expression of mature synaptic properties.

Age Factors↗
PubMed1981

[Plasma 11-deoxycortisol response to single dose metyrapone in prostatic cancer patients (author's transl)].

A radioimmunoassay procedure for plasma 11-deoxycortisol (S) was developed using an antiserum prepared by immunizing rabbits with S-21-hemisuccinate bovine serum albumin and S-3-oxime-bovine serum albumin. Thereafter plasma S, cortisol (F) and adrenocorticotropic hormone (ACTH) responses to metyrapone were investigated in 13 normal adult males and 39 patients with prostatic cancer. The results were as follows: 1) The antiserum against S-3-oxime-bovine serum albumin had less cross reactivity (less than 10%) with other steroids than that against S-21-hemisuccinate bovine serum albumin and obtained a good standard curve. The intra-assay variance and interassay variance of this method using the former antiserum (N = 10) were 12.4% asd 14.9% respectively, and the blank value was 3.7 +/- 1.6 pg. 2) Basal levels of S. F and ACTH in plasma from 13 normal adult males, ranged 21 approximately 80 years, old, were 98.4 +/- 15.7 ng/dl (mean value +/- S.E.), 12.7 +/- 0.78 micrograms/dl and 30.6 +/- 3.02 pg/ml respectively. Those level increased to 7060 +/- 598 ng/dl, 24.3 +/- 1.69 micrograms/dl and 24.3 +/- 1.6 pg/ml at 9 a.m. following oral administration of metyrapone (30 mg/kg b.w.) at midnight. 3) Both basal levels and responses of plasma S and F to metyrapone increased remarkably, while those of ACTH were within the normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and AC normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and AC normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and ACTH responses to metyrapone were unchanged compared to normal adult males 2 approximately 4 weeks after discontinuation of the therapy, and this data suggested that estrogens had no inhibitory effect on the pituitary-adrenal axis. However, in cases treated with progestational agents over a long-term period, plasma S and ACTH responses to metyrapone decreased slightly but returned to the normal range 2 approximately 4 weeks after discontinuation of the therapy. This suggested that the inhibitory effect of these agents on the pituitary-adrenal axis was mild and reversible.

17-Hydroxycorticosteroids↗
PubMed1981

Activation of murine lymphocytes by 2-mercaptoethanol and related thiol compounds and its mechanism. I. Relationship between mitogenic activities and augmenting effects on antibody synthesis in vitro.

Seven thiol compounds, namely, 2-mercaptoethanol (2-ME), alpha -thioglycerol (alpha -TG), dithiothreitol (DTT), cysteamine, L-cysteine (Cys), glutathione (GSH), and sodium thioglycollate (TGL) were examined for their mitogenic activities, the effects on mitogen-induced 3H-thymidine uptake, and the effects on antibody synthesis in vitro in murine spleen lymphocytes. All these thiols showed mitogenic activities in RPMI-1640 medium containing 10% fetal calf serum (FCS) with the following order of effectiveness: 2-ME greater than or equal to alpha -TG greater than DTT greater than cysteamine greater than Cys greater than or equal to GSH greater than TGL. A close correlation was observed between the enhancement of the response to lipopolysaccharide (LPS) and the mitogenic activities of these thiol compounds in their magnitude and dose-response profiles. The primary antibody response in vitro to sheep red blood cells (SRBC) (thymus-dependent) or dinitrophenyl (DNP)-Ficoll (thymus-independent) was augmented in a similar fashion by these compounds. T-cells depletion did not influence the enhancement by 2-ME of the antibody response to DNP-Ficoll. There was a discrepancy between the dose-response profiles of mitogenic activities of these compounds and their augmenting effects on antibody responses. Particularly, 2-ME and DTT significantly enhanced the antibody response to DNP-Ficoll or SRBC even at the nonmitogenic doses. Ethyl mercaptan (HSCH2 CH3) showed similar activities to 2-ME, but methylthioethanol (CH3 SCH2 CH2 OH) and ethanol (CH3 CH2 OH) were inactive, thus indicating that the thiol group would play an essential role in the above activities of 2-ME.

Animals↗
PubMed1981

Site-specific interaction of DNA gyrase with DNA.

DNA gyrase, in the presence of the inhibitor oxolinic acid, can induce double-strand DNA breakage at specific sites. The sequences at several sites have been determined. In addition, the structure of complexes formed between DNA gyrase and restriction fragments containing an oxolinic acid-promoted cleavage site has been examined by DNase protection methods. DNA gyrase protects more than 120 base pairs of DNA against pancreatic DNase in a region surrounding the cleavage site. Protection is observed both in the presence and absence of oxolinic acid. Protected DNA flanking the cleavage site contains DNase I-sensitive sites spaced on the average 10 or 11 base pairs apart. This result supports the view that, in the DNA gyrase--DNA complex, the DNA is largely wrapped on the outside of the enzyme.

Adenosine Triphosphate↗
PubMed1981

Single K+ channel currents of anomalous rectification in cultured rat myotubes.

The currents through single K+ channels of the anomalous (or inward) rectifier were recorded in tissue cultured rat myotubes by using the "gigohm seal" patch clamp technique developed by Sigworth and Neher. These unitary currents were detected as current fluctuations due to the blocking and unblocking of channels by Ba2+. The single-channel conductance was obtained from the slope of the linear relationship between unitary current amplitude and membrane potential. When the external solution contained 155 mM K+, the single-channel conductance was 10.4 +/- 2.6 pS (+/- SD; n = 6). This value was independent of the the concentration of blocking ions but increased with increasing external K+ concentration. The behavior of the unitary current agreed with that expected from the blocking kinetics of Ba2+ on the macroscopic K+ current of the anomalous rectifier. The density of the channel is likely to be small and may even be less than 1/micrometers 2.

Animals↗