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K Okabe

Publications and source records attributed to K Okabe.

At least 181 records · Page 10Linked to original sources
PubMed1988

Effects of inositol phosphates on the membrane activity of smooth muscle cells of the rabbit portal vein.

The effects of intracellular perfusion of inositol 1,4,5-trisphosphate (InsP3) or inositol 1,3,4,5-tetrakisphosphate (InsP4) on electrical responses of smooth muscle cell membranes of the rabbit portal vein were studied using the whole cell voltage clamp technique. Depolarisation to 0 mV from a holding potential of -60 mV, evoked inward Ca (Ica), transient outward (ISO), oscillatory outward (IOO) and sustained outward (ISO) currents. Generation of IOO was dependent on the [Ca]o, but it was also generated in 0 mM Ca solution for over 10 min. From amplitude histograms, IOO was divided into two components. Reduction in [Ca]o inhibited the appearance of but not the amplitudes of both IOO components. However, the larger component of IOO was more resistant to a reduction in [Ca]o than the smaller one. InsP3 (10 microM) increased the frequency of both IOO components to a greater extent than their amplitude, but the larger component was more sensitive to InsP3 than the smaller one. The increase in the occurrence of IOO induced by InsP3 did not occur following pretreatment with 3 mM caffeine or 1 nM A23187. In normal PSS, InsP3 was evoked by a depolarising pulse positive to -40 mV, whereas following perfusion with InsP3 (10 microM), IOO was evoked at -60 mV. In normal PSS, intracellular perfusion with 10 microM InsP4 changed neither the frequency nor the amplitude of IOO, and the amplitudes of ICa, ITO and ISO were also unchanged. However, in 10 mM Ca solution, 10 microM InsP4 generated IOO at a membrane potential of -60 mV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Characteristics of cromakalim-induced relaxations in the smooth muscle cells of guinea-pig mesenteric artery and vein.

1. The effects of cromakalim (BRL 34915) on the smooth muscle cells of guinea-pig mesenteric artery and vein were investigated with microelectrode and tension recording methods. 2. Cromakalim (greater than 10 microM) produced membrane hyperpolarization with an increase in ionic conductance. The hyperpolarization occurred to a greater extent and lasted longer in the vein than in the artery. 3. The hyperpolarization induced by cromakalim in mesenteric vein comprised two components, one of which was Mn sensitive. In mesenteric artery, the hyperpolarization was relatively insensitive to Mn. 4. From the current-voltage relationship measured from arterial smooth muscle membranes, the reversal potential of cromakalim was estimated to be -80 mV. The cromakalim-induced hyperpolarization was not modified in Na- or Cl-deficient solution. 5. In both mesenteric artery and vein, cromakalim relaxed tissues precontracted with high K with (below 40 mM) or without (above 40 mM) hyperpolarization of the membrane. 6. In the mesenteric artery, action potentials evoked by electrical stimulation ceased before the generation of hyperpolarization. 7. Cromakalim produced a cross-desensitization with nicorandil on the evoked membrane hyperpolarization in mesenteric artery. 8. It is concluded that the relaxing actions of cromakalim result from the hyperpolarization which follows the opening of Ca-dependent K channels. The inhibition of a voltage-dependent Ca current may also be involved in this inhibitory effect.

Action Potentials↗
PubMed1988

Importance of cell surface marker to the prognosis of non-Hodgkin's lymphoma.

We studied the correlation between the cell surface markers and prognosis of non-Hodgkin's lymphoma (NHL) patients treated in the Shikoku Cancer Center Hospital from 1980 to 1986. Thirty-one cases were selected on the basis of having a lymphnode as a primary lesion, having been immunophenotyped before chemotherapy, being in the intermediate histologic grade and being in stage II, III or IV. Thirteen cases of the T-cell type (T-lymphomas) and 18 cases of the B-cell type (B-lymphoma) were identified. The complete remission rate was 54% among T-lymphoma patients and 78% among B-lymphoma patients. The median length of survival was 12+ months in T-lymphoma and 26+ months in B-lymphoma. The survival rate of T-lymphoma patients was significantly lower than that of B-lymphoma patients. The importance of making surface marker studies was reappraised in our study.

Antigens, Surface↗
PubMed1988

[Clinical study on the effect of natural alpha-interferon (HLBI) in the treatment of adult T-cell leukemia].

The phase II trial of natural interferon-alpha (HLBI) in treatment of adult T-cell leukemia was carried out as a cooperative study. Of the 24 cases which could be evaluated, 3 cases in crisis type and 5 cases in chronic type with lymphadenopathy and/or skin infiltration achieved PR, giving a response rate of 33.3%. The anti-tumor effect of HLBI for skin lesion could be assessed in 16 cases with skin infiltration, giving a response rate of 50.0% (5 CR and 3 PR) and demonstrating a high efficacy. Of the 31 eligible patients, side effects were recognised in 27 (87.1%). Major subjective and objective symptoms were fever (38.7%), fatigue (25.8%), anorexia (12.9%) and nausea (12.9%), and leukopenia (22.6%), granulocytopenia (38.7%), thrombocytopenia (38.7), elevation of GPT (12.9%) and GOT (12.9%) were observed.

Adult↗
PubMed1987

Features of 4-aminopyridine sensitive outward current observed in single smooth muscle cells from the rabbit pulmonary artery.

The 4-aminopyridine (4AP) sensitive outward current of enzymatically dispersed single smooth muscle cells of the rabbit main pulmonary artery were investigated using the voltage clamp method. When the cell was exposed to physiological salt solution (PSS) in the bath and high K+ in the pipette no inward current was generated by depolarization of the membrane, but when 4AP was present in the bath or when Cs+ with tetraethylammonium+ (Cs+-TEA+) in the pipette, an inward current was generated. This current was enhanced by Ba2+ or high Ca2+ and was blocked by inorganic or organic Ca2+ channel blockers. The outward current was partly inhibited by the Ca2+ channel blockers, Ca2+-free or Mn2+ containing solution. The residual outward current was blocked by external application of 10 mM 4AP, whereas it was inhibited by half with 100 mM TEA+. To investigate further natures of 4AP sensitive outward current, the following experiments were done in the bath solution containing 2.5 mM Mn2+. The reversal potential of this outward current, estimated from the tail current, remained the same in Na+-deficient solution, but shifted to near the K+-equilibrium potential in Cl- deficient solution. Thus, the main current carrier for the outward current seems to be K+, but Cl- may participate to some extent. The amplitude of the outward current decreased slowly. However, the reversal potential was not changed, suggesting the reduction in amplitude of the outward current was not due to the accumulation of K+ on the outer surface of the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Aminopyridine↗
PubMed1987

Treatment of recurrent subareolar abscess.

Recurrent subareolar abscess is an infrequent but troublesome disease of the breast among young women. Recent experience with 5 patients indicated that successful treatment of recurrent subareolar abscess requires excision of the diseased ducts and necrotic cavity, including the inverted section of the nipple. The operative procedure described herein allows us to radically manage recurrent subareolar abscess and at the same time leave a nipple with a good cosmetic appearance.

Abscess↗