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Biomedical subjects

S Morishima

Publications and source records attributed to S Morishima.

35 records · Page 2Linked to original sources
PubMed1995

A mini Cl- channel sensitive to external pH in the basolateral membrane of guinea-pig parietal cells.

1. Voltage-independent whole-cell Cl- currents were recorded from both single, isolated parietal cells and parietal cells within gastric glands obtained from the fundus of guinea-pig stomach. 2. The Cl- currents were rapidly suppressed by a Cl- channel blocker, NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate), added to the (basolateral) bathing solution in a concentration-dependent manner with a half-maximal inhibition concentration of 12 microM. 3. The selectivity sequence among anions was I- > Br- > Cl- > F-, corresponding to Eisenman's sequence I. 4. The Cl- currents were independent of cytosolic Ca2+, cyclic AMP, cyclic GMP, GTP-gamma-S and cell volume, and were not affected by application of acid secretagogues, omeprazol, arachidonic acid or prostaglandin E2. 5. Reduction of pH in the (basolateral) bathing solution immediately inhibited the Cl- current with a pK (-log of KD) of 6.3, whereas changes in intracellular pH had no effect. 6. The single-channel conductance was estimated to be 0.46-0.6 pS by variance noise analysis during inhibition of whole-cell Cl- currents by NPPB or acidic pH. 7. It is concluded that pH-sensitive 'mini' Cl- channels, with a sub-picosiemens unitary conductance, exist in the basolateral membrane of guinea-pig parietal cells.

Animals↗
PubMed1994

Inconsistency between the fimbrilin gene and the antigenicity of lipopolysaccharides in selected strains of Porphyromonas gingivalis.

Immunochemical specificity of lipopolysaccharide and the molecular property of the gene encoding the fimbrilin (fimA) of Porphyromonas gingivalis strains were examined using 'fimbriated' strains 381 and HG564 and 'non-fimbriated' strains 381FL and W50. Lipopolysaccharide from strains 381, 381FL and HG564 reacted with monoclonal antibody raised to lipopolysaccharide from strain 381 to give a fused precipitin band by the immunodiffusion test. However, silver staining and Western blotting of lipopolysaccharide clearly revealed a difference in profile of bands between strains 381 and 381FL. On the other hand, lipopolysaccharide from W50 formed another precipitin band and reacted with the antibody, but only at higher concentrations of lipopolysaccharide. The fimA genes in these strains were amplified by polymerase chain reaction and cloned. Sequencing of the fimA gene revealed that the fimA(W50) was almost identical to fimA(HG564), but a notable difference was observed at the start codon of the open reading frame, while the fimA(381FL) was considerably different from fimA of other strains and its open reading frame was found to be missing. These results indicate that the molecular structure of the fimA genes of these strains is not homologous, indicating that molecular modifications in the fimA gene should occur during in vitro passages and maintenance of strains of P. gingivalis in laboratories.

Antibodies, Monoclonal↗
PubMed1994

Voltage- and time-dependent K+ channel currents in the basolateral membrane of villus enterocytes isolated from guinea pig small intestine.

Patch-clamp studies were carried out in villus enterocytes isolated from the guinea pig proximal small intestine. In the whole-cell mode, outward K+ currents were found to be activated by depolarizing command pulses to -45 mV. The activation followed fourth order kinetics. The time constant of K+ current activation was voltage-dependent, decreasing from approximately 3 ms at -10 mV to 1 ms at +50 mV. The K+ current inactivated during maintained depolarizations by a voltage-independent, monoexponential process with a time constant of approximately 470 ms. If the interpulse interval was shorter than 30 s, cumulative inactivation was observed upon repeated stimulations. The steady state inactivation was voltage-dependent over the voltage range from -70 to -30 mV with a half inactivation voltage of -46 mV. The steady state activation was also voltage-dependent with a half-activation voltage of -22 mV. The K+ current profiles were not affected by chelation of cytosolic Ca2+. The K+ current induced by a depolarizing pulse was suppressed by extracellular application of TEA+, Ba2+, 4-aminopyridine or quinine with half-maximal inhibitory concentrations of 8.9 mM, 4.6 mM, 86 microM and 26 microM, respectively. The inactivation time course was accelerated by quinine but decelerated by TEA+, when applied to the extracellular (but not the intracellular) solution. Extracellular (but not intracellular) applications of verapamil and nifedipine also quickened the inactivation time course with 50% effective concentrations of 3 and 17 microM, respectively. Quinine, verapamil and nifedipine shifted the steady state inactivation curve towards more negative potentials. Outward single K+ channel events with a unitary conductance of approximately 8.4 pS were observed in excised inside-out patches of the basolateral membrane, when the patch was depolarized to -40 mV. The ensemble current rapidly activated and thereafter slowly inactivated with similar time constants to those of whole-cell K+ currents. It is concluded that the basolateral membrane of guinea pig villus enterocytes has a voltage-gated, time-dependent, Ca(2+)-insensitive, small-conductance K+ channel. Quinine, verapamil, and nifedipine accelerate the inactivation time course by affecting the inactivation gate from the external side of the cell membrane.

Animals↗
PubMed1994

Assessment of quantitative exercise thallium-201 emission computed tomography in patients with vasospastic angina--value of washout rate analysis.

This study was performed to assess the value of washout rate analysis of quantitative exercise thallium-201 emission computed tomography in vasospastic angina patients without significant coronary stenosis. Quantitative analysis of both thallium-201 perfusion and washout rate before and after drug treatment was performed in 48 patients with vasospastic angina and no significant coronary artery stenosis. All of the patients attained more than 90% of their age-predicted heart rate during each exercise test. Before drug treatment, 26 patients exhibited exercise-induced ischemia (perfusion defects on stress polar map), 17 did not exhibit exercise-induced ischemia (normal stress and washout rate polar maps), and the remaining 5 patients showed no perfusion defects, but did show extensive abnormal washout rates. On coronary angiography, multivessel coronary spasm was documented in 12 of the 26 patients with exercise-induced ischemia, in 7 of the 17 patients without exercise-induced ischemia and in 4 patients with an extensive abnormal washout rate and a normal stress polar map. In the 17 patients without exercise-induced ischemia, the mean washout rate was significantly decreased (p < 0.05) in association with a significant decrease in the double product (p < 0.05) after drug treatment. Of the 26 patients with exercise-induced ischemia, 18 (group 1) showed an increase in the mean washout rate with improved perfusion defect after drug treatment. The remaining 8 patients (group 2) showed a decrease in the mean washout rate with improved perfusion defect after drug treatment, which increased significantly on repeat exercise test performed after additional increased doses of antianginal drugs were administered (p < 0.01). The number of patients with multivessel coronary spasm was significantly high in group 2 (p < 0.01). Thirteen patients showed an extensive abnormal washout rate before drug treatment, including 8 patients with exercise-induced ischemia and 5 patients with no perfusion defects, who showed an increased mean washout rate after drug treatment (p < 0.05). These findings indicate that washout rate analysis aids in the diagnosis in vasospastic angina patients with exercise-induced ischemia. Some patients with exercise-induced ischemia can not be detected by thallium-201 perfusion analysis alone, especially those with multivessel coronary spasm and when this procedure is performed after drug treatment. In addition, a high frequency of abnormal washout rate in vasospastic angina may result not only from exercise-induced ischemia due to main epicardial coronary artery spasm, but also from microspasm, or impairment of microcirculation or myocyte.

Aged↗
PubMed1994

Osmotic swelling activates intermediate-conductance Cl- channels in human intestinal epithelial cells.

During osmotic swelling of a human intestinal epithelial cell line, stepwise closing unitary events of Cl- channels could be observed in cell-attached patches upon application of large positive potentials only when inactivating whole-cell Cl- currents were simultaneously observed. The closing process became faster with increasing positive command pulses. The unitary conductance was around 32 pS at 60 mV, 37 pS at +100 mV, and 47 pS at +140 mV exhibiting outward rectification.

Cell Line↗
PubMed1994

Properties of volume-sensitive Cl- channels in a human epithelial cell line.

A regulatory volume decrease is accomplished by parallel activation of Ca(2+)-dependent K+ channels and Ca(2+)-independent Cl- channels in cultured human intestinal epithelial cells (Intestine 407). The anion selectivity of whole-cell currents recorded in osmotically swollen cells falls into the Eisenman type I sequence corresponding to a low-field anion channel. The volume-sensitive Cl- channel has an intermediate unitary conductance. Both the whole-cell and single-channel Cl- currents exhibit unique voltage-dependency. The Cl- current can be maintained in the activated state in the physiological voltage range. However, at very large depolarizations (over +50 mV), the current is quickly inactivated. The Cl- current shows moderate outward rectification. The whole-cell Cl- current is sensitive to Cl- channel blockers such as SITS and NPPB as well as to cis unsaturated fatty acids such as arachidonic acid and oleic acid. The whole-cell current is totally independent of Ca2+ and cyclic AMP, but inhibited by increases in cytosolic free Mg2+ ions. Removal of intracellular ATP, but not Mg2+, abolishes the Cl- current. The ATP role can be substituted for non-hydrolyzable ATP analogs. Therefore, it is likely that intracellular ATP maintains the channel activity through non-hydrolytic binding.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1994

Single-channel recordings of volume-sensitive Cl- channels in human intestinal epithelial cells.

Under the double-patch configuration, stepwise closing unitary events could be observed in the on-cell patch upon applications of large positive potentials only when inactivating whole-cell Cl- currents were simultaneously observed in cultured human epithelial cells (Intestine 407) after osmotic swelling. Under the cell-attached configuration, the single channel events exhibited similar time- and voltage-dependent inactivation upon large depolarizations. The inactivation time course became shorter with increasing positive command pulses. The unitary slope conductance was around 63 pS at +140 mV and 46 pS at +100 mV exhibiting outward rectification.

Chloride Channels↗
PubMed1993

Molecular cloning and sequencing of the fimbrilin gene of Porphyromonas gingivalis strains and characterization of recombinant proteins.

The fimA gene encoding the subunit protein of fimbriae, fimbrilin, from nine strains of Porphyromonas gingivalis was cloned using polymerase chain reaction and the nucleotide sequence was determined. Analysis of the nucleotide and the deduced amino acid sequences revealed that the fimA gene of the test strains was composed of 1044 to 1083 bp, and the molecular weight of the deduced polypeptides was calculated to be 37,527 to 38,239. All the test strains shared the same or similar sequences, but simultaneously considerable differences in the sequences were found among the strains. Western blot analysis using rabbit antiserum to P. gingivalis 381 fimbriae demonstrated that the recombinant fimbrilins of 8 out of 9 strains expressed in Escherichia coli reacted with the antiserum exhibiting a 43 to 48 kDa band. Taken together, these results indicate that four genetical clusters are noted among the fimA gene of P. gingivalis strains.

Amino Acid Sequence↗
PubMed1993

[Comparison of bioavailability of salbutamol between oral and rectal administration in rabbits].

In order to obtain a basic knowledge for developing the rectal dosage form of salbutamol (SB), a comparison of the bioavailability was made between oral and rectal administrations. After the intravenous, oral and rectal dosing of SB solution in rabbits, SB and its glucuronide (SBG) in plasma and urine were determined. The bioavailability estimated by the area under the blood concentration-time curve (AUC) of SB from 0 to 9 h after oral and rectal administrations were 1.1 +/- 0.5% and 7.8 +/- 2.2% (mean +/- S. E., n = 5), respectively. Percent of dose excreted in urine as total SB (SB+SBG) 10 h after oral and rectal administrations were 77.3 +/- 3.82% and 9.80 +/- 0.15% (mean +/- S. E., n = 3), respectively, which indicating relatively good oral and poor rectal SB absorption. A partial avoidance of first-pass-effects might contribute to higher bioavailability after the rectal administration.

Administration, Oral↗
PubMed1992

Time course of myocardial infarction evaluated by indium-111-antimyosin monoclonal antibody scintigraphy: clinical implications and prognostic value.

To investigate the clinical implications of 111In-antimyosin antibody scintigraphy in the chronic stage of myocardial infarction, 34 studies were performed in 26 patients with 36 infarcts of various infarct ages. The infarcts were divided into three groups according to time from onset of chest pain to scintigraphy. Positive antimyosin images were obtained in 93% of Group I patients (3 days to 1 mo), 71% of Group II patients (1.5 mo to 1 yr) and none were obtained from Group III patients (1.5-6 yr). A negative correlation was observed between antimyosin uptake and the time after myocardial infarction. In Group II, patients with coronary artery patency and patients showing redistribution on exercise 201TI scintigraphy were more likely to have positive antimyosin images compared to patients without these features. Recurrent angina may also relate to chronic antimyosin uptake. Indium-111-antimyosin antibody scintigraphy may be a useful method in assessing the course of myocardial infarction and for the patient follow-up.

Aged↗
PubMed1991

Detection of adriamycin cardiotoxicity with indium-111 labeled antimyosin monoclonal antibody imaging.

Myocardial imaging with indium-111 labeled antimyosin monoclonal antibody (antimyosin imaging) has been reported to be useful in the noninvasive detection of myocardial cell necrosis in dilated cardiomyopathy as well as in myocardial infarction and myocarditis. We used antimyosin imaging to detect myocardial damage in 2 patients with malignant lymphoma in whom adriamycin cardiotoxicity was suspected. Patients were injected with 74 MBq of indium-111 labeled antimyosin (Fab. fraction). Forty-eight hours later, planar imaging and single-photon emission computed tomography were performed using a gamma camera with a medium energy general purpose collimator. Antimyosin imaging demonstrated diffuse myocardial uptake not only in one patient with congestive heart failure but also in another patient at the early stage without congestive heart failure. Antimyosin imaging may be a sensitive method for noninvasive visualization of myocardial cell damage and useful in the early diagnosis of specific heart muscle disease.

Aged↗
PubMed1990

[Indium-111 antimyosin monoclonal antibody uptake in patients with cardiomyopathy and myocarditis].

Prognostic significance of myocardial uptake of indium-111 antimyosin antibody was evaluated in 17 patients with idiopathic cardiomyopathy; 10 patients with dilated cardiomyopathy and 7 patients with hypertrophic cardiomyopathy. Seven of 10 patients with dilated cardiomyopathy showed positive images. Three of these 7 patients with strongly positive scans died after scintigraphic examination. Six of 7 patients with hypertrophic cardiomyopathy showed positive images. Three of the patients with dilated left ventricle had prominent positive scans and higher heart to lung ratio. The heart to lung ratio of antimyosin uptake in total patients was correlated with left ventricular end-diastolic dimension and ejection fraction measured by echocardiography. In patients with myocarditis, all three patients showed positive scintigrams within 4 weeks after the onset of the disease and 1 of 6 patients was positive thereafter, who had dilated ventricle and decreased cardiac function. Thus, indium-111 antimyosin antibody imaging may be useful to evaluate prognosis of patients with cardiomyopathy and myocarditis.

Adult↗