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Biomedical subjects

K Fukui

Publications and source records attributed to K Fukui.

At least 217 records · Page 12Linked to original sources
PubMed1994

Protective effects of sulfhydryl compounds on HOCl-induced intracellular Ca2+ increase in single rat ventricular myocytes.

Effects of sulfhydryl compounds on cell injuries caused by hypochlorous acid (HOCl) were studied in isolated rat cardiomyocytes by way of continuous measurement of intracellular Ca2+ using calcium sensitive fluorescent dye, fura-2. Ten minutes exposure of the cell to 100 microM HOCl induced a significant increase in the intracellular free calcium concentration ([Ca2+]i) from 90 +/- 20 nM to 266 +/- 74 nM (n = 44, mean +/- S.D.). This increase in [Ca2+]i was reversed by subsequent application of dithiothreitol (DTT) in a dose dependent manner; 30 microM DTT was found effective, while 2 mM DTT almost completely restored the [Ca2+]i to the control level. Similar to DTT, cysteine ethyl ester and cysteine methyl ester could also reverse the HOCl-induced rise of [Ca2+]i where the order of the potency was DTT > cysteine ethyl ester > cysteine methyl ester. In contrast, increase in [Ca2+]i induced by HOCl was not recovered by application of other sulfhydryl compounds such as cysteine and glutathione. Since HOCl administrated in the presence of cysteine failed to induce an increase in [Ca2+]i, we conclude that membrane permeable sulfhydryl compounds may reverse the increase in [Ca2+]i caused by HOCl.

Animals↗
PubMed1994

In vitro protective effects of nicorandil on hypothermic injury to immature cardiac myocytes: comparison with nitroglycerin.

The purpose of the present study was to evaluate the functional and biochemical effects of nicorandil and nitroglycerin on cardiac myocytes incubated under hypothermic conditions. Nicorandil is a coronary vasodilator with mixed nitrate-potassium channel agonist activity. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days with MCDB 197 medium. Myocytes (12.5 x 10(5) myocytes/flask) were then incubated at 4 degrees C for 24 hours in media containing various concentrations of nicorandil (NRD) or nitroglycerin (NTG). After hypothermic incubation, CPK and LDH were measured. The myocytes were cultured for an additional 24 hours at 37 degrees C to evaluate the recovery of the myocyte beating rate. In the nicorandil group, 10(-4) M NRD showed a significant beating rate recovery compared to control (44.2% vs. 24.6%, respectively, as a percent of control; i.e., beating rate prior to hypothermic incubation). Nitroglycerin treatment had no effect on either beating rate recovery or release of CPK and LDH from myocytes. However, the release of CPK and LDH was significantly suppressed by 10(-4) M nicorandil compared to the control (10(-4) M NRD: 24.1, 257.2; control: 125.4 mIU/flask, 459.5 mIU/flask, respectively). Thus nicorandil showed an approximate two-fold recovery of myocyte functional activity after hypothermic incubation with only minor biochemical effects, and therefore may be suitable for cardiac preservation.

Animals↗
PubMed1994

In vitro evaluation of phosphate, bicarbonate, and Hepes buffered storage solutions on hypothermic injury to immature myocytes.

In this study we evaluated cardiac myocyte viability and function under hypothermic conditions using three types of buffer solutions: phosphate buffer solution (PBS), Krebs-Henseleit bicarbonate buffer solution (KHB), and Hepes buffered minimum salt solution (MSS). As a control, normal saline solution (NSS) was used. Cardiac myocytes were isolated from neonatal rat ventricles. Myocytes (12.5 x 10(5) myocytes/culture flask) were then incubated at 4 degrees C for 6, 12, 18, and 24 hours in various buffer solutions. After each incubation time, CPK and LDH were measured. The myocytes were then incubated for an additional 24 hours at 37 degrees C to evaluate the recovery of the myocyte beating rate. Group MSS had a significantly better beating rate recovery than group NSS (control) after 18 hours (MSS, 32.7%, NSS, 0.0% of control; i.e., beating rate prior to hypothermic incubation). In contrast, group KHB showed a significantly lower recovery ratio than group NSS at 12 hours (41.0%, 78.8%, respectively), and the lowest recovery was observed in group PBS beginning at 6 hours of hypothermic incubation (27.6%). Group MSS significantly suppressed the release of CPK and LDH compared to group NSS at 24 hours (MSS, 246.7 and 440.2 mIU/flask; NSS, 369.7 and 821.3 mIU/flask, respectively). In contrast, groups PBS and KHB showed significantly increased CPK and LDH levels compared to group NSS after 12 hours (PBS, 388.6 and 721.4 mIU/flask; KHB, 340.5 and 540.5 mIU/flask; NSS, 91.5 and 222.7 mIU/flask, respectively). In conclusion, Hepes buffer has cytoprotective characteristics that may be suitable for long-term hypothermic preservation of immature myocardium compared to phosphate or bicarbonate buffer.

Animals↗
PubMed1994

An in vitro evaluation of prostaglandin E1 and I2 on hypothermic injury to immature myocytes.

The purpose of this study was to evaluate the functional and biochemical effects of Prostaglandin E1 (PGE1) and prostaglandin I2 (PGI2) on cardiac myocytes incubated under hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days with MCDB 107 medium. Following this, 12.5 x 10(5) myocytes/flask were incubated at 4 degrees C for 24 h in media with PGE1, at concentrations of 0 M (group E0), 10(-9) M (group E1), 10(-8) M (group E2), 10(-7) M (group E3), or 10(-6) M (group E4); or with PGI2 at concentrations of 0 M PGI (group I0), 10(-9) M (group I1), 10(-8) M (group 12), 10(-7) M (group I3), or 10(-6) M (group I4). After hypothermic incubation, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) were measured, and the myocytes were then cultured for 24 h at 37 degrees C to evaluate the recovery of the myocyte beating rate. Of the PGI2 groups, only group I2 recovered significantly more than the control group (group I0), at 47.9 +/- 28.5% (mean +/- SD) of the control, being the beating rate prior to hypothermic incubation, whereas it was 18.1 +/- 9.7% in group I0 (P < 0.025); however, there were no significant differences among the PGE1 groups. Moreover, the release of CPK and LDH was significantly suppressed in group 12 compared to the control, being 57.7 +/- 27.6 mIU/flask (P < 0.05) and 275.1 +/- 83.0 mIU/flask (P < 0.025), respectively, in group I2, and 96.8 +/- 38.3 mIU/flask and 439.6 +/- 147.1 mIU/flask in group I0. Again, no significant differences were observed among the PGE1 groups. In conclusion, PGI2 was found to have a direct cytoprotective effect on immature myocytes which suggests that PGI2 may promote cardiac preservation in the neonatal period.

Alprostadil↗
PubMed1994

Possible deleterious effects of glucose on immature myocytes under hypothermic conditions.

The purpose of the present study was to evaluate the functional and biochemical effects of glucose-based solutions in combination with potassium or insulin (or both) on immature myocytes under hypothermic conditions. Myocytes were isolated from neonatal rat ventricles and cultured for 4 days with MCDB 107 (University of Colorado solution). Initially, myocytes (12.5 x 10(5) myocytes/flask) were incubated at 4 degrees C for 6 hours in 5% glucose solution containing various potassium concentrations ranging from 0 to 80 mEq/L to evaluate the protective effects. Next, myocytes were incubated at 4 degrees C for 3, 6, 12, 18, and 24 hours in three types of solutions: normal saline solution (control), glucose-potassium solution, and glucose-insulin-potassium solution (glucose: 50 g/L; NaHCO3, 20 mEq; potassium, 20 mEq; insulin, 20 IU/L). After each incubation, creatine kinase and lactate dehydrogenase levels were measured in the incubation solutions. The myocytes then were cultured for an additional 24 hours at 37 degrees C to evaluate the recovery of myocyte beating rate. The 20-mEq potassium treatment showed significantly better beating rate recovery and lower enzymal release than the glucose-only control. The saline solution showed the best protection of all three solutions, both functionally and biochemically, by 12 hours. The greatest damage was observed with glucose-potassium solution, beginning at 3 hours of hypothermic incubation. Although potassium and insulin have additional protective effects on hypothermic preservation, the high concentration of glucose has noxious characteristics for immature myocytes that may not be suitable for cardiac preservation in the neonatal period.

Animals↗
PubMed1994

Detection of Streptococcus mutans by PCR amplification of spaP gene.

Synthetic oligonucleotide primers were used in the polymerase chain reaction (PCR) to amplify a sequence of the spaP gene, which encodes the surface protein antigen I/II of Streptococcus mutans. A DNA fragment of c. 192 bp was amplified from lysed S. mutans cells or isolated DNA. With S. mutans cells, the lower limit of detection was 4-40 cfu. With these primers, 13 reference and 50 clinical strains of S. mutans were identified. Amplification of the 192-bp product was not demonstrated when 41 strains of other streptococcal and non-streptococcal species were tested. The spaP gene PCR has potential for the rapid diagnosis of S. mutans infections.

Adult↗
PubMed1994

Metabolic and energetic aspects of the growth response of Streptococcus rattus to environmental acidification in anaerobic continuous culture.

Streptococcus rattus, a serotype b strain of mutans streptococci, was grown in an anaerobic glucose-limited chemostat. The molar growth yield of glucose [Yglucose, g dry wt (mol glucose)-1] together with the maximum growth yields (Ymax) and maintenance coefficients for glucose utilization and calculated ATP generation were estimated as a function of pH. When the pH was lowered from 7.0 to 5.0, Yglucose decreased, with a concomitant gradual change in the composition of the end product from a mixture of formate, acetate and ethanol to one mostly of lactate. Whereas the Ymax for glucose decreased without any change in the Ymax for ATP on acidification, both of the maintenance coefficients markedly increased. Kinetic and immunochemical examinations indicated the presence of an F1F0-type proton-translocating ATPase in the membrane fraction prepared from bacterial cells grown under acidic conditions; no detectable level of the enzyme was found in cells grown at neutral pH. However, when incubated with glucose under non-growing conditions, these acid-adapted and unadapted cells showed an insignificant difference in the ability to maintain the intracellular pH alkaline relative to the acidic environments. These results suggest that the organism responds and adapts to environmental acidification by sacrificing some energy cost in terms of both the efficiency of glucose utilization to generate ATP and the extra maintenance required to continue biomass production as efficiently as under neutral pH.

Adenosine Triphosphate↗
PubMed1994

Activation of chloride current by P2-purinoceptors in rat ventricular myocytes.

1. Rat ventricular myocytes were dissociated and their responses to extracellularly applied ATP were recorded using patch pipettes under the whole cell configuration. 2. ATP initially induced an inward current followed by an outward current at -50 mV. With a Cs-rich pipette solution the late outward current was blocked, leaving a sustained inward current (IATPs) suggesting that a K+ conductance underlies the late response. 3. When the extracellular Cl- concentration was changed, the reversal potential of IATPs corresponded well to the shift of the Cl- equilibrium potential. IATPs was reversibly blocked by the chloride channel blocker, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). 4. The concentration-response curve of IATPs had a Hill coefficient of 0.98 and an EC50 value of 5.2 x 10(-6) M. 5. ATP was more potent than ADP, while AMP and adenosine were ineffective, suggesting that P2-purinoceptor activation induced IATPs. 6. The activation of IATPs was depressed by depleting the extracellular Mg2+ and increased by adding Mg2+. 7. Our results strongly suggest that P2-purinoceptor activation by ATP induces both a Cl(-)-conductance (IATPs) and a K(+)-conductance in rat ventricular myocytes.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Physical mapping of 5S rDNA loci by direct-cloned biotinylated probes in barley chromosomes.

5S rDNA loci have been mapped on barley chromosomes by in situ hybridization using five reciprocal translocation lines. Two kinds of DNA probes covering either the 5S rDNA coding region or the 5S rDNA coding and flanking noncoding regions were used. They were prepared by direct cloning from interphase nuclei and simultaneous direct labeling in PCR. Four 5S rDNA loci were detected in a haploid genome by the 5S rDNA coding region, whereas in addition, the four or six 5S rDNA related sites, depending on the variety used, were revealed by the probe covering the flanking region. The four 5S rDNA loci revealed and mapped on the barley chromosomes: 2 (2I), 3 (3I), 1 (7I), and 4 (4I) were designated 5SRrn-I1, 5SRrn-I2, 5SRrn-I3 and 5SRrn-I4, respectively, in descending order of copy number of 5S rRNA genes.

Base Sequence↗
PubMed1994

Extent of pontine pyramidal tract Wallerian degeneration and outcome after supratentorial hemorrhagic stroke.

BACKGROUND AND PURPOSE: Pyramidal tract Wallerian degeneration has been detected on magnetic resonance imaging (MRI) as T2-weighted high-intensity areas. We analyzed the relation between the extent of brain stem Wallerian degeneration and activities of daily living (ADL) after supratentorial hemorrhagic stroke. METHODS: Twenty-six patients with supratentorial hemorrhage were examined on the coronal T2-weighted image of the pons 3 months or later after stroke, and the percentage of Wallerian degeneration in the pons was calculated. The patients were divided into three groups. In group A (n = 6), MR films were taken 3 to 6 months from the onset, and the ADL assessment was done within 2 months from the MRI. In group B (n = 11), MR films were taken 3 to 6 months from the onset, and the ADL assessment was done within 10 months from the MRI (mean, 15.5 months from the onset). In group C (n = 9), MR films were taken after 10 to 17 months (mean, 12.0 months) from the ictus, and the ADL assessment was done simultaneously. Barthel Index score was used for quantitative ADL assessment. RESULTS: All patients showed various degrees of pontine pyramidal tract Wallerian degeneration associated with capsular involvement by the hematoma. In group A, the percentage of degeneration did not correlate with the Barthel Index score (r = .2101, P = .6895). An inverse relation between percentage of degeneration and Barthel Index score was seen in groups B (r = .7354, P = .0099) and C (r = .888, P = .0014). In groups B and C, Wallerian degeneration was higher in patients with Barthel scores less than 60 (P = .005). CONCLUSIONS: The extent of pontine Wallerian degeneration on MRI 3 months or later after the stroke correlated with the patient's Barthel Index score 1 year after the stroke.

Activities of Daily Living↗
PubMed1994

Cytoprotective effects of nicorandil on hypothermic injury to immature cardiac myocytes--comparison with nitroglycerin, diltiazem and prostaglandin E1.

The purpose of this study was to evaluate the functional and biochemical effects of nicorandil (NRD), nitroglycerin (NTG), diltiazem (DTZ) and prostaglandin E1 (PGE) on cardiac myocytes incubated under hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days with MCDB 107 medium. Myocytes (12.5 x 10(5) myocytes/flask) were then incubated at 4 degrees C for 24 h in media containing various concentrations of NRD, NTG, DTZ or PGE. After hypothermic incubation, creatine kinase (CK) and lactate dehydrogenase (LDH) were measured. The myocytes were cultured for an additional 24 h at 37 degrees C to evaluate the recovery of myocyte beating rate. In the nicorandil groups, 10(-4) M NRD showed a significantly increased beating rate recovery compared to the control (44% vs 25% respectively, as a percentage of the baseline values; i.e., beating rate prior to hypothermic incubation). Although treatment with 10(-6) M diltiazem showed no beneficial effects (10(-6) M; 25%, control; 30%), beating was not observed at all with 10(-4) M or 10(-5) M DTZ. There were no significant changes among the NTG and PGE groups. The release of CK and LDH was significantly suppressed with 10(-4) M NRD (10(-4) M: 24.1 mIU/flask, 257.2; control: 125.4, 459.5, respectively). In contrast, 10(-4) M DTZ showed significantly increased CK and LDH levels compared to its respective control (10(-4) M: 203.3 mIU/flask, 883.4; control: 112.3, 457.4, respectively). There were no significant differences in CK and LDH levels among the NTG and PGE groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1994

Effect of serum concentration on hypothermic preservation of cardiac myocytes isolated from neonatal rat ventricle.

The purpose of the present study was to evaluate the functional and biochemical effects of serum concentrations on hypothermic preservation of cardiac myocytes. Myocytes were isolated from neonatal rat ventricles and cultured for 4 days, and then incubated for 24 hrs at 4 degrees C in media containing 0, 2, 5, 10, and 20% fetal calf serum (FCS). The myocytes were then cultured for an additional 24 hrs at 37 degrees C to evaluate the recovery of myocyte beating rate. The recovery ratio of myocyte beating rate after hypothermic incubation was 25.3 +/- 14.2 percent of control in the serum-free, 33.0% in 2% FCS, 30.7% in 5% FCS, 22.3% in 10% FCS, and 24.3% in 20% FCS groups. Serum-free, 10% and 20% FCS groups had lower recovery ratios compared to the other two groups. The release of CPK and LDH after hypothermic incubation were similar in the serum-free, 2% and 5% FCS groups, however, significant increases were observed for the 10% and 20% FCS groups. It is suggested that fetal calf serum at high concentrations (> 10%) might be injurious to immature myocardium under hypothermic preservation, and that the optimum concentration of FCS is two percent or less.

Animals↗
PubMed1994

Evaluation of immature cardiac myocyte viability after 24 hours of hypothermic preservation.

In this study, we evaluated cardiac myocyte viability and function under hypothermic conditions using three types of storage solutions; saline solution (SS), Euro-Collins solution (ECS) and MCDB 107 medium (MM). Cardiac myocytes were isolated from neonatal rat ventricles by collagenase dispersion and cultured for 4 days with MCDB 107 medium. A total of 12.5 x 10(5) myocytes/culture dish were used and the myocytes were incubated at 4 degrees C for 6, 12, 18 and 24 hrs in the various storage solutions. After each incubation time, CPK and LDH were measured in the storage solutions. The myocytes were then cultured in MCDB 107 medium and incubated for 24 hrs at 37 degrees C to evaluate the recovery of the myocyte beating rate. In group MM (n = 7), the recovery ratio of the myocyte beating rate was 99.2 percent of control (beating rate prior to hypothermic incubation) at 6 hours, 104.6% at 12 hrs and 44.8% at 24 hrs. Groups SS and ECS (n = 7 each) had significantly lower recovery ratios than the MM group (at 6 hrs: 74.3, 34.0; at 12 hrs: 61.0, 32.2; at 24 hrs: 0.0, 0.0 percent of control, respectively). Release of CPK and LDH in the MM group gradually increased and at 24 hrs was 28.6 IU/l and 93.6 IU/l, respectively. However, the SS group had significantly increased CPK and LDH values at 24 hrs (CPK: 66.9, LDH: 164.2). The ECS group showed the greatest increase in both markers (CPK: 317.5, LDH: 421.2). In summary, saline solution showed a beneficial effect on recovery of myocyte viability at 12 hours compared to Euro-Collins solution, however, MCDB 107 medium had the best overall protective effect on cultured myocytes. Accordingly, alternate hypothermic storage solutions, such as cell-culture medium, may have protective characteristics that are suitable for cardiac preservation.

Amino Acids↗
PubMed1994

[Tetralogy of Fallot with absent pulmonary valve: a successful case by total corrective surgery in 25 days old infant].

A 25 days old neonate of tetralogy of Fallot with absent pulmonary valve underwent total corrective surgery which consisted of VSD patch closure, resection of anterior wall of both pulmonary arteries and right ventricular outflow tract reconstruction using a monocuspid equine pericardial patch. Postoperatively, the right pulmonary artery diameter decreased from 17.8 mm (307%N) to 7.5 mm (129%N) and the left pulmonary artery diameter from 16.9 mm (338%N) to 8.3 mm (166%N). The patient was weaned from the ventilator 2 days after operation, whose post-operative course was uneventful. Total corrective surgery may provide a great success to symptomatic patients during the neonatal period.

Cardiac Surgical Procedures↗
PubMed1994

Enhanced proteolytic activity is responsible for the aberrant morphogenetic development of SV40-immortalized normal human salivary gland cells grown on basement membrane components.

BACKGROUND: A reconstituted basement membrane extract, Matrigel, is a potent inducer of cell growth and differentiation in vitro in a number of cell types. In this study, we examined the effect of Matrigel on the morphogenesis of cultured normal human salivary gland cells. EXPERIMENTAL DESIGN: SV40-immortalized normal human salivary gland-cell clones with duct- (NS-SV-DC) or myoepithelial phenotype (NS-SV-MC), which had been established in our laboratory (Azuma M, et al., Lab Invest, 1993;69:24-42), were cultured on Matrigel in serum-free culture conditions, and then morphogenetic behavior of cell clones was examined. RESULTS: When cell clones were seeded on Matrigel, they formed round or zonal clusters on day 1; however, they failed to develop into a salivary gland morphogenesis. Semithin sections of cell clones cultured on Matrigel exhibited multicellular aggregates on day 1, whereas on days 2 and 3, these cells lost both cell-Matrigel and cell-cell interactions and eventually entered crisis. In an attempt to understand the mechanism involved in this phenomenon, we investigated proteolytic enzymes and their inhibitors secreted by cell clones. Although cell clones produced almost identical levels of gelatinases, they released increased amounts of plasminogen activators as compared with a neoplastic human salivary gland cell line, which had already been demonstrated to differentiate into acinar cells when cultured on Matrigel. Obvious difference of expression level of tissue inhibitor of metalloproteinases-1 was not observed in these cells, however, NS-SV-DC produced a relatively small amount of endothelial-type plasminogen activator inhibitor as compared with NS-SV-MC. Neutralization of excess plasminogen activators by exogenously added serine protease inhibitors corrected the aberrant in vitro morphogenesis of NS-SV-DC, but not of NS-SV-MC, and allowed NS-SV-DC to form glandular-like structures.

Animals↗
PubMed1994

Cardiac myocyte functional and biochemical changes after hypothermic preservation in vitro. Protective effects of storage solutions.

In this study, we evaluated cardiac myocyte viability and function under hypothermic conditions with four types of storage solutions, saline solution, Euro-Collins solution, University of Wisconsin solution, and MCDB 107 medium. Cardiac myocytes were isolated from neonatal rat ventricles by collagenase dispersion and cultured for 4 days with MCDB 107 medium. A total of 12.5 x 10(5) myocytes per culture dish was used and the myocytes were incubated at 4 degrees C for 6, 12, 18, and 24 hours in the various storage solutions. After each incubation time, creatine kinase and lactate dehydrogenase were measured in the storage solutions. The myocytes were then incubated for 24 hours at 37 degrees C to evaluate the recovery of the myocyte beating rate. In the MCDB 107 group (n = 7), the recovery ratio of myocyte beating rate was complete by 12 hours, then decreased to 44.8% of control (beating rate before hypothermic incubation) at 24 hours. The saline, Euro-Collins, and University of Wisconsin groups (n = 7 each) had significantly lower recovery ratios than the MCDB 107 group (at 12 hours: 61.0%, 32.2%, and 48.9%; at 18 hours: 0.0%, 5.5%, and 15.1% of control, respectively). Release of creatine kinase and lactate dehydrogenase in the MCDB 107 group gradually increased and at 24 hours was 143.2 mIU/flask and 486.2 mIU/flask, respectively. However, the saline and University of Wisconsin groups had significantly increased creatine kinase and lactate dehydrogenase values at 24 hours (creatine kinase: 334.6 and 319.6 mIU/flask; lactate dehydrogenase: 821.6 and 654.4 mIU/flask, respectively). The Euro-Collins group showed the greatest increase in both markers (creatine kinase: 1587.5, lactate dehydrogenase: 2106.9 mIU/flask). In summary, saline and University of Wisconsin solutions showed a beneficial effect on recovery of myocyte viability at 12 hours compared with Euro-Collins solution, however MCDB 107 medium had the best overall protective effect on cultured myocytes. Accordingly, alternate hypothermic storage solutions, such as cell-culture medium, may have protective characteristics that are suitable for cardiac preservation.

Adenosine↗