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Biomedical subjects

K Fukunaga

Publications and source records attributed to K Fukunaga.

At least 199 records · Page 11Linked to original sources
PubMed1992

Characterization of the phosphatase activity of a baculovirus-expressed calcineurin A isoform.

Calcineurin A was purified by calmodulin-Sepharose affinity chromatography from Sf9 cells infected with recombinant baculovirus containing the cDNA of a rat calcineurin A isoform. The Sf9-expressed calcineurin A has a low basal phosphatase activity in the presence of EDTA (0.9 nmol/min/mg) which is stimulated 3-5-fold by Mn2+. Calmodulin increased the Mn2+ stimulated activity 3-5-fold. Bovine brain calcineurin B increased the A subunit activity 10-15-fold, and calmodulin further stimulated the activity of reconstituted A and B subunits 10-15-fold (644 nmol/min/mg). The Km of calcineurin A for 32P-RII pep (a peptide substrate (DLDVPIPGRFDRRVSVAAE) for CaN), was 111 microM with or without calmodulin, and calmodulin increased the Vmax about 4-fold. The Km of reconstituted calcineurin A plus B for 32P-RII pep was 20 microM, and calmodulin increased the Vmax 18-fold without affecting the Km. CaN A467-492, a synthetic autoinhibitory peptide (ITSFEEAKGLDRINERMPPRRDAMP) from calcineurin, inhibited the Mn2+/calmodulin-stimulated activities of the reconstituted enzyme and the A subunit with IC50's of 25 microM and 90 microM, respectively. The reconstitution of the phosphatase activity of an expressed isoform of calcineurin A by purified B subunit and calmodulin may facilitate comparative studies of the regulation of calcineurin A activity by the B subunit and calmodulin.

Amino Acid Sequence↗
PubMed1992

Isolation and characterization of tributyltin chloride-resistant marine Vibrio.

Tributyltin chloride (TBTCl)-resistant marine bacteria were isolated from coastal sea water. One of these bacteria (Vibrio M-1) was highly resistant when grown in medium containing 125 microM of TBTCl. This strain was sensitive to other metals. Two polypeptides, 30 kDa and 12 kDa, increased when the strain was cultured in the medium supplemented with TBTCl. Initially TBTCl was taken up by the cell; however, the amount of TBTCl determined in the cellular fraction was low after the exponential growth phase of Vibrio M-1, suggesting the existence of a TBTCl-efflux system.

Biological Transport↗
PubMed1992

Hydroxypropylcyclodextrins in parenteral use. I: Lipid dissolution and effects on lipid transfers in vitro.

Hydroxypropyl ethers of cyclodextrins form water-soluble inclusion complexes with lipids. Of the three hydroxypropylcyclodextrins examined, hydroxypropyl-alpha-cyclodextrin had limited specificity for phospholipids, and hydroxypropyl-beta-cyclodextrin had limited specificity for cholesterol, and hydroxypropyl-gamma-cyclodextrin was nonspecific. The formation of inclusion complexes was found to be a fast and reversible process in which complexation of cholesterol did not inhibit its oxidation by cholesterol oxidase, and cholesterol of the erythrocyte membrane could be exchanged within a minute for cholesteryl methyl ether which was in the inclusion complex. Thus, hydroxypropylcyclodextrin in the circulation may catalyze the transport of lipids in the direction of equilibrium distribution.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1992

Hydroxypropylcyclodextrins in parenteral use. II: Effects on transport and disposition of lipids in rabbit and humans.

Hydroxypropyl ethers of cyclodextrins, after parenteral administration, come into contact with lipids in tissues and in circulation and form water-soluble inclusion complexes with these lipids. A single intravenous administration of hydroxypropyl-beta-cyclodextrin to a hereditary hyperlipidemic Watanabe rabbit slightly and temporarily decreased the level of total cholesterol in serum. Single injections of hydroxypropyl-alpha-cyclodextrin and of the corresponding gamma-homologue, both of which are less potent solubilizers of cholesterol, had lesser effects. Repeated administration of hydroxypropyl-beta-cyclodextrin to rabbits led to a gradual increase in total cholesterol in circulation and eventually to a slight relief of atherosclerotic lesions in the thoracic aorta. The only untoward effects of repeated treatments (total doses of up to 40 g/kg) were vacuoles in cells of proximal convoluted tubules in the kidneys. Repeated administration also strongly increased cholesterol in urine, probably because of excretion of the soluble cholesterol-hydroxypropyl-beta-cyclodextrin complex. Proteins in urine increased significantly, whereas triglycerides increased only moderately after repeated administrations. Intravenous infusion of hydroxypropyl-beta-cyclodextrin into a patient with hypervitaminosis A led to a release of liver-stored retinoids into serum in quantities much higher than those that could be directly solubilized by hydroxypropyl-beta-cyclodextrin. Levels of total cholesterol in the circulation of this patient decreased during the infusion. Thus, hydroxypropylcyclodextrins may serve as artificial lipid carriers in the circulation, and because the exchanges that involve inclusion complexation occur very quickly, the presence of hydroxypropylcyclodextrins in organisms may catalytically augment the establishment of equilibria in lipid distribution.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1992

Bone mineral density for patients with bone metastasis of prostate cancer: a preliminary report.

Patients with prostate cancer frequently have osseous metastases which are qualitatively assessed with bone scannings. We have studied the quantitative evaluation of skeletal diseases by measuring bone mineral density (BMD) in the lumbar vertebrae and radius. Forty-four patients with prostate cancer, nine with non-prostatic urogenital cancer and 90 controls were entered in this study. Among the patients with prostate cancer, the values of BMD in the lumbar vertebrae were significantly higher in patients with osseous metastasis than in those without metastasis, whereas the values of BMD in the radius were insignificantly different. Most of the patients with high levels of BMD in the lumbar vertebrae had osseous metastatic disease with no relationship between BMD in the lumbar vertebrae and the radius. The values of BMD in the lumbar vertebrae where hot spot scans were observed were related to X-ray findings. The alterations of BMD levels in the lumbar vertebrae were quantitatively evaluable as responses to androgen deprivation therapy. Measurement of BMD is useful for the accurate diagnosis of osteosclerotic lesions. BMD measurements of the lumbar vertebrae compared with those in the radius were variable in individuals.

Adenocarcinoma↗
PubMed1992

Patchy distribution of rejection changes in small intestinal transplantation.

The aim of this study is to determine the distribution of histological changes of rejection in small intestinal transplantation. Thirty-nine rats were randomized into two groups: group I (n = 15), syngeneic transplants and group II (n = 24), allogeneic transplants. Grafts were excised and examined on days 2, 4, and 8 after transplantation. All grafts of the syngeneic group showed normal mucosa by day 4. However, by this time, all grafts of the allogeneic group demonstrated rejection changes with a patchy distribution in the mucosa. Therefore, with a biopsy from the stoma site there is a risk of missing early rejection.

Animals↗
PubMed1992

Acute toxicity of ozone against morphology of gill and erythrocytes of Japanese charr (Salvelinus leucomaenis).

1. Acute toxicity of ozone exposure to Japanese charr (Salvelinus leucomaenis) was studied histopathologically, and hematologically on gill tissue and red blood cells (RBC) under different ozone concentrations (0-0.7 ppm). 2. Exposure of ozone above 0.7 ppm led to characteristic symptoms and all died of choking in 30 min. 3. Many swollen RBC were seen under the scanning electron microscope. 4. RBC congestion was serious in the gill where degeneration of lamellar epithelium was observed. However, injury to chloride cells was not clear.

Animals↗
PubMed1992

Ischemia-induced loss of brain calcium/calmodulin-dependent protein kinase II.

Forebrain ischemia in gerbils, produced by brief bilateral carotid occlusion, induced the dramatic loss of Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II) as determined by both kinase activity assays and western blot analysis. In cortex and hippocampus, cytosolic CaM-kinase II was completely lost within 2-5 min of ischemia. Particulate CaM-kinase II was more stable and decreased in level approximately 40% after 10 min of ischemia followed by 2 h of reperfusion. CaM-kinase II in cerebellum, which does not become ischemic, was not affected. The rapid loss of CaM-kinase II within 2-5 min was quite specific because cytosolic cyclic AMP kinase and protein kinase C in hippocampus were not affected. These data indicate that cytosolic CaM-kinase II is one of the most rapidly degraded proteins after brief ischemia. Because the multifunctional CaM-kinase II has been implicated in the regulation of numerous neuronal functions, its loss may destine the neuronal cell for death.

Animals↗
PubMed1992

Regional and temporal alterations in Ca2+/calmodulin-dependent protein kinase II and calcineurin in the hippocampus of rat brain after transient forebrain ischemia.

We have investigated regional and temporal alterations in Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and calcineurin (Ca2+/calmodulin-dependent protein phosphatase) after transient forebrain ischemia. Immunoreactivity and enzyme activity of CaM kinase II decreased in regions CA1 and CA3, and in the dentate gyrus, of the hippocampus early (6-12 h) after ischemia, but the decrease in immunoreactivity gradually recovered over time, except in the CA1 region. Furthermore, the increase in Ca2+/calmodulin-independent activity was detected up to 3 days after ischemia in all regions tested, suggesting that the concentration of intracellular Ca2+ increased. In contrast to CaM kinase II, as immunohistochemistry and regional immunoblot analysis revealed, calcineurin was preserved in the CA1 region until 1.5 days and then lost with the increase in morphological degeneration of neurons. Immunoblot analysis confirmed the findings of the immunohistochemistry. These results suggest that there is a difference between CaM kinase II and calcineurin in regional and temporal loss after ischemia and that imbalance of Ca2+/calmodulin-dependent protein phosphorylation-dephosphorylation may occur.

Animals↗
PubMed1992

[Clinical studies on pediatric purulent meningitis--clinical symptoms and prognosis].

In 149 patients with purulent meningitis we encountered in the period of 20 years from 1970 to 1990, their clinical symptoms and prognosis were investigated. Death or sequela was noted in many of the patients having loss of consciousness, stiffness of the members and/or cyanosis as primary clinical symptoms, or having hypoalbuminemia (less than 2.5 g/dl) and/or thrombocytopenia as abnormal laboratory findings, or having excessive protein levels and/or excessively low sugar levels in cerebro-spinal fluid. Early initiation of adequate antibiotic therapy, as well as symptomatic treatment using transfusion, steroids and anticonvulsants, are important.

Female↗
PubMed1992

[Clinical studies on pediatric purulent meningitis--statistical analysis of etiology and therapy].

In a total of 149 children with purulent meningitis we encountered in our institute in the last 20 years, the causatives, the changes in therapeutic management and the prognosis were investigated. The causatives could be detected in 109 patients (73%): H. influenzae; 30 patients (20%), S. pneumoniae; 18 patients (12%), E. coli; 13 patients (9%), GBS; 7 patients (5%) and S. aureus; 6 patients (4%). These five causatives were detected in 49% of the total patients, or 67% of the patients in whom causatives could be detected. Of these five causatives, E. coli were detected the most frequently in the first half of 1970's, but, in recent years, the detection of GBS, S. pneumoniae and H. influenzae has been remarkably increasing. In spite of progress in antibiotics, the prognosis of the disease due to S. pneumoniae, GBS and S. aureus was poor. In the majority of the patients who died, the death came within five days after hospitalization due to loss of consciousness, convulsion etc. It is therefore necessary not only to initiate strong antibiotic treatment as soon as possible after early diagnosis, but also to take symptomatic measures such as steroidal treatment, treatment of shock etc.

Anti-Bacterial Agents↗
PubMed1992

Lysophosphatidylcholine inhibits surface receptor-mediated intracellular signals in endothelial cells by a pathway involving protein kinase C activation.

Lysophosphatidylcholine (lysoPC) transferred from oxidatively modified low density lipoprotein (Ox-LDL) to the endothelial surface membrane has been shown to produce a selective unresponsiveness to cell surface receptor-regulated endothelium-dependent relaxation (EDR) in the rabbit aorta. To determine its mechanism we examined the effects of lysoPC on endothelial surface receptor-mediated transmembrane signals. Incubation for 1 minute with palmitoyl lysoPC (5-10 microM) decreased thrombin (Th, 2 units/ml)- or histamine (His, 0.1 mM)-stimulated inositol 1,4,5-trisphosphate (IP3) production in primary cultures of human umbilical vein endothelial cells (HUVECs). LysoPC also decreased Th- or His-induced intracellular calcium ([Ca2+]i, fura 2) elevation. Pretreatment with protein kinase C (PKC) inhibitors staurosporine (100 nM) or H-7 (50 microM) prevented the inhibitory actions of lysoPC, but HA-1004 had no effect. Incubation for 5 minutes with phorbol 12-myristate 13-acetate (PMA, 100 nM) produced the inhibitory actions on the Th- or His-induced intracellular signals, which closely mimic those exhibited by lysoPC. However, the inhibitory effect of lysoPC was lost in cells that were depleted of PKC by pretreatment for 24 hours with 100 nM PMA. Furthermore, incubation of the cells for 1 minute with lysoPC stimulated PKC activity in the membrane fraction. In organ chamber experiments with porcine coronary artery rings, pretreatment with staurosporine (20 nM) attenuated lysoPC-induced impairment of EDR in response to Th. These results indicate that lysoPC, which accumulates in Ox-LDL and atherosclerotic arterial walls, inhibits the early transmembrane signaling pathway in endothelial cells, and PKC activation could at least partially be involved in the negative regulation by lysoPC.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effect of ozone on the activities of reactive oxygen scavenging enzymes in RBC of ozone exposed Japanese charr (Salvelinus leucomaenis).

The effect of ozone exposure on the activities of reactive oxygen scavenging enzymes (SOD, catalase, GSH-Px) in RBC of Japanese charr (Salvelinus leucomaenis) was examined. Ozone (0, 0.4 and 0.7 ppm as initial concentrations) was exposed to Japanese charr for 30 min, which definitely caused serious membrane damage to RBC of fish. Ozone exposure at 0.4 and 0.7 ppm decreased activities of both catalase and GSH-Px by 80 to 57% of the control. On the other hand, the activities of SOD remained unaffected even by 0.7 ppm ozone exposure. A hypothesis on the RBC membrane damage and participation of SOD and heme-iron was proposed.

Animals↗
PubMed1992

[Pharmacokinetic and clinical evaluation of levofloxacin in obstetrics and gynecology].

Levofloxacin (LVFX, DR-3355), a new synthetic quinolone derivative antibacterial agent, was evaluated for its pharmacokinetics and clinical efficacy in obstetric and gynecological infections, and the following results were obtained. Concentrations of LVFX in serum and intrapelvic genital organs such as uterine and adnexal tissues were determined following oral administration of 100 mg. Tissue penetration of LVFX was found to be good, with its tissue levels (Cmax) of 1.17-2.16 micrograms/ml or g after inhalation anaesthesia and 1.15-2.17 micrograms/ml or g after lumbar spinal anaesthesia. LVFX was given to 22 cases of obstetric and gynecological infections with a daily dose of 200-600 mg for 3-14 days and its clinical efficacy was 95% and bacteriological response was 100%. No side effect was observed. From these findings, we consider that LVFX will be a useful antibacterial agent against obstetric and gynecological infections.

Administration, Oral↗