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Biomedical subjects

K Fukunaga

Publications and source records attributed to K Fukunaga.

At least 55 records · Page 3Linked to original sources
PubMed2001

Neuroprotective effect of sodium orthovanadate on delayed neuronal death after transient forebrain ischemia in gerbil hippocampus.

In transient forebrain ischemia, sodium orthovanadate as well as insulinlike growth factor-1 (IGF-1) rescued cells from delayed neuronal death in the hippocampal CA1 region. Adult Mongolian gerbils were subjected to 5-minute forebrain ischemia. Immunoblotting analysis with anti-phospho-Akt/PKB (Akt) antibody showed that phosphorylation of Akt at serine-473 (Akt-Ser-473) in the CA1 region decreased immediately after reperfusion, and in turn transiently increased 6 hours after reperfusion. The decreased phosphorylation of Akt-Ser-473 was not observed in the CA3 region. The authors then tested effects of intraventricular injection of orthovanadate and IGF-1, which are known to activate Akt. Treatment with orthovanadate or IGF-1 30 minutes before ischemia blocked delayed neuronal death in the CA1 region. The neuroprotective effects of orthovanadate and IGF-1 were associated with preventing decreased Akt-Ser-473 phosphorylation in the CA1 region observed immediately after reperfusion. Immunohistochemical studies with the anti-phospho-Akt-Ser-473 antibody also demonstrated that Akt was predominantly in the nucleus and was moderately activated in the cell bodies and dendrites of pyramidal neurons after orthovanadate treatment. The orthovanadate treatment also prevented the decrease in phosphorylation of mitogen-activated protein kinase (MAPK). Pretreatment with combined blockade of phosphatidylinositol 3-kinase and MAPK pathways totally abolished the orthovanadate-induced neuroprotective effect. These results suggest that the activation of both Akt and MAPK activities underlie the neuroprotective effects of orthovanadate on the delayed neuronal death in the CA1 region after transient forebrain ischemia.

Androstadienes↗
PubMed2001

Refractory gastrointestinal bleeding treated with thyroid hormone replacement.

Although bleeding diathesis has been associated with hypothyroidism, refractory gastrointestinal bleeding has not been previously described in association with hypothyroidism. We report a patient who presented with refractory gastrointestinal bleeding over an 8-week period. Extensive work-up demonstrated small intestinal vascular malformations as the source of bleeding. Despite endoscopic therapy and hormonal therapy, bleeding continued and required transfusion of 54 units of packed red blood cells. Surgical therapy was offered to the patient but was declined. Ultimately, correction of the patient's underlying hypothyroidism resulted in cessation of gastrointestinal bleeding, and no further blood transfusion was necessary. To date, the patient has remained euthyroid without further gastrointestinal bleeding for 30 months.

Aged↗
PubMed2001

Evaluation of histopathological differentiation in lung adenocarcinoma patients using 201Tl-chloride and 99Tcm-MIBI SPET.

The purpose of this prospective study was to evaluate the relationship between thallium-201 chloride (201Tl) and technetium-99m hexakis 2-methoxyisobutylisonitrile (99Tcm-MIBI) accumulation and histopathological differentiation in primary lung adenocarcinoma. A total of 43 patients with primary lung adenocarcinoma were investigated. The patients were divided into well differentiated (n = 17), moderately differentiated (n = 14) and poorly differentiated (n = 12) carcinoma groups. Simultaneous dual single photon emission tomography (SPET) images with 201Tl and 99Tcm-MIBI were acquired 15 min (early) and 2 h (delayed) after injection. Using a region of interest technique, the tumour-to-normal lung ratio was calculated for both early (early ratio) and delayed (delayed ratio) images. The retention index was calculated using the formula delayed ratio/early ratio. Uptake of the radionuclides was compared with the classification of tumour differentiation grading. The mean (+/- SD) values of the early ratio, delayed ratio and retention index using 201Tl were 2.19+/-0.72, 2.28+/-0.71 and 1.06+/-0.16, respectively, in the well differentiated group, 2.38+/-0.83, 2.48+/-0.84 and 1.08+/-0.23, respectively, in the moderately differentiated group, and 2.87+/-0.75, 3.60+/-1.51 and 1.22+/-0.21, respectively, in the poorly differentiated group. Both the ratios and the retention index using 201Tl were significantly lower in the well differentiated group than in the poorly differentiated group. The delayed ratio using 201Tl in the moderately differentiated group was also significantly lower than that in the poorly differentiated group. There were no significant differences in either ratio or the retention index among the three groups using 99Tcm-MIBI. 201Tl SPET is superior to 99Tcm-MIBI SPET for the grading of histopathological differentiation of primary lung adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Comparison of 99Tcm-MIBI with 201Tl chloride SPET in patients with malignant brain tumours.

The purpose of this study was to evaluate the usefulness of 99Tcm-MIBI accumulation for the differentiation of histological diagnosis of malignant brain tumours in comparison with the findings obtained using 201Tl chloride. A total of 25 patients with malignant brain tumours were investigated. The histological categories of tumours included glioblastoma multiforme (n = 5), anaplastic astrocytoma (n = 4), malignant lymphoma (n = 5), and metastatic tumour (n = 11). Simultaneous dual single photon emission tomography (SPET) images with 99Tcm-MIBI and 201Tl were acquired 15 min (early) and 2 h (delayed) after injection, and the early ratio, delayed ratio and retention index were measured. The new indices 201Tl/99Tcm-MIBI ratios and 201Tl/99Tcm-MIBI retention index were also calculated. With respect to the histological type, a higher retention index using 99Tcm-MIBI was noted in glioblastoma multiforme compared with metastatic tumour. Higher values of both ratios using 201Tl were noted in glioblastoma multiforme compared to metastatic tumour. The value of the delayed ratio obtained using 201Tl was higher in glioblastoma multiforme than in anaplastic astrocytoma, and the value was also higher in malignant lymphoma than in metastatic tumour. The 201Tl/99Tcm-MIBI early ratio of glioblastoma multiforme was significantly higher than that of metastatic brain tumour. The 201Tl/99Tcm-MIBI retention index of malignant lymphoma was significantly higher than that of glioblastoma multiforme. In the histological type of tumour, 99Tcm-MIBI is not superior to 201Tl, but the combined indices using 201Tl/99Tcm-MIBI may add new information about differential diagnosis.

Adult↗
PubMed2001

Genetic polymorphisms of CC chemokine receptor 3 in Japanese and British asthmatics.

Whole genome scan analyses have revealed that chromosomal region 3p21-24, which contains a gene cluster of CC chemokine receptors such as CCR3, is possibly linked to asthma. Because CCR3 ligands play a pivotal role in the selective recruitment and activation of inflammatory cells in the asthmatic airway, the authors examined whether there is any association between asthma and the CCR3 gene polymorphisms. Three polymorphisms were identified using the single stranded conformational polymorphism method in Japanese (Asian) and British (Caucasian) subjects; one silent mutation T51C and two missense mutations G824A and T971C. These polymorphisms were examined in 391 Japanese subjects (210 asthmatics and 181 nonasthmatic controls) and 234 British subjects (142 asthmatics and 92 nonasthmatic controls). Asthma diagnosis was based on episodic symptoms, documented wheeze, and the presence of reversible airflow limitation. CCR3 T51C demonstrated a significant association with the diagnosis of asthma in the British population (odds ratio 2.35, p<0.01), but not in the Japanese population. Multiple logistic regression analysis also showed that CCR3 T51C was associated with asthma (odds ratio 2.83, p < 0.02), independent of atopic phenotypes such as high levels of total or house dust mite-specific immunoglobulin-E in serum. In conclusion, a significant association between asthma and CCR3 T51C polymorphism localized on chromosome 3p21 was found.

Alleles↗
PubMed2001

Involvement of mitogen-activated protein kinase in cyclic adenosine 3',5'-monophosphate-induced hormone gene expression in rat pituitary GH(3) cells.

We examined whether mitogen-activated protein (MAP) kinase was activated by stimulation of the cAMP pathway and whether MAP kinase activation was involved in synthesis of PRL and GH in GH(3) cells. Treatment of the cells with a cAMP analog, 8-(4-chlorophenylthio)cAMP (CPT-cAMP), activated MAP kinase and increased PRL at both the protein and messenger RNA levels. The protein and messenger RNA of GH were decreased by the treatment. We constructed the luciferase reporter genes after the promoters of PRL and GH and found the activation of both promoters by the CPT-cAMP treatment. We confirmed that overexpression of the catalytic subunit of cAMP-dependent protein kinase had essentially the same effects on MAP kinase activation and synthesis of PRL and GH as the CPT-cAMP treatment. Furthermore, treatment of the cells with pituitary adenylate cyclase-activating polypeptide 27 activated MAP kinase. The activation of PRL promoter by CPT-cAMP and pituitary adenylate cyclase-activating polypeptide 27 was abolished by pretreatment with PD098059 and H89. Although the increase in PRL and GH secretion by CPT-cAMP was inhibited by H89, PD098059 had no effect on secretion. These results suggest that cAMP-induced MAP kinase activation is essential for PRL gene expression, but not for secretion of PRL and GH.

Animals↗
PubMed2001

Modification of lipases with poly(ethylene glycol) and poly(oxyethylene) detergents and their catalytic activities in organic solvents.

The alpha-chymotrypsin-poly(ethylene glycol) complex, which was prepared by lyophilizing an aqueous solution, was found to have high catalytic activity in organic media even when the molar ratio of polymer/enzyme in its preparation stage is unity. In this study, we obtained freeze-dried complexes of lipases and poly(ethylene glycol) or poly(oxyethylene) detergents including newly synthesized gemini-type detergents, and their transesterification activity in organic solvents was evaluated. The freeze-dried lipase from Pseudomonas cepacia prepared by using each modifier showed enhanced transesterification activity, exhibiting a similar dependence on the concentration of the modifier in the preparation stage to that of the alpha-chymotrypsin-poly(ethylene glycol) complex; in contrasts, the one from Candida rugosa did not do so.

Journal Article↗
PubMed2001

Sampling methods and residential factors affecting formaldehyde concentration in indoor air.

Formaldehyde (HCHO) is the most serious residential pollutant. In order to evaluate residential HCHO levels, two sampling methods have been recommended; one is a 30 minute sampling in a closed room, and the other is a 24 hour sampling with an ordinary lifestyle routine. The aim of this report was to clarify the difference between the HCHO levels obtained by the two sampling methods. Residential air in 58 rooms was sampled for 30 minutes by an active sampling method more than 5 hours after residents closed windows, and by a passive sampling method for 24 hours with an ordinary lifestyle routine. The HCHO concentration with the 30 minute sampling was 0.118+/-0.065 ppm (range: 0.034-0.295 ppm) and 36 rooms (62%) exceeded the Japanese guideline value of 0.08 ppm, while 5% were higher than 0.25 ppm. The HCHO concentration with the 24 hours sampling was 0.053+/-0.039 ppm (range: 0.02-0.167 ppm) and only 13 rooms (22%) exceeded 0.08 ppm. The relationship between the concentrations obtained by the two methods was linear. However, the level with the 24 hour sampling significantly reduced with prolonged window opening time, meaning that occupants made an effort to reduce the usual exposure to about 40% of the exposure in a closed room by opening windows in order to escape from irritation. Since major adverse effects of HCHO are irritation and sensitization, the occasional peak concentration must be focused. In order to evaluate residential HCHO levels, measurement in a closed room is recommended even if people are living there.

Air Conditioning↗
PubMed2001

Interstitial pneumonia accompanying ulcerative colitis.

We report a patient with ulcerative colitis complicated with idiopatic interstitial pneumonia, in whom the etiology of interstitial pneumonia was unknown, but immunological disturbance might have been involved. There are many complications with ulcerative colitis, but interstitial pneumonia is quite rare and its prognosis is quite poor. Antibiotic and steroid treatment were given under respiration supported therapy, but no response could be obtained. In the treatment of patients with ulcerative colitis, we must be mindful of interstitial pneumonia because the prognosis is quite poor.

Biopsy↗
PubMed2001

Quantitative evaluation of selenium contained in tea by high performance liquid chromatography.

For determination of selenium (Se) in biological materials, an improved method based on high performance liquid chromatographic determination of the fluorophore formed by reaction of selenite with 2,3-diaminonapththalene was developed. The concentration detection limits were 0.5 ng/g in dried materials and 0.03 ng/mL in fluid materials. In quadruplicate assays of 11 biological reference materials using the proposed method, measured Se concentrations were not significantly different from their certified values. Thus, the proposed method is reliable and suitable for the determination of trace levels of Se in foods. Using the proposed method, Se concentrations in various kinds of tea were determined to assess the contribution of tea to daily Se intake in the Japanese population. Se concentration in the leaves of general black, green and oolong tea obtained in local retail stores was 33 +/- 19 ng/g (n=440). The leaves of a particular Chinese green tea sold under the name "high Se tea" were found to contain 455 +/- 184 ng/g (n= 14) of Se. While the percentage of Se extractable by infusion was less than 5% for the general teas, that in the high Se tea was more than 20%. These results indicated that intake of tea does not contribute to daily Se intake in the Japanese population. However, since infusions from high Se tea contained over 5 ng/mL of Se, consumption of over 1 L/d of tea derived from such high Se teas may increase the daily Se intake by close to 10%.

2-Naphthylamine↗
PubMed2000

SHPS-1 regulates integrin-mediated cytoskeletal reorganization and cell motility.

The transmembrane glycoprotein SHPS-1 binds the protein tyrosine phosphatase SHP-2 and serves as its substrate. Although SHPS-1 has been implicated in growth factor- and cell adhesion-induced signaling, its biological role has remained unknown. Fibroblasts homozygous for expression of an SHPS-1 mutant lacking most of the cytoplasmic region of this protein exhibited increased formation of actin stress fibers and focal adhesions. They spread more quickly on fibronectin than did wild-type cells, but they were defective in subsequent polarized extension and migration. The extent of adhesion-induced activation of Rho, but not that of Rac, was also markedly reduced in the mutant cells. Activation of the Ras-extracellular signal-regulated kinase signaling pathway and of c-Jun N-terminal kinases by growth factors was either unaffected or enhanced in the mutant fibroblasts. These results demonstrate that SHPS-1 plays crucial roles in integrin-mediated cytoskeletal reorganization, cell motility and the regulation of Rho, and that it also negatively modulates growth factor-induced activation of mitogen-activated protein kinases.

Animals↗
PubMed2000

Pharmacologic graft protection without donor pretreatment in liver transplantation from non-heart-beating donors.

BACKGROUND: Non-heart-beating donors (NHBDs) are considered potential sources of transplant organs in an effort to alleviate the problem of donor shortage in clinical liver transplantation. We investigated the possibility of pharmacologic protection of hepatic allograft function from NHBDs without donor pretreatment. METHODS: Orthotopic liver transplantation was performed using pigs. In donors, cardiac arrest was induced by stopping the respirator. Forty-five minutes after cessation of the respirator, the liver was flushed with cold lactated Ringer's solution including heparin and with the University of Wisconsin (UW) solution, and then preserved for 8 hr at 4 degrees C in the UW solution. The pigs were divided into two groups: a control group and a treated group. In the treated group, an endothelin antagonist TAK-044 was added to the UW solutions (10 mg/L), and TAK-044 (10 mg/kg body weight) and a platelet activating factor antagonist E5880 (0.3 mg/kg body weight) were also administered to the recipients. RESULTS: TAK-044 and E5880 treatment significantly increased the 7-day survival rate of the recipients (100% vs. 17%, P<0.05). In the treated group, portal venous pressure immediately after reperfusion of the graft was significantly lower than in the control group, and postoperative increase in serum concentrations of glutamic oxaloacetic transaminase and total bilirubin was attenuated. Moreover, the energy charge and adenosine triphosphate concentration of the liver were rapidly restored after reperfusion. CONCLUSIONS: Pharmacologic modulation with TAK-044 and E5880 avoiding donor pretreatment can improve the viability of hepatic allografts procured from NHBDs.

Animals↗
PubMed2000

Systematic synthesis of sulfated sialyl-alpha-(2 --> 3)-neolactotetraose derivatives and their acceptor specificity for an alpha-(1 --> 3)-fucosyltransferase (Fuc-TVII) involved in the biosynthesis of L-selectin ligand.

Sulfated sialyl-alpha-(2 --> 3)-neolactotetraose (IV3NeuAcnLcOse4) derivatives at C-6 of GlcNAc (6-O-sulfo), terminal Gal (6'-O-sulfo), and both GlcNAc and Gal (6,6'-di-O-sulfo) residues have systematically been synthesized. (Methyl 5-acetamido-4,7,8,9- tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2-nonulopyranosy lonate)-(2 --> 3)-2,4-di-O-benzoyl-6-O-levulinoyl-D-galactopyranosyl trichloroacetimidate was coupled with 2-(trimethylsilyl)ethyl (2-acetamido-2-deoxy- 3-O-benzyl-6-O-p-methoxyphenyl-beta-D-glucopyranosyl)-(1 --> 3)-(2,4,6-tri-O-benzyl-beta-D-galactopyranosyl)-(1 --> 4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside to give the suitably protected pentasaccharide which, upon selective removal of the p-methoxyphenyl and/or levulinoyl groups at C-6 of the GlcNAc and the terminal Gal residues, successive O-sulfation(s) and deprotection, afforded the desired three sulfated IV3NeuAcnLcOse4 derivatives. Acceptor specificity of the synthetic IV3NeuAcnLcOse4 probes for a human alpha-(1 --> 3)-fucosyltransferase (Fuc-TVII) was examined to study the biosynthetic pathway of L-selectin ligand. Only the 6-sulfated derivative at C-6 of GlcNAc was recognized by Fuc-TVII to give 6-O-sulfo sialyl LeX.

Binding, Competitive↗
PubMed2000

Inhibition of neuronal nitric oxide synthase activity by 3-[2-[4-(3-chloro-2-methylphenyl)- 1-piperazinyl]ethyl]-5, 6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate (DY-9760e), a novel neuroprotective agent, in vitro and in cultured neuroblastoma cells in situ.

DY-9760e, 3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5, 6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate, a novel calmodulin (CaM) antagonist, possesses neuroprotective activity. In the current study, we examined the effects of DY-9760e on nitric oxide synthase (NOS) activities in vitro and on calcium ionophore-induced NO production in situ. DY-9760e inhibited both neuronal NOS and endothelial NOS activities without affecting inducible NOS activity. It also inhibited purified neuronal NOS activity with a potency similar to that seen for purified CaM kinase II activity in vitro. Furthermore, DY-9760e significantly inhibited Ca(2+) ionophore (A23187)-induced NO production in mouse N1E-115 neuroblastoma cells, at a concentration of less than 1 microM. In contrast, no apparent inhibitory effect on Ca(2+)/CaM-dependent protein kinase II activity was observed in cultured hippocampal neurons up to 5 microM. These results suggest that the inhibitory effect of DY-9760e on CaM-dependent NOS activities underlies neuroprotective effects of the agent.

Analysis of Variance↗
PubMed2000

Both amino- and carboxyl-terminal domains of TRAF3 negatively regulate NF-kappaB activation induced by OX40 signaling.

OX40 is a member of the tumor necrosis factor receptor (TNF-R) superfamily. We observed that overexpression of OX40 activated NF-kappaB, which was inhibited by dominant negative forms of TRAF2, NF-kappaB-inducing kinase (NIK), and IkappaB kinase (IKK) alpha. This indicates that OX40 signaling leads to NF-kappaB activation through the same cascade as TNF-R2. We then investigated the negative regulatory function of TRAF3 on OX40-induced NF-kappaB activation. TRAF3 blocked OX40-, TRAF2-induced NF-kappaB activation, but not NIK- and IKKalpha-induced NF-kappaB activation, indicating that TRAF3 blocks the pathway between TRAF2 and NIK. C-terminal deletion mutants as well as the N-terminal deletion mutant of TRAF3 inhibited NF-kappaB activation induced by OX40 or TRAF2. Since TRAF3 bound to OX40 through the C-terminal TRAF domain, the C-terminal domain is likely to work as a dominant negative mutant to compete the recruitment of TRAF2 to the receptor, which transmits the signal from OX40 to the downstream, NIK kinase. On the other hand, the N-terminal domain of TRAF3 seems to affect the downstream of TRAF2 binding. Thus, it is suggested that TRAF3 actively inhibits NF-kappaB activation induced by OX40.

Binding Sites↗
PubMed2000

A study on the surface hydrophobicity of lipases.

Surface properties, including surface net and local hydrophobicities, of bovine serum albumin, gamma-globulin, and six lipases of different origins were evaluated using the aqueous two-phase partitioning method. Each showed a specific and characteristic pattern of surface properties. Correlations between the protein surface hydrophobicities and the coverages of the proteins by lipid-coating with a synthetic detergent, dioleyl glucosyl L-glutamate, were discussed. The results indicated that the surface net hydrophobicity of each protein was indicative of the affinity of the protein for the coating detergent applied in lipid-coating.

Journal Article↗
PubMed2000

Activation of CA(2+)/calmodulin-dependent protein kinase IV in cultured rat hippocampal neurons.

Ca(2+)/calmodulin-dependent protein kinase IV (CaM kinase IV) is a multifunctional enzyme that is abundantly present in the nuclei of neurons. We report the properties of phosphorylation and activation of CaM kinase IV in comparison to CaM kinase II in cultured rat hippocampal neurons. Phosphorylation and activity of CaM kinase IV as well as CaM kinase II were increased by treatment of neurons either with glutamate or high K(+). Glutamate-induced phosphorylation and activity of CaM kinase IV were blocked by N-methyl-D-asparate (NMDA) antagonists, and NMDA application instead of glutamate did increase CaM kinase IV phosphorylation. CaM kinase IV phosphorylation was also increased by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and was blocked by an inhibitor of NMDA receptor. The AMPA-induced phosphorylation was blocked by tetrodotoxin, a Na(+) channel blocker, that was expected to block endogenous glutamate transmission indirectly. On the other hand, high K(+)-induced phosphorylation and activation were not blocked by inhibitors of glutamate receptors, and effectively blocked by nifedipine, an L-type Ca(2+) channel blocker. These properties were similar between CaM kinase IV and CaM kinase II.

Animals↗