Biomedical subjects

T Kanda

Publications and source records attributed to T Kanda.

At least 217 records · Page 12Linked to original sources

PubMed1999

Sodium/hydrogen ion exchange inhibitor ameliorates ischaemia-reperfusion injuries in the rat hind limb.

PURPOSE: This study was designed to investigate the effect of a newly synthesised sodium/hydrogen ion exchange inhibitor, SM-20550, on ischaemia-reperfusion induced injury in a rat hind limb model. METHODS: In order to induce ischaemia of the hind limbs, the abdominal aorta just distal to the renal arteries and the bilateral femoral arteries were clamped. Nineteen rats were divided into three groups. In the sham group (n=5), the vessels were only dissected and a vehicle solution was administered. In the control group (n=7), the vessels were clamped for five hours, and a vehicle solution was administered 10 minutes prior to clamping and continued for five hours after reperfusion. In the SM group (n=7), clamping was maintained for five hours with a bolus injection of SM-20550 and continuous infusion of the solution for five hours after reperfusion. Water content of the left gastrocnemius muscle was calculated. The right gastrocnemius was fixed in 10% formalin. A transverse thin section was stained with antimyoglobin antibody. Stained cells of the right gastrocnemius were counted and the myoglobin staining index was calculated. RESULTS: Water content was significantly (p<0.002) lower in the SM group than in the control group. The myoglobin staining index was significantly (p<0.01) higher in the SM group than in the control group. There was no significant difference between the control and the SM groups in creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH). CONCLUSIONS: Our results indicate that the sodium/hydrogen ion exchange inhibitor, SM-20550, ameliorates oedema formation and ischaemia-reperfusion induced injury of the skeletal muscle.

Amidines↗

PubMed1999

N-acetyl-beta-D-glucosaminidase is not a predictor, but an indicator of kidney injury in patients with cardiac surgery.

The urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) was evaluated in terms of its ability to predict renal failure following open-heart surgery. Twenty-two patients were divided into three groups; 6 patients with post-operative renal failure (RF group), 9 without renal failure (non-RF group) and 7 who underwent non-cardiac surgery (non-ECC group). NAG levels during operation were significantly higher in the non-RF group than in the non-ECC group (2.28 +/- 0.50 U vs. 0.39 +/- 0.06 U, p < 0.01). NAG levels in the RF group were not significantly different from those in the non-ECC group (1.12 +/- 0.28 U/hr vs. 0.39 +/- 0.06 U/hr, p > 0.1), and in the non-RF group (1.12 +/- 0.28 U/hr vs. 2.28 +/- 0.50 U/hr, p > 0.1). Post-operative NAG levels were not significantly different between the RF and non-RF groups, whereas post-operative creatinine clearance values were significantly different (on 2, 6 and 7 post-operative day, p < 0.05). Our data suggest that the kidney is predisposed to renal failure by cardiopulmonary bypass and the chance of renal failure depends in some part on post-operative patient management.

Acetylglucosaminidase↗

PubMed1999

Effects of pericytes and various cytokines on integrity of endothelial monolayer originated from blood-nerve barrier: an in vitro study.

In the in vitro blood-brain barrier (BBB) model, astrocytes have been considered to strengthen the barrier function of brain microvascular endothelial cells (BMECs). Because the blood-nerve barrier (BNB) does not comprise cells equivalent to astrocytes, we hypothesized that the integrity of the BNB is supported by endoneurial pericytes, the only cells comprising endoneurial microvessels other than peripheral nerve microvascular endothelial cells (PnMECs). To estimate the barrier function of in vitro BBB/BNB models, we measured the transendothelial electrical resistance (TEER) and permeability for paracellular diffusion of [carboxyl-14C]- inulin across the layers of PnMECs or BMECs co-cultured with pericytes, astrocytes or fibroblasts. When co-cultured with astrocytes, both PnMECs and BMECs showed higher TEER values and significantly lower clearance of inulin. When co-cultured with pericytes, only PnMECs increased the TEER value and lowered the clearance of inulin as effectively as did those co-cultured with astrocytes. Hence, we conclude that endoneurial pericytes may strengthen the BNB function in a PnMEC-specific manner. The TEER values of the PnMEC monolayer challenged by IL-1beta, TNFalpha or VEGF decreased significantly. Based on the present results, the co-culture of PnMECs and pericytes appears to be a useful in vitro BNB model.

Animals↗

PubMed1998

Knocking out a specific tRNA species within unfractionated Escherichia coli tRNA by using antisense (complementary) oligodeoxyribonucleotides.

Methods for the preparation of an Escherichia coli tRNA mixture lacking one or a few specific tRNA species can be the basis for future applications of cell-free protein synthesis. We demonstrate here that virtually a single tRNA species in a crude E. coli tRNA mixture can be knocked out by an antisense (complementary) oligodeoxyribonucleotide. One out of five oligomers complementary to tRNA(Asp) blocked the aspartylation almost completely, while minimally affecting the aminoacylation with other 13 amino acids tested. This 'knockout' tRNA behaved similarly to the untreated tRNA in a cell-free translation of an mRNA lacking Asp codons.

Aspartic Acid↗

PubMed1998

Adenosine A2A receptors modify motor function in MPTP-treated common marmosets.

Both adenosine A1 and A2 receptor populations are located in the striatum and can modify locomotor activity, and they may form a therapeutic target for Parkinson's disease (PD). Administration of the selective adenosine A2A antagonist (E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-pu rine-2,6-dione (KW-6002) to MPTP-treated common marmosets increased locomotor activity. In contrast, administration of the selective A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxantine (DPCPX) had no effect on locomotion. Administration of the adenosine A2A receptor agonist 2-[p-[2-(2-aminoethylamino) carbonylethyl] phenethyl amino]-5'-N-ethylcarboxamidoadenosine (APEC) dose dependently suppressed basal locomotor activity. A minimally effective dose of APEC (0.62 mg/kg, i.p) completely reversed the increase in locomotor activity produced by administration of KW-6002. The adenosine A2A receptor appears to be an important target for the treatment of basal ganglia disorders, particularly PD.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1998

Human papillomavirus oncoprotein E6 binds to the C-terminal region of human minichromosome maintenance 7 protein.

Oncoprotein E6 of the human papillomavirus (HPV) associated with cervical cancer (HPV-16 and -18) degrades tumor suppressor protein p53, but seems to have p53-independent transforming functions. We searched for other cellular targets for the N-terminal region of HPV-16 E6 using a yeast two-hybrid system. The E6 was found to bind to the C-terminal region of a human minichromosome maintenance 7 (hMCM7) protein, which is a component of replication licensing factors. The full-length hMCM7 translated in vitro was capable of binding to bacterially expressed E6. In yeast cells the E6s of the cancer-associated HPVs (HPV-16, -18, and -58) bound to hMCM7 more strongly than those of the HPVs associated with a benign tumor (HPV-6 and -11). Binding of E6 with hMCM7 may cause chromosomal abnormalities found in the human cells expressing E6s of oncogenic HPVs.

Binding Sites↗

PubMed1998

A surface immunodeterminant of human papillomavirus type 16 minor capsid protein L2.

We used human papillomavirus type 16 (HPV-16) particles composed of capsid proteins L1 and L2 (L1/L2 capsids) as an antigen to produce mouse monoclonal antibodies (MAbs). Of 18 MAbs recognizing surface epitopes of L1/L2 capsids, 1 was an anti-L1 MAb and 17 were anti-L2 MAbs. Seven of 11 anti-L2 MAbs recognizing linear epitopes wer found to bind to a synthetic peptide with an HPV-16 L2 sequence of amino acids (aa) 69-81, which is within a highly conserved region among different HPVs. The synthetic peptide reacted with the human sera that had been shown to be positive for an antibody against HPV-16, -18, -58, or -6b capsids composed of L1 alone. The data suggest that the HPV-16 L2 region of aa 69-81 contains a type-common immunodeterminant exposed on the surface of HPV virions.

Animals↗

PubMed1998

Retroviral vector targeting human cells via c-Kit-stem cell factor interaction.

Targeted gene transfer into hematopoietic stem cells by retroviral vectors would greatly facilitate the development of in vivo strategies for stem cell gene therapy. We engineered a recombinant retroviral vector that can target human cells expressing a c-Kit receptor via a ligand-receptor interaction. The ecotropic (Moloney murine leukemia virus) envelope protein was modified by insertion of a sequence encoding the N-terminal 161 amino acids of murine stem cell factor (mSCF), the ligand for murine c-Kit. The chimeric envelope protein was correctly processed and incorporated into viral particles as efficiently as the wild-type envelope protein. Virions pseudotyped with the chimeric envelope proteins bound to 293 cells expressing murine c-Kit (293KIT) preferentially; however, they could not transduce any c-Kit-positive cells under conventional conditions. They could transduce 293KIT cells in the presence of chloroquine, and HEL cells expressing human c-Kit on a fibronectin fragment (CH296)-coated dish. The fact that recombinant mSCF in the medium at the time of transduction greatly reduced the efficiency of both gene deliveries implies that the vector utilized the mSCF-c-Kit interaction for the initial step of transduction in either case. The vector may prove useful for targeting cells expressing c-Kit on their surface.

Cells, Cultured↗

PubMed1998

Indirect dexamethasone down-regulation of the liver fatty acid-binding protein expression in rat liver.

The effects of glucocorticoids on the regulation of the liver fatty acid-binding protein (L-FABP) were studied in vivo and in primary culture of hepatocytes in rats. No change in L-FABP cytosolic content and mRNA levels occurred after adrenalectomy. By contrast, a twofold decrease in L-FABP expression was found in dexamethasone (Dex) treated rats. In primary culture of rat hepatocytes, insulin did not modify the L-FABP mRNA levels, whereas Dex produced a significant decrease. This down-regulation was independent of specific glucocorticoid receptors, of alteration in the turnover of L-FABP mRNA and did not require a de novo protein synthesis. However, it was totally prevented when 320 microM oleic acid was added in the culture medium. These findings show that the dex-mediated down-regulation of the L-FABP expression found in vivo is not due to a direct endocrine effect, but is likely secondary to changes in cellular lipid metabolism.

Adrenal Glands↗

PubMed1998

Histone-GFP fusion protein enables sensitive analysis of chromosome dynamics in living mammalian cells.

BACKGROUND: The amplification of oncogenes in cancer cells is often mediated by paired acentric chromatin bodies called double minute chromosomes (DMs), which can accumulate to a high copy number because of their autonomous replication during the DNA synthesis phase of the cell cycle and their subsequent uneven distribution to daughter cells during mitosis. The mechanisms that control DM segregation have been difficult to investigate, however, as the direct visualization of DMs in living cells has been precluded because they are far smaller than normal chromosomes. We have visualized DMs by developing a highly sensitive method for observing chromosome dynamics in living cells. RESULTS: The human histone H2B gene was fused to the gene encoding the green fluorescent protein (GFP) of Aequorea victoria and transfected into human HeLa cells to generate a stable line constitutively expressing H2B-GFP. The H2B-GFP fusion protein was incorporated into nucleosomes without affecting cell cycle progression. Using confocal microscopy, H2B-GFP allowed high-resolution imaging of both mitotic chromosomes and interphase chromatin, and the latter revealed various chromatin condensation states in live cells. Using H2B-GFP, we could directly observe DMs in living cancer cells; DMs often clustered during anaphase, and could form chromosomal 'bridges' between segregating daughter chromosomes. Cytokinesis severed DM bridges, resulting in the uneven distribution of DMs to daughter cells. CONCLUSIONS: The H2B-GFP system allows the high-resolution imaging of chromosomes, including DMs, without compromising nuclear and chromosomal structures and has revealed the distinctive clustering behavior of DMs in mitotic cells which contributes to their asymmetric distribution to daughter cells.

Animals↗

PubMed1998

Regulation of expression of human intestinal bile acid-binding protein in Caco-2 cells.

Molecular mechanisms of the bile acid active transport system in the ileal enterocytes remain unknown. We examined whether bile acids affect human enterocyte gene expression of intestinal bile acid-binding protein (I-BABP), a component of this transport system. Differentiated Caco-2 cells were incubated in the presence of human bile, bile acids or other lipids. The level of I-BABP expression was evaluated by Northern and Western blot analyses. A 24 h incubation of Caco-2 cells in a medium containing either bile or bile acids resulted in a remarkable 7.5-fold increase in the I-BABP mRNA level over the control level. Neither cholesterol, palmitic acid, phosphatidylcholine nor cholestyramine treated bile showed any difference in I-BABP mRNA expression from the control. Bile acid treatment increased the level of I-BABP mRNA in Caco-2 cells in a time- and dose-dependent manner. Western blot analysis showed that this induction led to increase in cytosolic I-BABP. Chenodeoxycholic acid and deoxycholic acid showed greater induction effects than other hydrophilic bile acids, including their own glycine conjugates. Pretreatment by actinomycin D or cycloheximide completely inhibited the up-regulation of I-BABP expression by bile acid. Bile acids, especially lipophilic bile acids, increase the I-BABP expression in Caco-2-cells, suggesting that luminal bile acids play an important role in regulating the I-BABP gene expression.

Bile Acids and Salts↗

PubMed1998

Combination of OK432 and human interferon-alpha for treating viral-induced diabetes mellitus in mice.

We investigated the therapeutic effects of OK432 (picibanil; CAS39325-1-4), an immunomodulator that is derived from the Su strain of Streptococcus pyogenes. This agent was administered alone or combined with human interferon-alpha in a murine model of insulin-dependent diabetes mellitus. Interferon-alpha inhibits viral replication, reducing the incidence of virus-induced IDDM. Groups of DBA/2 mice (N = 25 per group) received an intraperitoneal injection of OK432 and interferon-alpha daily for 16 d beginning 1 d after inoculation with 500 plaque-forming units of encephalomyocarditis virus (EMCV). The dose of OK432 was one clinical unit (corresponding to 0.1 mg dried cells) per mouse, and that of interferon-alpha was 1 x 10(4) u/g. The animals were killed at random at 3 or 7 d after inoculation with EMCV. The survival rate of mice treated with the combination of OK432 and with interferon-alpha was significantly greater than that of the non-treated infected control animals (P < 0.01). Fasting levels of blood glucose were significantly lower in the mice administered the combination, than in the controls, both on day 3 (68 +/- 21 mg/dl vs. 270 +/- 135 mg/dl, P < 0.01) and on day 7 (101 +/- 29 mg/dl vs. 219 +/- 112 mg/dl, P < 0.01). Serum levels of insulin were significantly higher in the treated mice than in the controls (65 +/- 5 vs. 55 +/- 1 microU/ml, P < 0.05). However, in the mice treated with OK432 or interferon-alpha alone, the survival rate and the blood level of glucose and insulin did not differ from those of infected controls. Natural killer (NK) cell activity was significantly higher in the mice treated with the drug combination than in the controls on both days evaluated: day 3, 65 +/- 5 vs. 55 +/- 1%, n = 3, P < 0.05; day 7, 44 +/- 3 vs. 22 +/- 8%, n = 3, P < 0.05). Serum levels of murine interferon in the treated mice exceeded those in controls on both days evaluated (day 3, 671 U/ml vs. 442 U/ml; day 7, 57 U/ml vs. 43 U/ml). There were no significant differences in NK cell activity or in the interferon level in mice treated with either OK432 or interferon-alpha alone as compared with the infected, non-treated controls. Results suggest that the combination of OK432 and interferon-alpha protects against virally induced IDDM by increasing the activity of NK cells as well as the plasma level of interferon.

Animals↗

PubMed1998

Unmyelinated nerve fibers in sural nerve in pure autonomic failure.

We examined sural nerve biopsy specimens from 7 patients with pure autonomic failure (PAF). The mean unmyelinated nerve fiber density in these patients was 40% less than in age-matched controls. Increased numbers of clusters of collagen pockets not containing unmyelinated axons were the most prominent finding in PAF. This appears to reflect recent dropout of a group of sympathetic efferents and suggests grouping of unmyelinated fibers by modality at the level of the sural nerve trunk.

Aged↗

PubMed1998

Adenosine A2A antagonist: a novel antiparkinsonian agent that does not provoke dyskinesia in parkinsonian monkeys.

Treatment of Parkinson's disease with L-dopa therapy leads to long-term complications, including loss of drug efficacy and the onset of dyskinesia. Adenosine A2A receptors in striatum are selectively localized to GABAergic output neurons of the striato-pallidal pathway and may avoid such problems. The novel adenosine A2A receptor antagonist KW-6002 has been examined for antiparkinsonian activity in MPTP-treated primates. Oral administration of KW-6002 reversed motor disability in MPTP-treated common marmosets in a dose-dependent manner. However, KW-6002 only modestly increased overall locomotor activity and did not cause abnormal movement, such as stereotypy. The ability of KW-6002 to reverse motor disability was maintained on repeated daily administration for 21 days, and no tolerance was observed. KW-6002 induced little or no dyskinesia in MPTP-treated primates previously primed to exhibit dyskinesia by prior exposure to L-dopa. These results suggest that selective adenosine A2A receptor antagonists represent a new class of antiparkinsonian agents that improve disability without producing hyperactivity and without inducing dyskinesia.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1998

Doubly entrapped baker's yeast survives during the long-term stereoselective reduction of ethyl 3-oxobutanoate in an organic solvent.

To attain long-term bioreaction in organic solvents with living microorganisms, we tried to protect the microorganisms from the toxicity of the solvent by immobilization. In this study, baker's yeast, which is not tolerant to organic solvents such as isooctane, was selected as a model microorganism and the immobilized living yeast cells were examined for activity in the steroselective reduction of ethyl 3-oxobutanoate to ethyl (S)-3-hydroxybutanoate in isooctane; an activity that correlated well with the viability of the yeast cells. It was found that double entrapment, that is, further entrapment of calcium-alginate-gel-entrapped cells with a urethane prepolymer, made it possible for the yeast to remain viable in isooctane, although other conventional immobilization methods, such as single entrapment using polysaccharide or synthetic resin prepolymers, were insufficient for its protection. Furthermore, doubly entrapped living yeast cells could carry out the stereoselective reduction in isooctane repeatedly for a long period (more than 1200 h) with occasional cultivation. Thus, double entrapment enabled a microorganism sensitive to organic solvents to survive over long-term bioreaction in an organic solvent.

Acetoacetates↗

PubMed1998

Blood-nerve barrier in IgM paraproteinemic neuropathy: a clinicopathologic assessment.

We report the pathologic findings in a patient with sensorimotor neuropathy associated with Waldenström's macroglobulinemia, particularly in relation to blood-nerve barrier defects. The monoclonal IgM was of kappa type and possessed anti-HNK-1 activity. A sural nerve biopsy specimen revealed severe loss of myelinated and unmyelinated nerve fibers and gaps between adjacent endothelial cells of small endoneurial vessels. Postmortem findings 3 years later included severe loss of myelinated nerve fibers and diffuse infiltration by lymphoplasmacytic B cells throughout the peripheral nervous system, sparing the central nervous system. Findings in this case suggest an immune attack against endoneurial endothelial cells with permeation of IgM into peripheral nerve tissue.

Aged↗

PubMed1998

Adverse effects on rabbit anterior cruciate ligament after knee immobilization: changes in permeability of horseradish peroxidase.

Changes in the permeability of horseradish peroxidase (HRP) and the histology of the rabbit anterior cruciate ligament (ACL) caused by knee immobilization were studied. The knees of adult rabbits were immobilized for 2-8 weeks by a long leg cast with the knee flexed at 120 degrees, and some joints were allowed to be remobilized for 4 weeks after 6 or 8 weeks' immobilization. After 1 ml of HRP was injected into the knee joint and allowed to permeate into the ACL, the degree of permeation at the mid-portion of the ACL between femur and tibia was visualized with diaminobenzidine tetrahydrochloride. The ACL was examined histologically by light and transmission electron microscopy. Although the HRP permeated into almost the entire area of the transverse section of the non-immobilized normal ACL, as the period of immobilization increased, the extent of permeation gradually decreased. The decrease was significant from week 4 to week 6 and from week 6 to week 8. Degenerative change with necrosis of cells at the central area of the ACL was noted in the 6-week immobilization group, and the 8-week period of immobilization increased the extent of this degeneration. Although the permeation recovered in both the 6-week and 8-week immobilization groups 4 weeks after remobilization, there were fewer cells with a normal morphology in the central area in the 8-week immobilization group than in the control. These results suggest that long-term immobilization adversely affects the ACL.

Analysis of Variance↗

PubMed1998

Type V phosphodiesterase inhibition modulates endogenous immunoreactivities of endothelin-1 and endothelial nitric oxide synthase in pulmonary arteries in rats with monocrotaline-induced pulmonary hypertension.

We evaluated the effects of oral administration of E4021 (100 mg/kg/day), a type V phosphodiesterase inhibitor, on immunoreactivities of endothelin-1, endothelin receptors, and nitric oxide synthases in pulmonary arteries in a rat model of pulmonary hypertension. Immunoreactivities of endothelin-1 and endothelial nitric oxide synthase were observed significantly less frequently, together with significant reduction of right ventricular overload and medial thickening in rats treated with E4021 than in the control with monocrotaline on day 28. The levels of plasma endothelin-1 and serum nitrite and nitrate were significantly lower in rats that received E4021 than in the control with monocrotaline. Oral administration of E4021 modulates endogenous immunoreactivities of endothelin-1 and endothelial nitric oxide synthase with the improvement or right ventricular overload and medial thickening.

3',5'-Cyclic-GMP Phosphodiesterases↗