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Biomedical subjects

K Ando

Publications and source records attributed to K Ando.

At least 271 records · Page 15Linked to original sources
PubMed1996

Purification, characterization and cDNA cloning of a novel anticoagulant of the intrinsic pathway, (prolixin-S) from salivary glands of the blood sucking bug, Rhodnius prolixus.

The salivary glands of the blood sucking insect, Rhodnius prolixus, have an anticoagulant, prolixin-S, which was reported as a specific inhibitor of intrinsic coagulant pathway. Prolixin-S was purified from the salivary glands extract of Rhodnius prolixus by gel filtration and anion exchange HPLC by assaying prolongation of activated partial thromboplastin time (APTT). The isolated protein specifically inhibited factor IXa-catalyzed activation of factor X in the presence of Ca2+ and phospholipids irrespective of the presence or absence of factor VIIIa. The anticoagulant factor had red color and a specific absorbance peak at 402 nm and thus it was identified as a heme protein. A Rhodnius prolixus salivary gland cDNA library was prepared, screened with an antibody against prolixin-S and its complete cDNA sequence was determined. cDNA and deduced amino acid sequences showed that prolixin-S is a novel anticoagulant of 19,922 Da, which has no sequence homology with any other anticoagulant reported so far.

Amino Acid Sequence↗
PubMed1996

[Essential hypertension].

Abnormal membrane sodium transport system is a hypothesis that might explain the mechanism of pathophysiology of essential hypertension. Increased intracellular sodium concentration, which is induced by altered function in either Na+ -K+ pump, Na+ -K+ cotransport, Na+ -Li+ countertransport, or Na+ -H+ antiport, may increased intracellular calcium ion and cause vasoconstriction. Increased intracellular pH by enhanced Na+ -H+ antiport may also play an important role of increment of vascular tone in hypertension.

Animals↗
PubMed1996

[Comparison of the effects of nicotine and methamphetamine on extracellular dopamine in the nucleus accumbens of behaviorally sensitized rats].

Repeated administration of nicotine (NCT) and methamphetamine (MAP) produced a progressive enhancement (sensitization) in the increasing effects on spontaneous motor activity in rats. The purpose of this study was to compare the effects of NCT and MAP on the extracellular levels of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens of behaviorally sensitized rats by in vivo microdialysis. NCT 0.5 mg/kg, sc did not change the DA and DOPAC levels in drug-naive rats, but it showed an increase in the DA levels in rats sensitized to NCT. MAP 0.5 mg/kg, sc increased DA levels and decreased DOPAC levels in drug-naive rats, but it showed a smaller increase in DA levels in rats sensitized to MAP than in drug-naive rats. On the other hand, the basal levels of DA were increased in sensitized rats produced by MAP, but not in those produced by NCT. The present results suggest that NCT and MAP produce behavioral sensitization through the action on the mesolimbic dopaminergic system, but the manner of action of these drugs is different.

Animals↗
PubMed1996

Effects of cholinergic drugs on scopolamine-induced memory impairment in rhesus monkeys.

Rhesus monkeys were trained to perform matching-to-sample responses in which monkeys had to choose one of two stimuli that had the same color as the previously presented sample. Half of a daily session consisted of simultaneous trials where the sample was present during the trial, and the other half consisted of delayed trials, where the sample had been presented at the start of the trial but was withheld at the time of choosing. With vehicle control, the percentage of correct responses (CR%) in both trials exceeded 85%. Scopolamine (4-32 micrograms/kg, SC) selectively decreased the CR% for delayed trials in five out of eight animals, suggesting impairment of short-term memory. Physostigmine (2-16 micrograms/kg, SC), arecoline (16-128 micrograms/kg, SC) and nicotine (4-32 micrograms/kg, SC) attenuated the scopolamine-induced impairment of CR% in delayed trials with concurrent administration with scopolamine. Methamphetamine (16-64 micrograms/kg, SC) did not show such effects. These results suggested that scopolamine-induced memory impairment could be recovered by cholinergic agonists.

Animals↗
PubMed1996

[Surgical strategy for the treatment of congenital biliary dilatation based on the location of intrahepatic bile duct dilatation].

Congenital biliary dilatation used to be regarded as having a good prognosis. However, some recent long-term follow-up studies have shown there to be quite a high incidence of postoperative intrahepatic bile duct (IHBD) stone formation. In most of the cases in whom IHBD stones form, the IHBD were found to be dilated as the time of initial surgery. Therefore, preoperative evaluation of IHBD dilatation using various imaging studies is extremely important. Surgically, in cases involving structure of the common hepatic duct (CHD) with dilatation above the structure, resection of the stricture and a wide hepaticointestinal anastomosis are strongly recommended. In cases where there is a stricture of the CHD or of the first branch of the IHBD, a reconstructive technique should be applied to dilate the stricture. Patients who have a structure and cystic dilatation of the IHBD above the second branch should be carefully followed-up postoperatively. Partial liver resection to remove the cyst may be required at the time of initial operation or at a later stage.

Bile Ducts, Intrahepatic↗
PubMed1996

[Myocardial metastasis in the right ventricle from uterine cervical carcinoma with high 67Ga-citrate accumulation: a case report].

We report a case of high 67Ga-citrate accumulation with myocardial metastasis in the right ventricle from uterine cervical carcinoma. A 41-year-old woman was admitted to our hospital because of acute abdomen after operation and radiotherapy for uterine cervical carcinoma. On performing 67Ga-scintigraphy for differentiation from fever of unknown origin, we found significant 67Ga-citrate accumulation in the right ventricle. To the best of our knowledge, this is a rare case.

Adult↗
PubMed1996

Poly-N-acetyllactosaminyl saccharide chains of band 3 as determinants for anti-band 3 autoantibody binding to senescent and oxidized erythrocytes.

Natural IgG antibodies to band 3 glycoprotein of erythrocyte membrane (anti-band 3 IgG) are known to bind to senescent erythrocytes, and believed to initiate antibody-dependent phagocytic removal of the senescent cells from blood circulation. Anti-band 3 antibodies also bind to the erythrocytes with hereditary hemoglobin abnormalities such as sickle, beta-thalassemic and hemoglobin Köln erythrocytes. Oxidative stress appears to be responsible for the generation of senescent cell antigen on erythrocytes, to which anti-band 3 antibodies bind, since erythrocytes oxidized in vitro bind anti-band 3 IgG, and various oxidative modifications are observed in senescent erythrocytes as well as the erythrocytes with abnormal hemoglobin. Major antigenic sites of band 3 for anti-band 3 IgG autoantibodies are its sialylated poly-N-acetyllactosaminyl saccharide chains. The poly-N-acetyllactosaminyl saccharide chains on senescent erythrocytes are indeed involved in the antigenic sites on senescent erythrocytes. The finding of the carbohydrate epitopes and possible involvement of oxidative mechanism are compatible with the band 3 clustering hypothesis, in which clustering of band 3 molecules in erythrocyte membrane is supposed to be responsible for effective binding of anti-band 3 IgG to the cell surface, because the carbohydrate epitopes of band 3 can form multivalent epitopes on cell surface when band 3 molecules cluster, and oxidative stress can induce such clusters. Interestingly, poly-N-acetyllactosaminyl chains of band 3 on oxidized erythrocytes are also recognized by macrophages directly. Thus, poly-N-acetyllactosaminyl chains may play dual roles as determinants for recognition by anti-band 3 IgG and by macrophages.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1996

Infection of an adult in Mie Prefecture, Japan by Bertiella studeri.

Two gravid strobila without scolex were passed by a 23-year-old male in Mie Prefecture, Japan. Morphological features were comparable to characteristics of Bertiella studeri. Although two children's cases have already been reported, this is the first case of an adult in Japan since the occurrence of B. studeri was proven in Japan.

Adult↗
PubMed1995

A comparison of biological effects of modulated carbon-ions and fast neutrons in human osteosarcoma cells.

PURPOSE: To compare the biological effects of a 135 MeV/u carbon-ion beam and 13 MeV fast neutron beam using human osteosarcoma cells. METHODS AND MATERIALS: We have studied the clonogenic cell survival, recovery of potentially lethal damage (PLD) in plateau phase cells, and spheroid cure in multicellular spheroid after irradiation at various positions in the plateau and spread out Bragg peak (SOBP) of a 135 MeV/u carbon-ion beam and with 13 MeV neutrons. The carbon beam had a 4-cm range in water and a range filter was used to produce a 3-cm extended-peak region. The reference radiation was 137Cs gamma-rays. RESULTS: The relative biological effectiveness (RBE) values for 10% survival level of plateau phase cells for carbon-ions at the position of plateau, proximal peak, midpeak, and distal peak within the SOBP, and neutrons were 1.71, 2.48, 2.63, 3.47, and 2.29, respectively. Corresponding RBE values at 1% level were 1.64, 1.93, 2.06, 2.49, and 2.05. The extent of recovery from PLD was reduced after carbon-ions at proximal peak, midpeak, and distal peak, and neutrons, although not substantially reduced after carbon-ions at plateau. The RBE values for 50% spheroid cure level of spheroids for carbon-ions at the position of plateau, proximal peak, midproximal peak, middistal peak, and distal peak within the SOBP, and neutrons were 1.69, 1.88, 1.87, 1.94, 2.03, and 1.90, respectively. CONCLUSIONS: The biological parameters measured all indicate an approximately comparable biological effectiveness between 75-80 KeV/microns carbon-ions of the SOBP and 13 MeV neutrons in the human tumor model studied in vitro.

Carbon↗
PubMed1995

Synthetic and structural studies of alpha-sialyl-(2-->6) and alpha-sialyl-(2-->3) 1-deoxynojirimycin derivatives potentially useful for biomedical applications.

Suitably protected derivatives of 1-deoxynojirimycin (1,5-dideoxy-1,5-imino-D-glucitol, DNJ) and its D-galacto analog were coupled with 2-thioglycosides of N-acetylneuraminic acid. The resulting disaccharides were converted into a variety of alpha-sialyl-(2-->6)-and alpha-sialyl-(2-->3)-DNJ derivatives, including the cyclic lactams 6-O-(5-acetamido-3,5-dideoxy-D-glycero-alpha-D-galacto-2-nonulopyrano sylono- 1',5-lactam)-1,5-dideoxy-1,5-imino-D-glucitol and -D-galactitol. The structural features of the synthetic compounds were investigated by ion-spray mass and 1H NMR spectrometry. The 1C4 conformation of N-tert-butoxycarbonyl-DNJ, a synthetic intermediate having the gluco configuration, was confirmed by X-ray crystallography.

1-Deoxynojirimycin↗
PubMed1995

Parathyroid hormone-related peptide as a locally produced vasorelaxant: regulation of its mRNA by hypertension in rats.

The present study was undertaken to examine the effect of parathyroid hormone-related peptide (PTHrP) on the vascular tone as well as the expression of its mRNA in the cardiovascular system and its regulation in response to systemic hypertension in Sprague-Dawley rats. In aortic rings precontracted with 0.3 microM norepinephrine PTHrP(1-34) caused a dose-dependent relaxation with the maximal response of 33% being observed at 10(-6) M. PTHrP was nearly equipotent to PTH or CGRP in the vasodilatory action. Ribonuclease protection assay and Northern blot analysis demonstrated that PTHrP mRNA levels in the heart and aorta were increased as a result of systemic hypertension induced by constant infusion of angiotensin II and salt loading. The results of our in vivo studies suggest an autocrine/paracrine role for PTHrP as a local regulator of the vascular tone.

Angiotensin II↗
PubMed1995

Breaking tolerance leads to autoantibody production but not autoimmune liver disease in hepatitis B virus envelope transgenic mice.

Hepatitis B virus (HBV) transgenic mice containing the HBV envelope open reading frame under the transcriptional control of the mouse albumin promoter express hepatitis B surface Ag (HBsAg) in all of their hepatocytes and secrete HBsAg (10 to 40 ng/ml) into the circulation. Because these transgenic mice show no signs of spontaneous liver cell injury or autoimmunity toward the viral (self-) Ag, we asked whether the state of self-tolerance could be reversed by the induction of an acute necroinflammatory liver disease or by immunization with HBV envelope proteins, with the aim of creating a transgenic model for chronic, immune-mediated hepatitis. Our studies indicate that repetitive administration of bacterial LPS, IFN-gamma, or HBsAg-specific CTL, all of which were previously shown to cause liver cell injury and inflammation, does not break tolerance at the T or B cell level, suggesting that the intrahepatic lymphomononuclear cell infiltrate induced by these agents consists of HBsAg-nonspecific cells. The adoptive transfer of HBsAg-primed nontransgenic CD4+ T cells into transgenic mice did not induce anti-HBs autoantibody production by transgenic B cells, even though transgenic B cells were fully responsive to immunization with HBsAg when appropriate T cell help was provided in a nontransgenic environment. Immunization of transgenic mice with purified HBsAg in CFA and repetitive infection with rHBV envelope vaccinia virus led to production of T cell-dependent anti-HBs autoantibodies that cleared HBsAg from the serum, but not to activation of HBsAg-specific CTL. We conclude that HBV envelope transgenic mice are largely tolerant to the transgene product at the T cell but not at the B cell level, and that the activation of an anti-HBs response was not sufficient to induce an autoimmune liver disease in this HBV envelope transgenic mouse model.

Animals↗
PubMed1995

Cdk4 integrates growth stimulatory and inhibitory signals during G1 phase of hematopoietic cells.

Proliferation of hematopoietic cells is controlled by both growth stimulatory and inhibitory cytokines acting primarily in G1, but the mechanisms which integrate these disparate signals are unknown. In a myeloid cell line dependent on interleukin-3 (IL-3) for proliferation, expression of the cyclin dependent kinase Cdk4 and D-type cyclin partners, D2 and D3, in mid G1 was found to be directly related to the concentration of IL-3. TGF beta 1, which induces cell cycle arrest in mid-G1, blocked IL-3-induced expression of Cdk4, but had no effect on expression of cyclins D2 or D3. Sublines made to constitutively express Cdk4, but not lines constitutively expressing cyclins D2 or D3, were hyper responsive to IL-3 and resistant to TGF beta 1. Using an in vitro kinase assay with recombinant retinoblastoma protein (Rb) as a substrate, cyclin D2-associated kinase activity was shown to be induced in G1 by IL-3 and inhibited by TGF beta 1. Constitutive expression of Cdk4, but not cyclin D2 or D3, increased cyclin D2-associated Rb kinase activity and this activity could no longer be inhibited by TGF beta 1. Also, in vivo phosphorylation of Rb was inhibited by TGF beta 1 in wild type but not in Cdk4 lines. Cdk2 kinase activity was also decreased by TGF beta 1, and restored by overexpression of Cdk4. These results implicate Cdk4 activity as a mid G1 checkpoint sensitive to both growth stimulatory and inhibitory cytokines.

Animals↗
PubMed1995

Differential expression of Fas antigen and Bcl-2 protein on CD4+ T cells, CD8+ T cells, and monocytes.

Fas antigen and Bcl-2 protein are considered to be involved in cellular homeostasis. We precisely analyzed the expression of human Fas antigen and Bcl-2 protein on CD4+ T cells, CD8+ T cells, and monocytes. The positivities of Fas antigen on CD4+ and CD8+ T cells increased with aging. In CD4+ T cells, the Fas-/CD45RO+ subpopulation was dominant compared with the Fas+/CD45RO- subpopulation. Conversely, in CD8+ T cells, the Fas+/CD45RO- subpopulation was dominant compared with the Fas-/CD45RO+ subpopulation. Monocytes exhibited high positivity of Fas antigen and low fluorescence intensity of Bcl-2 protein compared with T cells. These results suggest that Fas antigen acts in different processes of cellular homeostasis between CD4+ and CD8+ T cells and that expression of Fas antigen and Bcl-2 protein is involved in homeostasis of monocytes as well as lymphocytes.

Adult↗
PubMed1995

Analysis of target organs for the latency of murine cytomegalovirus DNA using specific pathogen free and germfree mice.

Cytomegalovirus (CMV) establishes a latent infection in its host; however, the organ sites of viral latency and its mechanism still remain to be fully clarified. To elucidate this issue, a latent infection with murine (M) CMV was attempted to induce in mice and the organ sites of the latent viral genome were examined for more than one year by a polymerase chain reaction (PCR). As a result, latent MCMV DNA was detectable in both the lung and the spleen as late as 59 weeks after infection. The heart was also observed to be a target organ of latent MCMV DNA, though the amount of viral DNA was much less than that seen in the lung and spleen. In germfree (GF) mice, on the other hand, no such latent viral DNA was observed in the spleens, while it was seen, but to a significantly smaller degree, in the lungs and the hearts than in the same organs of specific pathogen-free (SPF) mice. The amount of infectious virions generated in the host appeared to be almost equal between the GF and SPF mice. The above findings therefore suggest that the spleen, lung and heart are target organs for MCMV latency and the indigenous bacterial flora, which are not colonizing in GF mice, play an important role in the establishment of such viral latency in SPF mice.

Amino Acid Sequence↗