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Biomedical subjects

T Kikuchi

Publications and source records attributed to T Kikuchi.

At least 343 records · Page 19Linked to original sources
PubMed1995

Concentrations of metal elements in mouse organs after intratracheal administration of coal fly ash.

Size-density fractionated coal fly ash particles, 1-5 microns in diameter and 2.4-2.8 g/cm3 in density, were administered to mouse lungs intratracheally. The change in the concentrations of metal elements in the lungs, kidneys, livers and spleens was measured by inductively coupled plasma atomic emission spectroscopy and atomic absorption spectroscopy up to 16 weeks after administration. In the lungs, each elemental concentration increased 1 week after administration and decreased thereafter with time after administration. For example, the concentrations of Al were 1018 +/- 272 micrograms/g tissue at 1 week and decreased thereafter to 556 +/- 177 micrograms/g tissue at 16 weeks after administration. The concentrations of Ca, Mn and Ni decreased more rapidly than the other elements, suggesting that Ca, Mn and Ni were dissociated from the alumino-silicate matrix of the fly ash particles in the lungs. In the kidneys, the concentration of Ni significantly increased at 2, 8 and 16 weeks after administration; the concentration of Ni showed an increase of 0.4 +/- 0.2 micrograms/g over the control mouse at 16 weeks after administration. In the livers, increased concentrations of Ca and Mn were observed at 2, 4 and 16 weeks. On the other hand, no changes in the concentrations of these elements were observed in the spleen.

Animals↗
PubMed1995

[Texture segregation in large visual field].

Using large texture stimuli (72 degrees x 72 degrees or 20 degrees x 20 degrees), we investigated spatial properties of texture segregation. In Experiment 1, we used L-like forms, T-like forms, or tilted T-like forms to create a large background texture field, in which a small target region of the odd forms was embedded. The texture display was presented for 255 ms, and subjects were asked to detect the target and to recall its position. The target upright Ts in the tilted Ts and the target tilted Ts in the upright Ts segregated easily. In contrast to our expectation, however, the target upright Ts in the Ls and the target Ls in the upright Ts were detected better in the periphery than in the central area. In Experiment 2, subjects were asked to detect a single target element embedded in the background. The size of the elements was enlarged to that of the target texture region in Experiment 1. The target Ts and Ls were detected better in the central area than in the periphery. These results can be explained by the differential grouping processing and distribution of attention in the visual field.

Adult↗
PubMed1995

[Morphologic analysis of blood cells].

Accompanying hematology laboratory automation, the frequency of morphological observation of blood cells tends to decrease. Although 5-part differentials are performed by automated systems, counting of abnormal cells such as immature cells or leukemia cells still must be performed manually using smears. In the automated hematology laboratories, technicians more frequently find abnormal cells than before. Therefore, poor microscopic observation of blood cells markedly affects the diagnosis. Continuous training of the technologist is mandatory. Also, preparation of smear samples is important, i.e, well prepared slides must be stained properly with an appropriate dye. Technicians must be familiar with staining technology together with the knowledge of the characteristics of several staining methods. On the other hand, the technician's ability to differentiate white blood cells depends on the instructor's knowledge. This makes quality control and the standardization of differentials difficult. Still the problems must be solved under the cooperation of the various societies concerned.

Automation↗
PubMed1995

[Ubiquitin immunoreactivity in the central nervous system of gracile axonal dystrophy (GAD) mouse].

In order to know the relationship of ubiquitin and axonal degeneration in the central nervous system (CNS) of the gracile axonal dystrophy (GAD) mutant mouse, the immunocytochemical study was performed in the spinal cord, medulla oblongata and brain of normal and GAD mice at 4, 9, 18 and 32 weeks of age. The polyclonal antibodies of ubiquitin were used for this study. The results were as follows: Many ubiquitin-positive dot-like structures (DS) were first observed in the gracile nucleus affected primarily with axonal degeneration. They extended to the gracile fasciculus on the dorsal part of spinal cord in accordance with the dying-back type degeneration. The second-order neurons at Clarke's nucleus were also affected slightly later stages and revealed ubiquitin-positive DS along the posterior spinocerebellar tract and the white matter of certain lobes of cerebellum. In 18th week, the transneuronal degeneration started from the distal axonal ends of the primary sensory neurons came up to the some parts of cortical neurons through the secondary neurons in the thalamus. The ubiquitin-positive DS were detected on the ventral surface of the medulla oblongata and increased progressively in number along the corticospinal (pyramidal) tract of spinal cord which consists of the descending fibers derived from the cortical neurons. These findings suggest that abnormal proteins in the degenerating axons were ubiquitinated rapidly before they accumulated in the preterminal axons whose neuron stems are far away from the place, and that GAD mouse would be a useful animal model to know the mechanism(s) of the naturally occurring transneuronal degeneration from the distal axonal ends of both ascending sensory neurons and descending pyramidal neurons in the CNS.

Animals↗
PubMed1995

[Open heart surgery with bloodless priming for ventricular septal defect and pulmonary hypertension].

In 17 patients with ventricular septal defect and pulmonary hypertension (VSD, PH) weighing 5.2 kg to 9.5 kg, open heart surgery was conducted with bloodless priming (total priming volume: 370-470 ml). None of the patients required blood transfusion during their hospital stay. The post-operative respiratory status was excellent in all cases with duration of intubation being 6 +/- 3 hours. While 12 patients weighing over 6.6 kg maintained individual constant hematocrit (Hct) values during cardiopulmonary bypass (CPB), all 5 patients weighing under 6.1 kg showed significant decrease during rewarming (17 +/- 2% after initiation of CPB to 14 +/- 2% during rewarming). The lowest Hct value was 12% during rewarming in 6.0 kg infant. The pre-operative circulating blood volume (CBV) was calculated retrospectively from the priming volume, the Hct value after anesthetic induction and the Hct value after initiation of CPB. The relationship, CBV (ml) = body weight (kg) x 72-13 (r = 0.85, p < 0.01) was derived. Using this equation, we calculated the predicted Hct level after initiation of CPB using the 370 ml bypass circuit in 43 VSD PH patients weighing 3.4 kg-5.9 kg. The Hct values were 17 +/- 2% in 13 patients weighing over 5 kg with 12 (91 percent) above 15%, and 13 +/- 2% in 30 patients weighing under 4 kg with 3 (11 percent) above 15%. Hct levels of 34%-36% before CPB were essential in patients weighing 4.0 kg-4.9 kg for the Hct level after initiation of CPB to exceed 15%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMed1995

7-(4-[4-(2,3-Dichlorophenyl)-1-piperazinyl]butyloxy)-3,4-dihydro-2(1H)-quinolinone (OPC-14597), a new putative antipsychotic drug with both presynaptic dopamine autoreceptor agonistic activity and postsynaptic D2 receptor antagonistic activity.

The effects of 7-(4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butyloxy)-3,4-dihydro-2 (1H)- quinolinone (OPC-14597), a derivative of the dopamine (DA) autoreceptor agonist 7-(3-[4-(2,3-dimethylphenyl)piperazinyl]propoxy)-2(1H)-quinolinone (OPC-4392), on DA receptors were biochemically and behaviorally studied and compared with those of OPC-4392. Both OPC-14597 and OPC-4392 inhibited reserpine- and gamma-butyrolactone (GBL)-induced increase in tyrosine hydroxylase activity in the mouse and rat brain. The effects of OPC-14597 were comparable to those of OPC-4392 and were completely antagonized by haloperidol. OPC-14597, unlike apomorphine, did not evoke postsynaptic DA receptor-stimulating behavioral signs such as hyperlocomotion in the reserpinized mice and contralateral rotation in rats with unilateral striatal 6-hydroxydopamine lesions. Both OPC-14597 and OPC-4392 inhibited such apomorphine-induced postsynaptic behavioral changes as stereotypy and hyperlocomotion in mice and rats and rotation in rats with unilateral striatal kainic acid lesions. The anti-apomorphine effects of OPC-14597 were about 30 to 140 times greater than those of OPC-4392 and were observed at doses that inhibit the increases in tyrosine hydroxylase activity. The affinities of OPC-14597 for 3H-spiperone-labeled D2 receptors in the rat frontal cortex, limbic forebrain and striatum were higher than those of OPC-4392. These results suggest that OPC-14597 is a unique antipsychotic drug candidate, being a DA autoreceptor agonist that has a stronger postsynaptic D2 receptor antagonistic activity than that of OPC-4392.

4-Butyrolactone↗
PubMed1995

[Valvuloannuloplasty for atrioventricular valvular regurgitation in complicated cyanotic cardiac anomalies].

Valvuloannuloplasty for atrioventricular (AV) valvular regurgitation was performed in 13 patients with univentricular AV connection and double outlet right ventricle. The suturing-up of free margins of the anterior and posterior common leaflets, which divides the common orifice into two parts, was performed in 4 children with quadricuspid or quintacuspid common AV valve and effectively reduced the regurgitation. The semicircular annuloplasty with a thin GORE-TEX graft was carried out in two patients having tricuspid AV valve, and a favourable result was obtained. In bicuspid AV valvular regurgitation, two patients received the suturing-up of free margins of prolapsed leaflets, and the results were satisfactory. From these results we consider that the semicircular annuloplasty for dilated tricuspid AV valve and the suturing-up of free margins of dilated or prolapsing leaflets in quadricuspid or quintacuspid and bicuspid AV valves are the recommendable procedures. If more than mild AV valvular regurgitation remained after these valvuloplasties, the Kay's and/or DeVega's annuloplasties should be added for eliminating the regurgitation.

Adolescent↗
PubMed1995

[Quantitative analysis of myocardial tracer distribution in patients with ischemic heart disease: comparison of 201T1 and 123I-15-(p-iodophenyl)-3-methylpentadecanoic acid (BMIPP)].

Quantitative assessment of myocardial tracer uptake in stress-delayed thallium and resting BMIPP imagings were performed in 24 patients with coronary artery disease. Each distribution was displayed on the bull's eye polar map and % uptake of each distribution was calculated as a mean value in 9 myocardial segments on the polar map. Redistribution index (% delayed uptake minus % stress uptake on thallium images) and discordance index (% delayed thallium uptake minus % BMIPP uptake) were also calculated. Each parameter was compared to the visual uptake score and wall motion score on contract left ventriculography. Excellent correlations were obtained between % uptake and the uptake score in each tracer. The % thallium and BMIPP uptake also correlated with regional wall motion score. Furthermore, a significant correlation was observed between redistribution and discordance indexes in the mildly hypoperfused segments. These data indicate that the quantitative analysis of thallium and BMIPP distributions seems to be valuable to understand relationship between perfusion and regional wall motion. The discordant BMIPP uptake may represent asynergic but viable segments. However, several important factors, such as attenuation factor should be also taken into consideration for such quantitative analysis.

Aged↗
PubMed1995

[Occlusion of left coronary ostium involving aortic stenosis and insufficiency].

Aortic valve replacement combined with enlargement of the valvar ring by the Nicks method and coronary artery bypass grafting via the left internal thoracic artery were performed for an 11-year-old girl with occlusion of the left coronary ostium. The left coronary sinus was covered with membranous tissue, so the left coronary ostium was not found. Aortic valve replacement with 21 mm prosthetic valve was possible by enlarging the valvar ring. The internal thoracic artery which is expected to grow with development of the body was used as the graft.

Aortic Valve Insufficiency↗
PubMed1995

[Multiple candida liver abscesses successfully treated by continuous intrahepatic arterial infusion of amphotericin B using a reservoir in a case with acute myelocytic leukemia (M2)].

A 49-year-old male was admitted with a diagnosis of AML (M2). One course of BHAC-DM regimen induced complete remission. During the consolidation therapy, he developed marked pyrexia resistent to antibiotics. Ultrasonography and CT scan revealed multiple small liver abscesses, which suggested mycotic etiology. After unsuccessful treatment with intravenous administration of fluconazole, a percutaneous transhepatic intraportal administration of Amphotericin B (AMPH-B) (20 mg/day) was started, followed by the consolidation chemotherapy. When the first positive blood culture was obtained for Candida, a reservoir was embedded in the subcutaneous layer of the right iliac region and the intrahepatic arterial administration of AMPH-B (5 to 20 mg/day) by the Infusor (Baxter Healthcare Corporation), a portable, disposable drug delivery system that provides a constant drug flow, was started. The liver abscesses has almost disappeared when the maintenance chemotherapy was completed. The side effects of AMPH-B were negligible. This case suggests the usefulness of the intrahepatic arterial infusion of AMPH-B using an inplantable drug delivery system in patients with hematological malignancies developing intractable multiple fungal liver abscesses.

Amphotericin B↗
PubMed1994

Vitamin A regulates the expression of apolipoprotein AI and CIII genes in the rat.

The effect of vitamin A on the expression of apoAI and CIII genes in intact rats was studied. In vitamin A-deficient rats, the hepatic level of apoAI mRNA was increased and enhanced by an oral administration of excess retinoic acid(RA). A similar administration to normal rats caused an increase in the apoAI mRNA level in the intestine without affecting that of hepatic mRNA. Though the hepatic level of apo CIII mRNA was not affected by the vitamin A status, the intestinal level was positively regulated by vitamin A. These findings show that vitamin A regulates the expression of apolipoprotein AI and CIII genes in a tissue-specific and complex fashion.

Animals↗
PubMed1994

Structural organization of the human oxytocin receptor gene.

We isolated and characterized the human oxytocin receptor gene. Southern blots indicated that the human genome has a single copy of the gene. Chromosomal localization by fluorescence in situ hybridization also showed that the gene was a single copy, assigned to 3p26.2 of the human chromosome. The gene spans approximately 17 kilobases and contains 3 introns and 4 exons. Exons 1 and 2 correspond to the 5'-non-coding region, followed by exons 3 and 4 encoding the amino acids of the receptor. Intron 3, which is the largest at 12 kilobases, separates the coding region immediately after the putative sixth transmembrane-spanning domain. The transcription start sites, demonstrated by primer extension analysis, lie 618 and 621 base pairs upstream of the methionine initiation codon. Near these putative transcription start sites, we found a TATA-like motif and a potential SP-1 binding site at about 30 and 65 base pairs, respectively. We also found other known binding sites of transcription regulating factors, such as AP-1, AP-2, GATA-1, Myb, nucleofactor-interleukin 6 binding consensus sequence, and an acute phase reactant-responsive element. No estrogen-responsive element was observed except three half-palindromic estrogen-responsive element motifs. Our findings of the oxytocin receptor gene structure should help to elucidate the mechanism by which the gene expression is induced drastically at parturition in the uterus and how the gene is regulated in other organs such as the mammary gland or central nervous system.

Amino Acid Sequence↗
PubMed1994

Trichokonin VI, a new Ca2+ channel agonist in bullfrog cardiac myocytes.

The effects of trichokonin VI (= gliodeliquescin A), a peptaibol isolated from the culture broth of Trichoderma koningii Oudemans, on L-type Ca2+ channel currents in single bullfrog atrial cells were investigated. Our results showed that trichokonin VI is a new potent agonist of L-type Ca2+ channels in cardiac membranes.

Alamethicin↗
PubMed1994

Cyclic hexapeptide endothelin receptor antagonists highly potent for both receptor subtypes ETA and ETB.

A cyclic hexapeptide, cyclo(-D-Asp-Trp-Asp-D-Leu-Leu-D-Trp-), designed from cyclo(-D-Glu-Ala-D-alloisoleucyl-Leu-D-Trp-), an ETA receptor-selective antagonist, possessed not only affinity similar to that of BQ-123 for ETA but also higher affinity for ETB than BQ-123. Further modification led to the discovery of cyclo(-D-Asp-Asp(Php)-Asp-D-Thg-Leu-D-Trp-) (Asp(Php): 1-beta-aspartyl-4-phenylpiperazine; Thg: 2-(2-thienyl)glycine) that inhibited [125I]ET-1 binding to the ETA and ETB receptors with IC50 values of 0.082 nM and 120 nM, respectively. Although this compound possesses 1470-fold less affinity for ETB than for ETA, it behaves as a non-selective antagonist that equipotently inhibits vasoconstriction mediated by both receptor subtypes ETA and ETB.

Amino Acid Sequence↗
PubMed1994

E-cadherin distribution in interleukin 6-induced cell-cell separation of ductal breast carcinoma cells.

E-cadherin is expressed in both the ZR-75-1-Tx and the ZR-75-1-Ro sublines of ductal breast carcinoma cells and is concentrated at cell-cell borders as shown by immunocytochemical examination. Free cell borders generally show no or little staining. The localized decrease in E-cadherin expression observed after interleukin 6 (IL-6) treatment of either subline correlates with the increase in free cell borders as IL-6 causes cell-cell separation. As we previously reported, many IL-6-treated ZR-75-1-Tx cells round up and detach from the substratum while ZR-75-1-Ro cells remain adherent and display prominent processes. The results are consistent with the view that E-cadherin expression is not responsible for the marked difference in the IL-6-induced phenotypes in these cell lines, although the localized decrease may play a role in cell-cell separation. ZR-75-1-Tx cells are deficient in desmosomes and show a wider intercellular space than ZR-75-1-Ro cells. Alternative mechanisms involving different aspects of the interlinked cytoskeletal and cell adhesion structures are considered to account for the IL-6-induced antimorphogenetic effect.

Antibodies, Monoclonal↗
PubMed1994

A single amino acid substitution in core residues of S-antigen prevents experimental autoimmune uveitis.

We have previously reported that microbial Ags, having a three- to six-amino-acid-sequence homology with a uveitopathogenic epitope (peptide M) of retinal soluble protein (S-Ag), induce experimental autoimmune uveitis (EAU). Another uveitopathogenic epitope (peptide G) of S-Ag also was characterized. In addition, we have characterized the core sequences by truncating peptides G and M from amino acid and carboxyl termini. In this study, we have further defined the core sequences using synthetic octapeptides with a single amino acid substitution. In addition, the analogues of peptides Gm5 or Mm4 are capable of inhibiting the proliferative response of T-lymphocytes from rats immunized with peptides G-8 or M-8, respectively. Co-injection of a pathogenic peptide with nonpathogenic substitution analogues blocked the induction of EAU. These results suggest that specific nonpathogenic analogues with single amino acid substitution derived from pathogenic peptides have potential for prevention and therapy of autoimmune diseases.

Amino Acid Sequence↗
PubMed1994

Cell-adhesion-disrupting action of interleukin 6 in human ductal breast carcinoma cells.

Recombinant baculovirus-derived interleukin 6 (IL-6) disrupts the attachment of human ductal breast carcinoma subline ZR-75-1-Tx cells to neighbors and the substratum in culture without inhibiting the proliferation of the cells. The nonadherent cells lack pseudopodia and do not translocate directionally. These findings stand in contrast to the earlier observations in the Ro subline of ZR-75-1 cells in which IL-6 induces cell-cell separation without detachment of the cells from the substratum, with the cells displaying pseudopodia, increased motility, and decreased proliferation. The IL-6-induced ZR-75-1-Tx cell detachment and rounding are reversible by incubation of the treated cells in IL-6-free medium for several days. The distinctive changes induced by IL-6 in ZR-75-1-Ro cells are similarly reversible. Either acidic fibroblast growth factor or phorbol 12-myristate 13-acetate can replace serum as a cofactor in IL-6-induced ZR-75-1-Tx cell detachment. Our findings indicate that genetic changes can occur in breast carcinoma cells that through cytokine action markedly affect cell structure, adhesiveness, and motility.

Breast Neoplasms↗