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Biomedical subjects

Y Ikarashi

Publications and source records attributed to Y Ikarashi.

At least 127 records · Page 7Linked to original sources
PubMed1992

Vitamin B12 improves cognitive disturbance in rodents fed a choline-deficient diet.

The effect of vitamin B12 on learning disturbance was tested in rats. Rats were fed a choline-enriched, choline-deficient, and choline-deficient diet with vitamin B12. Concentrations of acetylcholine in the brain were significantly lower in rats fed a choline-deficient diet than rats fed a choline-enriched diet. Passive avoidance learning shows that rats on a choline-deficient diet showed significantly impaired learning compared to rats on a choline-enriched diet. However, there was no significant difference of acetylcholine in the brain or in the passive avoidance learning between rats fed a choline-enriched and a choline-deficient with vitamin B12 diet. We, therefore, suggest that vitamin B12 potentiates learning in an acetylcholine-deprived brain.

Acetylcholine↗
PubMed1992

Detection of contact sensitivity of metal salts using the murine local lymph node assay.

The local lymph node assay (LLNA) is a predictive test for the detection of contact allergens. Nickel and chromium sensitization are common cases in man. However, in a previous study topical application of nickel sulfate and potassium dichromate in aqueous solution failed to induce activation in the draining lymph node. This study describes the application of LLNA to evaluate the contact sensitivity of metal salts. The metal salts were applied in dimethylsulfoxide or aqueous ethanol solution. In some experiments, the skin of the ears was gently abraded using a needle prior to application of metal salts. The ability of seven metal salts to induce lymph node cell (LNC) proliferation was compared. Nickel, cobalt, chromium and copper salts increased LNC proliferation, whereas zinc, manganese and iron salts failed to induce LNC proliferation in this assay.

Animals↗
PubMed1992

A method for identifying causative chemicals of allergic contact dermatitis using a combination of chemical analysis and patch testing in patients and animal groups: application to a case of rubber boot dermatitis.

A 63-year-old woman developed allergic contact dermatitis from rubber boots. Initial investigation, by patch testing in the patient and chemical analysis of the causative rubber boots, revealed that mercaptobenzothiazole (MBT) and dibenzothiazyl disulfide (MBTS) were the causative chemicals. Subsequent investigations were performed by patch testing in animal groups. An extract of the causative rubber boots, MBT and MBTS were used for sensitization of guinea pigs by the guinea pig maximization test (GPMT). 3 animal groups, A (with the boot extract), B (with MBT) and C (with MBTS) were successfully prepared. The boot extract was fractionated by column chromatography and thin-layer chromatography (TLC). Each fraction was subjected to patch testing in the animal groups. Positive reactions in all groups would show that the active fractions contained MBT-type compounds, whereas a positive reaction in group A but negative ones in group B and C would show that the active fractions did not contain any MBT-type compounds. Each fraction was then analyzed by gas chromatography (GC), GC-mass spectrometry (GC-MS), direct inlet-MS (DI-MS) and high-performance liquid chromatography (HPLC). By this investigation, we found not only known allergens (MBT, MBTS), but also unknown allergens: S-substituted MBT-type compounds and styrenated phenol (SP). Thus, SP was shown to be a candidate as a human sensitizer even though the patient did not react to it.

Allergens↗
PubMed1992

[Effects of ambroxol HCl on the guinea pig tracheal mucous secretion and the rat pulmonary surfactant secretion].

The effects of orally administered ambroxol HCl (ambroxol) on guinea pig tracheal mucous secretion and rat pulmonary surfactant secretion were investigated histologically and biochemically. Ambroxol significantly increased the number of active goblet cells in guinea pig tracheal epithelium and total mucopolysaccharide level. Moreover, ambroxol significantly increased the neutral mucopolysaccharide level and PAS-positive substance in the guinea pig tracheal submucosal glands. Ambroxol did not show a significant effect on the content of the total phosphatidylcholine in rat lung lavage fluid, while ambroxol significantly increased the ratio of disaturated phosphatidylcholine to total phosphatidylcholine. From these results, it is suggested that ambroxol increases both the tracheal mucous secretion, especially the neutral mucopolysaccharide, and pulmonary surfactant secretion and these effects reflect part of the expectorant mechanism of the drug.

Ambroxol↗
PubMed1992

Histological characteristics of lupus nephritis in F1 mice with chronic graft-versus-host reaction across MHC class II difference.

Renal lesions at the chronic phase of MHC class-II-disparate graft-versus-host reaction (GVHR) were examined. To induce GVHR, C57BL/6 (B6) spleen cells were injected twice into either (B6 x bm12)F1 (class-II-disparate), (B6 x bm1)F1 (class-I-disparate) or (bm1 x bm12)F1 mice (class-I + II-disparate). For comparison, (C57BL/10 x DBA/2)F1 (BDF1) mice injected with DBA/2 spleen cells were also used. (B6 x bm12)F1 and BDF1 recipients showed marked elevation of anti-DNA antibodies, circulating immune complexes (CIC) and the number of immunoglobulin producing cells (IgPC). At 20 weeks after cell injection, severe immune complex glomerulonephritis (ICGN) was observed in (B6 x bm12)F1 recipients, but was far less severe in (bm1 x bm12)F1 recipients and was not observed in (B6 x bm1)F1 recipients. ICGN was also observed in BDF1 recipients at 12 weeks after cell injection. By immunofluorescent microscopy, IC deposition was detected along the capillary loops and also in the mesangial area in (B6 x bm12)F1 recipients, while BDF1 recipients showed only a capillary pattern. By light microscopy, the renal lesion of (B6 x bm12)F1 recipients appeared similar to those of BDF1 recipients. Histologically, (B6 x bm12)F1 recipients serve as a good model for lupus glomerulonephritis induced by class-II-disparate GVHR.

Animals↗
PubMed1991

Applicability of high-performance liquid chromatography--continuous-flow fast atom bombardment mass spectrometry for simultaneous quantitation of multiple neurochemicals.

A method is described for the analysis of multiple neurochemically important compounds. The technique involves high-performance liquid chromatographic separation in combination with ultraviolet and continuous-flow fast atom bombardment mass spectrometric detection. High-performance liquid chromatographic elution behaviour and relative detection responsiveness as correlated with chemical structure are also presented.

Choline↗
PubMed1991

Intrastriatal dialysis evidence for a direct inhibitory effect of benztropine on dopamine re-uptake.

A direct inhibitory effect of benztropine on dopamine (DA) reuptake in the striatum was established by in vivo microdialysis of anesthetized rats. Benztropine was infused by means of a microdialysis probe positioned stereotaxically in the striatum. Extracellular DA collected from dialysate was measured by high-performance liquid chromatography using an electrochemical detector. Benztropine was found to cause a dose-dependent inhibition of re-uptake of DA in the nerve terminal area of the dopaminergic system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Application of FRIT fast atom bombardment liquid chromatography/mass spectrometry for the determination of acetylcholine levels in rat brain regions.

This report describes the use of FRIT fast atom bombardment (FAB) liquid chromatography/mass spectrometry for the analysis of acetylcholine in rat brain regions. Direct assessment of acetylcholine levels is possible without the need for either derivatization or extensive sample preparation. Quantification is accomplished by monitoring intact molecular cations of acetylcholine and a deuterated internal standard. The results are compared with those obtained by conventional pyrolysis gas chromatography/mass spectrometry and by liquid chromatography with electrochemical detection.

Acetylcholine↗
PubMed1991

Evaluation of biocompatibility, based on quantitative determination of the vascular response induced by material implantation.

The biocompatibility of nine different materials, including positive and negative references, 4 polyurethane based and 3 latex based materials was investigated by (1) cytotoxic assay using V79 chinese hamster cells, (2) the thickness of inflammatory layer at 3 and 7 days after intramuscular implantation test, and (3) the course of the blood flow in tissue reaction around subcutaneously implanted materials using Laser Doppler Flowmetry (LDF) over 14 days following implantation. In addition, for some materials, different modes of sterilization were compared. Although the three methods explore different reactive systems, the material ranking obtained was highly similar for the three methods, suggesting a relative accuracy between them. For one latex however, an absence of cytotoxic effect in culture and a highly intense response by LDF investigation of the same order of magnitude as for the positive reference implant suggest that bioincompatibility may result from the material itself and cannot be exclusively investigated by the leaching of toxic components.

Anesthesia↗
PubMed1991

Nicotine improves cognitive disturbance in rodents fed with a choline-deficient diet.

The effect of nicotine on learning disturbances was tested in rats. Rats were fed either a choline-enriched or a choline-deficient diet. Concentration of acetylcholine in the whole brain was significantly lower in rats fed with choline-deficient diet than rats fed with choline-enriched diet. Passive avoidance learning shows that rats on a choline-deficient diet showed significantly impaired learning compared to rats on a choline-enriched diet. Nicotine (0.04 mg/kg) administered intraperitoneally significantly potentiated learning in rats on a choline-deficient diet, as well as in rats on a choline-enriched diet. We, therefore, suggest that nicotine may potentiate learning in an acetylcholine-deprived brain.

Acetylcholine↗
PubMed1991

Allergic contact dermatitis from para-tertiary-butylphenol-formaldehyde resin (PTBP-FR) in athletic tape and leather adhesive.

4 girls with severe allergic contact dermatitis from a brand of athletic tape and a cobbler with allergic contact dermatitis from leather adhesive are presented. Alkylphenol resin with unknown chemical structure had been compounded in both products. One of the girls developed foot dermatitis later from the adhesive used on the inside of new sneakers. By patch testing and chemical analysis of alkylphenol resin and the products, the 5 patients were given a specific diagnosis of allergic contact dermatitis from PTBP-FR.

Adhesives↗
PubMed1991

[Development of a liquid chromatography/multiple electrochemical detector (LCMC) and its application in neuroscience].

A liquid chromatographic system with multiple electrochemical detectors (LCMC) was newly developed for quantitating 20 to 30 neurochemicals simultaneously within 20 to 25 min from one sample derived from biological specimens. The device can be used for estimating neurofunctional changes in the central nervous system under the influence of CNS drugs, behavioral changes of experimental animals and psychic effects in clinical stages, etc. The system consists of four parallel liquid chromatographs with multiple electrochemical detectors. The first three systems determine catecholamines, indoleamines and related compounds. The fourth system is for measuring acetylcholine and choline with an internal standard. A new type of electrochemical detector was developed that consists of 4 electrodes set at a different potentials: each of the eluting components was identified by the variation of 4 current peaks on each electrode. Twenty-eight standard compounds, including four internal standards, could be clearly separated; and the detection limits of these compounds were at least 0.1 to 0.4 pmol per injection. In this report, the usefulness and applicability of this system were confirmed by measuring neurochemicals in the striatum of rats sacrificed either by decapitation or microwave irradiation and in the human ventricular cerebrospinal fluid of patients with Parkinson's disease and essential tremor.

Animals↗
PubMed1990

Determination of succinylcholine hydrolytic enzyme activity in human plasma.

Succinylcholine is frequently employed in surgical procedures as a pre-anaesthetic. However, the lack of existing metabolic activity for this compound in some individuals entails a substantial risk. Normally, the risk is assessed indirectly through the measurement of pseudocholinesterase activity using other substrates, such as acetylcholine, rather than the agent itself. Thus, a method was devised to assess directly the hydrolysis of succinylcholine in human plasma samples. This method was applied to plasma samples derived from healthy men, healthy women, pregnant women and patients with silent pseudocholinesterasaemia.

Acetylcholine↗
PubMed1990

Depletion of CD8+ cells exacerbates organ-specific autoimmune diseases induced by CD4+ T cells in semiallogeneic hosts with MHC class II disparity.

Autoimmune diseases are known to be induced in some donor-recipient combinations of mice undergoing the graft-vs-host reaction (GVHR). In this paper, we report on the development of primary biliary cirrhosis (PBC)-like hepatic lesions and also on pancreatic insulitis in (B6 x bm12)F1 mice injected with B6 CD4+ T cells. At the sites of these lesions, cellular infiltration around ductal structure was observed. Immunohistochemical studies revealed that both CD4+ and CD8+ T cells were present in the lesions of the liver and pancreas. To clarify the role of the CD8+ T cells, which were probably of host origin, we used a mAb against the Lyt-2 molecule. Both the PBC-like hepatic lesions and pancreatic insulitis were exacerbated by eliminating CD8+ T cells from mice with MHC class II GVHR. Also, autoantibodies against the pyruvate dehydrogenase-E2 component, which has been recently found to contain an immunodominant site (autoepitope) for B cell reactivity in patients with PBC, were detected in the sera of these mice by ELISA and their presence was confirmed by immunoblotting procedures. Our findings suggest that similar mechanisms as in GVHR caused by MHC class II disparity are active in the development of PBC. It should also be noted that, in addition to the hepatic lesions, insulitis closely resembling that seen in the nonobese diabetic mouse was induced in our experimental system. The results suggest that our model provides a unique opportunity to study organ-specific autoimmune diseases. Because the effector in our experimental system was defined to be CD4+ T cells responding to Iabm12 Ag, our findings support the hypothesis that an excessive immune response directed against Ia Ag can produce autoimmune disease.

Animals↗
PubMed1990

Phosgene (chlorophenyl)hydrazones, strong sensitizers found in yellow sweaters bleached with sodium hypochlorite, defined as causative allergens for contact dermatitis by an experimental screening method in animals.

12 young men developed allergic contact dermatitis from wearing yellow cotton sweaters. We attempted to identify the causative agents by an experimental screening method in animals. Guinea pigs were sensitized with an acetone extract of the sweater material, by means of the guinea pig maximization test (GPMT). Active ingredients were then separated from the extract, by step-by-step patch test screening of chromatographic fractions in the guinea pigs, and finally analyzed by gas chromatography-mass spectrometry (GC-MS). Although there were 2 allergens with important activity (1 in the fraction eluted from the silica gel column with hexane, and 1 in the methanol fraction), the present study is focussed on the fat-soluble allergens in the hexane fraction. GC-MS analysis revealed that 4 kinds of phosgene (chlorophenyl)hydrazones (PCPHs) were present in the hexane fraction. PCPHs prepared in our laboratory showed strong eliciting activities, not only in the guinea pigs sensitized with the extract, but also in a male volunteer sensitized by exposure to a yellow sweater during irritancy testing. Phosgene (2,5-dichlorophenyl)hydrazone, which was the main component among the PCPHs found in the sweater, sensitized guinea pigs even at the 1 ppm level. From these results, we conclude that PCPHs were one of the allergens responsible for the cases.

Animals↗
PubMed1990

[Effect of anti-ulcer drugs and PGE2 on the proliferation of rat gastric cultured cells].

The effects of anti-ulcer drugs and PGE2 on the proliferation of rat gastric cultured cells were investigated. To study the cell proliferation, the rate of incorporation of 3H-thymidine into the cultured cells was measured. ULTROSER G, corresponding to fetal bovine serum, was found to dose-dependently increase the incorporation of 3H-thymidine into the cultured cells at a dose range of 1-4%. The incorporation of 3H-thymidine was highest at 36 hr after the inoculation of cells. Therefore, the effect of the drugs on the proliferation was performed under the condition of 2% ULTROSER G and evaluated at 36 hr. Aldioxa, cetraxate HCl, cimetidine (10(-7)-10(-5) M) and PGE2 (10(-8)-10(-6) M) had no effect on the cell proliferation, while indomethacin (0.35-1.41 x 10(-3) M) inhibited the proliferation in a dose-dependent manner. Aldioxa, cetraxate HCl (10(-5) M) and PGE2 (10(-6), 10(-8) M) antagonized the inhibitory effect by indomethacin at a concentration of 0.5 x 10(-3) M, but cimetidine (10(-7)-10(-5) M) did not. From the above results, it was concluded that this method was useful for investigating the effect of drugs on the proliferation of gastric cultured cells.

Animals↗