Biomedical subjects

Y Ikarashi

Publications and source records attributed to Y Ikarashi.

At least 37 records · Page 2Linked to original sources

PubMed2001

Effects of the extract of the bark of Magnolia obovata and its biphenolic constituents magnolol and honokiol on histamine release from peritoneal mast cells in rats.

We have previously reported that saiboku-to, an Oriental herbal remedy composed of a mixture of 10 different herbal extracts, possesses anti-histamine release effect on mast cells in rats. This effect may be due mainly to the extract of the bark of Magnolia obovata (M. obovata), a constituent herb of saiboku-to. In the present study, it was demonstrated that the bark extract inhibited compound 48/80 (C48/80)-induced histamine release from mast cells in a concentration-dependent manner (50 % inhibitory concentration, IC(50) = 56.98 microg/ml). Furthermore, the inhibitory activity was found in the methanol fraction, but not in water and 50 % aqueous methanol fractions derived from the bark extract. Magnolol and honokiol isolated from the methanol fraction inhibited C48/80-induced histamine release from mast cells. The potency of magnolol (IC(50) = 1.04 microg/ml) was greater than that of honokiol (IC(50) = 2.77 microg/ml). Furthermore, the actual amount of magnolol (49.76 +/- 1.14 mg) contained in the bark of M. obovata (5 g) was greater than that (8.58 +/- 0.19 mg) of honokiol. Taken together, the present results suggest that magnolol may be responsible for the biological efficacy of the bark extract of M. obovata.

Animals↗

PubMed2001

Effects of an oriental herbal medicine, "Saiboku-to", and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats.

Effects of a traditional oriental herbal medicine, "Saiboku-to" and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats were investigated. Saiboku-to inhibited Compound 48/80-induced degranulation of and histamine release from the mast cells, suggesting that Saiboku-to not only possesses anti-histamine release effect from mast cells, but also contains active herbs with this effect. Significant inhibitions were found in 4 of 10 constituent herbs of Saiboku-to: Magnoliae Cortex, Perillae Herba, Bupleuri Radix and Hoelen. In the dose-response curves of the four herbs, the logarithmic linearity was observed for each herb, and 50% inhibitory concentration, the IC50 values, were calculated to be 56.8 microg/ml for Magnoliae Cortex, 175.8 microl/ml for Perillae Herba, 356.6 microg/ml for Bupleuri Radix, and 595.8 microg/ml for Hoelen. One mg/ml of Saiboku-to showing 75% inhibition of Compound 48/80-induced histamine release level from mast cells contains 88.5 microg of Magnoliae Cortex (it was estimated from the dose-response curve that this dose inhibits 62.68% of the Compound 48/80-induced histamine release level), 58.8 microg of Perillae Herba (21% inhibition), 205.9 microg of Bupleuri Radix (35.24% inhibition), and 147.1 microg of Hoelen (11.15% inhibition). From these results, it is suggested that the anti-histamine release effect of Saiboku-to, which contains 10 herbs, may be due mainly to the effect of Magnoliae Cortex and the synergism of the 3 other herbs.

Animals↗

PubMed2000

Differential distribution of ionic channels and muscarinic receptors at the cat tracheal neuromuscular junction.

The ionic and pharmacological properties of atropine-sensitive excitatory junction potentials (EJPs) were investigated by the double sucrose gap and microelectrode membrane potential recording methods, and compared with those of inward currents evoked by carbachol (I(CCh)), in cat tracheal smooth muscle. A single and repetitive field stimulation (10-30 V, 50 micros, 20 Hz) evoked atropine-inhibitable EJPs and associated twitch-like contractions. Reduction in external Na+ concentration strongly, but in the external Cl- concentration, decreased the EJP amplitude after 5 min superfusion, although prolonged exposure to low Cl- solutions attenuated the EJPs modestly. Chloride channel blockers such as 9-AC and niflumic acid (each 100 microM), at concentrations high enough to inhibit I(CCh) almost completely, failed to abolish the EJPs. Pirenzepine, AF-DX116 and 4-DAMP all effectively inhibited the EJPs at their concentrations to block respective muscarinic receptor subtypes relatively specifically, while depletion of internal stores by 10 mM caffeine and/or 3 microM ryanodine caused only a partial decrease in the EJP amplitude. These properties are considerably different from those of I(CCh) which is activated exclusively through activation of the M3 receptor/IP3-mediated Ca2+ release pathway and reflects mostly a Ca2+-dependent Cl- current, and suggests the differential distribution of muscarinic receptors and ionic channels inside and outside of the cholinergic neuromuscular junction of this muscle.

Acetylcholine↗

PubMed2000

Effect of 2-deoxy-D-glucose on acetylcholine and histamine levels in gastric juice of pylorus-ligated rats anesthetized with urethane.

Acetylcholine (ACh) in gastric juice was detected and measured by pretreatment of acetylcholinesterase inhibitor, 1 mM eserine (1 ml/rat, p.o.), in pylorus-ligated rats, by liquid chromatography with electrochemical detection. In order to elucidate whether or not the ACh level in gastric juice reflects the activity of cholinergic neurons, the effect of 2-deoxy-D-glucose (2-DG), a vagus stimulant, on the levels of ACh, histamine and gastric acid in gastric juice was investigated in pylorus-ligated rats anesthetized with urethane (1.25 g/kg, i.p.). Under the non-anesthetic condition, ACh, histamine and gastric acid levels were 100+/-25 pmol/h, 120+/-10 ng/h, and 240+/-32 microequiv./h, respectively. These levels were completely inhibited by urethane anesthesia. Under the anesthetized condition, 2-DG (50-200 mg/kg, i.v.) significantly increased ACh and histamine levels in gastric juice, as well as acid secretion. The 2-DG (200 mg/kg, i.v.)-induced increases in these levels were completely inhibited by vagotomy. These results suggest that ACh level measured in gastric juice reflects the activity of cholinergic transmission. Furthermore, these results also support the conclusion that vagus stimulation facilitates not only cholinergic transmission but also histaminergic transmission related to gastric acid secretion.

Acetylcholine↗

PubMed2000

Establishment and usefulness of an anti-human CD57 IgG1 monoclonal antibody.

In the present study we established a new monoclonal antibody, JNK-1, which recognizes all cells recognized by CD57/HNK-1 mAb. JNK-1 and CD57 mAbs inhibited the binding of each other, suggesting that the molecules they recognize are either identical or sufficiently close to cause steric hindrance in the binding assay. JNK-1 mAb detected the 110-kDa protein, which is identical to the protein recognized by CD57/HNK-1 mAb in Western immunoblot analysis combined with immunoprecipitation. Therefore, JNK-1 mAb appears to recognize homogeneous molecules identified by the currently available CD57 mAb. Notably, JNK-1 mAb is composed of mouse IgG1 heavy chains, and thus can be used easily in immunoprecipitation, which cannot easily be performed with the available CD57 mAb because it is an IgM isotype. Thus, JNK-1, which is an IgG isotype, may present a useful tool to elucidate the CD57 protein.

Animals↗

PubMed2000

Cytokines production of U5A2-13-positive T cells by stimulation with glycolipid alpha-galactosylceramide.

We have previously established and reported a novel monoclonal antibody (mAb), U5A2-13, which recognizes a phenotypically similar population of natural killer (NK)-like T cells. Using U5A2-13 mAb, we now describe the functional properties of U5A2-13(+) T cells in both NK1.1-positive or -negative mouse strains. Similar to NK1.1(+) T cells, hepatic U5A2-13(+) T cells of C57BL/6 (NK1.1(+) strain) mice, but not U5A2-13(-) T cells, could be induced to produce large amounts of IL-4 and IFN-gamma by stimulation with glycolipid alpha-galactosylceramide (alpha-GalCer) present on dendritic cells (DC) in a dose-dependent manner. The abundant production of these cytokines from U5A2-13(+) T cells of BALB/c (NK1.1(-) strain) mice is similar to that noted in C57BL/6 mice. Cytokine production by cultures stimulated with DC of beta2-microglobulin-deficient mice was significantly less than that of cultures stimulated with DC of intact mice. Overall, U5A2-13(+) T cells recognize alpha-GalCer presented by CD1d, indicating that U5A2-13(+) T cells can be used to analyze NK-like T cell function in various strains of mice.

Animals↗

PubMed2000

Effects of drugs acting as histamine releasers or histamine receptor blockers on an experimental anxiety model in mice.

Experimental anxiety in mice was evaluated using a light/dark test at 60 min after injection of various histaminergics. Thioperamide, a histamine H(3) receptor inhibitor (5-20 mg/kg, intraperitoneal [IP]), Compound 48/80, a mast cell degranulator (0.1-10 microg/2 microl, intracerebroventricularly [ICV]), mepyramine, a histamine H(1) receptor antagonist (0.1-10 microg/2 microl, ICV) or cimetidine, a histamine H(2) receptor antagonist (0.1-10 microg/2 microl, ICV) alone did not affect the locomotive activity, the time spent in the light zone, and number of shuttle crossings in the light/dark test. However, the time spent in the light zone and the number of shuttle crossings significantly decreased only when cimetidine (0.1-10 microg/2 microl, ICV) was co-treated with either thioperamide (10 mg/10 ml/kg, IP) or Compound 48/80 (1.0 microg/2 microl, ICV). The decrease in these behavioral parameters suggests induced experimental anxiety in mice. The experimental anxiety was antagonized by mepyramine (10 microg/2 microl, ICV). These results suggest that not only neuronal histamine release induced by thioperamide but also non-neuronal (mast cells) histamine release induced by Compound 48/80 play an important role in inducing experimental anxiety via post-synaptic H(1) and H(2) receptors. In addition, it is likely that the anxiety may be mediated by the stimulation of H(1) receptors, while H(2) receptors may inhibit the anxiety produced by the activation of H(1) receptors.

Animals↗

PubMed2000

Anxiolytic-like effect of saiboku-to, an oriental herbal medicine, on histaminergics-induced anxiety in mice.

Effect of saiboku-to, an oriental herbal medicine, on anxiety in mice was investigated using a light/dark test. Anxiogenic- and anxiolytic-like effects were evaluated on the basis of shortened and prolonged time spent in the light zone of the test. Subacute administration (once a day for 7 days) of saiboku-to (0.5-2.0 g/kg, p.o.) induced anxiolytic-like effect. To assess the effect of saiboku-to on brain histaminergic system in a state of anxiety, Compound 48/80 (1.0 microg/2 microl, i.c.v.), a non-neuronal mast cell histamine releaser, or thioperamide (10.0 mg/kg, i.p.), a neuronal histamine releaser possessing the inhibitory effect of histamine H(3) autoreceptors, induced decrease in the time spent in the light zone by co-injection with cimetidine (10.0 microg/2 microl, i.c.v.), a H(2) inhibitor, suggesting anxiety-like effect. These histaminergics-induced experimental anxieties were inhibited by pre-treatment with subacute administration of saiboku-to, as well as single treatment with diazepam. The results suggest that saiboku-to exhibits anxiolytic-like effect closely related to histaminergic system in the brain.

Animals↗

PubMed2000

Learning and memory in mice treated with choline oxidase, a hydrolytic enzyme for choline.

Learning and maintenance of memory in mice intraperitoneally (IP) injected with choline oxidase (ChO, 6 units/g), a hydrolytic enzyme for choline (Ch), were assessed by means of a step-through passive-avoidance task. The ChO treatment induced a hydrolysis of free Ch in plasma, which in turn, induced a decrease in cerebral acetylcholine (ACh) release. In the learning test, the ChO-treated mice showed significant inhibition to learn the avoidance from electric shock. In the retention test, the impairment of the memory once established was not produced by posttreated ChO. We concluded that the decreased cerebral cholinergic neurotransmission induced by ChO retarded acquisition of passive-avoidance learning more readily than the maintenance of memory.

Alcohol Oxidoreductases↗

PubMed2000

Effect of heat treatment of poly(L-lactide) on the response of osteoblast-like MC3T3-E1 cells.

Poly(L-lactide) (PLLA) products are molded by heat extrusion. These treatments may change chemical properties and biological response of the PLLA to cells. In this study, the effect of heat treatment of PLLA on osteoblast proliferation and differentiation was examined in vitro. Osteoblast-like MC3T3-E1 cells were cultured for 2 weeks on the PLLA subjected to various heating temperature and time combinations. The protein, DNA, and hydroxyproline (HYP) contents and alkaline phosphatase (ALP) activity of cells cultured on the untreated (non-heated) PLLA with a weight average molecular weight (Mw) of 1,000,000 (high Mw PLLA) were not significantly different from those of cells cultured on glass. The activation of osteoblast differentiation by the high Mw PLLA was weak. In contrast, increases in ALP activity and HYP content were found for cells cultured on the PLLA heated at a high temperature of 200 or 250 degrees C. Heat treatment of high Mw PLLA increased differentiation of MC3T3-E1 cells cultured upon it. Significant degradation of PLLA (decrease in molecular weight and increase in molecular weight distribution) were observed following heat treatment. The Mw of PLLA decreased from 1,000,000 to below 20,000, and 14.4 microg of L-lactic acid was released from 10 mg of PLLA by heating at 250 degrees C. Therefore, the effect of low Mw chemicals, which were expected to be the degradation products of high Mw PLLA after heat treatment, on MC3T3-E1 cell activities was examined. Increases in the protein, DNA and HYP amounts and ALP activity for cells cultured with L-lactide or L-lactic acid were observed at 100 microg/ml, but not at 10 microg/ml. When the cells were cultured on the low Mw PLLA (Mw 20,000), their biological parameters also increased. Twelve micrograms of L-lactic acid released from 10 mg of the low Mw PLLA during 2 weeks incubation. The concentration of L-lactic acid in the incubation solution of low Mw PLLA or heat-treated PLLA was too small to cause cell activation. These results suggested that increases in osteoblast differentiation on the heat-treated PLLA was not to due to soluble degradation chemicals, such as L-lactic acid, rather than the remaining low Mw PLLA.

Absorbable Implants↗

PubMed2000

Potentiation of brain acetylcholine neurons by Kami-Untan-To (KUT) in aged mice: implications for a possible antidementia drug.

The effects of a traditional Japanese herbal medicine, Kami-Untan-To (KUT), on brain choline (Ch) and Acetylcholine (ACh) levels in aged mice were examined. Further, the expression of choline acetyltransferase (ChAT) in the medial septum (MS), the vertical limbs of the diagonal band of Broca (VDB), and the nucleus basalis Meynert (NBM) was examined by immunohistochemistry. Following an oral administration of KUT to the aged mice for 3 months, ACh levels in the cortex, striatum and hippocampus were increased significantly. The density of ChAT-immunoreactive cells located in MS, VDB, and NBM in the KUT-treated group was increased significantly as compared to the non-treatment group. The survival rate of aged mice was significantly higher in the KUT-treated group as compared to that in the nontreated group. Our results suggest that KUT potentiates the brain acetylcholinergic system, and may become a possible anti-dementia drug.

Acetylcholine↗

PubMed2000

Activation of osteoblast-like MC3T3-E1 cell responses by poly(lactide).

This study examined the osteoblast-like MC3T3-E1 cell responses to poly(DL-lactide) (PDLLA) and poly(L-lactide) (PLLA) with different weight average molecular weight (M.W.). Colony formation of MC3T3-E1 cells on the PLLA with M.W. 270000 or 1370000 was slightly lower than that on glass. The protein, DNA and hydroxyproline (HYP) content and alkaline phosphatase (ALP) activity for cells cultured on the PLLA (M.W. 270000 or 1370000) for 14 d were almost similar to those on glass. In contrast, the ALP activity of the cells cultured on low M.W. PLLA (M.W. 20000) increased. Osteoblast differentiation was stimulated by low M.W. PLLA but not by high M.W. PLLA. The addition of low M.W. PDLLA (M.W. 5000 or 10000), L-lactide or L-lactic acid into culture increased the protein, DNA and HYP content and ALP activity for cells at 100 microg/ml. Compared with four chemicals, PDLLA (M.W. 10000) had the strongest simulation effect on the cell. The release of L-lactic acid from PLLA and PDLLA into aqueous solution during incubation only slightly affected cell activity. In a cell-free condition, in the presence of PDLLA, the ALP activity was maintained without inactivation, even after 24 h incubation. Such a phenomenon was not seen with L-lactide and L-lactic acid. This may be a reason why PDLLA has a stronger effect on osteoblast differentiation relative to L-lactic acid. These results suggested that increased osteoblast differentiation was induced by low M.W. PDLLA and PLLA, and these may be used as a effective material in the field of orthopedic and drug delivery systems for the treatment of bone diseases.

Alkaline Phosphatase↗

PubMed2000

[Determination of antimicrobial, 10,10'-oxybis-10H-phenoxarsine, in artificial leather used for the seat of chairs].

Recently, a case of patients with allergic contact dermatitis caused by the poly (vinyl chloride) (PVC) seat, containing 10,10'-oxybis-10H-phenoxarsine (OBPA), of a chair was reported. OBPA was developed as an antimicrobial for plastics such as PVC and polyurethane, and it has been widely used in artificial leather for the seats of chairs and sofas. To identify causative chemicals for allergic contact dermatitis, a combination of patch testing in the patients and chemical analysis of causative products is valuable. However, no analytical method and data of OBPA in commercial products was reported. In this study, a method for the determination of OBPA in the artificial leather (PVV base) was developed. OBPA was extracted from PVC samples with methanol. The extract was loaded on an aluminum oxide column, and washed with diethyl ether:hexane, and eluted with ethanol:hexane. The eluate was evaporated, dissolved in methanol and injected to a HPLC equipped an ODS column and an UV detector (detection wavelength 300 nm). OBPA standard crystal was isolated from commercial agents containing OBPA. The calibration curve for OBPA was linear in the range of 0.1-100 micrograms/ml. The minimum detection and determination concentrations of OBPA in samples were 0.07 and 0.25 microgram/g. By this method, eight PVC sheets for the seat of a chair were analyzed. In two PVC sheets, 52.7 and 84.9 micrograms/g of OBPA were detected. In the PVC product that caused contact dermatitis, OBPA was not found.

Arsenicals↗

PubMed1999

Modulation of acetylcholine release via GABAA and GABAB receptors in rat striatum.

In order to investigate whether changes in acetylcholine (ACh) release induced by GABA receptors are due to a direct or indirect effect on cholinergic neurons in the striatum, GABAA and GABAB receptor bindings were assayed in the striatum microinjected with ethylcholine mustard aziridinium ion (AF64A), a cholinergic neurotoxin. Intra-striatal injection of a selective concentration of AF64A (10 nmol) reduced GABAA receptor binding without significantly altering GABAB receptor binding. Treatment with a higher, less selective concentration of AF64A (20 nmol) reduced all markers examined. These results suggest that GABAA, but not GABAB receptors, are located on cholinergic neurons in the striatum, and that GABA can directly modulate ACh release through stimulation of GABAA receptors. Findings further suggest that GABA can also indirectly modulate ACh release through stimulation of GABAB receptors located on non-cholinergic neuronal elements in the striatum.

Acetylcholine↗

PubMed1999

Functional and phenotypical characteristics of hepatic NK-like T cells in NK1.1-positive and -negative mouse strains.

We previously reported and partially characterized a unique monoclonal antibody (mAb), U5A2-13, which recognizes a T cell subset similar to NK1.1+ T cells, not only in NK1.1-positive mouse strains but also in NK1.1-negative strains. In NK1.1-positive C57BL/6 mice, U5A2-13+ TCRalphabeta+ cells produced abundant IL-4 as well as extremely high levels of IFN-gamma upon CD3 cross-linking, but this did not occur with U5A2-13- TCRalphabeta+ cells. In NK1.1-negative C3H/He mice, U5A2-13+ TCRalphabeta+ cells produced high levels of IL-4 and IFN-gamma upon CD3 cross-linking, but this was not observed with U5A2-13- TCRalphabeta+ cells. To the best of our knowledge, this is the first direct evidence of the presence of NK-like T cells defined phenotypically by U5A2-13 mAb and functionally by IL-4/IFN-gamma production in NK1.1-negative mouse strains. We also demonstrated that U5A2-13- NK1.1+ T cells and U5A2-13+ NK1.1- T cells in C57BL/6 mice could produce both IL-4 and IFN-gamma. In addition, Vbeta8 or Vbeta7 usage by U5A2-13+ NK1.1- T cells was lower than that by U5A2-13+ NK1.1+ T cells, but remained higher than that by U5A2-13- NK1.1- T cells. Based on the present results, U5A2-13 mAb appears to be a valuable tool in the study of NK-like T cells.

Animals↗

PubMed1999

Evaluation of serum uric acid changes in different forms of hepatic vascular inflow occlusion in human liver surgeries.

Uric acid values in serum have been analyzed as one of the markers to predict cellular damage due to ischemia reperfusion injury in the field of organ transplantation. The present study was conducted to confirm that uric acid values in serum could be an efficient marker of ischemic injury of liver parenchyma following hepatic vascular occlusion in human liver surgery. The changes in serum uric acid values were analyzed at fixed intervals during different liver surgeries. Significant increases in serum uric acid values were observed in patients who received the Pringle's maneuver in which hepatic vascular inflow was manipulated with a repetition of 15 min occlusion and 5 min perfusion, whereas almost no changes in uric acid values were found in both groups of patients who received the hemilobal occlusion of the Glisson's triad in which the right or left vessels were manipulated with a repetition of 30 min occlusion and 5 min perfusion and the "control method" in which the hepatic vessels of the lesion side were previously cut before liver resection. Uric acid values in serum increased in patients of Pringle's maneuver compared to those of the hemilobal occlusion of the Glisson's triad and the control method though these procedures were used in larger hepatectomies rather than Pringle's maneuver. The results indicated that serum uric acid values do not always reflect the severity of ischemia of the liver parenchyma but reflect intestinal congestion because marked intestinal congestion was observed in patients of Pringle's maneuver but not in patients of the hemilobal occlusion of the Glisson's triad and the control method. The evaluation of the severity of the ischemic injury of the liver should be done with caution when uric acid is used as a marker in human liver surgery.

Adolescent↗

PubMed1999

Neurochemical determination of the location of NMDA and GABA receptors on rat striatal cholinergic neurons.

This paper reports on the protocol for neurochemical determination of the location of various receptors on cholinergic neurons in various brain regions. We applied this protocol to investigate whether NMDA and GABA receptors are located on rat striatal cholinergic neurons. When striatal cholinergic neurons were selectively destroyed by intrastriatal injection of cholinergic neurotoxin, ethylcholine mustard aziridinium ion (AF64A), the number of NMDA and GABA(A) receptors decreased. However, no significant changes were observed on the number of GABA(B) receptors. These results suggest that NMDA and GABA(A), but not GABA(B) receptors are located on cholinergic neurons in the striatum. These results also indicate the usefulness and scientific applicability of the present protocol.

Animals↗

PubMed1999

Effect of Saiboku-to, an Oriental Herbal Medicine, on gastric lesion induced by restraint water-immersion stress or by ethanol treatment.

The effect of saiboku-to on gastric lesions induced by restraint water-immersion stress and ethanol has been examined in rats. Thirty minutes after oral administration of saiboku-to, the rats were placed in restraint cages and immersed in water at 23 degrees C for 7 h, or orally administered 99.5% ethanol (1 mL) and placed in normal cages for 1 h. The stress for 7 h or the ethanol treatment for 1h induced erosion in the glandular area of the stomach. Histology showed that the surface epithelial cells were desquamated and part of the lamina propria mucosae was injured. The evaluation of lesion index, the cumulative length of the gastric lesion, on the gross appearance of the stomach, revealed that saiboku-to dose-dependently inhibited both the water-immersion stress-induced gastric erosion and ethanol-induced gastric erosion. To determine whether the anti-erosion effect of saiboku-to was because of a mild irritant effect, saiboku-to or 20% ethanol, which is known as a typical mild irritant, were given orally. After 30 min a strong irritant, 99.5% ethanol, was given orally. Histological examination was performed 30 min after administration of saiboku-to or the mild irritant, and 1 h after administration of the strong irritant. The mild irritant induced a reduction in surface epithelial cells 30 min after administration. Furthermore, the mild irritant protected the stomach against mucosal erosion produced by the strong irritant. Saiboku-to protected the strong irritant-induced erosion without producing mild irritation as observed in stomach treated with 20% ethanol. Pretreatment with saiboku-to also inhibited the decrease in the levels of hexosamine, gastric mucus glycoprotein, induced by the strong irritant. In pylorus-ligated rats, saiboku-to dose-dependently inhibited gastric acid secretion, a gastric aggressive factor. These results suggest that the anti-erosion effect of saiboku-to which is not a mild irritant, involves both inhibition of aggressive factors, such as gastric acid secretion, and augmentation of defensive factors, such as gastric mucus cells.

Animals↗