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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 199 records · Page 11Linked to original sources
PubMed1997

The expulsion of Echinostoma trivolvis: worm kinetics and intestinal reactions in C3H/HeN mice treated with dexamethasone.

C3H/HeN mice were each infected with 40 Echinostoma trivolvis metacercarial cysts on day 0, given intramuscular injections of dexamethasone (DEX) daily for 30 days, and necropsied on days 5, 8, 12, 15, 20 and 30 p. i. Control mice were each infected with 40 echinostome cysts on day 0, but were not treated with DEX and necropsied on the same days as the DEX-treated mice. DEX treatment caused an inhibition of worm expulsion and suppressed the increase in goblet cell numbers that peaked around day 12 p. i. in the untreated control mice. Increase in the number of mucosal mast cells and eosinophils in the control mice that peaked around day 15 and 12 p. i., respectively, was also suppressed by the DEX treatment. The mean body area of the worms from the DEX-treated mice was about the same as that of the control worms on day 5 p. i., and then significantly greater than the control worms on days 8 and 12 p. i. The worms in the treated mice continued to grow until the end of the experiment, on day 30 p. i. Enzyme-linked immunosorbent assay (ELISA) showed that serum IgM from the treated and control mice increased from day 12 p. i., peaked on day 15 p. i., and then decreased. An IgM titre of the treated mice was slightly higher than that of the controls. No marked rise in IgG and IgA titres occurred throughout the experiment in both groups.

Animals↗
PubMed1997

Effects of rebamipide, a novel anti-ulcer agent, on gastric mucosal injury induced by platelet-activating factor in rats.

We examined the role of gastric mucosal blood flow, lipid peroxidation, and neutrophil accumulation mediated by platelet-activating factor in the protective effect of rebamipide against gastric mucosal injury in rats. The intravenous injection of platelet-activating factor induced hyperemia and hemorrhagic erosions in rat stomachs. Rebamipide did not affect the decrease in the gastric mucosal blood flow induced by platelet-activating factor. The increase in gastric injury score after platelet-activating factor injection and the increase in thiobarbituric acid-reactive substances were significantly inhibited by the administration of rebamipide. The gastric injury score was closely correlated with the accumulation of lipid peroxides. Tissue-associated myeloperoxidase activity in the gastric mucosa significantly increased after platelet activating factor injection; this increase was not influenced by rebamipide treatment. The protective effect of rebamipide against the platelet-activiting factor-induced gastric mucosal injury may be due to direct inhibition of lipid peroxidation or scavenging of oxygen radicals that initiate lipid peroxidation.

Alanine↗
PubMed1997

Effect of L-lactic acid, short-chain fatty acids, and pH in cecal infusate on morphometric and cell kinetic parameters of rat cecum.

We studied the influences of cecal infusion of NaCl, short-chain fatty acids (SCFA), and L-lactic acid at pH 5.0 or 7.0 for seven days on morphometric and cell kinetic parameters of the rat cecum. SCFA increased relative weight of the mucosa and submucosa, crypt size, and mitotic index in the cecum. L-Lactic acid stimulated mitosis only at pH 5.0. Crypt size correlated positively to epithelial proliferative activity only when NaCl or L-lactic acid was infused. SCFA should have changed the balance between production and loss of the cecal epithelial cells. The infusate pH by itself had no effect, but modified the effects of SCFA and L-lactic acid in different ways. Crypt size correlated positively to the logarithm of daily proton load of infusates. The above results indicate that epithelial cell proliferation in the cecum is influenced by both SCFA and L-lactic acid, although differently, and by proton load.

Acetic Acid↗
PubMed1997

Soluble selectins and ICAM-1 modulate neutrophil-endothelial adhesion and diapedesis in vitro.

We observed that normal plasma dramatically reduces neutrophil-endothelial adhesion. Therefore, we identified factors in plasma which might limit PMN adhesion in vitro. We found that the anti-adhesive effect was not mediated by vasoactive lipids present in plasma. Immunoprecipitation of soluble adhesion molecules, P and E-selectins and ICAM-1 restored PMN adhesion to control values. We further examined whether soluble adhesion molecules in plasma might also regulate PMN endothelial migration in response to fMLP (10(-6) M). Plasma significantly reduced PMN migration, and this effect was prevented only by the simultaneous removal of soluble P and E selectins and ICAM-1 together, but not individually. These data show that soluble selectins and ICAM-1 may regulate PMN adhesion and diapedesis, and that alterations in the levels of these molecules may regulate PMN-endothelial interactions in vivo.

Adult↗
PubMed1997

Gene identification in 1.6-Mb region of the Down syndrome region on chromosome 21.

The Down syndrome (DS) region has been defined by analyses of partial trisomy 21. The 2.5-Mb region between D21S17 and ERG is reportedly responsible for the main features of DS. Within this 2.5-Mb region, we focused previously on a distal 1.6-Mb region from an analysis of Japanese DS patients with partial trisomy 21. Previously we also performed exon-trapping and direct cDNA library screening of a fetal brain cDNA library and identified a novel gene TPRD. Further screening of a fetal heart cDNA library was performed and a total of 44 possible exons and 97 cDNA clones were obtained and mapped on a BamH1 map. By rescreening other cDNA libraries and a RACE reaction, we isolated nearly full-length cDNAs of three additional genes [holocarboxylase synthetase (HCS), G protein-coupled inward rectifier potassium channel 2 (GIRK2), and a human homolog of Drosophila minibrain gene (MNB)] and a coding sequence of a novel inward rectifier potassium channel-like gene (IRKK). The gene distribution and direction of transcription were determined by mapping both ends of the cDNA sequences. We found that these genes, except IRKK, are expressed ubiquitously and are relatively large, extending from 100 kb to 300 kb on the genome. These nearly full-length cDNA sequences should facilitate understanding of the detailed genome structure of the DS region and help to elucidate their role in the etiology of DS.

Amino Acid Sequence↗
PubMed1997

Vitamin B12 treatment for delayed sleep phase syndrome: a multi-center double-blind study.

The active form of vitamin B12 (methylcobalamin) has been reported to be effective on sleep-wake rhythm disorders. Previous studies, however, were performed under open trial, and the effect of vitamin B12 has not been properly evaluated. The aim of this double-blind study was to investigate the efficacy of methylcobalamin on delayed sleep phase syndrome (DSPS). Methylcobalamin (3 mg/day) or placebo was administered for 4 weeks. The subjects were 50 patients with DSPS aged 13-55 years (26.8 +/- 1.3), 27 of whom received the active drug while 23 received the placebo. No significant differences were observed between the 2 groups in subjective evaluations of mood or drowsiness during the daytime or in night sleep by sleep-log evaluation. These results indicate that 3 mg methylcobalamin administered over 4 weeks is not an effective treatment for DSPS.

Adolescent↗
PubMed1997

Biocompatibility of heparin-coated circuits in pediatric cardiopulmonary bypass.

In this study, we evaluated the biocompatibility of heparin-coated circuits in pediatric cardiopulmonary bypass (CPB). Eight patients were divided into 2 groups: the control group (Group C) and heparin-coated group (Group H). In Group H, CPB circuits, including the arterial pump, oxygenator, and cannulas were heparin-coated. Before, during, and after CPB, blood samples were obtained to assess the platelet counts (Plat), alpha 2-plasmin plasminogen inhibitor complex (PIC), thrombin-antithrombin III complex (TAT), C3 activation products (C3a), interleukin (IL)-6, IL-8, and polymorphonuclear neutrophil leukocyte (PMN) elastase. There was no significant difference in Plat, PIC, or TAT between groups. Group H showed significantly low levels of C3a (during and after CPB), PMN elastase (during CPB), and IL-6 (after CPB). These data demonstrated that in pediatric CPB, heparin-coated CPB circuits reduced the activation of complements and the production of PMN elastase and IL-6, suggesting the superior biocompatibility of the heparin-coated circuits.

Anticoagulants↗
PubMed1997

Exogenous xanthine promotes neutrophil adherence to cultured endothelial cells.

Oxidants generated by endothelial xanthine oxidase (XO) can help trigger free radical-mediated tissue injury. An important event in oxidant-mediated tissue injury is neutrophil-endothelial adhesion. Although activation of endothelial XO increases adhesion, little is known about xanthine in the adhesive effect of XO. This study examined administered xanthine on the adhesion of neutrophils. Endothelial [human umbilical vein endothelial cells (HUVEC)] monolayers were exposed to xanthine (15 min), and neutrophils were allowed to adhere to HUVEC in an adhesion assay. Adhesion was dose dependently increased by xanthine (3-100 microM). Either catalase (1,000 U/ml), oxypurinol (XO inhibitor; 100 microM), or platelet-activating factor (PAF) receptor antagonist (WEB 2086; 10 microM) reduced neutrophil adhesion. Superoxide dismutase (1,000 U/ml) had no effect. Pretreatment of HUVEC with 50 microM tungsten also blocked xanthine-induced adherence. Adhesion was also inhibited by preincubation with 100 U/ml heparin. Finally, anti-P-selectin antibody (PB1.3; 20 micrograms/ml) attenuated adhesion. Our results indicate that xanthine may promote neutrophil-endothelial adhesion via a hydrogen peroxide- and PAF-mediated P-selectin expression.

Antioxidants↗
PubMed1997

Molecular mechanisms of anoxia/reoxygenation-induced neutrophil adherence to cultured endothelial cells.

The objectives of this study were to (1) determine the time course of neutrophil adhesion to monolayers of human umbilical vein endothelial cells (HUVECs) that were exposed to 60 minutes of anoxia followed by 30 to 600 minutes of reoxygenation and (2) define the mechanisms responsible for both the early (minutes) and late (hours) hyperadhesivity of postanoxic HUVECs to human neutrophils. The results clearly demonstrate that anoxia/reoxygenation (A/R) leads to a biphasic increase in neutrophil adhesion to HUVECs, with peak responses occurring at 30 minutes (phase 1) and 240 minutes (phase 2) after reoxygenation. Oxypurinol and catalase inhibited phase-1 adhesion, suggesting a role for xanthine oxidase and H2O2. In comparison, platelet activating factor (PAF) contributed to both phases of neutrophil adhesion. Anti-intercellular adhesion molecule-1 (ICAM-1) and anti-P-selectin antibodies (monoclonal antibodies [mAbs]) attenuated phase-1 neutrophil adhesion, consistent with roles for constitutively expressed ICAM-1 and enhanced surface expression of preformed P-selectin. Phase-2 neutrophil adhesion was attenuated by an anti-E-selectin mAb, indicating a dominant role of this adhesion molecule in the late phase response. Pretreatment with actinomycin D and cycloheximide or with competing ds-oligonucleotides containing the nuclear factor-kappa B or activator protein-1 cognate DNA sequences significantly attenuated phase-2 response, suggesting a role for de novo macromolecule synthesis. Surface expression of ICAM-1, P-selectin, and E-selectin on HUVECs correlated with the phase-1 and -2 neutrophil adhesion responses. Collectively, these findings indicate that A/R elicits a two-phase neutrophil-endothelial cell adhesion response that involves transcription-independent and transcription-dependent surface expression of different endothelial cell adhesion molecules.

Azepines↗
PubMed1997

Design and preparation of gadolinium-reservoir microcapsules for neutron-capture therapy by means of the Wurster process.

Gadolinium (Gd)-containing microcapsules designed for neutron-capture therapy (NCT) were prepared by a spouted bed coating process. Microcapsules were designed as a Gd-reservoir. They were prepared with the following properties: particle size was smaller than 50 microns, Gd-content was as high as possible, and release of Gd was suppressed as long as possible. Calcium carbonate (20-32 microns) was selected as a speed particle. As a Gd-source, gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) or a synthesized water-insoluble Gd-DTPA derivative, Gd-DTPA-distearylamide (Gd-DTPA-SA), was layered onto the seed particles. The release-suppressing layer was composed of aqueous acrylic latex of 9:9:4 poly(ethyl acrylate/methyl methacrylate/2-hydroxyethyl methacrylate). In preliminary studies, Gd-DTPA microcapsules with 41-45 microns (mass median diameter) were prepared; they released Gd with a short lag-time and 3h-prolongation. Complete release suppression was, however, difficult to achieve because of high water-solubility of Gd-DTPA. Hence, a hydrophobic derivative, Gd-DTPA-SA, was next used as a Gd source. Gd-DTPA-SA microcapsules could be prepared with a mass median diameter of 52 microns. Gd-DTPA-SA content of the microcapsules was 38% and release of Gd was suppressed to less than 0.2% over 60 d.

Acrylates↗
PubMed1997

Effect of additives on dissolution and swelling of soybean lecithin microcapsules prepared using the Wurster process.

Microcapsules whose membranes contained soybean lecithin (SL), cholesterol (CH), stearic acid (SA) and polyvinylpyrrolidone (PVP) at various compositions were prepared. Then, dissolution and swelling behaviors of the microcapsules in a 0.9% saline solution were studied to be related to the phase diagram of three components containing 42% of PVP in anhydrous state. In the aqueous solution, when an anhydrous microcapsule membrane was composed of SL not saturated with both CH and SA, the microcapsules showed rapid release of carbazochrome sodium sulfonate (CCSS, a model drug), poor particle-swelling and spouting of droplets containing CCSS. Long-delayed release of CCSS and drastic particle-swelling with no spouting of droplets were observed when the anhydrous membrane was composed of SL saturated with both CH and SA and the composition was not close to the two-component line, CH-SA, or to the saturation line. The spouting of droplets would be attributable to the CH and/or SA-poor SL phase and to the SL phase which dissolved CH and SA, but contained either CH or SA only in a small amount, and the delayed release would be due to the CH and SA-rich SL phase dissolving a great amount of CH and SA formed by hydration. The degree of release suppression and particle-swelling depended on the SL content. At 20-45% of SL content, the prolonged-release, great particle-swelling and no spouting of droplets at the early stage were observed only when the CH and SA-rich SL phase formed by hydration contained a high content of CH and SA.

Adrenochrome↗
PubMed1997

[Surgical treatment of malignant hemangioendothelioma originated from the right atrium: a case report].

A 32-year-old man was admitted to our hospital because a cardiac tumor had been pointed out by a physician. CT scans showed a mass lesion with irregular patterns in the right atrium. The patient had the diagnosis of a malignant cardiac or pericardial tumor and an operation was performed. The mass originated from the right atrium included massive coagulated blood, and was resected with the pericardium and the right pleura. The histological diagnosis was malignant hemangioendothelioma. We present this case because only 35 patients with cardiac malignant hemangioendothelioma were reported in Japan.

Adult↗
PubMed1997

[A case report of type A dissection of the aorta presenting as a superior vena cava syndrome 10 years after aortic valve replacement].

Aortic dissection usually result in chest pain and back pain. This patient is a 58 year-old man who received aortic valve replacement for aortic regurgitation 10 years ago. In this case, the patient had superior vena cava syndrome as a result of a painless aortic dissection. The superior vena cava was compressed by the ascending aorta itself, which had become very large but had not ruptured into the mediastinum. He underwent modified Carbrol's operation under hypothermic cardiopulmonary bypass and circulation arrest on May 8, 1995. Dissecting aneurysm in the late term after aortic valve replacement is rare, and for it to result in superior vena cava syndrome is especially rare.

Aortic Dissection↗
PubMed1997

[A case of basilar artery occlusion associated with one-and-a-half syndrome, paralytic pontine exotropia and WEBINO-syndrome].

We report a 79-year-old woman with basilar artery occlusion. She had a sudden onset of tetraplegia and disturbed consciousness, and within four days from the onset she showed a varied, fluctuating eye symptoms. On admission, she showed ocular bobbing, skew deviation with the right eye lower-positioned, upward gaze palsy, one-and-a-half syndrome, and paralytic pontine exotropia (PPE). On the third day after the onset, she showed wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome, and on the fourth day, she showed one-and-a-half syndrome again. Her right-gaze palsy improved repeatedly, and on the 19th day from the onset, only right MLF syndrome remained. Her eye symptoms fluctuated probably according to the distal migration of emboli, there by the responsible lesion and the mechanism of these eye symptoms are considered to be closely inter-correlated. On the fourth day after onset, the magnetic resonance imaging revealed cerebral infarctions in bilateral middle pons, the left paramedian lower pons, and the right paramedian midbrain, and a hemorrhagic infarction in the right inferior cerebellar hemisphere. We believe that that the eye symptoms of this patient were caused by lesions in the paramedian midbrain or pons.

Aged↗
PubMed1997

[Hemorheological effects of autologous blood storage before surgery for cardiac valvular diseases].

The hemorheological effects of autologous blood storage with or without the use of erythropoietin were examined before surgery for valvular disease. There was no rheological difference between patients with aortic (16 cases) or mitral (10 cases) valve disease. Before storage, the levels of hematocrit, whole blood viscosity, and especially coefficient of rheology, were lower (p < 0.05) in the blood stored with erythropoietin, but this difference disappeared after storage. The plasma viscosity of both groups did not change before and after storage. The viscosity of blood was equalized after the storage of blood, irrespective of the use of erythropoietin.

Adult↗
PubMed1997

Signal averaged electrocardiography (SAECG) in patients on hemodialysis.

Cardiovascular diseases are the major cause of mortality in patients on hemodialysis (HD). Recently, signal averaged electrocardiography (SAECG) has been developed to detect ventricular late potentials (LP) noninvasively from the body surface for identifying patients at sudden death or ventricular tachycardia. We performed SAECG in 42 patients before and after HD. As a result, postdialysis total filtered QRS duration (FQRS) was significantly increased compared with predialysis FQRS. Postdialysis duration of low amplitude signal under 40 microV in the latter part of QRS (LAS40) tended to increase compared with predialysis LAS40. Before HD, there were no patients with LP and only one patient (2.4%) with abnormal SAECGs. In contrast, after HD, there were three patients (7.1%) with LP and three more patients (7.1%) with abnormal SAECGs. Furthermore, there was a significant correlation between the changes in LAS40 (delta LAS40) and those in potassium (K) (delta K) during HD. We further examined the relation between LAS40 and the concentration of K, by comparing the correlation coefficient between patients in the high-K group (predialysis K > or = 5.0 mEq/L; 20 patients) and those in the low-K group (predialysis K < 5.0 mEq/L; 22 patients). In the low-K group, there was no significant correlation between delta LAS40 and delta K. However, in the high-K group, there was a significant correlation between delta LAS40 and delta K. In conclusion, SAECG indices worsened during HD, and an insufficient decrement of serum potassium by HD is suggested to have been an arrhythmogenic factor in the high-K group.

Adult↗