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Biomedical subjects

M Kikuchi

Publications and source records attributed to M Kikuchi.

At least 325 records · Page 18Linked to original sources
PubMed1998

Angioimmunoblastic lymphoma (AILD-type T-cell lymphoma) with hyperplastic germinal centers.

Angioimmunoblastic T-cell lymphoma (or angioimmunoblastic lymphadenopathy with dysgammaglobulinemia [AILD]) was originally considered to be an abnormal immune reaction in which reactive follicles with germinal centers (GCs) are usually absent. When hyperplastic GCs are present along with an angioimmunoblastic reaction, the lesion has been interpreted as a benign hyperimmune reaction. We report seven patients with angioimmunoblastic T-cell lymphoma (AITL) who initially had hyperplastic GCs, shown to be malignant lymphoma by further studies and clinical follow-up. Clonal T-cell populations were observed in all specimens evaluated, and sequential biopsies showed histologic progression to typical AITL in two patients. Clinical presentation was characterized by generalized lymphadenopathy of acute onset, constitutional symptoms, hepatosplenomegaly, skin rash, and polyclonal hypergammaglobulinemia in five patients; regional adenopathy preceded generalized adenopathy in two patients. Five patients had rapid progression of disease, and three patients whose treatment was delayed due to inadequate evidence to diagnose lymphoma died of infection. The initial biopsy findings of each patient were similar and showed angioimmunoblastic proliferation, hyperplastic GCs with ill-defined borders, and interfollicular tingible-body macrophages. These GCs differed from occasional residual follicles of typical AITL in that the GCs were enlarged and hyperplasia of follicular dendritic cells was not seen. Diagnostic clear cells were not observed. Apoptotic bodies were markedly increased and bcl-2+ lymphocytes were sparse compared with typical AITL. Results of in situ hybridization for Epstein-Barr virus were positive in each case. We conclude that hyperplastic germinal centers with ill-defined borders and frequent interfollicular tingible-body macrophages occur in a histologic variant of AITL that is necessary to recognize for early diagnosis and treatment.

Adult↗
PubMed1998

Clinicopathological study of severe chronic active Epstein-Barr virus infection that developed in association with lymphoproliferative disorder and/or hemophagocytic syndrome.

Chronic active Epstein-Barr virus (CAEBV) infection has been previously reported to be sometimes associated with an aggressive clinical course. However, the role of EBV in the CAEBV is not well clarified. A retrospective study was performed on nine adult and five child patients (eight males and six females). Histologically, at first admission, the presence of neoplastic lesions could not be confirmed. The lymph nodes in half of all cases revealed paracortical hyperplasia with transformed lymphocytes (hyperplastic type). Half of the cases showed non-suppurative necrosis and an increased number of histiocytes with phagocytosis (histiocytic type). Activated histiocytes with lymphokine positivity were frequently detected in the histiocytic type. In the phenotypical study, 10 of the examined 11 cases showed increased numbers of natural killer (NK) cells and/or CD8-positive T lymphocytes. In situ hybridization (ISH) showed EBV-infected lymphoid cells, but the number of EBV-infected cells varied. Double-labeling immunochemistry/ISH demonstrated EBV-infected T cells, including NK cells, but not B cells. In addition, three cases showed a monoclonal dissemination of EBV terminal repetitive sequence (TR), and two cases showed oligoclonal dissemination. From those findings, monoclonal, oligoclonal and polyclonal populations of EBV-infected T or NK cells were considered to be present in CAEBV states. During the clinical course, 12 of the 14 cases died within 5 years. Six cases died from EBV-associated hematopoietic tumors (histiocytic tumor, T cell lymphoma, B cell lymphoma, plasmacytoma, and NK cell leukemia); one from non-EBV-associated acute myelogenous leukemia, and five due to hemophagocytic syndrome. The examined EBV-associated hematopoietic tumors showed monoclonal EBV terminal repetitive sequences. There is a possibility that the monoclonal dissemination of EBV-infected cells develops from oligoclonal or polyclonal EBV-infected cells. And active histiocytes with lymphokine positivity were frequently detected in the cases with histologically histiocytic type. These findings seem to be related with the causes of death due to hemophagocytic syndrome.

Adolescent↗
PubMed1998

In vitro and in vivo antibacterial activities of OPC-20011, a novel parenteral broad-spectrum 2-oxaisocephem antibiotic.

OPC-20011, a new parenteral 2-oxaisocephem antibiotic, has an oxygen atom at the 2- position of the cephalosporin frame. OPC-20011 had the best antibacterial activities against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae: MICs at which 90% of the isolates were inhibited were 6.25, 6.25, and 0.05 microg/ml, respectively. Its activity is due to a high affinity of the penicillin-binding protein 2' in MRSA, an affinity which was approximately 1,050 times as high as that for flomoxef. Against gram-negative bacteria, OPC-20011 also showed antibacterial activities similar to those of ceftazidime. The in vivo activities of OPC-20011 were comparable to or greater than those of reference compounds in murine models of systemic infection caused by gram-positive and -negative pathogens. OPC-20011 was up to 10 times as effective as vancomycin against MRSA infections in mice. This better in vivo efficacy is probably due to the bactericidal activity of OPC-20011, while vancomycin showed bacteriostatic activity against MRSA. OPC-20011 produced a significant decrease of viable counts in lung tissue at a dose of 2.5 mg/kg of body weight, an efficacy similar to that of ampicillin at a dose of 10 to 20 mg/kg on an experimental murine model of respiratory tract infection caused by non-ampicillin-susceptible S. pneumoniae T-0005. The better therapeutic efficacy of OPC-20011 was considered to be due to its potent antibacterial activity and low affinity for serum proteins of experimental animals (29% in mice and 6.4% in rats).

Animals↗
PubMed1998

Effect of rebamipide, a novel antiulcer agent, on Helicobacter pylori adhesion to gastric epithelial cells.

Helicobacter pylori is a major etiological agent in gastroduodenal disorders. The adhesion of H. pylori to human gastric epithelial cells is the initial step of H. pylori infection. Inhibition of H. pylori adhesion is thus a therapeutic target in the prevention of H. pylori infection. Experiments were performed to evaluate the effect of rebamipide, a novel antiulcer agent, on H. pylori adhesion to gastric epithelial cells. MKN-28 and MKN-45 cells, derived from human gastric carcinomas, were used as target cells. Ten H. pylori strains isolated from patients with chronic gastritis and gastric ulcer were used in the study. We evaluated the effect of rebamipide on H. pylori adhesion to MKN-28 and MKN-45 cells quantitatively using our previously established enzyme-linked immunosorbent assay. The adhesion of H. pylori to MKN-28 and MKN-45 cells was significantly inhibited by pretreatment of these cells with 100 microg of rebamipide per ml. However, the adhesion was not affected by the pretreatment of H. pylori with rebamipide. On the other hand, the viabilities of H. pylori, MKN-28 cells, and MKN-45 cells were not affected by rebamipide. Our studies suggest that rebamipide inhibits the adhesion of H. pylori to gastric epithelial cells.

Alanine↗
PubMed1998

Inhibition of pulmonary eosinophilia does not necessarily prevent the airway hyperresponsiveness induced by Sephadex beads.

BACKGROUND: The Lewis rat among highly inbred strains exhibits significant airway hyperresponsiveness (AHR) following intravenous administration of Sephadex G-200 (Sephadex). The aim of this study was to investigate the association of Sephadex-induced AHR with changes in airway inflammation in Lewis rats. METHODS: A suspension (0.5 mg/ml/rat) of Sephadex was intravenously administered to male Lewis rats on days 0, 2 and 5. Measurement of airway responsiveness to serotonin, bronchoalveolar lavage (BAL) and histological study were performed on day 2-11. RESULTS: Significant AHR induced by Sephadex was recognized on day2 (p < 0.05), and AHR reached a maximum on day 7 (p < 0.001). In the BAL study, eosinophils increased on day2 (p < 0.01) with a peak on day 5 (p < 0.05). In the histological study, we found Sephadex beads trapped in small arteries of the lung and granulomatous arteritis on day 2 or later. Pulmonary granulomas, horseshoe-shaped multinuclear giant cells, eosinophils and goblet cell hyperplasia were observed on day 2, and the degree became intense on day 5-7. GCC-AP0341 (10 mg/kg, i.p. x 3) inhibited the recruitment of eosinophils in BAL fluid and in lung tissue, but it did not inhibit AHR. The compound also inhibited pulmonary granulomas and goblet cell hyperplasia. CONCLUSION: The mechanism of Sephadex-induced AHR may not be directly associated with inflammatory changes such as recruitment of eosinophils, pulmonary granulomas and hyperplasia of goblet cells in rats.

Animals↗
PubMed1998

Aberrant functional organization in schizophrenia: analysis of EEG coherence during rest and photic stimulation in drug-naive patients.

EEG coherence provides a measure of functional correlations between two EEG signals. The present study was conducted to examine intrahemispheric EEG coherence at rest and during photic stimulation (PS) in 18 drug-naive patients with paranoid schizophrenia and 30 control subjects. Compared with the controls, the schizophrenic patients had significantly higher intrahemispheric coherence of the resting EEG for the delta band, although no significant group differences were found for other frequency bands. EEG analysis during PS showed that the patients also had significantly higher EEG coherence over the left posterior regions. In this study, we also examined the changes in intrahemispheric coherence from rest to the stimulus condition (i.e., PS-related coherence reactivity); the patients were found to show significantly smaller changes, with significant group differences being also confined to the posterior regions in the left hemisphere. These findings provide evidence that schizophrenic patients have abnormal EEG coherence in both resting and stimulus conditions and suggest more diffuse, undifferentiated functional organization within hemispheres. In addition, diminished coherence reactivity suggests a failure of PS-related functional reorganization in schizophrenia.

Adult↗
PubMed1998

Developmental changes in galanin receptors in the quail oviduct and the effect of ovarian sex steroids on galanin receptor induction.

We have recently isolated an oviposition-inducing peptide from mature quail oviducts identified as avian galanin. This peptide evoked vigorous contractions of the uterine oviduct through binding to receptors located in the uterus. The questions arising from these findings are: what changes occur in galanin receptors in the uterus during maturation, and what is the hormonal factor(s) that induces uterine galanin receptors? Therefore, the present study examined changes in uterine galanin receptors with age and the effect of administration of ovarian sex steroids on galanin receptors in the quail. Immature females reared under long day (LD) photoperiods from 4 weeks of age demonstrated a progressive increase in specific galanin binding per both unit uterine weight and per whole uterus concurrent with uterine development during 4-13 weeks. Scatchard plot analyses of the binding to the uterine preparation showed that the equilibrium dissociation constant (Kd) was about 0.30-0.34 nM regardless of age, and the change in galanin binding during uterine development was due to a change in the number of binding sites. Plasma 17beta-estradiol and progesterone concentrations were almost constant between 4-6 weeks and tended to increase thereafter. Administration of 17beta-estradiol to immature females for 1 week increased not only uterine weight but also specific galanin binding per unit uterine weight, whereas progesterone increased only the binding per unit uterine weight. Both sex steroids also induced an increase in total binding per uterus. Combined administration of 17beta-estradiol and progesterone induced marked increases in the galanin binding, and the effect was not additive but, rather, was synergistic. Scatchard plot analysis showed that the number of binding sites, but not the Kd, was increased by steroid treatment. Administration of 17beta-estradiol or progesterone increased each circulating steroid level to that relatively similar to the maximal levels observed in females exposed to LD. Thus, ovarian sex steroids may contribute at least in part as hormonal factors to galanin receptor induction, which takes place in the uterine oviduct during development.

Age Factors↗
PubMed1998

A novel anti-allergic drug, betotastine besilate, suppresses interleukin-5 production by human peripheral blood mononuclear cells.

The effect of a novel anti-allergic drug, betotastine besilate (betotastine) on interleukin (IL)-5 production by human peripheral blood mononuclear cells (PBMC) was investigated. PBMC of Dermatophagoides farinae extract (Df)-sensitive donors produced IL-5 and showed a proliferative response upon stimulation with relevant antigen (10 microg/ml). Df-induced IL-5 production by PBMC was significantly inhibited by betotastine at 10 and 100 microM. Betotastine also suppressed proliferation of PBMC with less potency. The effect of betotastine on IL-5 production was enhanced and significant even at 0.1 microM when the drug was added 120 min before antigen stimulation. Ketotifen and cetirizine also inhibited IL-5 production, but the effects of these drugs were significant only at 100 microM. These findings indicate that the suppression of IL-5 production may be involved in the anti-allergic effect of betotastine.

Adult↗
PubMed1998

Synthesis of 4-hydroxy-3(2H)-furanone acyl derivatives and their anti-cataract effect on spontaneous cataract rats (ICR/f).

4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 2(or 5)-ethyl-4-hydroxy-5(or 2)-methyl-3(2H)-furanone (EHMF) are known to inhibit cataract development in spontaneous cataract rats (ICR/f). Forty-five acylated hydroxyfuranone derivatives were designed and synthesized for an anti-cataract test, and their hydrophobic constants were also tested. Among these derivatives, 2,5-dimethyl-4-pivaloyloxy-3(2H)-furanone (HDMF pivalate) exerted a marked protective effect against the development of cataract in a galactose-induced model using cultured rat lens (in vitro). When tested on an ICR/f cataract model (in vivo), HDMF pivalate showed more significant inhibition of cataract development than parent compound HDMF. This derivative is more lipophilic than HDMF, so that HDMF pivalate can penetrate the cornea more easily than HDMF. The inhibition of cataract development by HDMF converted from HDMF pivalate is supported by the fact that HDMF was observed in the lens of ICR/f rats treated with HDMF pivalate.

Acylation↗
PubMed1998

Altered expression levels and impaired steps in the pathway to phosphatidylinositol 3-kinase activation via insulin receptor substrates 1 and 2 in Zucker fatty rats.

To elucidate the mechanism of obesity-related insulin resistance, we investigated the impaired steps in the processes of phosphatidylinositol (PI) 3-kinase activation through binding with insulin receptor substrates 1 and 2 (IRS-1 and IRS-2) in liver and muscle of Zucker fatty rats. The expressions of IRS-1 and IRS-2 were shown to be downregulated in both liver and muscle in fatty rats (hepatic IRS-1, 83%; hepatic IRS-2, 45%; muscle IRS-1, 60%; muscle IRS-2, 78%), resulting in decreased tyrosine phosphorylation in response to insulin stimulation. Despite the decrease in the tyrosine phosphorylation levels of hepatic IRS-1 and IRS-2 being mild to moderate, associated PI 3-kinase activities were dramatically decreased in fatty rats (IRS-1, 14%; IRS-2, 10%), which may suggest alteration in the sites of phosphorylated tyrosine residues of hepatic IRS-1 and IRS-2. In addition, we demonstrated that the expressions of p85alpha and p55alpha regulatory subunits of PI 3-kinase were reduced (p85alpha, 67%; p55alpha, 54%), and that the p50alpha regulatory subunit was markedly upregulated (176%) in the livers of fatty rats without apparent alterations in expressions of the catalytic subunits p110alpha and p110beta. These alterations may reflect the obesity-related insulin resistance commonly observed in human NIDDM.

Albumins↗
PubMed1998

Dose-dependent effects of dichloropropanol on liver histology and lipid peroxidation in rats.

A rare outbreak of acute hepatic damage in workers exposed to dichloropropanols (DCPs) was reported recently. The purpose of the present study is to examine the effects of DCPs on various organs, the dose dependency and the pathogenetic potential of DCP hepatotoxicity. A single intraperitoneal injection was given to six groups of rats with 0.2 ml of 20% ethanol (control), or 1/8 x, 1/4 x, 1/2 x, 1 x, and 2 x LD50 (0.11 ml/kg) of 1,3-dichloro, 2-propanol (DC2P) diluted in 20% ethanol. After blood samplings, all organs were subjected to histologic examinations with light and electron microscopes. Fresh liver tissues from further 4 control and 4 experimental rats sacrificed 6 hours after the injection of 20% ethanol and 1 x LD50 of DC2P were homogenized and subjected to evaluate lipid peroxidation, glutathione S-transferase activity and reduced glutathione contents in the liver. The rats administered with only ethanol or 1/8 and 1/4 LD50 of DC2P showed no serological or histopathological abnormalities. Marked elevation of serum glutamate pyruvate transaminase (SGPT) with a diffuse massive necrosis of the liver cells were noted in all rats of both the 1 x and 2 x LD50 groups, and irregular zonal necroses were found in 3 of 4 rats injected with 1/2 LD50. There were no serious toxic changes in other organs. Hepatic malondialdehyde level was significantly increased, associated with decreases of liver glutathione S-transferase activity and reduced glutathione content. It was concluded that the serious DC2P-toxicity was mainly found in the livers, dose dependently, and one of the causative mechanisms of this hepatotoxicity might be the lipid peroxidation.

Alanine Transaminase↗
PubMed1998

Hb Peterborough [beta 111(G13)Val-->Phe] in Japan; rapid identification by ESI/MS using proteolytic digests of oxidized globin.

A variant hemoglobin was found in a Japanese female whose hemoglobin was studied to clarify the cause of a low Hb A1c value, found during a routine medical examination. The detection and identification of the variant was performed by electrospray ionization mass spectrometry. Its structure was revealed to be the same as Hb Peterborough [beta 111(G13)Val-->Phe]. For sequence determination, oxidized globin as well as non-derivatized globin were cleaved by trypsin and lysyl endopeptidase. An abnormal peptide was found in digests of oxidized globin, as shown by electrospray ionization mass spectrometry. Cysteic acid in oxidized peptides enhanced the abundance of fragment ions in tandem mass spectrometry, which helped to quickly and accurately determine the substitution in beta T-12, a peptide in the core region. Electrospray ionization mass spectrometry analysis of the hemolysate also showed a low level of glycated hemoglobin. The patient's hemolysate showed decreased stability in the isopropanol test. An abnormal band was detected on isoelectrofocusing on the cathodic side of normal Hb A. This is the second report of Hb Peterborough and the first of its occurrence in Japan.

Adult↗
PubMed1998

Intravascular large cell lymphoma associated with hypoalbuminemia.

We report here a 71-yr-old Japanese woman who presented with severe anasarca and hypoalbuminemia. She had a postmortem diagnosis of intravascular large B-cell lymphoma, which is a rare type of lymphoma characterized by an intravascular proliferation of lymphoma cells. Severe generalized edema was thought to be attributed to vascular and/or lymphatic obstruction due to proliferation of lymphoma cells within the lumina and/or an increase in catabolism induced by tumor proliferation.

Aged↗
PubMed1998

Protective effects of FK506 against glutamate-induced neurotoxicity in retinal cell culture.

PURPOSE: To examine the effects of FK506 on glutamate neurotoxicity in cultured retinal neurons. METHODS: Experiments were performed with primary retinal cultures obtained from 17- to 19-day-old rat fetuses. To assess the effects of FK506 and other drugs on glutamate neurotoxicity, cultures were treated with a drug beginning 10 minutes before application of glutamate and continuing during the subsequent 10 minutes of glutamate exposure. The treated cells were then incubated for 1 hour in a drug-free and glutamate-free medium. After a 1-hour incubation, cell viability was quantitatively measured by the trypan blue exclusion method. RESULTS: Brief exposure to glutamate markedly decreased cell viability. FK506 protected against glutamate neurotoxicity in a dose-dependent manner. Rapamycin is a competitive inhibitor of FK506 that binds FK506 binding protein. Simultaneous application of rapamycin and FK506 negated the protective effects of FK506. Cyclosporin A, which binds and inhibits calcineurin, mimicked the protective effects of FK506. Treatment with FK506 did not affect the intracellular maximum Ca2+ concentration induced by glutamate application. Although FK506 exhibited protective action against Ca2+ ionophore-induced neurotoxicity, it had no effect on nitric oxide-induced neurotoxicity. Treatment with FK506 reduced the activity of nitric oxide synthase (NOS). CONCLUSION: FK506 protected against glutamate neurotoxicity by inhibiting NOS activity in cultured retinal neurons.

Animals↗
PubMed1998

Possible mechanisms of vascular relaxation induced by pulsed-UV laser.

This study was designed to examine the mechanism of vasorelaxation induced by pulsed-UV laser. Luminal diameters of rat femoral arteries were measured prior to and following krypton-fluoride excimer laser irradiation of 248 nm in wavelength. The diameter was enlarged to 1.3 times the preirradiated size at 1 or 10 Hz irradiation when the fluence was over 2.0 mJ/pulse/mm2, while the diameter reached 1.8 times at 100 Hz with a fluence of 0.8 mJ/pulse/mm2. Vasorelaxation by the 100 Hz irradiation was inhibited when the artery was pretreated with methylene blue but was enhanced with superoxide dismutase. Pathological analysis revealed an ablation crater and vacuole formation in the vessel at 1 or 10 Hz irradiation, but these changes were not remarkable in the 100 Hz-exposed sample. These findings suggest that vasorelaxation induced by the pulsed UV irradiation at 1 or 10 Hz results from structural alteration of vascular smooth muscle by the ablation crater or vacuolization. On the other hand, a possible mechanism of vasorelaxation at the 100 Hz irradiation is partially related to nitric oxide.

Animals↗
PubMed1998

IFN-gamma-induced iNOS mRNA expression is inhibited by rebamipide in murine macrophage RAW264.7 cells.

To investigate the effects of rebamipide, an antigastritis and anti-gastric ulcer drug, on inducible nitric oxide synthase (iNOS), murine macrophage RAW264.7 cells were treated with interferon-gamma (IFN-gamma) in the presence of rebamipide. NO production was stimulated by IFN-gamma, and the level was attenuated by rebamipide in a dose-dependent manner. Therefore, we investigated the possibility that either rebamipide directly inhibited iNOS enzyme activity or that it reduced iNOS mRNA expression. In a cell-free system, rebamipide did not affect iNOS enzyme activity; however, rebamipide inhibited iNOS mRNA and protein expression induced by IFN-gamma. Thus, we concluded that rebamipide inhibited IFN-gamma-induced NO production as a result of its inhibitory action on iNOS mRNA expression.

Alanine↗