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Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 487 records · Page 27Linked to original sources
PubMed1997

CD95 (Fas) may control the expansion of activated T cells after elimination of bacteria in murine listeriosis.

CD95 (Fas) is known to mediate activation-induced T-cell death by apoptosis. To understand the role of CD95 during the course of bacterial infection, we examined the kinetics of alphabeta and gammadelta T cells in the peritoneal cavities and livers of 5-week-old CD95-defective MRL/lpr mice after an intraperitoneal infection with Listeria monocytogenes. The number of bacteria in the spleen decreased to an undetectable level by day 10 after infection with 7 x 10(3) Listeria cells similar to the number in MRL/+/+ mice. The number of alphabeta T cells expressing CD44 and CD95 reached a maximum in the peritoneal cavity on day 6 after listerial infection and thereafter decreased gradually in MRL/+/+ mice, whereas CD44+ alphabeta T cells without CD95 expression continued to increase throughout the course of listerial infection in MRL/lpr mice. Freshly isolated T cells from MRL/+/+ mice infected with L. monocytogenes 10 days previously showed DNA fragmentation with apoptosis, whereas such fragmentation was not prominent in T cells from infected MRL/lpr mice. In correlation with the increased number of CD44+ alphabeta T cells, Listeria-specific T-cell proliferation of peritoneal exudate cells was significantly greater in MRL/lpr mice than in MRL/+/+ mice on day 10 after listerial infection. In contrast to alphabeta T cells, gammadelta T cells increased in number only transiently in the peritoneal cavity and liver after listerial infection in both MRL/lpr mice and MRL/+/+ mice. These results suggest that CD95-mediated cell death with apoptosis may be involved in termination of the alphabeta-T-cell-mediated immune response after the battle against L. monocytogenes has been won, whereas gammadelta T cells may undergo apoptosis independently of CD95 during the course of listerial infection.

Animals↗
PubMed1997

Possible role of macrophage-derived soluble mediators in the pathogenesis of encephalomyocarditis virus-induced diabetes in mice.

Pancreatic islets from DBA/2 mice infected with the D variant of encephalomyocarditis (EMC-D) virus revealed lymphocytic infiltration with moderate to severe destruction of pancreatic beta cells. Our previous studies showed that the major population of infiltrating cells at the early stages of infection is macrophages. The inactivation of macrophages prior to viral infection resulted in the prevention of diabetes, whereas activation of macrophages prior to viral infection resulted in the enhancement of beta-cell destruction. This investigation was initiated to determine whether macrophage-produced soluble mediators play a role in the destruction of pancreatic beta cells in mice infected with a low dose of EMC-D virus. When we examined the expression of the soluble mediators interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS) in the pancreatic islets, we found that these mediators were clearly expressed at an early stage of insulitis and that this expression was evident until the development of diabetes. We confirmed the expression of these mediators by in situ hybridization with digoxigenin-labelled RNA probes or immunohistochemistry in the pancreatic islets. Mice treated with antibody against IL-1beta or TNF-alpha or with the iNOS inhibitor aminoguanidine exhibited a significant decrease in the incidence of diabetes. Mice treated with a combination of anti-IL-1beta antibody, anti-TNF-alpha antibody, and aminoguanidine exhibited a greater decrease in the incidence of disease than did mice treated with one of the antibodies or aminoguanidine. On the basis of these observations, we conclude that macrophage-produced soluble mediators play an important role in the destruction of pancreatic beta cells, resulting in the development of diabetes in mice infected with a low dose of EMC-D virus.

Animals↗
PubMed1997

Possible different mechanism between amyloid-beta (25-35)-and substance P-induced chemotaxis of murine microglia.

The mechanism of murine microglial chemotaxis induced by amyloid-beta protein (A beta (25-35)) was investigated. A beta (25-35) dose-dependently stimulated microglial chemotaxis at concentrations between 100 pM and 10 nM. Substance P, a NK-1 agonist, stimulated chemotaxis at concentrations of 10 nM or more. GR-64349, a NK-2 agonist, and senktide, a NK-3 agonist, did not stimulate microglial chemotaxis. We examined whether homologous desensitization of chemotaxis would occur by A beta (25-35). The chemotactic effect of microglia was homologously desensitized by 10 nM A beta (25-35). On the other hand, substance P at 10 nM did not desensitize the A beta (25-35)-induced chemotaxis. These data show that A beta (25-35) induces the chemotaxis of microglia probably through a receptor other than the NK-1 receptor.

Amyloid beta-Peptides↗
PubMed1997

Value of the maternal interleukin 6 level for determination of histologic chorioamnionitis in preterm delivery.

The present study examined whether maternal serum cytokine levels are useful for the diagnosis of histologic chorioamnionitis. The blood samples of 29 women who delivered preterm between 22 and 34 weeks of gestation were collected at delivery, and placentas were histopathologically examined for chorioamnionitis. The interleukin (IL) 6 titer was higher in 18 mothers with histologic chorioamnionitis (median 12.0 pg/ml, range 4.9-63.5 pg/ml) than that in 11 mothers without histologic chorioamnionitis (median 3.5 pg/ml, range 1.7-14.9 pg/ml; p < 0.0001). The C-reactive protein (CRP) titer also differed significantly between these two groups (chorioamnionitis group: median 5.2 mg/dl, range 0.1-12.3 mg/dl; no chorioamnionitis group: median 0.2 mg/dl, range 0.1-0.5 mg/dl; p = 0.0001). The IL-6 titer showed better clinical diagnostic indices and a higher odds ratio (9.78, 95% confidence interval 1.50-63.82) than did CRP (3.26, 95% confidence interval 1.22-8.67). The levels of IL-8, monocyte chemotactic and activating factor, and soluble IL-6 receptor did not differ between the two groups. These data suggest that the level of maternal serum IL-6 is more useful than other markers, including CRP, for the identification of women at risk of impending preterm labor with histologic chorioamnionitis.

Adult↗
PubMed1997

Characterization of canine herpesvirus glycoprotein D (hemagglutinin).

Glycoprotein D (gD) of canine herpesvirus (CHV) YP2 strain was expressed in COS-7 and insect (Spodoptera frugiperda; Sf9) cells. The gDs expressed in COS-7 and Sf9 cells reacted with a panel of monoclonal antibodies (MAbs) against CHV gD (hemagglutinin) and an MAb 25C9 against feline herpesvirus type 1 (FHV-1) gD by indirect immunofluorescence assay, and possessed a molecular weight (MW) of approximately 51-55 and 41-46 kilodalton (kDa), respectively, when examined by immunoblot analysis. After treatment with tunicamycin, the MW of the gD expressed in Sf9 cells became approximately 37 kDa. By hemadsorption (HAD) tests using canine or feline red blood cells (RBC), COS-7 cells expressing CHV gD adsorbed only canine RBC, but not feline RBC, whereas control COS-7 cells expressing FHV-1 gD adsorbed feline RBC, but not canine RBC. By hemagglutination (HA) tests, lysates of Sf9 cells expressing CHV gD agglutinated canine RBC, but not feline RBC. These HA and HAD activities were inhibited by HA-inhibition MAbs against CHV gD. Control lysates of Sf9 cells expressing FHV-1 gD agglutinated only feline RBC. Serum from mice inoculated with lysates of Sf9 cells expressing CHV gD possessed a high titer of virus-neutralizing activities against CHV infection. These results indicated that CHV gD is structurally similar to FHV-1 gD, but is functionally different from FHV-1 gD.

Alphaherpesvirinae↗
PubMed1997

Role of one N-linked oligosaccharide chain on canine herpesvirus gD in its biological activity.

The YP11mu strain of a plaque-selected canine herpesvirus (CHV) encoded a smaller molecular weight (MW) of gD than those of other strains including YP2 strain (Xuan et al., 1990). When nucleotide sequence of the mutated gD of YP11mu strain (gD(YP11mu)) was compared with that of gDs of other CHV strains, gD(YP11mu) lacked 12 nucleotides encoding 4 amino acids, NKTI, including one predicted potential N-linked glycosylation site and no other change was found in other regions. When the gD(YP11mu) and gD of YP2 strain (gD(YP2)) expressed in COS-7 and insect (Spodoptera frugiperda; Sf9) cells were compared each other, both gDs reacted with a panel of monoclonal antibodies (MAbs) against CHV gD by indirect immunofluorescence analysis and the gD(YP11mu) possessed an MW of approximately 47-51 and 39-44 kDa in COS-7 and Sf9 cells, respectively, which were smaller than the expressed gD(YP2) (approximately 51-55 and 41-46 kDa, respectively) by immunoblot analysis. After treatment with tunicamycin, the MW of both gDs in Sf9 cells became approximately 37 kDa. When hemagglutination (HA) test using canine red blood cells (RBC) were carried out, lysates of Sf9 cells expressing CHV gDs agglutinated canine RBC. Serum from mice inoculated with lysates of Sf9 cells expressing the gDs possessed a high titer of virus-neutralizing (VN) activities against CHV. These results indicated that the deletion of 4 amino acids possessing approximately 4 kDa of glyco-chain from gD of CHV in mammalian cells does not affect HA activity and VN antibody-inducing activity and that this deletion of gD(YP11mu) might be a good selective marker for development of recombinant viruses as a live vaccine.

Amino Acid Sequence↗
PubMed1997

Adhesion of insect cells expressing the feline herpesvirus type 1 hemagglutinin (gD) to feline cell lines.

Feline herpesvirus type 1 (FHV-1) gD-expressing Sf9 cells adhered to two feline cell lines, but not to the porcine, bovine, or canine cell lines tested. In addition, this adhesion activity was inhibited by a monoclonal antibody against FHV-1 gD. These results showed that the FHV-1 gD might bind to a specific-molecule(s) on the surface of feline cell lines. We discussed a possible importance of the FHV-1 gD in host cell restriction to FHV-1 infection.

Alphaherpesvirinae↗
PubMed1997

Recombinant viral vector vaccines for the veterinary use.

Recently, genetically engineering using recombinant DNA techniques has been applied to design new viral vaccines in order to reduce some problems which present viral vaccines have. Up to now, many viruses have been investigated for development of recombinant attenuated vaccines or live viral vectors for delivery of foreign immunogenic antigens. In this review, we introduced three kind of viruses; herpesviruses, vaccinia viruses, and adenoviruses, which have best widely been studied as recombinant vaccines or delivery vaccines for the veterinary use.

Animals↗
PubMed1997

Generation of monoclonal antibodies against a feline CD antigen (CD4) expressed by a recombinant baculovirus.

We attempted to establish a system to generate monoclonal antibodies (mAbs) recognizing CD antigens on lymphocytes of domestic animals using the expressed CD antigens by a baculovirus expression system. For this purpose, we selected feline CD4 (fCD4) antigen and expressed it in an insect cell line (Sf9 cells). To obtain mAbs, BALB/c mice were immunized with feline peripheral blood mononuclear cells (fPBMCs) or Sf9 cells expressing the fCD4 (Sf-fCD4 cells), and then hybridomas secreting antibodies were screened by indirect immunofluorescence assay against the opposite antigens of Sf-fCD4 cells or fPBMCs, respectively. Five mAbs recognizing the fCD4 were obtained in total. The system established here might be useful to obtain mAbs recognizing CD antigens of domestic animals.

Animals↗
PubMed1997

Apoptosis of murine hepatocytes induced by high doses of galactosamine.

Apoptosis induced by high doses of Galactosamine (GalN) was investigated in mice hepatocytes in vivo. In mice intraperitoneally (i.p.) treated with GalN 3 g/kg, the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells were first observed at 6 hr postadministration (PA). Both acidophilic bodies in hematoxylin and eosin (HE)-stained sections and TUNEL-positive cells were markedly found at 24 hr PA. At 48 hr PA, cellular degeneration and necrosis of hepatocytes were prominently observed, and TUNEL-positive cells were scarcely found. In the mice ip treated with GalN 1.5 g/kg, the lesion was milder than that in those treated with GalN 3 g/kg. Acidophilic bodies and TUNEL-positive cells were scarcely found at 24 hr PA, whereas they were markedly seen at 48 hr PA. In addition, a ladder-like DNA fragmentation pattern by agarose gel electrophoresis was observed most remarkably at 24 hr PA with GalN 3 g/kg and at 48 hr PA with GalN 1.5 g/kg, and less distinctly at 48 hr PA with GalN 3 g/kg. On the other hand, sGOT and sGPT activities increased prominently at 48 hr PA with GalN 3 g/kg. These results suggest that the cell death induced by high dose of GalN may be caused by apoptosis, and subsequently by necrosis in vivo.

Alanine Transaminase↗
PubMed1997

Advanced glycation end products enhance osteoclast-induced bone resorption in cultured mouse unfractionated bone cells and in rats implanted subcutaneously with devitalized bone particles.

Advanced glycation end products (AGE) are formed in long-lived matrix proteins by a nonenzymatic reaction with sugar. The presence of AGE in beta 2-microglobulin-amyloid fibrils of dialysis-related amyloidosis, one of the characteristic features of which is an accelerated bone resorption around amyloid deposits, was recently demonstrated. This suggested a potential link of AGE in bone resorption and initiated this investigation of whether AGE enhance bone resorption. When mouse unfractionated bone cells containing osteoclasts were cultured on dentin slices, both AGE-modified beta 2-microglobulin and BSA increased the number of resorption pits formed by osteoclasts, whereas their normal counterparts of those modified with the early glycation products did not. AGE proteins, however, did not increase the number of newly formed osteoclasts, even in the coculture of mouse bone marrow cells with osteoblastic cells isolated from mouse calvaria. Enhanced bone resorption was also observed when unfractionated bone cells were cultured on AGE-modified dentin slices. AGE-enhanced bone resorption was effectively inhibited by calcitonin and ipriflavone, both of which are inhibitors of bone resorption. AGE-enhanced bone resorption was further supported by in vivo evidence that rat bone particles-upon incubation with glucose for 60 days (AGE-bone particles)-when implanted subcutaneously in rats, were resorbed to a much greater extent than control bone particles upon parallel incubation without glucose. These findings suggest that AGE enhance osteoclast-induced bone resorption. Although the mechanism remains unknown, AGE are unlikely to promote differentiation of osteoclast progenitors into osteoclasts, suggesting that AGE activate osteoclasts or alter microenvironments favorable for bone resorption by osteoclasts. The modification of bone matrices with AGE might play a role in the remodeling of senescent bone matrix tissues, further implicating a pathological significance of AGE in dialysis-related amyloidosis or osteoporosis associated with diabetes and aging.

Amyloidosis↗
PubMed1997

Endovascular stenting of a traumatic dissecting aneurysm of the extracranial internal carotid artery--case report.

A 57-year-old male presented with a traumatic dissecting aneurysm of the distal, extracranial internal carotid artery (ICA). Stent placement resulted in complete occlusion of the aneurysm and preservation of the carotid blood flow. He also had an atherosclerotic stenosis of the ipsilateral middle cerebral artery, which was uneventfully treated by angioplasty 3 months after stent placement. Endovascular reconstruction of the ICA with a stent may be the best way to occlude dissecting aneurysms, especially in patients who cannot tolerate ICA occlusion, are at risk from delayed ischemia, or have wide-necked or multiple aneurysms.

Aortic Dissection↗
PubMed1997

Association of alexithymia with low utilization and perception on a measure of social support in patients on peritoneal dialysis.

This study examined the association of social support and alexithymia in 63 patients with end-stage renal failure on peritoneal dialysis. Scores on the Toronto Alexithymia Scale were significantly higher for the patient group than the control group. Social support was measured with the Stress and Coping Inventory. For scores on the Existence of social support there was no significant difference between the two groups; however, scores on the Utilization and Perception of social support were significantly lower for the patients than for the control group. The alexithymia scores were significantly and negatively correlated with the scores on the Utilization and Perception of social support. Our findings suggest that patients with peritoneal dialysis score higher on a measure of alexithymia associated with low utilization and perception of social support.

Adaptation, Psychological↗
PubMed1997

Cyclosporine treatment for polymyositis/dermatomyositis: is it possible to rescue the deteriorating cases with interstitial pneumonitis?

Polymyositis and dermatomyositis are inflammatory muscular diseases of unknown etiology which have interstitial pneumonitis as a serious complication. From 1987 to 1994, we used cyclosporine to treat 14 polymyositis/dermatomyositis patients (8 with and 6 without interstitial pneumonitis). In combination with prednisolone, cyclosporine was either added to or substituted for conventional cytotoxic drugs (azathioprine, cyclophosphamide and methotrexate). Cyclosporine was effective against both myositis and interstitial pneumonitis when used early in the course of the disease.

Adult↗
PubMed1997

Occurrence of severe vasospasm following intraventricular hemorrhage from an arteriovenous malformation. Report of two cases.

The authors present two rare cases of severe cerebral vasospasm following the rupture of arteriovenous malformations (AVMs). Computerized tomography revealed intracerebral hemorrhage in the thalamus in one case and in the putamen in the other, both accompanied by cast formation of intraventricular clots without radiological evidence of subarachnoid hemorrhage. Initial angiograms showed arterial narrowing of the bilateral internal carotid arteries in the supraclinoid portion but failed to demonstrate an arteriovenous shunt. Subsequent angiograms clearly demonstrated the existence of an AVM. Radiological features and possible mechanisms are discussed.

Adolescent↗
PubMed1997

The relationship of preoperative magnetic resonance imaging findings and closed system drainage in the recurrence of chronic subdural hematoma.

Although chronic subdural hematoma (CSDH) is a well-known entity, its recurrence rate has remained uncertain. There is little knowledge concerning whether the results of radiological imaging can be used to predict CSDH recurrence or whether surgical methods can influence this rate. The first aim of this study is to evaluate the relationship between the recurrence rate of CSDHs and their appearance on preoperative magnetic resonance (MR) or computerized tomography images. The second aim is to evaluate by means of a prospective randomized method the usefulness of closed-system drainage. From January 1988 through June 1996, the authors surgically treated 257 consecutive adult patients with CSDHs. Data obtained in 199 patients who were evaluated preoperatively by MR imaging were analyzed. Thirty-one of these patients underwent bilateral operations and thus 230 operative sites of CSDH were included in the analyses. The cases of CSDH were separated into high- and nonhigh-intensity groups on the basis of the appearance on T1-weighted MR images. From July 1992 to June 1996, the authors conducted a prospective randomized study on the recurrence rate of CSDH in patients undergoing burr-hole irrigation with or without closed system drainage. The recurrence rate of 3.4% in the high-intensity group was significantly lower than the 11.6% rate found in the nonhigh-intensity group (p < 0.05). The recurrence rates following irrigation with and without closed system drainage were significantly different (p < 0.025): 3.1% with closed system drainage and 17% following burr-hole irrigation alone. The surgical procedures were correlated with the MR findings. In the high-intensity group, 1.1% of CSDHs recurred in patients in whom closed system drainage was used and 11.1% in patients without closed system drainage. In the nonhigh-intensity group, 8.1% of CSDHs recurred in patients in whom drainage was used and 23.1% in patients without closed system drainage. Magnetic resonance T1-weighted imaging was useful in predicting the propensity of CSDHs to recur. Closed system drainage significantly reduced the recurrence rate of CSDHs regardless of MR findings.

Adult↗