Biomedical subjects

M Tsuji

Publications and source records attributed to M Tsuji.

At least 19 recordsLinked to original sources

PubMed2001

Complete, long-lasting protection against malaria of mice primed and boosted with two distinct viral vectors expressing the same plasmodial antigen.

We report that complete protection against malaria and total inhibition of liver stage development and parasitemia was obtained in 100% of BALB/c mice primed with a replication-defective recombinant adenovirus expressing the circumsporozoite (CS) protein of Plasmodium yoelii (AdPyCS), followed by a booster with an attenuated recombinant vaccinia virus, expressing the same malaria antigen, VacPyCS. We found increased levels of activated CS-specific CD8(+) and CD4(+) T cells, higher anti-sporozoite antibody titers, and greater protection in these mice, when the time between priming and boosting with these two viral vectors was extended from 2 to 8 or more weeks. Most importantly, by using this immunization regimen, the protection of the immunized mice was found to be long-lasting, namely complete resistance to infection of all animals 3 1/2 months after priming. These results indicate that immunization with AdPyCS generates highly effective memory T and B cells that can be recalled long after priming by boosting with VacPyCS.

Animals↗

PubMed2001

Induction of neurite outgrowth in PC12 cells by alpha -phenyl-N-tert-butylnitron through activation of protein kinase C and the Ras-extracellular signal-regulated kinase pathway.

The spin trap alpha-phenyl-N-tert-butylnitron (PBN) is widely used for studies of the biological effects of free radicals. We previously reported the protective effects of PBN against ischemia-reperfusion injury in gerbil hippocampus by its activation of extracellular signal-regulated kinase (ERK) and suppression of both stress-activated protein kinase and p38 mitogen-activated protein kinase. In the present study, we found that PBN induced neurite outgrowth accompanied by ERK activation in PC12 cells in a dose-dependent manner. The induction of neurite outgrowth was inhibited significantly not only by transient transfection of PC12 cells with dominant negative Ras, but also by treatment with mitogen-activated protein kinase/ERK kinase inhibitor PD98059. The activation of receptor tyrosine kinase TrkA was not involved in PBN-induced neurite outgrowth. A protein kinase C (PKC) inhibitor, GF109203X, was found to inhibit neurite outgrowth. The activation of PKCepsilon was observed after PBN stimulation. PBN-induced neurite outgrowth and ERK activation were counteracted by the thiol-based antioxidant N-acetylcysteine. From these results, it was concluded that PBN induced neurite outgrowth in PC12 cells through activation of the Ras-ERK pathway and PKC.

Acetylcysteine↗

PubMed2001

Fluorimetric determination of magnesium and aluminum via complexation with oxine in high-performance liquid chromatography.

Aluminum and magnesium were determined by fluorimetric detection via pre-column and/or in-column derivatization with 8-hydroxyquinoline (oxine) in high-performance liquid chromatography. The oxine complex of aluminum was selectively detected when the eluent contained no oxine, whereas the aluminum and magnesium complexes could be simultaneously detected when the eluent contained oxine. The sensitivity was improved by using eluents containing oxine by a factor of 7.1 for aluminum, and the detection limits at S/N=3 were 18 and 16 ng/ml for magnesium and aluminum, respectively. The present system was applied to the determination of magnesium and aluminum in various water samples.

Aluminum↗

PubMed2001

The novel kappa-opioid receptor agonist TRK-820 suppresses the rewarding and locomotor-enhancing effects of morphine in mice.

The effects of the novel kappa-opioid receptor agonist TRK-820 on the rewarding and locomotor-enhancing effects of morphine were investigated in mice. Morphine (1-5 mg/kg, s.c.) caused a dose-related preference for the drug-associated place. In contrast, TRK-820 (0.003-0.03 mg/kg, s.c.) did not produce a significant preference for either compartment of the test box. In combination studies, co-injection of TRK-820 (0.01 and 0.03 mg/kg, s.c.) with morphine significantly suppressed the morphine (5 mg/kg, s.c.)-induced place preference, and this effect of TRK-820 was antagonized by pretreatment with nor-BN1 (3 mg/kg, s.c.), a selective kappa-opioid receptor antagonist. TRK-820 also suppressed morphine-induced hyperlocomotion, and this suppression was also blocked by nor-BNI. These results suggest that TRK-820 suppresses the rewarding and locomotor-enhancing effects of morphine through the activation of kappa-opioid receptors. Thus, we propose that TRK-820 may be useful for controlling pain while reducing undesirable side-effects.

Animals↗

PubMed2001

Prognostic significance of expression of thymidine phosphorylase and vascular endothelial growth factor in human gastric carcinoma.

BACKGROUND AND OBJECTIVES: Both thymidine phosphorylase (dThdPase) and vascular endothelial growth factor (VEGF) are well-characterized inducers of angiogenesis. The purpose of this study was to examine the expression of these antigens and their prognostic significance in gastric carcinoma. METHODS: Medical records of 102 patients with stage II tumor were retrospectively reviewed. Primary tumors were studied by immunohistochemical staining for dThdPase and VEGF. RESULTS: Positive dThdPase expression was observed in 52 (51%) tumors and positive VEGF expression in 53 (52%) tumors. There was a significant correlation between the positive expression of VEGF and lymphatic invasion. The patients with dThdPase-positive carcinoma showed a significantly worse prognosis than those with dThdPase-negative carcinoma in stage II. Moreover, the frequency of hepatic recurrence was significantly higher in the patients with dThdPase-positive and VEGF-positive tumors than in those with dThdPase-negative and VEGF-negative tumors. CONCLUSIONS: Combination analysis of dThdPase and VEGF expression in gastric carcinoma appears to be well-characterized inductors of prognosis and metastasis.

Adult↗

PubMed2001

Gastric T-cell lymphoma presenting with epithelioid granulomas mimicking tuberculosis in regional lymph nodes.

In patients with malignant lymphomas, a sarcoid reaction is occasionally observed. However, lymphoma-related granulomas with caseous necrosis are rare. We describe such a case of T-cell gastric lymphoma that was difficult to diagnose. A 50-year-old man was referred to our hospital because of abnormal gastric endoscopic findings: hypertrophic folds with narrowing of the gastric lumen and multiple ulcers in the body. Gastric biopsy specimens showed non-specific inflammation. An open biopsy of the enlarged gastric regional lymph nodes was performed. The sections revealed effacement of the normal architecture and replacement by numerous epithelioid granulomas accompanied by Langhan's type giant cells with or without central caseous necrosis, strongly suggesting tuberculosis. However, mycobacteria and other causative organisms were not detected, and an anti-tuberculous regimen was ineffective. Repeat gastric biopsies were performed and, finally, atypical lymphocytes were observed infiltrating the mucosa. The patient was diagnosed with gastric T-cell lymphoma based on the results of immunohistochemical stainings. After chemotherapy, a total gastrectomy was performed. The diagnosis of gastric T-cell lymphoma with a sarcoid reaction was confirmed by histological findings of the sections. Namely, the gastric wall was replaced by atypical lymphocytes showing the phenotype of helper T cells, admixed with epithelioid granulomas with Langhan's type giant cells. Thus, this case suggests that regional lymph nodes in gastric lymphomas may be present as epithelioid granulomas with caseous necrosis, mimicking tuberculosis.

Antitubercular Agents↗

PubMed2001

Cyst fluid levels of carcinoembryonic antigen, carbohydrate antigen 19-9, squamous cell carcinoma antigen, and amylase in thyroglossal duct and branchial cleft cysts.

Cyst fluid was aspirated from five thyroglossal duct cysts (TDCs) and four branchial cleft cysts (BCCs). The cyst fluid levels of carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, squamous cell carcinoma antigen (SCC), and amylase were measured and compared between the two types of cyst. The enzyme immunoassay technique was used for CEA and CA19-9, while SCC and amylase levels were measured by the immunoradiometric assay and nitrophenol method, respectively. Immunostaining for CEA, CA19-9, and amylase was also performed. The serum levels of these markers in both groups of patients were within the normal ranges. In contrast, their cyst fluid levels were extremely high. There was no significant difference in the cyst fluid levels of CEA and SCC between the two types of cyst; however, the cyst fluid from the TDCs showed significantly higher levels of CA19-9 and significantly lower levels of amylase compared with that from the BCCs. Immunostaining revealed expression of CA 19-9 in nearly half the columnar epithelial cells in the TDCs, but not in the squamous epithelial cells in the BCCs. CEA and amylase were not found in the epithelial cells of either type of cyst. These findings seem to reflect the difference in etiology between TDCs and BCCs.

Adult↗

PubMed2001

Detection of malaria liver-stages in mice infected through the bite of a single Anopheles mosquito using a highly sensitive real-time PCR.

We describe a highly sensitive real-time PCR to detect and measure the development of the liver-stages of malaria parasites in mice infected with sporozoites ranging in number from 25 to more than 164,000, using the same reaction conditions. Furthermore, this assay detects and measures parasite loads in the livers of mice exposed to the bite of a single malaria-infected Anopheles mosquito. This unique method should greatly facilitate studies aimed at evaluating very precisely the efficacy of anti-malarial experimental drug treatments and vaccination regimens in conditions of infection resembling those found in the field.

Animals↗

PubMed2001

Study on the metabolites of 1alpha,25-dihydroxyvitamin D4.

Three major metabolites of 1alpha,25-dihydroxyvitamin D(4) were isolated from the bile of rat and the structures were elucidated on the basis of spectral data and the periodate oxidative cleavage of the diol structures of the metabolites. One of the metabolites was the known calcitroic acid. Another two metabolites were isomers and identified as 9,10-secoergosta-5,7,10(19)-triene-1alpha,3beta,24,25-tetrahydroxy-26-oic acid and 9,10-secoergosta-5,7,10(19)-triene-1alpha,3beta,24,25-tetrahydroxy-28-oic acid. It was found that 1alpha,25-dihydroxyvitamin D(4) is metabolized in a similar manner in vivo to that of 1alpha,25-dihydroxyvitamin D(2) but differently from 1alpha,25-dihydroxyvitamin D(3).

Animals↗

PubMed2001

Protective effects of 5-HT1A receptor agonists against emotional changes produced by stress stimuli are related to their neuroendocrine effects.

1. The effects of the 11beta-hydroxylase inhibitor metyrapone on the protective effects of serotonin (5-hydroxytryptamine; 5-HT)(1A) receptor agonists against emotional changes produced by acute restraint stress were examined in mice. 2. Changes in the emotional state of mice were evaluated in terms of changes in exploratory activity, i.e. total locomotor activity, number and duration of rearing and head-dipping behaviours, and latency to the first head-dipping, using an automatic hole-board apparatus. 3. Treatment with the 5-HT(1A) receptor agonists flesinoxan (1 mg kg(-1), i.p.) and R(+)-2-di-n-propylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide (8-OH-DPAT; 1 mg kg(-1), i.p.) 24 h prior to exposure to stress significantly suppressed the decrease in various exploratory behaviours that was observed immediately after the exposure to acute restraint stress (60 min). The effects of flesinoxan (1 mg kg(-1), i.p.) and 8-OH-DPAT (1 mg kg(-1), i.p.) were antagonized by co-injection with N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY100635; 1 mg kg(-1), i.p.), a selective 5-HT(1A) receptor antagonist. 4. Flesinoxan (1 mg kg(-1), i.p.) and 8-OH-DPAT (1 mg kg(-1) i.p.) significantly increased the plasma corticosterone level, and these effects of 5-HT(1A) receptor agonists were dose-dependently blocked by pretreatment with metyrapone (12.5 and 25 mg kg(-1), s.c.). 5. Metyrapone (25 mg kg(-1), s.c.) alone did not modify the stress-induced changes in exploratory behaviours. Pretreatment with metyrapone (12.5 and 25 mg kg(-1), s.c.) partly antagonized the protective effects of flesinoxan (1 mg kg(-1), i.p.) and 8-OH-DPAT (1 mg kg(-1), i.p.) with regard to only the number and duration of head-dipping behaviours. 6. These results suggest that activation of the adrenocortical system via 5-HT(1A) receptors may facilitate some adaptive mechanism(s) involved in the recognition of and/or ability to cope with stressful situations.

Animals↗

PubMed2001

Human babesiosis in Japan: isolation of Babesia microti-like parasites from an asymptomatic transfusion donor and from a rodent from an area where babesiosis is endemic.

To determine the source of infection for the Japanese index case of human babesiosis, we analyzed blood samples from an asymptomatic individual whose blood had been transfused into the patient. In addition, we surveyed rodents collected from near the donor's residence. Examination by microscopy and PCR failed to detect the parasite in the donor's blood obtained 8 months after the donation of the blood that was transfused. However, we were able to isolate Babesia parasites by inoculating the blood sample into SCID mice whose circulating red blood cells (RBCs) had been replaced with human RBCs. A Babesia parasite capable of propagating in human RBCs was also isolated from a field mouse (Apodemus speciosus) captured near the donor's residential area. Follow-up surveys over a 1-year period revealed that the donor continued to be asymptomatic but had consistently high immunoglobulin G (IgG) titers in serum and low levels of parasitemia which were microscopically undetectable yet which were repeatedly demonstrable by inoculation into animals. The index case patient's sera contained high titers of IgM and, subsequently, rising titers of IgG antibodies, both of which gradually diminished with the disappearance of the parasitemia. Analysis of the parasite's rRNA gene (rDNA) sequence and immunodominant antigens revealed the similarity between donor and patient isolates. The rodent isolate also had an rDNA sequence that was identical to that of the human isolates but that differed slightly from that of the human isolates by Western blot analysis. We conclude that the index case patient acquired infection by transfusion from a donor who became infected in Japan, that parasitemia in an asymptomatic carrier can persist for more than a year, and that A. speciosus serves as a reservoir of an agent of human babesiosis in Japan.

Animals↗

PubMed2001

Modification of the effects of benzodiazepines on the exploratory behaviors of mice on a hole-board by diabetes.

The effect of diabetes on the emotional behavior of mice was examined using an automatic hole-board apparatus. Changes in the emotional state of mice were evaluated in terms of changes in exploratory activity; i.e., total locomotor activity, numbers and duration of rearing and head-dipping, and latency to the first head-dipping. The number and duration of head-dipping in diabetic mice were less than those in non-diabetic mice. Diazepam (0.1-0.56 mg/kg, i.p.) dose-dependently increased the number and duration of head-dipping at doses that did not produce sedation in both diabetic and non-diabetic mice. In contrast, methyl-beta-carboline-3-carboxylate (1 and 2 mg/kg, i.p.) decreased the number and duration of head-dipping in non-diabetic mice, but not in diabetic mice. The number and duration of head-dipping in diabetic mice were increased by treatment with flumazenil (0.1 and 0.3 mg/kg, i.v.). These doses of flumazenil did not affect the number or duration of head-dipping in non-diabetic mice. The present data indicate that diabetic mice exhibited anxiety in the hole-board test and that a benzodiazepine receptor antagonist affected the attenuated number and duration of head-dipping in diabetic mice. The heightened anxiety in diabetic mice may be due to the dysfunction of the benzodiazepine receptor and/or of central inhibitory systems.

Animals↗

PubMed2001

Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III.

Alpha-glucosidase III, which was different in substrate specificity from honeybee alpha-glucosidases I and II, was purified as an electrophoretically homogeneous protein from honeybees, by salting-out chromatography, DEAE-cellulose, DEAE-Sepharose CL-6B, Bio-Gel P-150, and CM-Toyopearl 650M column chromatographies. The enzyme preparation was confirmed to be a monomeric protein and a glycoprotein containing about 7.4% of carbohydrate. The molecular weight was estimated to approximately 68,000, and the optimum pH was 5.5. The substrate specificity of alpha-glucosidase III was kinetically investigated. The enzyme did not show unusual kinetics, such as the allosteric behaviors observed in alpha-glucosidases I and II, which are monomeric proteins. The enzyme was characterized by the ability to rapidly hydrolyze sucrose, phenyl alpha-glucoside, maltose, and maltotriose, and by extremely high Km for substrates, compared with those of alpha-glucosidases I and II. Especially, maltotriose was hydrolyzed over 3 times as rapidly as maltose. However, maltooligosaccharides of four or more in the degree of polymerization were slowly degraded. The relative rates of the k0 values for maltose, sucrose, p-nitrophenyl alpha-glucoside and maltotriose were estimated to be 100, 527, 281 and 364, and the Km values for these substrates, 11, 30, 13, and 10 mM, respectively. The subsite affinities (Ai's) in the active site were tentatively evaluated from the rate parameters for maltooligosaccharides. In this enzyme, it was peculiar that the Ai value at subsite 3 was larger than that of subsite 1.

Animals↗

PubMed2001

Infectivity and oocyst excretion patterns of Cryptosporidium muris in slightly infected mice.

To determine the infectivity of Cryptosporidium to hosts in slight infections, we examined the infectivity and oocyst output patterns of Cryptosporidium muris in mice inoculated with small numbers of oocysts. One of the 25 ICR mice inoculated with 2.4 x 10(1) oocysts and 19 of the 25 mice inoculated with 2.4 x 10(2) oocysts shed oocysts in the feces after inoculation. Four of the 50 mice inoculated with 2.4 x 10(1) oocysts for 10 consecutive days also shed oocysts and their OPG values were similar to that of the mice which received 2.4 x 10(2) oocysts. Consequently, it is clear that less than 10% of the mice which received 2.4 x 10(1) C. muris oocysts for 10 consecutive days.

Animals↗

PubMed2001

In vitro antibody response to the tetrapeptide repeats of Plasmodium falciparum circumsporozoite protein by splenocytes from mice infected with P. yoelii yoelii.

The antibody response to the recombinant protein, R32tet32, which contained the repetitive sequence (NANP)n of Plasmodium falciparum CSP was determined in C57BL/6 mice during the course of nonlethal infection with Plasmodium yoelii 17X. Marked suppression of the IgG antibody response to R32tet32 occurred when mice were immunized at peak parasitemia (on day 16). In vitro antibody responses of spleen cells from acutely infected mice to R32tet32 were similarly suppressed. Stimulation of normal spleen cells cultured for 5 days with 100 ng/ml of R32tet32 gave an optimal IgG antibody response, but spleen cells from infected mice obtained at peak parasitemia failed to respond to a broad range of antigen concentrations. Cocultivation studies employing enriched lymphocyte populations from infected and uninfected C57BL/6 mice indicated that both T and B cells from infected mice were defective in their response to R32tet32. The response to the repetitive region was restored by the addition of recombinant mouse interleukin-2 (IL-2) at a dose of 50 U/ml to cultures of spleen cells from infected mice.

Animals↗

PubMed2001

Progress toward a malaria vaccine: efficient induction of protective anti-malaria immunity.

Malaria can be a very severe disease, particularly in young children, pregnant women (mostly in primipara), and malaria naïve adults, and currently ranks among the most prevalent infections in tropical and subtropical areas throughout the world. The widespread occurrence and the increased incidence of malaria in many countries, caused by drug-resistant parasites (Plasmodium falciparum and P. vivax) and insecticide-resistant vectors (Anopheles mosquitoes), indicate the need to develop new methods of controlling this disease. Experimental vaccination with irradiated sporozoites can protect animals and humans against the disease, demonstrating the feasibility of developing an effective malaria vaccine. However, developing a universally effective, long lasting vaccine against this parasitic disease has been a difficult task, due to several problems. One difficulty stems from the complexity of the parasite's life cycle. During their life cycle, malaria parasites change their residence within the host, thus avoiding being re-exposed to the same immunological environment. These parasites also possess some distinct antigens, present at different life stages of the parasite, the so-called stage-specific antigens. While some of the stage-specific antigens can induce protective immune responses in the host, these responses are usually genetically restricted, this being another reason for delaying the development of a universally effective vaccine. The stage-specific antigens must be used as immunogens and introduced into the host by using a delivery system that should efficiently induce protective responses against the respective stages. Here we review several research approaches aimed at inducing protective anti-malaria immunity, overcoming the difficulties described above.

Animals↗

PubMed2001

[Estimation of daily dietary intake of aluminum].

The daily dietary intake of aluminum was estimated through a total diet study from 1996 to 1998. In ten institutes, total diet study samples were prepared and their aluminum concentration was determined. The average daily intake of aluminum was 3.5 mg and the range was 1.8-8.4 mg. The validity of the analytical result was supported by analyses of certified reference materials.

Aluminum↗

PubMed2001

[A case of vaginal implantation of transitional cell carcinoma of the bladder].

An 82-year-old female presented with asymptomatic gross hematuria in June 1997. Urethrocystoscopy revealed a multiple papillary tumor of the bladder and posterior urethra. Histology of the punch biopsy specimens of the tumor revealed transitional cell carcinoma (TCC), grade 2 (G2). CT scan showed no distant metastasis and extravesical invasion. The patient was treated by intravesical instillation of adriamycin (ADM), drip infusion of low dose cisplatin (CDDP) and irradiation of the bladder. As the treatment caused a significant tumor shrinkage, transurethral resection of the tumor was performed. Histologically, the tumor revealed no invasion to the muscular layer of the bladder. In April 1998 she noticed genital bleeding, and a multiple papillary tumor was found on the vaginal wall. Histology of punch biopsy specimens of the vaginal tumor showed non-invasive TCC, G2. MRI and specimens of all layer needle biopsy showed no infiltration outside the bladder wall and the vaginal wall. Irradiation of the cavity of the vagina and uterus was made under the diagnosis of superficial vaginal TCC. We assume that vaginal implantation via irrigating fluid or urine has occurred.

Aged↗