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Biomedical subjects

M Tsuji

Publications and source records attributed to M Tsuji.

At least 199 records · Page 11Linked to original sources
PubMed1996

Involvement of GABAB receptor systems in experimental depression: baclofen but not bicuculline exacerbates helplessness in rats.

There are two gamma-aminobutyric acid (GABA) hypotheses of the antidepressants action: an increase in GABAA neurotransmission or a decrease in GABAB neurotransmission may contribute to action of antidepressants. In this study, involvement of GABAA and GABAB receptor systems was examined in the learned helplessness paradigm in rats. Rats were injected with bicuculline or baclofen for 14 days. On day 14, the rats were subjected to 15 inescapable shocks. On day 15, they underwent the 40-trial escape test. Baclofen exacerbated the escape failures in the rats subjected to the inescapable shocks, although baclofen had no effects in the animals without shock pre-treatment. Bicuculline failed to influence the escape failures in the rats with the 15-shock pre-treatment. These results suggest that the long-term increase in GABAB neurotransmission but not the long-term attenuation of GABAA neurotransmission may be related to helplessness in rats.

Animals↗
PubMed1996

Activation of ventral tegmental GABAB receptors inhibits morphine-induced place preference in rats.

The effect of microinjection of a GABAB receptor agonist, baclofen, into the ventral tegmental area on the rewarding effect of morphine was investigated using the conditioned place preference paradigm in rats. Morphine (1-8 mg/kg, s.c.) caused a dose-related place preference for the drug-associated place. In contrast, microinjection of baclofen (0.1-1 nmol/side) into the ventral tegmental area did not produce a significant preference for either compartment of the test box. Pretreatment with baclofen (0.1-1 nmol/side) into the ventral tegmental area dose dependently suppressed the morphine (8 mg/kg, s.c)-induced place preference. This suppression of the morphine (8 mg/kg, s.c.)-induced place preference by baclofen (1 nmol/side), but not with the GABAA receptor antagonist bicuculline (1 nmol/side). The present results suggest that a decrease in GABAB neurotransmission in the ventral tegmental area, which may be produced via inhibition of a tonic GABAergic input by morphine, may be involved in the expression of the rewarding effect of morphine.

Animals↗
PubMed1996

Characterization of in vivo primary and secondary CD8+ T cell responses induced by recombinant influenza and vaccinia viruses.

We characterized the in vivo primary and secondary murine CD8+ T cell responses induced by immunization with influenza and vaccinia viruses, which were engineered to express the same H-2K(k)- and H-2K(d)-restricted epitopes. Our results show that the induction and magnitude of the primary CD8+ T cell response closely depends on the viral dose used for immunization, while it is not affected by the route of immunization. The induction of secondary CD8+ T cell responses appears to be highly restricted, as suggested by the lack of in vivo expansion of antigen-specific CD8+ T cells after repeated immunization with the same virus. In contrast, a 20- to 30-fold increase in the frequency of antigen-specific CD8+ T cells could be induced after combined immunization with recombinant influenza and vaccinia viruses. These findings may provide the basis for the development of new prophylactic and therapeutic strategies to prevent or control intracellular infections and certain malignancies.

Animals↗
PubMed1996

The proliferation index of MIB-1 as a prognostic factor for patients with transitional cell carcinoma of the upper urinary tract.

BACKGROUND: Recently, several reports have shown that immunohistochemical analysis using MIB-1 antibody, which recognizes Ki-67 (a human nuclear antigen expressed of proliferating cells), is a useful method for determining the proliferative activity of various cancers. In this study, the authors evaluated the prognostic usefulness of the proliferation index using MIB-1 antibody in transitional cell carcinoma of the upper urinary tract. METHODS: Proliferation activity was investigated immunohistochemically using monoclonal antibody MIB-1 in formalin fixed, paraffin embedded tissues obtained from 67 specimens of renal pelvic and ureteral cancer. The MIB-1 proliferation index values were calculated from each sample as the percentage of positive nuclei expressed in tumor cells and the clinicopathologic correlation evaluated. RESULTS: The MIB-1 proliferation index values were correlated with prognostic parameters such as pathologic stage ( < or = pT1 vs. > or = pT2, P < 0.0005), histologic grade (G1 vs. G2, P < 0.01; G1 vs. G3, P < 0.0001; G2 vs. G3, P < 0.001), and prognosis (P < 0.0001). When patients were subgrouped using index values, patients with higher indices ( > or = 24%) had significantly poorer survival (P < 0.0001). This was especially observed in the G2 group, in which 9 of 10 patients in the higher indices subgroup had a high incidence of recurrence and died. In contrast, only 2 of 29 patients in the lower indices subgroup died. The higher indices subgroup had significantly worse cause specific survival (P < 0.0001). Furthermore, with regard to the muscle invasive tumors ( > or = pT2), the higher indices subgroup also had significantly worse cause specific survival (P < 0.0001). CONCLUSIONS: The results of the evaluation of prognostic parameters indicate that the MIB-1 proliferation index is a useful prognostic factor and may enhance the accuracy of conventional morphologic grading and pathologic staging systems.

Adult↗
PubMed1996

Involvement of GABAB receptor systems in action of antidepressants. II: Baclofen attenuates the effect of desipramine whereas muscimol has no effect in learned helplessness paradigm in rats.

Involvement of GABAergic systems in action of antidepressants was examined in the learned helplessness paradigm in rats. Rats were treated with desipramine, baclofen or muscimol for 14 days. On day 14, the rats were subjected to 90 inescapable shocks. On day 15, the rats received the 40-trial escape test. The inescapable shocks induced the subsequent increase in escape failures in the escape test. Desipramine dose-dependently improved the increased escape failures induced by the inescapable shocks. Baclofen attenuated the escape failures-improving effect of desipramine, although baclofen had no effects on the increased escape failures when it was injected alone. Muscimol at any dose failed to influence the increased escape failures. Therefore, it is suggested that the long-term decrease in GABAB neurotransmission may be involved in the action of antidepressants. Our present results do not support the hypothesis that activation of GABAA receptors may contribute to the action of antidepressants.

Animals↗
PubMed1996

Expression of c-fos gene inhibits proteoglycan synthesis in transfected chondrocyte.

The effect of expression of c-fos gene on proteoglycan synthesis, one of the important markers of cartilage metabolism, was examined by introducing the c-fos DNA into HCS 2/8 chondrocytes. The [35S]sulfate incorporation into proteoglycan was decreased in the c-fos transfectants expressing exogenous c-fos mRNA, when compared to a control transfectant. A significant increase in transcription of MMP-3 with the suppressed transcription of aggrecan and TIMP-1 were also observed in the c-fos transfectants. Moreover, analysis of the effect of AP-1 proteins on the collagenase and TIMP-1 promoters in gastric carcinoma KKLS cells revealed that c-Fos combined with any of the Jun-related proteins failed to stimulate the TIMP-1 promoter, though collagenase promoter was effectively activated by any Fos/Jun-related protein heterocomplex. These findings indicate that the c-fos expression may govern the cartilage metabolism and hence may play an important role in the pathogenesis of joint destruction in arthritis.

Base Sequence↗
PubMed1996

Plasmodium yoelii: peptide immunization induces protective CD4+ T cells against a previously unrecognized cryptic epitope of the circumsporozoite protein.

In this study we characterized the CD4+ T cell response directed against two distinct epitopes located in the circumsporozoite (CS) protein of Plasmodium yoelii. The immunization of mice with P. yoelii sporozoites induced CD4+ T cells which were mostly directed against one of these peptides, Py-1, previously reported to contain a CD4+ epitope. The CD4+ T cells directed against this immunodominant epitope were mostly of the Th-1 type. Another newly identified peptide, AS44, induced a specific CD4+ T cell response, which was mainly detectable after immunization with the corresponding peptide. Several CD4+ T cell clones, recognizing this epitope, were generated and their lymphokine expression was characterized, as well as their surface markers and their anti-parasite activity in vivo. It was noteworthy that some of these CD4+ T cell clones, which recognize this cryptic epitope and were of different Th subtypes, were shown to have a strong inhibitory effect on the development of liver stages of malaria parasites.

Adoptive Transfer↗
PubMed1996

Anorectal stenosis in a neonate: report of a case and review of the Japanese literature.

We report herein the case of an infant with anorectal stenosis successfully treated by staged surgery. At 1 day of age, the anal orifice showed circumferential stenosis located 5 mm from the anal verge and extending into the anal canal for approximately 1 cm; however, no hypertrophic raphe or bucket handle appearance were observed, and no associated anomalies such as a presacral mass or sacral dysgenesis were found. At 2 days of age, the infant underwent a sigmoid colostomy under the diagnosis of low anorectal stenosis, followed by a successful anorectoplasty, performed through a sacroperineal approach when he was 8 months old. An analysis of 13 other cases of anorectal stenosis from the Japanese literature indicates that this type of malformation should be treated by staged surgery, as an initial colostomy in the neonatal period, followed by anorectoplasty through a sacroperineal approach during infancy.

Anus Diseases↗
PubMed1996

Prolapse of the small intestine through a ruptured vagina caused during sexual intercourse: report of a case.

We report herein the rare case of a 56-year-old woman who suffered vaginal rupture into the peritoneal cavity during sexual intercourse, through which the small intestine prolapsed out from the vaginal opening. The patient had undergone abdominal hysterectomy 4 years earlier. An emergency laparotomy was performed which revealed rupture in the posterior fornix of the vagina and peritonium through which prolapse of the small intestine had occurred. The prolapsed intestine was pulled back into the pelvic cavity, and the vagina and peritonium were repaired. Macroscopically, the operative findings revealed no inflammatory changes or evidence of malignancy in the abdominal cavity. Thus, although rare, a ruptured vagina caused by sexual intercourse should also be considered in the field of surgery, even when a middle-aged woman presents with acute abdominal symptoms without a history of any other traumatic episode.

Coitus↗
PubMed1996

The effects of dopamine D1 and D2 receptor antagonists on the rewarding effects of delta 1 and delta 2 opioid receptor agonists in mice.

The effects of the dopamine D1 antagonist SCH23390 and the D2 antagonist sulpiride on the rewarding effects of delta opioid receptor agonists were examined in mice. Both [D-Pen2, Pen5]enkephalin (DPDPE, 1-15 nmol, ICV), a selective delta 1 opioid receptor agonist, and [D-Ala2]deltorphin II (DELT, 0.5-5 nmol, ICV), a selective delta 2 opioid receptor agonist, produced a dose-dependent place preference in mice. The DPDPE (15 nmol, ICV)-induced place preference was abolished by BNTX (0.5 mg/kg, SC), a delta 1 opioid receptor antagonist, but not by NTB (0.5 mg/kg, SC), a delta 2 opioid receptor antagonist. In contrast, the DELT (5 nmol, ICV)-induced place preference was antagonized by NTB, but not BNTX. Pretreatment with SCH23390 (3 micrograms/kg, SC) abolished the DPDPE-induced place preference, but not affect the DELT-induced place preference. Moreover, pretreatment with sulpiride (40 mg/kg, SC) did not modify the place preference induced by DPDPE or DELT. In the present study, we found that the activation of both central delta 1 and delta 2 opioid receptors produced rewarding effects. Furthermore, these results suggest that the rewarding effects of delta 1 opioid receptor agonist may be produced through activation of the central dopaminergic system, especially dopamine D1 receptors, whereas the rewarding effects of delta 2 opioid receptor agonists may be produced by some other mechanism(s).

Animals↗
PubMed1996

Strangulation ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion.

We treated a patient with a mechanical ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion. Apart from its occurrence postoperatively with laparotomy, strangulation of small intestine into the omentum is very rare, and its occurrence without underlying disease, except in children, has not been documented previously.

Aged↗
PubMed1996

Production of interleukin 10 during malaria caused by lethal and nonlethal variants of Plasmodium yoelii yoelii.

We investigated the induction of T-helper cell subsets during the course of lethal or nonlethal bloodstage Plasmodium yoelii 17X infection in C57BL/6 mice, which are relatively susceptible to these intraerythrocytic parasites. C57BL/6 mice infected with the nonlethal variant (PyNL) showed a moderate level of parasitemia and resolution of primary acute infection by week 4. Mice infected with the lethal variant (PyL) developed fulminating parasitemia and ultimately died. T-helper subset function was assessed during infection by determining the kinetics of in vitro production of the Th1-derived cytokine interferon-gamma (IFN-gamma) and the Th2-derived cytokine interleukin 10 (IL-10) by means of bioassay and enzyme-linked immunosorbent assay (ELISA), respectively. Spleen cells obtained from mice infected with PyL within the 1st week of infection produced high levels of IL-10 and IFN-gamma in response to malaria antigen. IL-10 also appeared in sera from PyL-infected mice at the same time at which the in vitro IL-10 response peaked. In contrast, spleen cells from mice infected with PyNL failed to produce IL-10 during the course of infection. CD4+ T-lymphocytes from mice infected with the lethal variant were a major source of IL-10, although non T-cells were also involved in the production of IL-10 during this malaria infection. In addition, the initial burst of IL-10 in response to malaria antigens was seen concomitantly with the production of IFN-gamma within the 1st week of infection. These results indicate that both Th1 and Th2 subsets of T-helper lymphocytes are activated during infection with the lethal variant of P. yoelii and support the contention of other investigators that a strong Th2 response early in infection is associated with the lethal outcome of malaria.

Animals↗
PubMed1996

The large difference in infectivity for mice of Plasmodium berghei and Plasmodium yoelii sporozoites cannot be correlated with their ability to enter into hepatocytes.

Sporozoites of P. yoelii nigeriensis are 50-100-times more infective to mice than the strain NK65 of P. berghei. To study the mechanisms involved in this striking difference in the infectivity of these closely related species of malaria parasites, we have developed a quantitative PCR targeted to parasite-specific ribosomal RNA. Using this method, we detect RNA from a single sporozoite, and exo-erythorcytic forms of RNA in the livers of mice injected with 200 sporozoites. We find that 20 h after sporozoite injection, there is no significant difference between the amounts of P. berghei and P. yoelii rRNA in the livers of C57/BL6 mice, indicating that these two parasite species invade hepatocytes with similar efficiency. Between 20 and 40 h, however, P. yoelii RNA increases 11 times, while P. berghei RNA increases only 1.6 times. We conclude that the greater infectivity of P. yoelii sporozoites in these mice reflects, at least in part, their superior development in hepatocytes. These data provide for the first time in vivo evidence supporting the notion that species-specificity of malaria is not determined by mechanisms associated with sporozoite attachment and penetration into the hepatocytes.

Animals↗
PubMed1996

Reduced hydrogen peroxide production in neutrophils from patients with diabetes.

We evaluated the effects of granulocyte colony-stimulating factors (G-CSF), granulocyte-macrophage colony-stimulating factors (GM-CSF) and phorbol myristate acetate (PMA) on H2O2 production in purified neutrophils from patients with diabetes mellitus (DM), using flow cytometry. Twenty-two age-matched male subjects were selected: 11 were normal volunteers and the remainder had DM. No significant differences in intracellular H2O2 production per 60 min was observed in the "resting' neutrophils from DM patients (37.2 +/- 20.4 A.U.) compared with those from normal volunteers (24.9 +/- 8.4 A.U.). The PMA-stimulated neutrophils from normal volunteers generated approximately 4-fold increases in H2O2 per 60 min compared with those from DM patients. Under similar culture conditions, G-CSF caused 1.6-fold increases of H2O2 in neutrophils from normal volunteers compared with those of DM patients. Increases after GM-CSF stimulation were 2-fold higher in volunteer neutrophils compared with those from DM patients. The levels of G-CSF- or GM-CSF-stimulated H2O2 production in neutrophils from DM patients were low and were little different from non-stimulated resting cells. These data showed that H2O2 production in neutrophils induced by PMA is impaired in patients with DM, and neither G-CSF nor GM-CSF enhances its production.

Adult↗
PubMed1996

A mouse model for cerebral babesiosis.

Clinical symptoms and pathology observed in the cattle infected with Babesia bovis are quite similar to those of human cerebral malaria. Mechanisms involved in the pathogenesis of cerebral babesiosis, however, are still poorly understood because of the lack of a suitable experimental animal model. In this report, Masayoshi Tsuji and his colleagues describe B. bovis infection in severe combined immunodeficiency (SCID) mice, whose circulating red blood cells (RBCs) have been substituted with bovine RBCs (Bo-RBC-SCID mice). The infected mice not only develop a substantial level of parasitemia, but also show nerve symptoms and pathology similar to those observed in infected cattle.

Journal Article↗
PubMed1996

Attenuation of Eimeria caviae by selection for precocious development.

An attenuated line of Eimeria caviae was produced by selection for early maturation of oocysts during serial passage in guinea pigs. The prepatent period of the parasite was reduced from 11 to 6 days. Parasites of the precocious line and the parent strain were found in the crypts of the epithelial cells of caecum and colon and were morphologically indistinguishable. The period of development of type I, type II and type III merozoites of the E. caviae precocious line in guinea pigs was similar to that of the parent strain until the 3rd day. The time of the transition from gametocytes to oocysts was 2 days in both the precocious line and the parent strain. The maximum number of oocysts per gram of faeces and the pathogenicity of the precocious line were less than those of the parent strain.

Aging↗
PubMed1996

Phenotypic and functional properties of murine gamma delta T cell clones derived from malaria immunized, alpha beta T cell-deficient mice.

Six murine T cell clones expressing gamma delta TCR were generated from malaria immunized, alpha beta T cell-deficient mice. Phenotypic characterization of these clones has revealed that, in contrast to conventional alpha beta T cells, there is a considerable degree of heterogeneity among these gamma delta clones with regard to their surface markers and their lymphokine profile. One clone was found to display significant anti-parasite activity in vivo upon adoptive transfer. We attempted to determine whether the protective clone differs in one or more key characteristics from the non-protective clones. Although no obvious pattern peculiar to the protective gamma delta clone was observed, it appears that more than one parameter may, in combination, define a distinct protective phenotype, and thus explain the functional difference between the protective and non-protective gamma delta clones.

Animals↗