Search PubMed⌕ Search

Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 631 records · Page 35Linked to original sources
PubMed1996

[Primary Non-Hodgkin's lymphoma in the chest wall without preceding disease].

An 80-year-old man was admitted to our hospital with complaints of left-sided chest pain and swelling. A chest roentgenogram revealed a left chest-wall mass. Examination of a biopsy specimen of the mass led to the diagnosis of Non-Hodgkin's lymphoma of diffuse mixed-cell type. Immunohistological examination revealed that it was B-cell type. The chest-wall mass was markedly smaller after radiation therapy, and the patient had a complete remission. About 1 year and 10 months later, Non-Hodgkin's lymphoma developed in the right femur. Combination chemotherapy (cyclophosphamide, adriamycin, vincristine, and prednisolone) and radiation therapy were given. The patient went into a complete remission, and is alive at the time of this writing, 2 years and 6 months after he was first treated. Almost all malignant lymphomas of the chest wall arise in cases of chronic tuberculous pyothorax or tuberculous pleuritis, but in this case there was no preceding disease. When the chest roentgenogram shows a chest-wall mass, we must consider the possibility of malignant lymphoma, even if there is no preceding disease.

Aged↗
PubMed1996

[The evaluation of three dimensional image distortion of helical scanning CT].

We developed a computer algorithm to simulate distortion in the three-dimensional (3D) displays obtained by helical scanning. The algorithm constitutes calculation of the image profile in the longitudinal direction, which is assumed to be a convolution of the object function with the slice sensitivity profile (SSP) of helical scanning. Experiments were performed to examine the algorithm for its validity with the use of a K2HPO4 phantom. Simulated results and measurements was in a good agreement. The distortion was investigated by the computer simulation. The model simulated was a high density object (Ol) surrounded by low density tissue (Os). The helical interpolation used was 360-degree linear interpolation. Two parameters were defined: delta Lz, which is the difference in length between the 3D image and the actual object Ol in the longitudinal direction, and the cut level index (CLI), which is defined as CLI = (Cut Level CT Number-CT Number of Os)/(CT Number of OI-CT Number of Os). We found that magnitude of delta Lz increased depending on the table feed distance per 360-degree scan (Dt). When Ol was twice as long as Dt, delta Lz directly depended on CLI, but was independent of Ol length. When Ol length was longer than Dt, delta Lz was shown to be 0 at CLI not equal to 0.5 at every Dt. When Ol was shorter than Dt, delta Lz decreased remarkably depending on the length of Ol in higher CLI. The simulations, with the use of a newly developed algorithm, were demonstrated to be useful for evaluating the amount of distortion and for better understanding the characteristics of 3D displays of helical scanning.

Algorithms↗
PubMed1996

Antioxidants inhibit tumor necrosis factor-alpha mediated stimulation of interleukin-8, monocyte chemoattractant protein-1, and collagenase expression in cultured human synovial cells.

OBJECTIVE: To study whether the induction of mRNA for interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), and collagenase by tumor necrosis factor-alpha (TNF-alpha) is suppressed by antioxidants in human synovial cells. TNF-alpha has been shown to exert some of its effects by stimulating production of reactive oxygen intermediates in some cell lines other than synovial cells. METHODS: Amounts of mRNA for IL-8, MCP-1, and collagenase were determined by Northern blot analysis. Electrophoretic mobility shift assays were performed for the detection of a transcription factor, nuclear factor-kappa B(NF-kappa B). The concentration of IL-8 in the medium was determined by ELISA. RESULTS: TNF-alpha increased the expression of IL-8, MCP-1, and collagenase mRNA in human synovial cells. NF-KB known to induce IL-8 gene transcription was also increased in nuclear extracts from the synovial cells treated with TNF-alpha. Prior addition of antioxidant, N-acetyl-L-cysteine (NAC) or 2-oxothiazolidine-4-carboxylate (OTC), suppressed TNF-alpha stimulated expressions of IL-8, MCP-1, and collagenase mRNA in a dose dependent manner. Treatment with NAC also suppressed TNF-alpha induced increase in NF-kappa B. The changes of IL-8 in the medium reflected the mRNA levels. Hydrogen peroxide (H2O2) induced the expression of mRNA for the cytokines but not collagenase mRNA, and NAC suppressed the effect of H2O2. CONCLUSION: Our data suggest that TNF-alpha induces expression of proinflammatory cytokines such as IL-8 and MCP-1 through generation of reactive oxygen intermediates and subsequent activation of NF-kappa B in human synovial cells, and the antioxidants may inhibit, at least in part, the activation of NF-kappa B by TNF-alpha. These results indicate that antioxidants such as NAC may be useful in treating rheumatoid arthritis.

Acetylcysteine↗
PubMed1996

A change in the localization of the region trapping immune complexes in rat popliteal lymph nodes during development of germinal centers, with regard to the distribution of follicular dendritic cells.

A study was conducted to clarify changes in the relationship between the region of immune complex (IC) trapping by follicular dendritic cells (FDCs) and the distribution of FDC during reaction of germinal centers (GCs), and to examine the relationship between the tridimensional shape of the IC-trapping regions and their two-dimensional shape. Five-week-old rats were given footpad injections of sheep red blood cells, and then their popliteal lymph nodes were excised between days 0 and 42, 24 h after injection of peroxidase-antiperoxidase complex (PAP) as an IC. The specimens were immunostained for PAP trapping on serial paraffin sections, and for S-100 protein as a marker of FDCs. It was found that during the GC reaction, PAP trapping became weak and then disappeared on the basal side of developing GCs where S-100 protein-positive FDCs were still present. All of the 1933 lymph follicles examined were found to trap PAP. Whereas the tridimensional shapes of the trapping regions showed similar patterns according to the development of lymph follicles, their two-dimensional shapes varied. We suggest that FDCs in primary follicles may differentiate into FDCs in the light zone and FDCs in the dark zone in secondary follicles. To evaluate each of the compartments of a lymph follicle more accurately, investigators should pay attention to the tridimensional shape of the compartment.

Animals↗
PubMed1996

Antitumor activities of combined treatment with a novel immunomodulator, (2S,3S,4R)-1-O-(alpha-D-Galactopyranosyl)-2-(N-Hexacosanoylamino)-1,3,4 - octadecanetriol (KRN7000), and radiotherapy in tumor-bearing mice.

The novel immunomodulator (2S,3S,4R)-I-O-(alpha-D-galactopyranosyl)-2- (N-hexacosanoylamino)-1,3,4-octadecanetriol (KRN7000) in combination with high-dose (20 and 30 Gy) local x-ray irradiation or low-dose (3 Gy) fractionated whole-body irradiation showed significantly stronger antitumor activities against Meth A-and Colon26-bearing mice than treatments by radiation or KRN7000 alone, and 60% of mice in combination treatment groups were cured. Furthermore, the results of tests rechallenging the cured mice with Meth A and Colon26 cells strongly suggested that tumor-specific immunity was induced by the combination treatment. The suggestion was supported by the result that the systemic administration of KRN7000 could produce large amounts of interleukin-2 and interferon-gamma, which contribute to induction of tumor-specific cytotoxic lymphocytes not only in normal mice but also in whole-body irradiated mice. Furthermore, it was also suggested that KRN7000 contributes to protecting antitumor effector cells, such as natural killer cells, from impairments caused by radiation. Taking together the results and the knowledge that tumor-specific cytotoxic lymphocytes play a critical role in prevention of tumor recurrence and distant metastasis, it is strongly suggested that combined therapy with KRN7000 and radiation could be quite useful for cancer treatment.

Adjuvants, Immunologic↗
PubMed1996

[Allergic granulomatous angiitis in a patient with positive reactions on serological tests for parasite antigens].

A 68-year-old woman with bronchial asthma complained of fever, right thigh pain, sensory disturbance at the tips of the upper and lower limbs, and abdominal pain. She had severe eosinophilia and radiologic examination showed a mass-like shadow in the left lower lobe of the lung. Allergic granulomatous angiitis was diagnosed on the basis of findings from a muscle biopsy (gangrenous vasculitis with eosinophilia). This patient also had positive results of serological tests (Ouchterlony method) for various parasite antigens, despite the fact that no eggs of parasites were found in her feces. After steroid administration, the serological reactivity to parasite antigens had decreased. The positive reactions to parasite antigens was probably related to the cause of the vasculitis.

Aged↗
PubMed1996

5-Lipoxygenase inhibitory and antihistamine activities of linetastine.

The ability of linetastine (TMK688, 1-[¿5'-(3"-methoxy-4"-ethoxycarbonyloxyphenyl)-2',4'-pentadieno yl¿ aminoethyl]-4-diphenylmethoxypiperidine, CAS 110501-66-1) to inhibit leukotriene production and to antagonize the effect of histamine was examined in comparison with the ability of azelastine, an antiallergic drug having an antihistamine activity. Linetastine and its active metabolite TMK777 (1-[¿5'-(3"-methoxy-4"-hydroxyphenyl)-2',4'-pentadienoyl¿ aminoethyl]-4-diphenylmethoxypiperidine, CAS 101619-11-8) inhibited the release of leukotrienes B4 and C4 from calcium ionophore-stimulated human leukocytes. The respective IC50 values of leukotriene B4 were 1.2 x 10(-7) mol/l and 8.6 x 10(-8) mol/l, and those of leukotriene C4 were 1.5 x 10(-7) mol/l and 7.1 x 10(-8) mol/l. Azelastine also inhibited the release of leukotriene B4 and C4, but its IC50 values were higher than 1 x 10(-5) mol/l. Linetastine at 1-10 mg/kg p.o. inhibited the increase in leukotriene B4 and C4 production in the lungs during late asthmatic responses in actively sensitized guinea-pigs. The effect of 3.2 mg/kg lasted for more than 16 b. Since repeated oral administration of linetastine, 1 mg/kg once a day for 7 successive days, showed the same inhibitory effect on the increase in respiratory resistance and the leukotriene production as single oral administration, the effect of linetastine was neither tachyphylactic nor cumulative. Azelastine at 10 mg/kg had no effect on the leukotriene production. Linetastine TMK777 and azelastine dose-dependently inhibited the histamine-induced contraction of isolated guinea-pig trachea in a noncompetitive manner, the respective pD2 values were 7.28, 7.98 and 8.07. Linetastine inhibited histamine-induced bronchoconstriction dose-dependently at 1-10 mg/kg (p.o.) in guinea-pigs, and the effect lasted for more than 24 h. Repeated oral administration of linetastine, 0.32 to 3.2 mg/kg once a day for 7 successive days inhibited the histamine-induced bronchoconstriction, the same as single oral dosing. Azelastine at 0.32 mg/kg p.o. also showed antihistamine activity. In conclusion, linetastine inhibits both the production of leukotrienes and the effect of histamine at almost the same dose and the effects were long lasting.

Animals↗
PubMed1996

Regional difference in cerebral blood flow and oxidative metabolism in human cortex.

UNLABELLED: We sought to determine if there are regional differences in cerebral blood flow (CBF) and cerebral metabolic ratio for oxygen (CMRO2) in normal subjects during the resting state. METHODS: Regional CBF, CMRO2 and oxygen extraction fraction (OEF) in 15 normal volunteers (mean age 58.8 +/- 8.2 yr) were measured during rest using PET and a 15O-gas steady-state technique. RESULTS: CBF and CMRO2 in the visual cortex were significantly higher than those in other cortices. Additionally, OEF in the sensorimotor cortex was significantly lower than that in other cortical regions. CONCLUSION: CBF and CMRO2 in the visual cortex are always high, and low OEF in the sensorimotor cortex exists even in resting state in normal subjects. We hypothesize that these regional functional differences would result in different resistances to degeneration.

Brain↗
PubMed1996

Increased population of high fluorescence 1F7 (CD26) antigen on T cells in synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: To investigate the activation of T cells in peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA). METHODS: The expression of CD26 (Ta1 and 1F7) antigen on T cells was analyzed in 7 women with RA and 7 healthy control subjects by immunofluorescence. RESULTS: The percentage of CD3+ CD26+ cells was significantly higher in PB of patients with RA compared with healthy subjects. The IF7+ cell population was divided into high (1F7+high cells) and low fluorescence populations (1F7+low cells), based on 1F7 antigen density. The percentage of 1F7+high cells in SF of RA was markedly increased compared with PB of patients and healthy subjects. However, RA SF contained lower percentages of whole 1F7+ cells compared with PB. CONCLUSION: Our results indicate that SF of patients with RA contains activated T cells, and suggest that T cells with high levels of CD26 antigen may preferentially migrate into the rheumatoid synovium to induce inflammation and tissue destruction.

Adult↗
PubMed1996

Enhancing effects of (2S,3S,4R)-1-O-(alpha-D-galactopyranosyl)-2-(N-hexacosanoylamino) -1,3,4-octadecanetriol (KRN7000) on antigen-presenting function of antigen-presenting cells and antimetastatic activity of KRN7000-pretreated antigen-presenting cells.

(2S,3S,4R)-1-O-(alpha-D-galactopyranosyl)-2-(N-hexacosanoylamino)- 1,3, 4-octadecanetriol (KRN7000), with an alpha-galactosylceramide structure, is an immunomodulator showing potent antimetastatic activities. In an in vitro study, KRN7000 potently stimulated proliferation and enhanced natural killer activity in spleen cells from BALB/c euthymic mice, but not BALB/c athymic (nu/nu) mice, suggesting that T cells play an important role in these activities. To study the detailed immunostimulatory mechanisms of KRN7000, syngeneic mixed leukocyte reactions were then performed using dendritic cell-enriched fractions (DCEFs) from spleens of BALB/c euthymic and athymic mice. In these studies, KRN7000 enhanced the antigen-presenting cell activities of the DCEFs. In addition, marked production of interleukin-2 and interferon-gamma in BALB/c euthymic mice was observed following treatment with KRN7000 in vitro and in vivo. Because of these strong immunostimulating effects of KRN7000, its antimetastatic effects were also evaluated. Adoptively transferred KRN7000-treated DCEF markedly prolonged the survival time of mice bearing B16 pulmonary metastases. These results demonstrate that KRN7000 may be useful for cancer therapy not only as an antitumor agent but also as an activator of antigen-presenting cells such as dendritic cells, which can be used for adoptive cellular therapy.

Adjuvants, Immunologic↗
PubMed1995

Prognostic value of plasma soluble intercellular adhesion molecule-1 and endothelin-1 concentration in patients with chronic congestive heart failure.

We tested the hypothesis that plasma endothelin-1 (ET-1) and soluble intercellular adhesion molecule-1 (sICAM-1) in patients with congestive heart failure (CHF) are related to subsequent survival, and assessed whether the measurements of these substances provide additional prognostic information to that obtained from clinical and biochemical variables previously known to be associated with high mortality. Plasma levels of sICAM-1 and ET-1 were measured in 102 patients with CHF (left ventricular ejection fraction [LVEF] < 0.45), and patients were followed up for > 18 months. The plasma level of sICAM-1 increased with the severity of CHF (normal, 149 +/- 10 ng/ml, mild CHF [New York Heart Association functional class II], 207 +/- 9.4 ng/ml, severe CHF [functional class III or IV], 293 +/- 18 ng/ml). The plasma level of ET-1 also increased with the severity of CHF (normal, 1.5 +/- 0.2 pg/ml, mild CHF, 2.1 +/- 0.1 pg/ml, severe CHF, 4.0 +/- 0.4 pg/ml). Plasma levels of both sICAM-1 and ET-1 decreased after treatment in 14 patients, with improvements in symptoms (from functional class IV to II) during the follow-up period. There was a significant positive correlation between the plasma level of ET-1 and plasma sICAM-1 (r = 0.44, p < 0.001). A significant negative correlation was observed between LVEF and plasma ET-1 (r = -0.34, p < 0.001), and plasma sICAM-1 (r = -0.36, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Relationship between susceptibility to apoptosis and Fas expression in peripheral blood T cells from uremic patients: a possible mechanism for lymphopenia in chronic renal failure.

Chronic renal failure (CRF) is often complicated by lymphopenia, which may be partly responsible for immune deficiency. We hypothesized that lymphopenia in CRF might result from apoptosis of T cells in vivo. To elucidate the involvement of Fas antigen which mediates apoptosis, we analyzed Fas expression on peripheral blood T cells in uremic non-dialyzed (non-HD) patients and hemodialysis (HD) patients. T cells from both uremic groups expressed Fas with higher intensity than control T cells. When two uremic groups were compared, Fas intensity on T cells was significantly higher in non-HD patients than in patients on HD. Moreover, uremic T cells were shown to undergo accelerated apoptosis when cultured in vitro, in correlation with Fas expression. Our results suggest that T cells in CRF may undergo apoptosis by the Fas system and that hemodialysis treatment has beneficial effects in the light of the inhibition of T cell apoptosis.

Apoptosis↗
PubMed1995

Gamma delta T cells play an important role in hsp65 expression and in acquiring protective immune responses against infection with Toxoplasma gondii.

Previously, we reported that the expression of hsp65 within and on host macrophages correlates closely with protection against infection with Toxoplasma gondii in mice. Herein, we propose that gamma delta T cells play a crucial role in the induction of hsp65 and also in the protective immune response to T. gondii. Intraperitoneal inoculation with this protozoan resulted in hsp65 being expressed on and in host peritoneal macrophages and resulted in an increase of T cells bearing the gamma delta receptor with Thy-1+ and Thy-1- phenotypes in the peritoneal cavity and spleen. When mice were depleted of gamma delta T cells by the administration of a mAb, hsp65 expression was markedly decreased. In contrast, the expression of this protein was rather enhanced and gamma delta T cells were prominently expanded in mice depleted of alpha beta T cells. The protection in mice treated with the mAb paralleled the magnitude of hsp65 expression. Mice depleted of gamma delta T cells died most frequently in the early stages of infection, whereas most of those depleted of alpha beta T cells survived the early stages of lethal infection with T. gondii. However, the latter group of mice did not definitely control the T. gondii infection in its late stages. IFN-gamma was not essential for either the expression of hsp65 or the resistance induced by gamma delta T cells, as demonstrated in mice treated with mAb to murine IFN-gamma. These findings indicated that gamma delta T cells having both the Thy-1+ and Thy-1- phenotypes contribute to hsp65 expression within and on macrophages in an IFN-gamma-independent manner. This, in turn, plays a role in the development of protective immunity during the early stage of this parasitic infection.

Animals↗
PubMed1995

Comparison of hemodynamic effects and plasma cyclic guanosine monophosphate of nicorandil and nitroglycerin in patients with congestive heart failure.

Hemodynamic tolerance has been observed within several hours of continuous infusion of nitroglycerin (NTG). We examined the hemodynamic parameters as well as femoral arterial and venous cyclic guanosine monophosphate (cGMP) concentrations during intravenous infusion of NTG or nicorandil, a nitrate and potassium channel opener, in patients with congestive heart failure. Doses of NTG or nicorandil were titrated to achieve a > or = 25% reduction in pulmonary capillary wedge pressure (PCWP) within 1 hour, and the infusion was maintained at a constant rate for 24 hours. The reduction in PCWP and mean arterial blood pressure was identical after a 1-hour infusion of either NTG or nicorandil. In the NTG group, PCWP and mean blood pressure were not significantly different from the baseline value at 12 hours, but in the nicorandil group PCWP and mean blood pressure remained significantly lower than the preinfusion value for 24 hours. The cGMP production with NTG (assessed by the difference between the plasma arterial and venous cGMP level) paralleled the changes in PCWP, suggesting that the plasma arteriovenous cGMP difference is a biochemical indicator of nitrate tolerance. Although the sustained decrease in PCWP was observed in the nicorandil group, cGMP production with nicorandil was also attenuated at 24 hours of continuous infusion. These findings suggest that the absence of the hemodynamic tolerance of nicorandil, a nitrate and potassium channel opener, is likely due to its action as a potassium channel opener, and not to its nitrate activity.

Adult↗
PubMed1995

The C/EBP site in the feline immunodeficiency virus (FIV) long terminal repeat (LTR) is necessary for its efficient replication and is also involved in the inhibition of FIV LTR-directed gene expression by pseudorabies virus ICP4.

We investigated effects of site-specific mutation of the putative C/EBP binding site in the feline immunodeficiency virus (FIV) long terminal repeat (LTR) on the basal promoter activity in Crandell feline kidney (CRFK) cells and on replication efficiency in CRFK cells and a T-lymphoblastoid cell line, MYA-1 cells. Mutation of the C/EBP site reduced the basal promoter activity in CRFK cells and prevented efficient FIV replication in both CRFK and MYA-1 cells. Gel-mobility-shift assay using nuclear extracts from CRFK and MYA-1 cells revealed that the nuclear factor(s) actually binds to the C/EBP site, but there was a clear difference in the binding patterns to the C/EBP site between CRFK and MYA-1 cell nuclear proteins. Furthermore, we demonstrated that the C/EBP site is necessary for inhibition of FIV LTR-directed gene expression by pseudorabies virus (PRV) ICP4. The C/EBP site is sufficient to confer inhibitory effect by PRV ICP4 on heterologous promoters. These data suggest that the C/EBP site in the FIV LTR is important for the positive regulation of FIV gene expression and replication and is also required for the negative regulation of FIV gene expression by PRV ICP4.

Animals↗