Search PubMed⌕ Search

Biomedical subjects

M Sasada

Publications and source records attributed to M Sasada.

At least 37 records · Page 2Linked to original sources
PubMed1997

Demonstration of functionally distinct human polymorphonuclear leukocyte fractions by simultaneous measurement of phagocytosis and oxygen radical generation.

Phagocytosis and oxygen radical generation by human polymorphonuclear leukocytes (PMNLs) were studied by a two-color flow cytometric analysis, where the red fluorescent product(s) of hydroethidine was used as an indicator of intracellular generation of oxygen radicals and opsonized zymosan (OZ) as an indicator of phagocytosis. Unstimulated cells formed a single population of cells without any significant fluorescence. PMNLs stimulated by OZ exhibited a high red fluorescence. Most PMNLs phagocytosed OZ and generated oxygen radicals when stimulated by zymosan particles opsonized with human AB serum at concentrations of more than 10%, whereas three distinct subpopulations (designated as R1, R2 and R3) appeared when stimulated by zymosan particles opsonized with 3% serum; R1 cells enhanced neither green nor red fluorescence, R2 cells enhanced green fluorescence but not red fluorescence, and R3 cells enhanced both green and red fluorescence. The R2 cells completely disappeared by the addition of Trypan blue. Most of the R3 cells disappeared by the addition of cytochalasin B. These findings on the three fractions were confirmed by the observation under fluorescence microscopy of cells in each fraction obtained by sorting. In conclusion, PMNLs could be separated into three functionally distinct subpopulations when stimulated by zymosan particles opsonized with a suboptimal concentration of serum.

Cell Differentiation↗
PubMed1997

[Clinical efficacy of lomefloxacin for associated infection in patients with hematological diseases].

We have studied the clinical effect of lomefloxacin (LFLX) for the documented infections in the patients with hematological disorders, and also analyzed the prophylactic usefulness of LFLX for the prevention of succeeding infection after the chemotherapy. Fifty five patients were entered in the trial, and 51 patients were eligible. Among 51 eligible patients, 40 patients were suffered from accompanied infections, and 11 patients were registered for the prophylaxis of the infection. In the group of documented infection, the ratio of out-patients was 62.5%, and 63.0% in prophylactic usage. In the treatment of the documented infection, LFLX was effective in 20 patients; the efficacy rate was 50.0%. In the prophylactic administration, LFLX was effective in 9 patients, yielded the efficacy rate of 81.8%. LFLX was effective for all 5 patients with urinary tract infection, in 10 out of 18 patients with respiratory tract infection (efficacy rate; 55.6%), in 5 out of 12 patients with fever from undetermined origin (41.7%), showed no effect for cholecystitis, colitis, and phlegmon. Bacteriological examinations revealed that all of the bacteria detected as pathogens were eradicated. The efficacy rate in the group of the malignant disorders such as leukemia/ lymphoma was smaller than that of non-tumorigenic diseases as aplastic anemia. As myelodysplastic syndrome (MDS), four infection-bearing patients and five patients with prophylactic usage were analyzed. The efficacy rate of LFLX was 50.0 and 80.0%, respectively, and the overall efficacy rate was 66.7%. All MDS patients without prophylactic administration failed to have infections. Thus, LFLX was thought to be useful in the prevention of succeeding infections after the chemotherapy. No clinical and laboratory adverse reactions were reported.

Adolescent↗
PubMed1997

Interleukin-12 gene expression in human monocyte-derived macrophages stimulated with Mycobacterium bovis BCG: cytokine regulation and effect of NK cells.

Macrophage-derived interleukin-12 (IL-12) is essential for the activation of a protective immune response against intracellular pathogens. In this study, we examined the regulation of IL-12 mRNA expression by monocyte-derived macrophages (MDM) in response to Mycobacterium bovis BCG stimulation. A reverse transcription-PCR assay detected p40 mRNA of IL-12 at 3 h and showed a peak at 6 to 12 h with a subsequent decline. Semiquantitation of mRNA levels by competitive PCR revealed that pretreatment with gamma interferon (IFN-gamma) amplified the expression approximately 100-fold, while pretreatment with tumor necrosis factor alpha (TNF-alpha) or granulocyte-macrophage colony-stimulating factor augmented this expression about 10-fold. In contrast, pretreatment with IL-10 and IL-4 inhibited IL-12 mRNA expression. These results were further confirmed by measuring the p70 bioactive protein level in each conditioned medium by an enzyme-linked immunosorbent assay. Since IL-12 mRNA expression was weak without cytokine pretreatment and IFN-gamma strongly augmented production, we speculated that IFN-gamma might have a role in BCG stimulation of IL-12 mRNA expression. Unexpectedly, the addition of three different kinds of anti-IFN-gamma antibodies and anti-IFN-gamma receptor antibody and the coaddition of anti-TNF-alpha antibody with anti-IFN-gamma receptor antibody all failed to inhibit IL-12 mRNA expression. However, the MiniMACS method used to remove NK cells from a mononuclear cell suspension inhibited the expression of p40 mRNA but not the expression of mRNA of TNF-alpha or IL-1beta. We concluded that the coexistence of NK cells was essential for the induction of IL-12 in MDM stimulated with BCG rather than through the secretion of IFN-gamma.

Cytokines↗
PubMed1996

Diamide primes neutrophils for enhanced release of superoxide anion: relationship to S-thiolation of cellular proteins.

Stimulation of the respiratory burst in phagocytes induces the formation of mixed disulfides between sulfhydryl groups of proteins and low-molecular-weight thiols. We hypothesized that this process (S-thiolation) might be involved in turning off the respiratory burst. However, induction of S-thiolation by pretreatment of neutrophils with diamide, a direct thiol oxidizing agent, actually primed the cells for a two- to fivefold increase in total release and fourfold increase in rate of release of 02- on stimulation by f-Met-Leu-Phe. Generation of intracellular oxidants (hydroethidine fluorescence) was increased ninefold. Priming and S-thiolation were apparent at 1 min of incubation and peaked at 5-10 min. Diamide pretreatment also reduced the lag time between addition of phorbol diester and release of 02- by a mean of 23 s (41%). Dithioerythritol, a sulfhydryl-reducing agent, abolished both the S-thiolation and priming mediated by diamide. H202 also induced priming and S-thiolation; and these were eliminated by dithioerythritol. In contrast to the effect of endotoxin, diamide priming did not affect Ca2+ homeostasis of the neutrophils. Diamide did not significantly alter NADPH oxidase activity in a cell-free system. These findings suggest that sulfhydryl groups on one or more proteins play an important role in modulating the respiratory burst.

Blood Proteins↗
PubMed1995

[Effect of a combination treatment using imipenem/cilastatin sodium with G-CSF on infections in neutropenic patients with hematological malignancies].

The clinical effectiveness of a combination treatment using imipenem/cilastatin sodium (IPM/CS) with G-CSF was studied in neutropenic patients (< 500/mm3) with hematological malignancies and secondary infections. Thirty seven patients were entered in the trial, and 30 patients were eligible. This combination was effective in 20 patients, thus the overall efficacy rate was 66.7 percent. The combination was effective in all 6 cases with septicemia, in 10 case out of 15 cases with fever after chemotherapy (efficacy rate; 66.7%), in 3 out of 8 cases with respiratory infections including 7 cases with pneumonia (efficacy rate; 37.5%), and a case with laryngopharyngitis. According to the order of the administration, the efficacy rates were 60.0% in 5 cases in whom G-CSF treatment was started before IPM/CS, 66.7% in 21 cases given both G-CSF and IPM/CS simultaneously, and 75.0% in 4 cases in whom IPM/CS was started before G-CSF. The difference was statistically not significant on the efficacy rates in the three groups. The efficacy in 18 cases treated with monotherapy on antibiotic was 72.2% and that in 12 cases treated with IPM/CS in combination with other antibiotics was 58.3%, and the difference in the efficacy rates in these two groups was not statistically significant. According to the neutrophil counts before and after the treatment, high response rate (60.0%) was obtained in cases of severe neutropenia (less than 100/mm3). Bacteriological examinations showed that all of bacteria detected as pathogens (10 strains of Gram-positive bacteria and 6 strains of Gram-negative bacteria) were eradicated, though 3 strains were replaced by other pathogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Mechanism of leukemic cell lysis by activated human macrophages: leukemic cells can be lysed without direct contact.

We recently reported that human macrophages effectively destroyed leukemic cells. In this study, we investigated the mechanism of leukemic cell lysis by human macrophages. Human peripheral blood monocyte-derived macrophages were activated with interferon-gamma and lipopolysaccharide. Activated macrophages exhibited lytic activity against leukemic cells (K562 and HL-60 cells) by cocultivation. When macrophages and these leukemic cells were separated by a microporous membrane, activated macrophages did not show any lytic activity against these leukemic cells. However, activated macrophages interacting with leukemic cells under the microporous membrane exhibited lytic activity against leukemic cells that were placed on the microporous membrane. Different kinds of leukemic cells were also effective to induce such lytic activity in the macrophages, but normal lymphocytes could not. Culture supernatants of activated macrophages incubated with leukemic cells did not have cytolytic activity against leukemic cells. The leukemic cells used in this study were confirmed to be resistant to tumor necrosis factor (TNF), but the activated macrophage-mediated cytolytic activity was significantly inhibited by the anti-TNF antibody. These findings suggested that the contact between macrophages and leukemic cells triggered the secretion of lytic factor(s), and that TNF and other labile factor(s) co-operatively functioned to lyse leukemic cells.

Cytotoxicity, Immunologic↗
PubMed1994

[Analysis of platelet-derived factors that modulate functions of polymorphonuclear leukocytes].

Interactions between platelets and polymorphonuclear leukocytes (PMN) modulate their functions and play a role in the development of pathogenesis of some disease. Platelets secret various kinds of factors that affect PMN functions. They seemed to have important role in vivo, but little has been elucidated on exact mechanism of action and physiological meaning of each factor in relation to PMN functions. We studied the effects of platelets and released substances from activated platelets on the functions of PMN. Results were as follows. 1) Platelets enhanced bactericidal activities of PMN against E.coli. 2) Platelets had effects on the generation of superoxide anion (O2-) of PMN. Their effects were quite different according to the assay condition of PMN, that is, platelets inhibited O2- generation when PMN were at rest or stimulated slightly and they enhanced O2-generation of PMN that were stimulated with optimal condition. 3) Thrombin-activated platelets and their supernatant elicited a transient elevation of [Ca2] of PMN. The activity of the supernatant decreased by treating with hexokinase that decomposed ATP. Further treatment with trypsin abolished its activity almost completely. Considering with our additional experiments, factors that induced [Ca2+] elevation of PMN were ATP, beta-thromboglobulin and some trypsin-sensitive factor(s). 4) Supernatant of thrombin-activated platelets decreased random migration and chemokinesis of PMN.

Adenosine Triphosphate↗
PubMed1993

Leukemic cell lysis by activated human macrophages: significance of membrane-associated tumor necrosis factor.

In this study, we analyzed the mechanism(s) of leukemic cell lysis by human macrophages. Peripheral blood monocyte-derived macrophages were activated with recombinant interferon-gamma and lipopolysaccharide and their lytic activity against two leukemic cell lines (K562 and HL-60 cells) was assessed by an 111In releasing assay. Activated macrophages lysed these leukemic cells, and the lytic activity against leukemic cells was almost completely inhibited by anti-tumor necrosis factor (TNF) antibody. The macrophage-lysate prepared from activated macrophages also exhibited significant lytic activity against leukemic cells; this lytic activity was inhibited by anti-TNF antibody. The leukemic cells that we used for the cytotoxicity assays were resistant to recombinant TNF. The culture supernatant of activated macrophages did not show any lytic activity. These findings suggest that cell-associated TNF plays a role in macrophage-mediated cytotoxicity against leukemic cells.

Cell Membrane↗
PubMed1993

[Clinical study of patients with deep-seated fungal infection associated with hematological diseases].

An assessment has been made regarding usefulness of measuring beta-D-glucan (beta-glucan) as fungal serodiagnosis in 50 cases of fungal infection with hematological diseases. Further, an assessment has been made regarding relation between hematological findings and therapeutic effect by administering miconazole, an antifungal agent (MCZ: Florid, clinically to the subjects. Positivity of beta-glucan (beta-glucan > or = 10 pg/ml) was observed in 54.5% (24/44), and the effective rate of MCZ in the positive cases was 75.0% (18/24). In the cases in whom fungus was detected, beta-glucan-positive rate was 50.0% (8/16), and MCZ-effective rate in beta-glucan-positive cases was 62.5% (5/8). The total effective rate of MCZ was 80% (40/50). Side effects were observed in 3 cases, but continual administration of MCZ was possible in all of the 3 cases. By the assessment regarding the relation between hematological findings and therapeutic effect of MCZ, it was found that the effective rates in the cases who underwent a transition with neutrophil and lymphocyte counts less than 500/microliters during the period of MCZ administration were 64.7% (11/17) and 50% (5/10), respectively, and large effects were observed in the cases who underwent a transition with the neutrophil and lymphocyte counts more than 500/microliters was 86.7% (19/22) and 91.7% (22/24), respectively. These results suggested that lymphocytes rather than neutrophils had an important role in the morbidity of fungal infection. It was noteworthy that MCZ was effective for the treatment of deep seated mycosis and significant effective rate was obtained in the group of patients who had neutrophils and lymphocytes less than 500/microliters.

Adolescent↗
PubMed1993

Decreased adenylate energy charge and superoxide anion release in polymorphonuclear leukocytes in septic patients after hepatectomy.

To clarify the process of multiple organ failure after hepatectomy, the adenylate energy charge (EC) and superoxide anion (O2-) release of polymorphonuclear leukocytes (PMN) were measured 19 times on 11 septic patients after curative hepatic resection in relation to arterial ketone body ratio (AKBR), which reflects hepatic mitochondrial redox potential. PMN EC was measured by labeling the adenine nucleotide pool of PMN with radioactive adenine. The data of the septic patients (n = 19) was divided into two groups according to the hepatic energy status: AKBR above 0.7 (septic state A; n = 8) and AKBR below 0.7 for at least 3 successive days (septic state B; n = 11). Thirteen nonseptic patients undergoing hepatic resection were applied to the control group, and all of them showed AKBRs higher than 0.7. The PMN EC of septic patients was significantly lower than that of nonseptic patients [0.80 +/- 0.01 (SEM) vs. 0.88 +/- 0.02, P < 0.01]. In septic patients, moreover, the PMN EC of septic state A was significantly higher than septic state B (0.85 +/- 0.01 vs. 0.77 +/- 0.03, P < 0.05). Superoxide anion release of septic patients was significantly lower than that of nonseptic patients (19.0 +/- 2.1 nmol/5 x 10(5) cells/15 min vs. 29.3 +/- 1.7 nmol/5 x 10(5) cells/15 min, P < 0.01). Superoxide anion release of septic state A was significantly greater than that of septic state B (26.0 +/- 2.8 nmol/5 x 10(5) cells/15 min vs. 15.0 +/- 1.9 nmol/5 x 10(5) cells/15 min, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1992

Bone marrow stromal cells attenuate mitoxantrone cytotoxicity against HL-60 leukemic cells.

We evaluated the effect of cultured human bone marrow (BM) stromal cells on the cytotoxicity of mitoxantrone (MIT) against the HL-60 leukemic cell line. BM-derived fibroblastoid cells (BMFC) suppressed colony formation of HL-60 cells in the absence of MIT. BMFC increased the survival of HL-60 colony-forming cells in the presence of 50 ng/ml MIT. A significant decrease in the drug concentration was not detected on BMFC. Our results suggest that BM stromal cells can modulate the antileukemic effect of an anticancer drug.

Cell Adhesion↗