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Biomedical subjects

M Deguchi

Publications and source records attributed to M Deguchi.

At least 109 records · Page 6Linked to original sources
PubMed1987

Mechanism of killing of Giardia lamblia trophozoites by complement.

Only antibodies of the IgM class support the lytic effect of complement on Giardia lamblia (GL). We sensitized GL trophozoites (SGL) at 4 degrees C with serum containing anti-GL antibodies or IgM purified from this serum, and either normal human serum (NHS), complement 2-deficient human serum (C2d-HS), or C4-deficient guinea pig serum was used as source of complement. SGL were killed by NHS (86%) and by the deficient sera (50 and 40%, respectively), suggesting activation of the alternative pathway. However, the reaction was inhibited by Mg-EGTA. These observations led to studies of the role of C1. The lytic effect of NHS and C2d-HS on SGL was abolished by immunochemically depleting C1 from these sera, and reconstituted by adding purified C1q plus C1r and C1s. Factor B-depleted C2d-HS also lost its capacity to mediate killing, but reconstitution with factor B led to a dose-dependent increase in the killing of SGL. We next investigated the participation of the membrane attack complex in this system. SGL carrying C5b to C7 were lysed when incubated with C8 alone (56%); the addition of C9 further increased killing (98%), while C9 in the absence of C8 had no effect. We concluded that although activation of the classical pathway produces lysis of SGL, lysis may also proceed through a unique pathway of complement activation that requires C1 and factor B, but is independent of C4 and C2. Lysis of SGL can be accomplished by C5b to C8 in the absence of C9.

Animals↗
PubMed1987

Anemia-inducing substance (AIS) in advanced cancer: inhibitory effect of AIS on the function of erythrocytes and immunocompetent cells.

The effects of anemia-inducing substance (AIS), found in the plasma of tumor-bearing subjects, on red blood cells (RBC) and cellular immunity were examined. The results obtained may be summarized as follows: 1) The osmotic resistance and the deformability of RBC were decreased in patients with terminal cancer. 2) Normal human RBC were made less deformable and their membrane was made fragile by treatment with cachectic plasma from those patients, and these changes in physical properties were irreversible. 3) Energy metabolism in RBC was affected by AIS, that is, ATP concentration and pyruvate kinase activity in RBC were lowered and transmembrane glucose influx was suppressed. 4) AIS was removed from cachectic plasma by repeated adsorption with normal RBC, and the inhibitory effect on cellular immunity was lessened as AIS was removed. 5) AIS was detected in cachectic RBC membrane, monocytes, and tumor tissue by indirect immunofluorescence assay using rabbit anti-AIS antibody prepared by us. These observations suggest strongly that tumor-derived AIS appears in the blood of patients with terminal cancer, shows cytotoxicity to RBC and immunologically competent cells, and plays a role in the pathogenesis of cancer cachexy.

Adenosine Triphosphate↗
PubMed1985

Studies on the ontogenesis and the regulatory mechanisms of placental lactogen and insulin binding sites (receptor) in rat liver.

The ontogenesis of specific binding of 125I-hPL and 125I-insulin was determined in rat liver cell membranes (10(5) X g pellets), and the regulatory mechanisms of these binding sites were also examined. There were striking differences in the mode of ontogenesis between binding sites of hPL and insulin in rats. HPL binding sites were very few in liver cell membranes from fetal and immature rats. They began to increase after puberty, and markedly increased in late pregnancy. On the other hand, insulin binding sites, which decreased in late pregnancy, were dominant in fetal liver and placenta. Consequently, the lipolytic and glycogenolytic activities of hPL in maternal liver were accentuated, whereas the effects of insulin on maternal liver were suppressed. In contrast, in fetal liver and placenta only the anabolic effects of insulin seemed conspicuous. According to the results of experiments on in vivo administration of estradiol-17 beta, progesterone, hydrocortisone or hPL to intact or hypox-rats, and the measurement of serum rat chorionic mammotropin (rCM), rPRL, estradiol-17 beta, and insulin during pregnancy in rats, the increase in hepatic hPL binding sites observed in late pregnancy might be, at least in part, due to rCM secreted from placenta, and the decrease in insulin binding sites due to the increase in serum insulin itself in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Insulin receptors in fat tissue of human and rat during pregnancy].

Insulin receptors in fat cell membranes (10(5)g pellets) were investigated by a conventional incubation method in pregnant and nonpregnant rats or women. Insulin binding in pregnant L20 rats was 8.1 +/- 2.1% (M +/- SD) less than that in nonpregnant rats (14.5 +/- 3.5%) in peripheral adipose tissues (p less than 0.05). In the former a reciprocal rise in the serum insulin level was observed. In pregnant women, insulin binding was determined in subcutaneous fat tissues obtained at cesarean section or other laparotomy. Insulin binding was 29.3 +/- 8.9% in nonpregnant women, and it did not change in early pregnancy (34.3 +/- 6.2%, NS). However, it decreased obviously in late pregnancy (20.4 +/- 6.4%) (p less than 0.05). Scatchard analysis indicated that the decrease in insulin binding was due to the changes in the number of insulin receptors in fat cell membranes. Their Kd values were indistinguishable from each other in rats and women. In addition, insulin binding correlated significantly with Insulin Sum, Glucose Sum at 75g OGTT, TG and FFA in serum. These results suggested that insulin receptors in adipose tissues were suppressed in late pregnancy, and this might be the cause of the "insulin resistance" observed in the maternal body in late pregnancy.

Adipose Tissue↗
PubMed1985

[Insulin receptors in pregnant nonobese diabetic (NOD) mice].

The dynamics of insulin receptors was investigated in the feto-placenta-maternal system of DM-onset pregnant nonobese diabetic (NOD) mice. Insulin binding experiments were carried out by conventional incubation methods using cell membrane fractions (10(5) X g pellets). The results were as follows. In the case of JCL-ICR mice, used as the control, insulin specific binding in liver cell membranes, which was 26.6 +/- 3.2% in the nonpregnant state, decreased in late pregnancy (20.7 +/- 2.7%). On the other hand, in pregnant NOD mice hepatic insulin binding was 24.3 +/- 1.0%, more than that of JCL-ICR pregnant mice. By Scatchard analyses, these changes were found to be due to the changes in the number of receptors especially in high affinity sites. The serum insulin level was 6.3 +/- 4.2 microU/ml in pregnant NOD mice, which was much lower than that in other mice (nonpregnant JCL-ICR: 14.8 +/- 6.4, pregnant JCL-ICR: 37.3 +/- 18.3). In fetal liver and carcasses of NOD fetuses, insulin binding was also much greater than that in JCL-ICR fetuses. In conclusion, the hormone sensitivity to insulin was accentuated in pregnant DM-onset NOD mice not only in the maternal body but also in the fetus. This is regarded as a metabolic adaptation to the environment in the insulin deficient state of these mice. And it is speculated that insulin receptors are also down-regulated in fetal liver as well as in adult mice.

Animals↗
PubMed1984

C3b receptor (CR1) on erythrocytes in various diseases.

Complement receptor for C3b (CR1) on erythrocytes was investigated in various diseases by immune adherence hemagglutination (IAHA) using aggregated human IgG. In normal controls, 21 out of 312 (6%) revealed defective CR1 reactivity, and there was no difference in the prevalence of defective CR1 reactivity between female (11/157, 7%) and male (10/155, 6%). Among diseases examined significantly high prevalence of defective reactivity of CR1 on erythrocytes was seen in systemic lupus erythematosus (SLE) (22/30, 73%) and malignancy of hematopoietic system, especially in acute myelogenous leukemia (AML)(6/11, 55%).

Connective Tissue Diseases↗
PubMed1980

[Effect of human chorionic somatomammotropin on release of glucose by perfused rat liver (author's transl)].

The biological action of hCS was studied in non-recirculating perfusion system of the pregnant rat liver. A modified method of Mortimore and of Millor for the liver perfusion was used. The perfusate was prepared with Krebs-Ringer bicarbonate buffer with the addition of BSA (2%), glucose (10 mM) and human erythrocytes (Ht. 12%). The results were as follows. 1) The biological condition of the liver remained good during 90 minutes of perfusion as judged by its gross appearance, O2 consumption, CO2 production, bile secretion and the levels of transaminase, K+, pH in effluent and the microscopic observation after the perfusion. 2) An addition of hCS (20 micrograms/ml) to the perfused pregnant liver resulted in a momentary increase of glucose, FFA and K+ concentration in the effluent. 3) The elevation of the glucose level was also observed after the repeated administration of hCS. This release of glucose from perfused liver after hCS administration took, place more rapidly with the progress of the pregnancy. 4) The elevation of glucose level was maintained longer by the continuous administration of hCS (10 micrograms/ml). 5) Hepatic glycogen decreased after the continuous administration of hCS, but it increased in the control group. The level of cyclic-AMP in the perfused liver rose after the continuous administration of hCS.

Animals↗
PubMed1979

Simultaneous presence of EBNA-positive and colony-forming cells in peripheral blood of patients with infectious mononucleosis.

EBNA-positive lymphoblast cells were detected in 0.1 to 0.9% of the T-cell-depleted lymphocytes obtained from peripheral blood samples of five patients with infectious mononucleosis (IM). The same blood specimens from four of the five patients contained cells that formed EBNA-positive colonies in soft agar containing EBV antibodies. The ratio of the colony formers to EBNA-positive cells was higher in blood samples taken early in the disease than in those obtained in later stages of the disease. The present results strongly suggest that EBV-transformed cells are present in the peripheral circulation of IM patients and that such cells can directly give rise to immortalized cell lines in vitro.

Adolescent↗
PubMed1978

A study on the effect of dehydroepiandrosterone sulfate on so-called cervical ripening.

Dehydroepiandrosterone sulfate (DHAS) is now used for a dynamic test of placental function by many obstetricians. While practicing this test, the authors found that DHAS markedly promoted so-called "cervical ripening". To study this problem, DHAS of 50 or 100 mg in multiple doses were injected into 132 Japanese pregnant women in their 38th--42nd week of gestation. The change in Bishop score was carefully recorded. Bishop score in the injected groups of primiparae (100 mg) began to rise much sooner than the control groups (p less than 0.01 on seventh day and 14th day). However, such significant difference in the rise of Bishop score was not noted in the multiparae and primiparae with 50 mg. Although the rise of score is not significant, the duration (day) from injection to delivery was shorter in the injected group than the control group (t=2.1529, p less than 0.05 in primiparae with 50 mg, t=3.8829, p less than 0.01 with 100 mg, t=2.1029, p less than 0.05 in multiparae with 50 mg). In some of these cases, labor began or delivery was finished within 24 hrs. Among the factors of Bishop score, mainly the effacement, consistency and dilatation of the cervix were remarkably improved by DHAS injection (p less than 0.01 and less than 0.05). Side effects of any type were not seen in the mothers and foetuses. As a conclusion, DHAS injection in considered to produce favorable conditions for delivery in women with "unripe cervix" by softening the soft birth canal. Furthermore, it is suggested that DHAS might play an important role in triggering labor.

Cervix Uteri↗