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Biomedical subjects

M Ichijo

Publications and source records attributed to M Ichijo.

At least 55 records · Page 3Linked to original sources
PubMed1993

[The effect of oxytocin stimulation on PGE2, 6keto PGF1 alpha production in human myometrial monolayer culture].

In order to clarify the mechanism by which oxytocin induces the generation of prostaglandin (PG) in human myometrial smooth muscle cell, we determined the concentration of PGE2 and 6ketoPGF1 alpha in the culture supernatant of human myometrial monolayer cells stimulated by oxytocin. PGE2 and 6ketoPGF1 alpha demonstrated a biphasic increasing curve when oxytocin was added. The first increase, phase 1, was a transient phenomenon with a peak at 20 seconds whereas the second increase, phase 2, was a continuous phenomenon starting at 120 seconds. Moreover, phase 1 was significantly inhibited by the DG lipase inhibitor, RHC80267. Phase 2 was significantly inhibited by the PLA2 inhibitor, Mepacrine. Phase 1 and 2 were dose dependent in the range 10(-10) to 10(-6) M. PG production at rest during which 6ketoPGF1 alpha was higher than PGE2, was reversed by oxytocin stimulation. These results suggest that oxytocin stimulation would actuate biphasic PG production, and this mechanism would probably regulate the myometrial construction in labor-pain initiation.

Calcium↗
PubMed1993

[The effect of oxytocin on production of free fatty acid in primary human uterine myometrial cell culture].

Oxytocin(OT) is considered to have several activities besides strongly inducing myometrial contraction by activating phosphatidilinositol-specific phospholipase C(PI-PLC). These include reconstructing the phospholipid constituents of the cell membrane and activating a variety of fatty acid producing systems. On the other hand, pregnancy-related steroid hormones which are produced by the fetus, placenta and mother are considered to be closely involved in the maintenance of pregnancy and the initiation of labor. In the present study with cultured myometrial cells, we examined what effect these steroid hormones might exert on the intramyometrial production of fatty acid by OT. Our results confirmed bi-phasic production of arachidonic acid(AA), linoleic acid(LA), palmitic acid(PA), and stearic acid(SA) by OT. Phase 1 was an increasing but transient phenomenon having its peak at 30 sec. It is considered to be derived from phosphatidylinositol bis-phosphate. Phase 2 was a persistent and increasing phenomenon which was initiated after 120 sec. It is considered to be mediated by Ca-dependent phospholipase. We also studied the effect of steroid hormones on the production of fatty acid. For AA, LA, and PA, we confirmed that dehydroepiandrosterone sulfate(DHAS) shortened the time taken in reaching the peak of Phase 1 to half of that of the control, and progesterone(P) extended the time 2-3 fold. These findings suggest that DHAS, P and F might modify the human myometrial construction mechanism as a factor which regulates the quantity and velocity of fatty acid production.

Arachidonic Acid↗
PubMed1993

[Effects of steroid hormones on change in [Ca2+]i following oxytocin stimulation in cultured human myometrial cells, and on myometrial oxytocin receptor].

It is considered that steroid hormones, the concentrations of which vary during pregnancy, play an important role in the initiation of delivery. In the present study, we measured intracellular Ca2+ ([Ca2+]i) change following oxytocin stimulation in cultured human myometrial cells with fura-2, a fluorescent Ca2+ indicator. We also studied the effect of the steroid hormones on changes in [Ca2+]i due to oxytocin stimulation. When the [Ca2+]i change due to 10(-6) M oxytocin reached 100%, the addition of 10(-6) M DHAS (dehydroepiandrosterone sulfate) just before the stimulation raised the [Ca2+]i level to 207%, whereas that of 10(-6) M progesterone dropped to 64%. Moreover DHAS accelerated the speed of increase until the maximum response of [Ca2+]i, while progesterone decelerated it. In another study, human myometrial plasma membrane was solubilized in 7.5mM CHAPSO solution and applied to a binding study. Oxytocin receptors of two different molecular weights, namely 350kD(OTR-1) and 39kD(OTR-2), were extracted from solubilized plasma membrane by employing a gel filtration column. Binding assays were performed for OTR-1 and OTR-2 in the presence of DHAS and progesterone (10(-5) M). The results showed that DHAS enhanced the binding affinity of the receptors, whereas progesterone reduced the maximum binding capacity. It is therefore considered that the steroid hormones added just before oxytocin stimulation might act on receptor levels and modify intracellular Ca2+ response over short periods.

Calcium↗
PubMed1992

A study on the placental transport mechanism of vitamin K2 (MK-4).

The present study was primarily concerned with in vitro investigation of vitamin K2 (MK-4) transport using human placental villous tissues, with the objective of elucidating the placental transport mechanism of vitamin K2. 1. When vitamin K2 (MK-4) was not administered to gravidae, the observed concentrations of vitamin K2 were 0.32 +/- 0.07 ng/ml in the maternal venous blood, undetectable in umbilical venous blood, and 1.01 +/- 0.37 ng/g wet tissue in the placental villous tissue. 2. When vitamin K2 was administered to gravidae, (20 mg/day x 7 days per os), the corresponding concentrations were 0.89 +/- 0.21 ng/ml in the maternal venous blood, 0.18 +/- 0.06 ng/ml in umbilical venous blood, and 5.38 +/- 1.05 ng/g wet tissue in the placental villous tissue. 3. In vitro studies using placental villous tissue indicated that vitamin K2 transport into villous tissue is not active, but suggested the existence of a highly vitamin K2 specific transport system in the human placenta. On the other hand, the results of comparison studies of transport of vitamin K2 and vitamin K1 into villous tissue indicated that transport activity with respect to the former vitamin was higher. Moreover, comparison of vitamin K2 transport into villous tissue at the end of the first trimester and at full term revealed that transport was somewhat higher during the final stage. In summary, the above results indicated that whereas transport of vitamin K1 into the fetus is not especially pronounced, transport into the placental villous tissue is comparatively good.

Biological Transport↗
PubMed1992

Origin of macrophage colony-stimulating factor (M-CSF) and granulocyte colony-stimulating factor (G-CSF) in amniotic fluid.

A large amount of M-CSF and G-CSF exists in human amniotic fluid and both are considered to have some physiological affect on maintaining pregnancy. We therefore examined the source of M-CSF and G-CSF found in the amniotic fluid. The average level of M-CSF in the amniotic fluid of patients without complications was 17.3 +/- 8.5 ng/ml and that of G-CSF 1.85 +/- 1.72 ng/ml, both being high values. In neonatal urine, the average level of M-CSF was also very high, 144.3 +/- 97.0 ng/ml, but that of G-CSF was below the determination limit of 60 pg/ml. Immunohistochemical staining indicated that production of M-CSF and G-CSF was localized in the epithelial cells of fetal membrane. On the basis of the above observations, M-CSF was found to derive from neonatal urine and the epithelial cells of fetal membrane, and G-CSF from the epithelial cells of fetal membrane.

Amniotic Fluid↗
PubMed1992

[The significance of determination of human herpesvirus-6 (HHV-6) antibody during pregnancy].

HHV-6 which was detected in peripheral blood lymphocytes of lymphocytic patients is now said to be an agent causing exanthema subitum. We investigated the titer of HHV-6 antibody in 100 primigravida and 30 patients with spontaneous abortion by means of the indirect immunofluorescence method (IF method). The positive incidence in which the titer of HHV-6 antibody was more than 10 times in 100 primigravida was 82%. That of HHV-6 IgM antibody was 3% in those who had no complication during pregnancy. This supposes that there may be some women who were infected or were reactivated while they were pregnant. The positive incidence in 30 spontaneous abortion patients was 90%. 3 of them had IgM antibody to HHV-6, and HHV-6 antigen was detected on the epitherium of the chorionic villi by the IF method with HHV-6 monoclonal antibody in two of them. This suggests that the infection or reactivation of HHV-6 may be one of the causes of spontaneous abortions.

Abortion, Spontaneous↗
PubMed1992

High serum human macrophage colony-stimulating factor level during pregnancy.

Using a specific enzyme immunoassay, we monitored the serum levels of human macrophage colony-stimulating factor (hM-CSF) in pregnant women during gestation and after delivery. During pregnancy there was a marked elevation of maternal serum hM-CSF level, which returned to the baseline level within 3 weeks after delivery. The changes in maternal serum hM-CSF level were associated with changes in the numbers of monocytes and neutrophils in the maternal peripheral blood. Fetal sera prepared from cord blood samples also had a high hM-CSF level. In contrast to the baseline level of hM-CSF in maternal sera after delivery, the hM-CSF levels of newborn infants at 1 to 7 days after birth were higher than fetal levels, indicating that fetuses and newborn infants are a source of hM-CSF. The serum hM-CSF levels of infants at 22 to 35 days were between fetal levels and normal adult levels. Human M-CSF found in the serum of pregnant women and in cord blood was predominantly the large form of M-CSF, with a molecular mass of 85 kDa. Human M-CSF levels in amniotic fluid at 30 to 40 weeks were higher than those in cord blood sera at the same stage, indicating that the uterus is another source of hM-CSF. The roles played by hM-CSF during pregnancy need to be investigated.

Adult↗
PubMed1992

[The platelet aggregation inhibiting activity in human placenta--study on the ADP degrading activity of human placental villi].

We studied the platelet aggregation inhibiting activity and ADP degrading activity of human placental villi (tissue culture supernatant) and brush border membrane vesicles (BBMV) and obtained the following results. 1. There existed a platelet aggregation inhibiting activity in tissue culture supernatant of villi (S-villi) but not in that of decidua or amnion. The S-villi inhibited the platelet aggregation induced by ADP, but not that induced by collagen, arachidonic acid or ristocetin. And, there was also ADP degrading activity (ADPase activity) in the S-villi. ADP was quickly degraded by S-villi. When ADP was preincubated with S-villi, the platelet aggregation induced by ADP was completely lost. 2. There was very strong platelet aggregation inhibiting activity in placental BBMV. The BBMV almost completely inhibited the platelet aggregation induced by ADP, collagen, arachidonic acid and ristocetin. And there was very strong ADP degrading activity in the placental BBMV. ADP was quickly degraded by BBMV. When ADP was preincubated with BBMV, the platelet aggregation induced by ADP was completely lost. 3. The enzymatic character (heat stability, enzymatic kinetics, Ca++ dependency and pH dependency) of ADP degrading activity in BBMV was very similar to that in S-villi. 4. The ADP degrading activity of both S-villi and solubilized BBMV were fractionated by anion exchange column chromatography and gel filtration column chromatography in similar patterns, and it was shown that ADP degrading substance of both S-villi and solubilized BBMV had a molecular weight of about 60K.

Apyrase↗
PubMed1992

Expression of activation antigens CD69, HLA-DR, interleukin-2 receptor-alpha (IL-2R alpha) and IL-2R beta on T cells of human decidua at an early stage of pregnancy.

T cells of human decidua at an early stage of pregnancy were examined by flow cytometry for the expression of the T-cell-activation antigens CD69, HLA-DR, interleukin-2 receptor-alpha (IL-2R alpha) and IL-2R beta. The decidua contained a small number of T cells and both CD4+ and CD8+ subsets expressed CD69, HLA-DR, IL-2R alpha and IL-2R beta antigens significantly whereas, in peripheral blood, only a small number of T cells expressed these activation antigens. These findings indicate that T cells in the decidua in the first trimester of pregnancy are regionally activated.

Antigens, CD↗
PubMed1991

Enhancing effects of human macrophage colony-stimulating factor on the secretion of human chorionic gonadotropin by human chorionic villous cells and tPA30-1 cells.

Human macrophage colony-stimulating factor (hM-CSF) concentration-dependently enhanced the secretion of human chorionic gonadotropin (hCG) by primary cultured human cytotrophoblastic cells and a human placental cell line, 3A-SubE (tPA30-1). Since this effect appeared 12 hours after the addition of hM-CSF and disappeared when protein synthesis was inhibited, it was surmised that hCG synthesis was enhanced by hM-CSF. When anti fms (hM-CSF receptor) antibody was added, hCG secretion by cultured human cytotrophoblasts in early pregnancy markedly decreased. These findings demonstrate that hM-CSF acts on the chorionic villous cells and promotes hCG synthesis by these cells.

Cell Line↗
PubMed1991

Detection of IL-6 in human milk and its involvement in IgA production.

A large amount of interleukin-6 (IL-6) was found to be contained in human whey. The concentration of IL-6 in colostrum was significantly higher than that in serum or in milk taken 1 month after parturition. Colostrum contained many more mononuclear cells than late milk. In terms of the proportion of monocytes, T cells and B cells, however, there is no difference between colostrum and late milk. There is a significantly positive correlation between the concentration of IL-6 and the number of mononuclear cells in milk. This demonstrates that IL-6 in whey is derived in part from mononuclear cells. Stimulation of human milk mononuclear cells by Staphylococcus aureus Cowan I in the presence of anti-IL-6 antibody markedly decreased the production of IgA. This suggests that IL-6 contained in milk is closely associated with the local production of IgA in the breast.

Breast↗
PubMed1991

Accumulation of CD16-CD56+ natural killer cells with high affinity interleukin 2 receptors in human early pregnancy decidua.

Most human peripheral blood natural killer (NK) cells express the phenotype CD16+CD56+. However, a very minor subset of NK cells express CD16-CD56+, and these NK cells bear both interleukin 2 receptor (IL-2R)alpha (p55) and IL-2R beta (p75) (high affinity IL-2 receptors). In this report, we demonstrate that in human early pregnancy decidua--an interface between maternal immunocompetent cells and fetus (placenta)--abundant (approximately 83%) CD16-CD56+ NK cells with high affinity IL-2 receptors were present, and these cells responded to low amounts of IL-2 (4.5 pM). These CD16-CD56+ NK cells significantly expressed an early activation antigen, CD69, in vivo, whereas peripheral CD16-CD56+ NK cells did not express CD69. These findings suggest that CD16-CD56+ NK cells in early pregnancy decidua may be activated in vivo, and may play an important role in immunoregulation during early pregnancy. Also, decidual lymphocytes may be useful materials to study the mechanism of MHC-unrestricted cytotoxicity of this type of NK cells.

Antigens, CD↗
PubMed1991

Use of universal and type-specific primers in the polymerase chain reaction for the detection and typing of genital human papillomaviruses.

By using polymerase chain reaction (PCR), we have developed a system for type-specific as well as universal detection of genital human papillomaviruses (HPVs). Primers and probes for specific detection of HPV-16, -18 and -33 were synthesized from the E7 open reading frame (ORF). They were capable of detecting corresponding HPV types with high specificity and sensitivity. Primers for detection of a broad spectrum of HPV (universal primers) were synthesized from the L1 ORF. The universal primers were shown to be capable of amplifying HPV-6b, -11, -16, -18, -33, -52b and -58. The system was applied to various cervical tissue specimens from Japanese patients. They consisted of 26 normal specimens, 18 from cervical dysplasias and 29 from cervical carcinomas. HPV was detected in none of the normal specimens. On the other hand, many of the specimens from cervical dysplasias and carcinomas were found to be positive for HPV, especially HPV-16. Except for one, all the specimens which were positive with the type-specific PCRs were also positive with the universal PCR. Furthermore, substantial numbers of specimens were found to be positive only with the universal PCR. Cloning and sequencing of DNA segments amplified by the universal primers were undertaken to characterize some of the unknown HPVs. Our PCR system may thus be useful for the specific detection of the three major types of oncogenic HPVs and also for the detection of a broad spectrum of HPVs including possibly novel HPV types.

Cell Line↗