Kimihiro Nagai

Endothelin-1 and big endothelin-1 increase in human endometrium during menstruation

OBJECTIVES Although the physiologic and pathologic roles of endothelin-1 in reproduction have been investigated, little is known about human uterine tissue levels. We studied the levels of immunoreactive endothelin-1 and immunoreactive big endothelin-1 in human endometrium and myometrium during each menstrual phase. STUDY DESIGN Materials were obtained at hysterectomy (endometrium, n = 33; myometrium, n = 27). We measured immunoreactive endothelin-1 and immunoreactive big endothelin-1 by radioimmunoassay and performed an immunohistochemical study of the tissue. Data were analyzed by the Mann-Whitney U test. RESULTS We detected larger amounts of immunoreactive endothelin-1 and immunoreactive big endothelin-1 in the endometrium than in the myometrium throughout the menstrual, proliferative, and secretory phases. Endometrial immunoreactive endothelin-1 and immunoreactive endothelin-1 were significantly increased in the menstrual phase (endothelin-1 68.8 +/- 23.3 pg/mg protein, n = 5, p < 0.005; big endothelin-1 45.2 +/- 5.7 pg/mg protein, n = 5, p < 0.003) compared with the other phases (endothelin-1 30.7 +/- 9.5 and 30.5 +/- 14.0 pg/mg protein; big endothelin-1 19.9 +/- 6.7 and 24.1 +/- 7.4 pg/mg protein). Immunohistochemistry demonstrated that the endometrial stromal cells were positive for antiendothelin monoclonal antibody only in the premenstrual and menstrual phases. CONCLUSION Levels of immunoreactive endothelin-1 and immunoreactive big endothelin-1 are different in each type of uterine tissue and in each phase of the menstrual cycle. These changes may indicate some role of endothelin-1 in menstruation.

Labile oligomeric structure of human placental 15-hydroxyprostaglandin dehydrogenase

NAD-dependent 15-hydroxyprostaglandin dehydrogenase has been isolated from human term placenta. About 9,000-fold enrichment was achieved with a yield of 7.6%. Electrophoretic analyses suggested that glycerol stabilized an active structure of the enzyme, and sodium dodecyl sulfate might dissociate it. The instability of the enzyme activity may relate to its labile oligomeric structure which is easily dissociated into subunits.

Purification of an NAD+-dependent 15-hydroxyprostaglandin dehydrogenase from the human placenta.

We purified 15-hydroxyprostaglandin dehydrogenase (PGDH) from the human placenta by gel filtration high performance liquid chromatography (GFHPLC) with spectrophotometric assay for the chromophore of 15-keto PG. Purification steps were as follows; homogenization and centrifugation at 10,000g, for 30 min, ammonium sulfate precipitation, DEAE-cellulose (DE-52), Sephadex G-100 gel filtration, NAD-affinity chromatography (AGNAD type 1), and GFHPLC. The specific activity was increased from 1.5 X 10(-2) unit/mg in the initial supernatant to 1272 X 10(-2) after GFHPLC. PGDH showed a single band on SDS-polyacrylamide gel electrophoresis and the molecular weight determined by GFHPLC and electrophoresis was approximately 50,000 daltons. After 4 months of storage, PGDH in a buffer containing 50% glycerol at -20 degrees C retained 80% of its activity. Michaelis constant for PGE2 was 0.4 microM at pH 7.0 with NAD as a cofactor. These properties of PGDH were compared with the results reported in other literature.

Prostaglandin dehydrogenase activity in placenta and in maternal lung, kidney, and gastric mucosa during rat pregnancy ☆

The purpose of this study was to investigate the changes in prostaglandin dehydrogenase (PGDH) activity in various organs of the rat during pregnancy. PGDH activity was evaluated in lung, kidney, and gastric mucosa of male and nonpregnant female rats, and in these tissues as well as in placenta of pregnant rats at various stages of gestation. The specific activity of PGDH in placenta decreased until day 15 of pregnancy; thereafter, the specific activity of PGDH increased, reaching maximal levels at term. The specific activity of PGDH in lung and kidney tissue of pregnant rats was greater than that in the same tissues of nonpregnant rats; in these tissues the specific activity increased from early pregnancy through day 21 of pregnancy but was decreased significantly on day 22. The specific activity of PGDH in kidney of male rats was significantly greater (10 times) than that in kidney of female rats. This sex-related difference in renal PGDH activity was not found in lung and gastric mucosa. In gastric mucosa, the specific activity of PGDH on day 10 of pregnancy was significantly lower than that in gastric mucosa of nonpregnant rats. A rapid decrease in the specific activity at term was a phenomenon common to lung, kidney, and gastric mucosa, and was distinctly different from the marked increase in the activity in placenta at term. Thus, in this study, we present evidence that the activity of PGDH is modulated in a tissue-specific manner during pregnancy. We speculate that PGDH in maternal, fetal, and placental tissues serves a role in the maintenance of pregnancy and in growth and development of the fetus by regulating the tissue levels of bioactive prostaglandins.

Atrial natriuretic peptide in transient puerperal hypertension

This study is the first approach to evaluate whether human atrial natriuretic peptide (hANP) is involved in the pathophysiology in transient puerperal hypertension (TPH). Five women who were normotensive throughout pregnancy, labor, and delivery developed hypertension between the first and sixth postpartum day. hANP (pg/ml) and plasma renin activity (PRA, ng/ml/h), angiotensin I, II (AI, II, pg/ml), and aldosterone (Aldo, pg/ml) in plasma were quantified by radioimmunoassay. Ten women without hypertension were also studied on hANP, PRA, AI, AII, and Aldo sequentially as the control group. hANP was apparently lower in women with TPH than in normotensive women. The levels of PRA, AI, AII, and Aldo were also clearly decreased in women with TPH, whereas those values in normotensive women were not altered from nonpregnant levels. Maternal natriuresis usually reaches the peak at 3-5 days postpartum. The decrease of hANP and PPA, AI, AII, and Aldo in TPH coincides with this natriuretic period. This observation suggests that hANP may serve an important role in the pathogenesis of TPH.

Regulation of placental 15-hydroxyprostaglandin dehydrogenase activity by obstetric drugs

The in vitro effects of obstetric drugs on 15-hydroxyprostaglandin dehydrogenase activity were investigated. Enzyme activity was inhibited by indomethacin, methylergometrine maleate, Solcoseryl, conjugated estrogen and progesterone, and was activated only by isoxsuprine-HCL. Methylergometrine maleate and isoxsuprine-HCl, which have opposite functions on uterine muscle, also exerted contrary effects on enzyme activity. Inhibitory and stimulatory effects of these drugs suggested that they could directly regulate uterine activity and also indirectly influence the uterus due to their effects on prostaglandin catabolism in vivo.

Epithelial Ovarian Carcinoma Associated with Metastases to Central Nervous System: Two Case Reports

We experienced two rare cases of metastases to the central nervous system (cerebral and leptomeningeal metastases) from primary epithelial ovarian carcinoma. The first case was a 55-year-old woman who developed carcinomatous meningitis while on chemotherapy for ovarian cancer stage IIIC. Cytological analysis confirmed carcinomatous cells of ovarian origin in the cerebrospinal fluid. Magnetic resonance imaging demonstrated abnormal hyperintensity in the cerebral sulci on fluid attenuated inversion recovery (FLAIR) sequence with enhanced gadolinium indicating leptomeningeal metastases. Her consciousness rapidly declined and she died 42 days after diagnosis. The second case was a 63-year-old woman who underwent surgery for ovarian cancer and who was diagnosed as stage IA. Thirty-eight months after surgery, she developed weakness of the left hand and headaches. A CT scan revealed metastases to the right cerebrum and she was treated with surgical resection followed by radiotherapy. Five months after resection, she developed ileus caused by multiple relapses in the pelvis. Despite chemotherapy, her performance status declined and she died nine months after the resection. Both cases were rare because the first case was isolated leptomeningeal metastases, and the second case was confirmed relapse site in the cerebrum due to neurological symptoms despite her early clinical stage.

Effects of actinomycin D on fetal growth in rats

Objective : The goal of this study was to determine the effects of actinomycin D on fetal growth and prostaglandin dehydrogenase activity and to determine whether these effects could be obtained by administering extracts of fetal calf serum (SS-094). Methods : Actinomycin D (7 w g/100 g body weight) was injected intraperitoneally on days 11 and 12 of pregnancy to induce growth restriction in rats. In another group, SS-094 was given (0.1 ml/100 g body weight) on days 12, 15, 17 and 19 of pregnancy, following the administration of actinomycin D. Placental prostaglandin dehydrogenase (PGDH) activity was measured on days 15 and 21 of pregnancy. Statistical analysis was performed by ANOVA and Dunnets test. Results : In the group injected with actinomycin D, fetal weight was significantly restricted (on day 15; p < 0.05; on day 21; p < 0.01), compared to the controls, and this restriction was successfully reversed by SS-094. PGDH activity in the placenta was significantly ( p < 0.01) decreased in growth-restricted rats and remained low even after fetal weight recovered. Conclusions : Growth restriction in pregnant rats was successfully induced by actinomycin D, and SS-094 reversed this restriction. It does not seem that prostaglandin metabolism in the placenta is responsible for growth restriction.