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Biomedical subjects

I Iwata

Publications and source records attributed to I Iwata.

13 recordsLinked to original sources
PubMed1992

[A case of idiopathic aneurysm of the inferior vena cava].

Congenital aneurysms of the inferior vena cava (IVC) are very rare, and to our knowledge, only 4 cases have been previously reported. We describe the fifth case of fusiform aneurysm and briefly review the literature. A 62-year-old woman was admitted to our hospital for investigation of a mass shadow on the right hemidiaphragm on a chest roentgenogram. CT, MRI, and DSA examinations revealed an aneurysmal dilatation of the IVC measuring 51x50x38 mm inferior to the right atrium, and the diagnosis of fusiform aneurysm of the IVC was made. The newer imaging techniques of CT, MRI, and DSA have facilitated the diagnosis of this abnormality.

Aneurysm↗
PubMed1991

Increase in the concentration of immunoreactive endothelin in human pregnancy.

Maternal plasma concentrations of immunoreactive endothelin (ir-ET) during pregnancy, labour and after birth were measured by radioimmunoassay. Concentrations of ir-ET in the umbilical artery, umbilical vein, amniotic fluid and neonatal urine were also examined. The mean (+/- S.E.M.) plasma ir-ET concentration in early pregnancy (4-7 weeks) was 13.7 +/- 0.5 pmol/l, which was significantly higher than that in non-pregnant women (5.9 +/- 0.3 pmol/l). During pregnancy, plasma ir-ET concentrations gradually decreased to a minimum of 11.5 +/- 0.4 pmol/l in weeks 20-23, and then increased again towards term (12.5 +/- 0.4 pmol/l after 36 weeks of pregnancy). In women undergoing vaginal delivery, the mean plasma ir-ET concentration (17.1 +/- 0.7 pmol/l) increased significantly, compared with that in late pregnancy. After delivery, the plasma ir-ET concentration decreased abruptly to 4.0 +/- 0.2 pmol/l on the first day. Plasma ir-ET concentrations in umbilical vessels were significantly higher than those in maternal plasma. In addition, concentrations in the umbilical artery were significantly higher than those in the umbilical vein in cases of vaginal delivery. Concentrations of ir-ET in amniotic fluid were much higher than those in maternal or fetal plasma. ir-ET concentrations in neonatal urine on day 1 after birth were below the detection limit (less than 0.1 pmol/l) by radioimmunoassay in 70% of the cases examined but on day 5 after birth ir-ET was present at measurable concentrations in all cases. It is suggested that endothelin may act as a circulating hormone during pregnancy and labour in both maternal and fetal circulations.

Amniotic Fluid↗
PubMed1991

[A case of Swyer-James syndrome diagnosed by selective alveolobronchography].

A 33-year-old male was admitted to our hospital for further investigation of unilateral hyperlucency of the left upper and middle lung fields on chest X-ray. A pulmonary scan showed decreased perfusion of the left upper and middle lung fields. Pulmonary arteriography demonstrated small left pulmonary arteries with diminished peripheral vascular branches. Left bronchogram showed almost normal distribution of main and subsegmental bronchi, but poor filling by contrast in the peripheral bronchi. From these findings, the patient was diagnosed as having Swyer-James syndrome. In order to demonstrate the alveoli in this syndrome, selective alveolobronchography (SAB) was performed. SAB revealed coarse ring shadows of B1+2.

Adult↗
PubMed1991

[Immunohistochemical and electromicroscopic study of a case of primary nodular pulmonary amyloidosis].

A 41-year-old man was hospitalized for further evaluation of an abnormal chest films which revealed a nodular shadow in the right middle lung field, which remarkably enlarged during one year. As no diagnostic procedures ruled out lung carcinoma of right S6, a right lower lobectomy was performed. Pathologically the nodules were composed of amorphous and eosionphilic materials which were diagnosed as amyloid by Congo-red stain and electron microscopic examination. Since there were no deposits in other organs and there was no abnormality of serologic and urinary protein analysis, a diagnosis of primary nodular pulmonary amyloidosis was established.

Adult↗
PubMed1991

[Prenatal evaluation of the platelet counts in the fetuses and the neonates of the mothers complicated with idiopathic thrombocytopenic purpura].

We investigated 25 pregnancies with ITP. The results were as follows. 1. The platelet counts of the maternal blood just before delivery were not correlated with those of the cord blood. 2. It was suggested that the maternal PAIgG value just before delivery could foretell the onset of neonatal thrombocytopenic purpura. 3. The platelet counts in fetal scalp blood were correlated with those of the cord blood, but falsely lower platelet counts were found in the fetal scalp samples. 4. We saw 5 cases of percutaneous umbilical blood sampling (PUBS) in pregnancies with ITP. PUBS was found to be a useful and safe method. The indications for PUBS and fetal platelet transfusion in pregnancy with ITP are discussed.

Cesarean Section↗
PubMed1990

Clinical evaluation of a direct colorimetic method for determination of amniotic phospholipids.

Evaluation of amniotic phospholipids, which are a parameter of fetal lung maturation, is important in the management of premature infants. The method available for measuring the lecithin/sphingomyelin (L/S) ratio, which appears to provide an index to fetal lung maturity, is laborious, involving determinations of phospholipids, and so is unsuitable for rapid quantitative measurement of phospholipids in the amniotic fluid in the perinatal period. We developed a simple, sensitive colorimetric assay for phospholipids without their extraction. This assay is based on the fact that phospholipids form stable hydrophobic complexes with Co(SCN)4, Fe(SCN)2- and Fe(SCN)3 within about 1 hr. Amniotic fluid samples (n = 115) were collected from women with normal and abnormal pregnancies in week 16-41 of pregnancy, and these samples were examined both by thin layer chromatography (TLC) and by our method of phospholipid determination. Good correlations were observed between the L/S ratio determined by TLC and the values obtained by this method. Moreover the distributions of the dipalmitoylphosphatidylcholine (DPPC) content and DPPC/sphingomyelin (SM) ratio were similar to those of the PC content and L/S ratio. This method was proved to be more accurate than other methods such as TLC and the shake test for predicting neonatal RDS.

Amniotic Fluid↗
PubMed1990

[Effect of low-dose aspirin therapy on utero-placental blood flow and malondialdehyde (MDA) as an indicator of its therapeutic effect].

Pregnancy-induced hypertension (PIH) and preeclampsia develop when an imbalance occurs between prostacyclin (PGI2) and thromboxane A2 (TXA2) production. PGI2 promotes vasodilation and decreases platelet adhesiveness, while TXA2 acts as a vasoconstrictor and enhances platelet aggregation and adhesion to vascular walls. The PGI2/TXA2 ratio appears to be important in pregnancy and the development of the functioning uteroplacental unit. Recently, antiplatelet treatment such as low-dose aspirin therapy has been effective in preventing the development of PIH and preeclampsia. TXA2 breaks down spontaneously into a stable substance, TXB2, which is inactive. Another stable, inactive metabolite, malondialdehyde (MDA), is formed via the same pathway. TXB2 and MDA are produced in approximately equimolar quantities. We studied the effects of a low-dose aspirin prescription. Production of MDA was remarkably suppressed during the low-dose aspirin therapy. Furthermore, pulsed doppler ultrasound assessment of blood flow was performed in the fetal descending aorta, umbilical artery and uterine artery of the low-dose aspirin therapy patients. Doppler abnormalities were improved during the therapy. It is concluded that low-dose aspirin improves the uteroplacental blood flow assessed by pulse doppler waveform and that determination of MDA is useful as an indicator of platelet thromboxane synthesis.

Adult↗
PubMed1989

Immunoreactive corticotropin-releasing hormone, adrenocorticotropin and cortisol in human plasma during pregnancy and delivery and postpartum.

The activity of the hypothalamo-pituitary adrenal axis was examined, by measuring the levels of immunoreactive (IR) corticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH) and cortisol (F) in human plasma during normal pregnancy and after delivery with or without complications and during normal postpartum using a specific RIA. The level of IR-CRH in maternal plasma increased progressively during pregnancy, increased further at delivery and declined rapidly to the non-pregnant level on the 1st day postpartum. The level of IR-F in maternal plasma also increased progressively during pregnancy, increased further at delivery, but decreased slowly postpartum, not returning to the non-pregnant level within 5 days. Significant correlations were found between the level of IR-CRH and IR-ACTH, IR-CRH and IR-F, and IR-ACTH and IRF in maternal plasma both during pregnancy and after delivery. It is noteworthy that the concentration of IR-CRH in the maternal plasma at delivery was higher in multiple pregnancy than in normal pregnancy, and that the level of IR-CRH in the umbilical cord in uncomplicated cases was much lower than that in the maternal plasma, and was significantly lower than those in the umbilical cord plasma in cases of asphyxia, IUGR or premature delivery. The level of IR-F, not IR-CRH and IR-ACTH, at normal vaginal delivery was significantly higher than that at elective cesarean section. On these results, we investigated the feto-maternal-hypothalamo-pituitary adrenal axis during pregnancy and delivery, in which CRH plays an important role.

Adrenocorticotropic Hormone↗
PubMed1989

Plasma concentrations of human atrial natriuretic peptide at vaginal delivery and elective cesarean section.

The change in plasma concentration of atrial natriuretic peptide (hANP) at delivery was examined by measuring the concentrations of hANP in plasma samples from 21 subjects after 36 weeks of normal pregnancy, 22 subjects after normal spontaneous delivery and 20 subjects after elective cesarean section. The maternal plasma concentration of hANP after normal delivery (38.0 +/- 8.2 fmol/ml, mean +/- S.E.M.) was significantly higher than that after 36 weeks of normal pregnancy (16.8 +/- 2.3 fmol/ml), but its concentration after cesarean section was not different from that after 36 weeks of pregnancy. After normal delivery, the plasma concentration of hANP in the umbilical artery (66.9 +/- 11.8 fmol/ml) was also significantly higher than that in the umbilical vein (35.1 +/- 7.3 fmol/ml). In contrast, after elective cesarean section, the hANP levels in the umbilical artery and vein were not significantly different. These results suggest that hANP secretion into the maternal and fetal circulation may be stimulated by the dynamic movement of the mother in labour and the stress of the fetus at delivery, respectively.

Adult↗
PubMed1987

Changes in concentration of human atrial natriuretic peptide in normal pregnancy and toxaemia.

Changes in concentration of human atrial natriuretic peptide (hANP) in normal and toxaemic pregnancy were examined. The maternal plasma concentration of hANP increased gradually during normal pregnancy to a maximum of 20.0 +/- 2.4 pmol/l (mean +/- S.E.M.) after week 36 of pregnancy. From week 20, the plasma concentrations of hANP were significantly higher than those in non-pregnant women (9.3 +/- 2.0 pmol/l). In toxaemia with hypertension, maternal plasma hANP levels were increased after week 26 of pregnancy (37.7 +/- 6.0 pmol/l) compared with those in normal gravida at the same time (17.1 +/- 1.6 pmol/l). Maternal plasma hANP levels in toxaemia only with oedema were not different from those in normal gravida.

Adult↗