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Biomedical subjects

S Tomoda

Publications and source records attributed to S Tomoda.

12 recordsLinked to original sources
PubMed1992

[Influence of low calcium diet on the vascular response to angiotensin II in pregnant and non-pregnant rabbit vascular endothelium].

This study was conducted in order to evaluate the influence of low calcium intake on the vascular response to angiotensin II (A-II) in pregnant and non-pregnant rabbits. Both were fed on a regular and a low calcium diet, respectively, for a period of at least 25 days. By using the common iliac arterial rings of each of the rabbits, and further classifying the respective arterial rings into those with intact endothelium and those with denuded endothelium, the response to A-II in the rings was compared. A greater degree of refractoriness to A-II was observed in the intact endothelial rings than in the denuded rings regardless of the difference in calcium intake, in both pregnant and non-pregnant rabbits. The refractoriness was however, particularly remarkable in the pregnant arterial rings. Therefore refractoriness to A-II in arterial rings on a low calcium diet is higher than that in the rings on a regular calcium diet regardless of the presence of endothelial cells, in both pregnant and non-pregnant rabbits. It is clear that reduction in the calcium intake results in an increase in the response to A-II, which is caused by increased reactivity of the vascular smooth muscle layer.

Angiotensin II↗
PubMed1992

[Changes in blood pressure in two types (absolute and relative) of pregnancy induced hypertension (hypertensive type of toxemia)].

The criteria for pregnancy induced hypertension (PIH: hypertensive type of toxemia) have been determined by the Japanese Obstetrics and Gynecology Society. Mild PIH is classified into two types. One is "Absolute PIH (A-PIH)" diagnosed by (1) systolic blood pressure (SBP) greater than or equal to 140 mmHg and less than 160 mmHg or (2) diastolic blood pressure (DBP) greater than or equal to 90 mmHg and less than 110 mmHg. The other one is "relative-PIH (R-PIH)" diagnosed by (3) an increase in SBP greater than or equal to 30 mmHg compared to the usual SBP or (4) an increase in DBP greater than or equal to 15 mmHg compared to the usual DBP (In this paper, blood pressure prior to the 12th gestational week is considered as "usual" blood pressure). However, there has been no report in which two types of PIH are assessed. Our hypothesis is that the pathophysiology of the two types of PIH is different. We have already reported the clinical background of two types of PIH. The purpose of this study is to clarify the pathophysiological difference by evaluating the blood pressure change during pregnancy. We evaluated 963 nullipara and 747 multipara whose pregnancies were recorded from the 1st trimester (multiple pregnancy and pre-term delivery before the 32nd gestational week were excluded). Among the nullipara, 765 women (79.4%) were diagnosed as having normal blood pressure (N-group), 7.1% as A-PIH, and 13.0% as R-PIH. Among the multipara, the N-group consisted of 632 women (84.6%), the A-PIH: 4.6% and R-PIH: 10.3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

[Fetal growth in two types (absolute and relative) of pregnancy induced hypertension (hypertensive type of toxemia)].

The criteria for pregnancy induced hypertension ("PIH" which is a hypertensive type of toxemia) have been determined by the Japanese Obstetrics and Gynecology Society. Mild PIH is classified into two types. One is "Absolute PIH (A-PIH)" diagnosed by (1) systolic blood pressure (SBP) greater than or equal to 140 mmHg and less than 160 mmHg or (2) diastolic blood pressure (DBP) greater than or equal to 90 mmHg and less than 110 mmHg. The other one is "relative-PIH (R-PIH)" diagnosed by (3) an increase in SBP greater than or equal to 30 mmHg compared to usual SBP or (4) an increase in DBP greater than or equal to 15 mmHg compared to usual DBP (In this paper, blood pressure prior to the 12th gestational week is considered as "usual" blood pressure). We have already investigated the pathophysiological difference through the background and the change in blood pressure throughout pregnancy and puerperium in these two types of PIH. The purpose of this study is to clarify the pathophysiological difference by evaluating the influence of hypertension on fetal growth. We evaluated 963 nullipara and 747 multipara whose pregnancies were recorded from the 1st trimester (multiple pregnancy and pre-term delivery before the 32nd gestational week were excluded). Among nullipara, 765 women (79.4%) were diagnosed as having normal blood pressure (N-group), 7.1% as A-PIH, and 13.0% as R-PIH. Among multipara, the N-group consisted of 632 women (84.6%), A-PIH: 4.6% and R-PIH: 10.3%. There is no difference among the three groups in gestational days but the body weight, the chest circumference, and the abdominal girth at birth of A-PIH show a significant difference from those of the R-PIH and N-groups in both nullipara and multipara.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1991

[Clinical backgrounds in two kinds (absolute and relative) of mild pregnancy induced hypertension].

The criteria for pregnancy induced hypertension (PIH) have been determined by the Japanese Obstetrics and Gynecology Society. Mild PIH is classified into two types. One is "Absolute-PIH (A-PIH)" diagnosed by 1) systolic blood pressure (SBP) greater than = 140mmHg and less than 160mmHg or 2) diastolic blood pressure (DBP) greater than = 90mmHg and less than 110mmg. Another one is "Relative-PIH (R-PIH)" diagnosed by 3) an increase in SBP greater than = 30mmHg compared to normal SBP or 4) an increase in DBP greater than = 15mmHg compared to normal DBP. However, there has been no report in which two types of PIH are assessed. Our hypothesis is that the pathophysiology of two types of PIH is different. The purpose of this study is to clarify the pathophysiological difference by evaluating the clinical backgrounds. We evaluated 963 nullipara and 747 multipara whose pregnancies were recorded from the 1st trimester (multiple pregnancy and pre-term delivery before 32 gestational weeks were excluded). Among 765 nullipara women, 79.4% were diagnosed as having normal blood pressure (N-group), 7.1% as A-PIH, and 13.0% as R-PIH. In the multipara N-group, the figures were 632 women (84.6%), A-PIH, 4.6% and R-PIH, 10.3%. Clinical backgrounds showed that the incidence of hypertensive family history, high hematocrit (greater than = 39.0) before the 12th gestational week or obesity (Kaup index greater than = 24 before pregnancy) was significantly higher in A-PIH than in the N-group of nullipara and higher in the A-PIH than in the R-PIH and N-groups of multipara.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Role of endothelial cells on refractoriness to angiotensin-II in pregnant and non-pregnant rabbits].

Vascular refractoriness to angiotensin-II (A-II) during pregnancy is well recognized. The present study was designed to evaluate how the response of endothelial cells of arterial rings to A-II changes in pregnant rabbits (n = 24) when compared with non-pregnant rabbits (n = 24). The response of the arterial rings with intact endothelium to A-II was markedly decreased in the pregnant rabbit group in comparison with the non-pregnant rabbit group. In contrast, in the case of the arterial rings whose endothelium had been removed, there was no difference between the two rabbit groups in the response to A-II. However, the maximum response of arterial rings to A-II was significantly lower in the pregnant group than the non-pregnant group under the presence of the endothelium. This study revealed that the arterial rings with intact endothelium prepared from the pregnant group shows markedly increased refractoriness to A-II, while no such difference is seen with rings from which the endothelium had been removed. That is, this study indicated that an endothelium-derived relaxing factor (EDRF) is deeply involved in refractoriness to A-II in pregnant rabbits.

Angiotensin II↗
PubMed1991

[Influence of estrogen and progesterone on the vascular response to angiotensin-II in non-pregnant rabbit vessels--intact or denuded endothelium].

During pregnancy, vascular sensitivity to A-II is reduced and it was clarified that this refractoriness to A-II is due to a change in EDRF output in pregnant rabbits. The present study aimed at elucidating whether estrogen or progesterone is responsible for the augmentation of EDRF output. 17-OH-estradiol was administered (200 micrograms/kg/day) for 7 days to 8 non-pregnant rabbits, while progesterone was similarly administered (2,000 micrograms/kg/day) to 8 other non-pregnant rabbits. Twenty-four nonpregnant rabbits were employed as the controls. Common iliac arterial rings prepared from each group were compared for the isometric response to A-II. The arterial rings with intact endothelium prepared from the progesterone-treated group were found to have a smaller pD2 value and a smaller maximum response to A-II than the estrogen-treated group. On the other hand, no differences between the progesterone group and estradiol group were observed in these values for the endothelium-denuded arterial rings. These findings indicated that the augmentation of EDRF output during pregnancy is brought about by progesterone.

Angiotensin II↗
PubMed1987

Amniotic fluid volume regulation: basal volumes and responses to fluid infusion or withdrawal in sheep.

To better understand the mechanisms that regulate amniotic fluid (AF) volume, we measured AF volume and the rates of fetal swallowing and urination in 33 pregnant sheep at 124-142 days gestation. In four of five ewes over 9-18 days, the spontaneous changes in amniotic fluid volume correlated positively with urine flow rate and negatively with the rate of swallowing (R = 0.686, P less than 0.01), such that 47% of the AF volume changes could be attributed to changes in rates of urination and swallowing. Following infusion of one liter of isotonic amniotic saline (n = 12) or mannitol (n = 5), AF volume increased 110%, and after 24 h returned to the control value in the saline group but it remained elevated 59% above control in the mannitol group. AF sodium was unchanged following saline infusion but remained reduced following mannitol. Following withdrawal of 61% of AF over 20-40 min, AF volume averaged 51 and 71% of control at 24 and 48 h, respectively, whereas AF sodium was unchanged. Variations in rates of fetal swallowing or urine formation could not explain the entire changes in AF volume following either the volume infusion or withdrawal. These data suggest that AF volume is regulated within a relatively narrow range and fetal urine formation and swallowing together and transplacental fluid flux each appear to contribute equally to the regulation of AF volume.

Amniotic Fluid↗
PubMed1986

Fate of labeled albumin and erythrocytes following injection into amniotic cavity of sheep.

We have previously described a method to measure the amniotic fluid (AF) volume and fetal swallowing rate in near-term sheep by use of 125I-labeled albumin (RISA) and 51Cr-labeled red blood cells (51Cr-RBC). However, when we measured these volumes on consecutive days, reentry of the radionuclides into the amniotic cavity from fetal urine affected the calculated values of AF volume and swallowing rates. In an attempt to clarify the recirculation problem, we injected RISA and Cr-RBC daily for 9 days into the AF of five chronically catheterized pregnant sheep (124 days gestation on the 1st experimental day). We calculated AF volume and fetal swallowing rate, comparing those values to the values corrected for fetal urine isotopic counts. The mean AF volume and fetal swallowing rate measured by RISA were 808 +/- 48 ml (mean +/- SE) and 559 +/- 29 ml/day, respectively. These values were only slightly different from the corrected volumes, 808 +/- 48 ml and 561 +/- 29 ml/day, respectively, because fetal urine 125I activity reached only 4.8% of AF activity even on the 9th day. In contrast, 51Cr-activity in fetal urine on the 9th day showed 47% of the activity of AF. The mean uncorrected AF volume (785 +/- 44 ml) and swallowing rate (561 +/- 31 ml/day) measured by Cr-RBC were different from the corrected values (790 ml and 570 ml/day, respectively). After the 4th day these differences were particularly conspicuous.(ABSTRACT TRUNCATED AT 250 WORDS)

Amnion↗
PubMed1985

Amniotic fluid volume and fetal swallowing rate in sheep.

To investigate amniotic fluid (AF) dynamics and volume regulatory mechanisms, we measured the concentration of radioiodinated (125I) serum albumin (RISA), 51Cr-labeled red blood cells (Cr-RBC), and 103Ru-labeled microspheres after injection into the amniotic cavity and determined AF volume and fetal swallowing rate in 22 singleton pregnant sheep. Under normal conditions 2-3 h were required for complete mixing of RISA and Cr-RBC within AF; however, when the fetus was dead only 3-5 h were required. AF volume of 17 sheep on the 5th postoperative day averaged 975 +/- 128 ml by RISA and 986 +/- 130 ml by Cr-RBC. AF volume determined with RISA and Cr-RBC correlated well. In contrast, AF volume measurement with microspheres produced erratic results. The disappearance rate of the labels in 17 ewes on the 5th postoperative day averaged 4.9 +/- 0.7%/h for RISA and 5.5 +/- 0.7 for Cr-RBC, and the calculated rates of fetal swallowing were 935 +/- 78 ml/day by RISA and 1,085 +/- 102 by Cr-RBC. In dead fetuses the disappearance rates were almost zero, suggesting that the labels disappear mainly by swallowing. Absolute volume swallowed and swallowed volume per fetal weight correlated with gestational age. AF volume correlated with fetal weight. Radiolabeled albumin or red blood cells may be used to simultaneously measure amniotic fluid volume and the rate of fetal swallowing. Furthermore it appears that fetal swallowing increases with gestational age.

Amniotic Fluid↗
PubMed1978

Simultaneous competitive enzyme immunoassay for human chorionic gonadotropin.

A simultaneous competitive enzyme immunoassay (SICEIA) for hCG was developed using beta-D-galactosidase (beta-Gal) as a labelled enzyme and anti-hCG antibody coated sheep red blood cells (SRBC) as a solid phase. In this report, a new coupling agent, MCAE, was used to couple beta-Gal with hCG. The sensitivity was improved to the degree of 2.5 mIU/ml, equal to that of RIA. The present procedure was safer and rapider than RIA. The value of hCG in urine by our procedure had good correlation with that by RIA.

Binding, Competitive↗
PubMed1976

Survival of 16-celled and morula stage rabbit embryos frozen to -196 degrees C,.

Preimplantation stage (16-celled and morula) rabbit embryos were successfully frozen to -196 degrees C. The cooling rate (from a room temperature to 0 degrees C), the presence of the mucin layer surrounding embryos, the ice-seeding treatment and the thawing procedure were examined to determine their effects on the survival of the frozen embryos of Japanese white, New Zealand white and Dutch-Belted rabbits. A high proportion (51%; 16-celled, 69%; morula) of Dutch-Belted rabbit embryos developed in vitro, when they were frozen to -196 degrees C, applying the ice-seeding at -4 degrees C in the presence of 12.5% DMSO, after being cooled to 0 degrees C at the rate of 7-9 degrees C/min, and were diluted by a stepwise addition of 4 different strength PBS on thawing. The highest rate of in vitro development (81%; Japanese white, 75%; New Zealand white, 82%; Dutch Belted embryos) was obtained when the morula stage embryos were frozen to -196 degrees C applying seeding at -4 degrees C after being cooled to 0 degrees C at the rate of 1 degrees C/2.5 min and were diluted, on thawing, by stepwise addition of 6, 3 and 1% DMSO solution and a culture medium. No great difference was found in the survival rate between the embryos covered with the mucin layer and those which had not the coat. All the embryos frozen without applying seeding treatment failed to develop in vitro after being thawed and diluted. Nine out of 27 does each of which received 6 reimplantations of the embryos frozen-thawed became pregnant and were found to be carrying 37 normal fetuses on the 12th day of pregnancy.

Animals↗