Atsuko Oya

Assessment of the hepatic arterial and portal venous blood flows during pregnancy with Doppler ultrasonography.

Abstract Purpose: The aim of this study was to evaluate whether the dual hepatic blood supply is altered in healthy pregnant women compared with that in nonpregnant women. Materials and methods: Flow waveforms in common hepatic artery and portal vein were obtained in 67 healthy pregnant women at 10–40 weeks gestation and 22 nonpregnant women by using Doppler ultrasonography. Results: In the nonpregnant group, the mean (SD) hepatic arterial blood flow, portal venous blood flow, and total liver blood flow were 0.57 (0.31) L/min, 1.25 (0.46) L/min, and 1.82 (0.63) L/min, respectively. In the healthy pregnant group, the portal venous blood flow and total liver blood flow significantly increased after 28 weeks gestation. However, the hepatic arterial blood flow remained unchanged during pregnancy. There was no relationship between the hepatic arterial blood flow and the portal venous blood flow. Conclusion: The results demonstrated that the hepatic perfusion increased during third trimester compared to nonpregnant level. Because the hepatic arterial blood flow remained unchanged during pregnancy, major determinant of the increase in the hepatic perfusion was the portal venous return. The data suggest that the hepatic arterial and portal venous vascular territories have regulatory mechanisms that allow for independent changes during pregnancy.

Developmental changes in mitochondrial activity and energy metabolism in fetal and neonatal rat brain

Experiments were undertaken to investigate mitochondrial activity and energy metabolism in the developing rat brain from the late fetal stage to the neonatal stage. Samples of cerebral cortical tissue were obtained from fetuses at 14, 16, 18, and 20 days of gestation, and from pups at 1 h, 1 day and 7 days after birth. Mitochondrial respiration was measured polarographically using homogenates. Fetal and neonatal brains were frozen in situ and fluorometric enzymatic techniques were used for the analysis of ATP, ADP, AMP, and lactate. In the fetal brain, there was a gradual increase in stimulated (+ADP) and uncoupled respiratory rates using glutamate and malate as substrates, from 14 days to 20 days of gestation, together with a moderate increase in ATP concentration and in the sum total of adenine nucleotides, and a significant decrease in lactate. Since non-stimulated (-ADP) respiratory rates did not change with increasing gestational age, the respiratory control ratio appeared to increase over the same period. An increase in mitochondrial activity was more pronounced immediately after birth, together with a marked increase in ATP concentration and in the sum total of adenine nucleotides. The highest rate of mitochondrial respiration was observed in 1-hour-old pups. These results indicate that, in the rat brain, there is maturation of oxidative metabolism in mitochondria that is initiated in late gestation. Acceleration in mitochondrial respiration occurs immediately after birth in order to maintain high-energy phosphate levels, and this may be crucial for the successful outcome of the newborn.

Influence of mild hypothermia on delayed mitochondrial dysfunction after transient intrauterine ischemia in the immature rat brain

The aim of this study was to determine the effect of different maternal thermal conditions during transient intrauterine ischemia on the mitochondrial respiratory activities in the immature rat brain. On 17 days of gestation, transient intrauterine ischemia was induced by 30 min of right uterine artery occlusion under hypothermic (33.5-34.5 degrees C, n=6), normothermic (36.5-37.5 degrees C, n=6), and hyperthermic conditions (39.5-40.5 degrees C, n=6). All of the pups were delivered by cesarean section at 21 days of gestation and cerebral neocortical tissue was sampled 1 h after delivery. The mitochondrial respiration was measured polarographically in homogenates. In the ischemic uterine horn, ADP-stimulated respiration of the normothermia and the hyperthermia groups decreased significantly to 73 and 74% of the non-ischemic controls, respectively. Since non-stimulated respiration remained unchanged, the respiratory control ratio (RCR) of the normothermia and the hyperthermia groups decreased significantly to 59 and 54% of the non-ischemic levels, respectively. In contrast, the mitochondrial respiratory activities of the hypothermia group showed no differences between the non-ischemic and the ischemic uterine horns. The results demonstrate that mild maternal hypothermia ameliorates the cerebral mitochondrial dysfunction in neonatal rats after intrauterine ischemia due to transient uterine artery occlusion and suggest that maternal thermal conditions, particularly during uteroplacental insufficiency, have important implications for the neuropathological outcome of the newborn.

Clinical efficacy of Kampo medicine (Japanese traditional herbal medicine) in the treatment of primary dysmenorrhea

Objective:  We intended to evaluate the clinical efficacy of Kampo medicine, a Japanese traditional herbal medicine, for primary dysmenorrhea which was prescribed according to the Kampo diagnosis, with classification of its severity.

Changes in uterine and ovarian arterial impedance during the periovulatory period in conception and nonconception cycles.

Objective: To evaluate whether the Doppler velocimetry of uterine and ovarian arteries during the periovulatory period in conception cycles differs from that in nonconception cycles.

Accuracy and Reproducibility of Ultrasound Measurements in Obstetric Management

Objective: The aim of this study was to assess the potential of ultrasonography as a routine diagnostic tool in obstetric management. Subjects and Methods: For the investigation on interobserver reproducibility, 2 sonologists independently measured the biparietal diameter (BPD), femur length (FL), amniotic fluid index (AFI), and resistance index (RI) of the umbilical and middle cerebral arteries in 20 healthy pregnant women between 28 and 36 weeks of gestation using color and pulsed Doppler ultrasound. A second group of 10 healthy pregnant women between 30 and 35 weeks of gestation were examined to assess the level of intraobserver reproducibility of the Doppler and ultrasound measurements by 2 sonologists. For each patient in this group, the flow waveform was measured three times in succession. Calculations of the intraclass correlation coefficient (Ri) were used to determine the levels of reproducibility. The agreement was considered acceptable only when the Ri value was ≧ 0.6. Results: The interobserver Ris for BPD, FL, AFI, and RI of the umbilical and middle cerebral arteries were 0.93, 0.8, 0.58, 0.49 and 0.56, respectively. The intraobserver Ris of the 2 sonologists in BPD, FL, and RI of umbilical artery were >0.6, whereas those in AFI and RI of middle cerebral artery were <0.6. Conclusion: Both the interobserver and intraobserver reproducibilities of BPD and FL were clinically acceptable, but not in the AFI and RI of umbilical and middle cerebral arteries.

Thermographic demonstration of nonshivering thermogenesis in human newborns after birth: its relation to umbilical gases

This study was undertaken to measure the extent of nonshivering thermogensis (NST) in brown adipose tissue of human newborns receiving routine thermal care and to examine the influence of oxygen levels at birth on the initiation of NST. Fifteen human neonates were studied in an incubator set at 31-31 degrees C. Thermographic measurements were made every 5 seconds for 5 minutes at 10 and 30 minutes, 1, 3, 6 and 24 hours, and 3 days after birth. The skin temperature and rate of heat dissipation from the interscapular area (location of subcutaneous brown adipose tissue), whole back area, and head area were measured. A heat dissipation ratio (HDR) was calculated as (A-B)/B, where A and B, expressed in Cal/cm2/h, represent rates of heat dissipation from the interscapular area and the whole back area, respectively. Umbilical arterial blood gases were measured immediately after birth. The skin temperature of the interscapular, whole back, and head areas increased significantly during the interval from 10 minutes to 1 hour after birth (p < 0.05). The skin temperature of the interscapular area was highest among the sampled sites during the first hour after birth (p < 0.05). The HDR was highest 10 minutes after birth (p < 0.05). By 1 hour after birth the temperature had reached constant values with low HDR. There was a negative correlation between the HDR and the temperature of the whole back area (p < 0.001). A positive correlation was found between the HDR within 30 minutes after birth and the PO2 of the umbilical arterial blood (p < 0.001). The data support the conclusion that nonshivering thermogenesis is initiated within minutes of birth and contributes to the elevation of body temperature. Furthermore, nonshivering thermogenesis after birth is reduced by low arterial PO2 at the time of birth.

Vitamins ameliorate secondary mitochondrial failure in neonatal rat brain

Recirculation after transient intrauterine ischemia has previously been found to be accompanied by secondary mitochondrial dysfunction in the immature rat brain. This study was performed to assess the efficacy of combined treatment with ascorbic acid and alpha-tocopherol in improving secondary brain damage. On the 17th day of gestation, transient intrauterine ischemia was induced by 30 minutes of uterine artery occlusion. Either vehicle, ascorbic acid, alpha-tocopherol, or combination of ascorbic acid and alpha-tocopherol was randomly administered to pregnant rats before and after occlusion. The pups were delivered by cesarean section at 21 days of gestation, and cerebral neocortical tissue was sampled. The mitochondrial respiration was measured polarographically in homogenates. In the ischemia uterine horn, mitochondrial activity of the vehicle treatment decreased significantly to 56% of nonischemic controls. Treatment with ascorbic acid or alpha-tocopherol alone demonstrated a moderate improvement of the secondary mitochondrial dysfunction to 64% and 62% of nonischemic controls, respectively. The combined treatment caused a normalization of mitochondrial activity to 91% of nonischemic controls. These results indicate that combined treatment with ascorbic acid and alpha-tocopherol has a more protective effect against secondary mitochondrial dysfunction after transient intrauterine ischemia compared with the administration of ascorbic acid or alpha-tocopherol alone.

Doppler ultrasound measurement of cerebral blood flow in healthy pregnant women

PurposeTo compare global cerebral blood supply in healthy pregnant women and nonpregnant women.Materials and MethodsFlow volumes in the common, internal, and external carotid, arteries and the vertebral arteries were determined using color Doppler ultrasonography in 17 nonpregnant women, 55 healthy pregnant women at 10 to 40 weeks gestation, and 24 puerperal women within 1 week after spontaneous delivery. Global cerebral blood flow was defined as the sum of flow volumes in the bilateral internal carotid and vertebral arteries.ResultsIn the nonpregnant group, mean flow volumes of the common, internal, and external carotid arteries and the vertebral arteries, and mean global cerebral blood flow volume were (mean±SD) 863±108 ml/min, 554 ±94 ml/min, 386±65 ml/min, 115±24 ml/min, and 669±104 ml/min, respectively. During the second trimester, flow volumes of the common and external carotid arteries increased significantly in the healthy pregnant women, to about 130 percent and 140 percent of the nonpregnant level, respectively. Global cerebral blood flow volume remained unchanged during pregnancy.ConclusionDuring pregnancy, increase in flow volumes in the common carotid arteries were accompanied by elevated flow volumes of the external carotid arteries but not the internal carotid arteries. This distribution would tend to regulate the volume of global cerebral blood flow throughout the period of pregnancy.

Short therapeutic window for nifedipine in transient intrauterine ischemia in fetal rat brain.

The aim of this study was to explore whether nifedipine influences the secondary deterioration of cerebral mitochondrial function after transient intrauterine ischemia in fetal rats. Intrauterine ischemia was induced by a 30-min occlusion of the right uterine artery at 20 days of gestation in Wistar rats. Nifedipine (1 mg kg(-1)) or vehicle was injected subcutaneously before the onset of ischemia or 1 h after the start of recirculation. Fetuses were delivered by cesarean section at the end of ischemia (n=6 with vehicle; n=6 with nifedipine pretreatment) or at 4 h of recirculation (n=6 with vehicle; n=6 with nifedipine pretreatment; n=6 with nifedipine posttreatment), and the cerebral mitochondrial respiration was measured polarographically. Tissue oxygen tension was evaluated in placental and fetal cerebral tissues (n=5 with vehicle; n=5 with nifedipine pretreatment). The vehicle treated animals showed a significant decrease in mitochondrial activities at the end of ischemia and 4 h of recirculation. Nifedipine attenuates the secondary deterioration at 4 h of recirculation when given just prior to ischemia, but had no neuroprotective activity when given 1 h after the start of recirculation. Nifedipine pretreatment had no influence on oxygen delivery in placenta and fetal cerebrum during and after ischemia. Despite the short therapeutic window, the treatment of nifedipine attenuates the secondary deterioration of cerebral mitochondrial function after transient intrauterine ischemia in fetal rats when given just prior to ischemia.