Biomedical subjects

Junichi Sugawara

Publications and source records attributed to Junichi Sugawara.

7 recordsLinked to original sources

PubMed2006

Fetal myocardial thickening measured by ultrasonic-based technique called 'phased-tracking method'.

OBJECTIVE: To evaluate fetal myocardial movement by using newly developed ultrasonic technique. METHODS: We analyzed 50 normal fetuses between 25 and 41 weeks' gestation for changes in thickness of fetal myocardium using the phased-tracking method, a technique with high vertical distance resolution and the potential to evaluate fine ventricular wall movements. We analyzed differences in the rate of change in ventricular wall thickness and in changes in the inner and outer wall layers with advancing gestation. We also analyzed myocardial thickening period and evaluated the ratio of increasing thickness period to stroke interval. RESULTS: Mean thickness changing rate was significantly higher in the right (1.18 +/- 0.34 m/s/m) than in the left ventricular wall (0.86 +/-0.31 m/s/m) (p < 0.001). Mean ratio of increasing thickness period to stroke interval was significantly higher in the right (0.57 +/- 0.064) than in the left ventricle (0.46 +/- 0.075) (p < 0.001), indicating that myocardial contraction in the fetal right ventricle predominates. The thickness-changing rate of the bilateral ventricular walls was positively and linearly correlated with gestational age. The myocardial-wall thickness-changing rate was higher in the outer layer than in the inner layer in late gestation. CONCLUSIONS: We conclude that measurement of the thickness-changing rate of fetal ventricular walls using the phased-tracking method might be useful for evaluation of fetal cardiac function.

Echocardiography↗

PubMed2006

Appearance of abnormal electrocorticogram patterns during umbilical cord compression in sheep fetus.

A frequent cause of fetal acidemia, which sometimes results in hypoxic-ischemic encephalopathy, is umbilical cord compression associated with uterine contraction. Using a sheep model of fetal acidemia, we examined the changes in electrocorticogram (ECoG), carotid artery blood flow, arterial blood pressure and fetal heart rate during cord compression. A characteristic burst of ECoG spikes emerged during cord compression at fetal arterial pH 7.18 even before the pH went down to severe fetal acidemia (less than 7.10). The administration of a neuromuscular blocking agent to the fetus did not abolish the appearance of the spikes. These results suggest that cord compression may cause abnormal brain excitement even in the absence of severe fetal acidemia and that this abnormal excitement can lead to fetal brain dysfunction, if cord compression is repeated or prolonged.

Acidosis↗

PubMed2005

Decrease and senescence of endothelial progenitor cells in patients with preeclampsia.

BACKGROUND: In preeclampsia, the precise mechanism of impaired vascular function is still unclear. We hypothesized that cellular function of circulating endothelial progenitor cells (EPCs) might be impaired in patients with preeclampsia. OBJECTIVE: The objective of this study was to investigate the number and status of cellular senescence of EPCs in the circulation of women with preeclampsia. METHODS: Circulating EPCs were cultured from patients with preeclampsia (n = 8) and normotensive pregnant women (n = 7). EPC numbers were assessed by colony-forming unit (CFU) methodology as previously reported. In addition, to assess cellular senescence, we measured endogenous beta-galactosidase activity. Moreover, we assessed whether the serum level of C-reactive protein (CRP), a marker for systemic inflammation, was associated with cellular impairment of EPCs. RESULTS: The number of circulating EPCs was decreased in women with preeclampsia controls (median, 10.0 vs. 34.0 CFU; P < 0.01). The rate of cellular senescence was significantly increased in patients with preeclampsia (33.9%) compared with that in controls (22.9%; P < 0.05). Patients with preeclampsia were divided into two subgroups: the CRP-negative group (CRP, <0.1 mg/dl; n = 4) and the CRP-positive group (CRP, > or =0.1 mg/dl; n = 4). Interestingly, EPC CFU counts were markedly decreased in CRP-positive patients compared with those in CRP-negative patients (5.0 and 25.0 CFU, respectively; P < 0.05). Median values for cellular senescence were greater in the CRP-positive group than in the CRP-negative group, although this did not achieve statistical significance (43.5% and 33.3%, respectively; P = 0.12). CONCLUSION: Depletion and cellular aging of EPCs in patients with preeclampsia might be associated with endothelial dysfunction and could be affected by systemic inflammation.

Adult↗

PubMed2005

Successful conservative treatment of a cesarean scar pregnancy with uterine artery embolization.

Ectopic pregnancy developing in a previous Cesarean section scar is rare and is associated with catastrophic complications, such as uterine rupture and uncontrollable bleeding, which may lead to loss of the uterus. The operative treatments that have been reported for cesarean scar pregnancy are dilatation and curettage and excision of trophoblastic tissues using either laparotomy or laparoscopy. Recently, conservative treatment of scar pregnancy with locally and/or systemically administered methotrexate (MTX) has been reported. However, recent reports demonstrated that cases treated with MTX sometimes required laparotomy later because of excessive bleeding. In this series of cases we have demonstrated that viable cesarean scar pregnancies can be treated safely by selective transarterial embolization in combination with subsequent dilatation and curettage and local or systemic injections of MTX. In these three cases, uterine artery embolization proved to be a useful procedure for preventing uncontrollable bleeding and unnecessary uterine loss.

Abortion, Induced↗

PubMed2004

Circulating endothelial progenitor cells during human pregnancy.

The precise molecular and cellular mechanisms that regulate maternal vascular development during gestation are largely unknown. Endothelial progenitor cells (EPCs), which play an important role in vascular homeostasis, have been discovered in the circulation. We examined the level of circulating EPCs throughout uncomplicated pregnancies (n = 20) and assessed the correlation between serum estradiol levels and the number of EPCs. The number of circulating EPCs increased gradually and paralleled the progression of gestational age. In addition, the number of EPCs correlated significantly with the level of serum estradiol. The present study suggests that EPCs may play an important role in the regulation and maintenance of the placental development and vascular integrity during pregnancy.

Adaptation, Physiological↗

PubMed2003

Fractal and periodic heart rate dynamics in fetal sheep: comparison of conventional and new measures based on fractal analysis.

The physiological significance of spectral and fractal components of spontaneous heart rate (HR) variability in the fetus remains unclear. To examine the relationship between circadian rhythms in different measures of HR variability, R-R interval time series obtained by fetal ECGs were recorded continuously over 24 h in five pregnant sheep at 116-125 days gestation. Conventional measures of short-term (STV) and long-term variability (LTV), low-frequency (LF; 0.025-0.15 cycles/beat) and high-frequency (HF; 0.2-0.5 cycles/beat) spectral powers, the LF-to-HF ratio, and fractal dimension values were calculated from 24-h ECG recordings and quantified every 60 min. STV, LTV, and LF and HF spectral powers were minimal during the day but increased significantly to their highest values at night. We found a significant positive correlation between these measures, whereas the cosinor method showed significant similarity between their circadian rhythm patterns. Fetal R-R intervals also exhibited fractal structures. Fetal HR variability had a fractal structure, which was similar between day and night. These results suggested that the circadian rhythms exhibited by STV and LTV during the day were mainly due to changes in frequency components rather than to fractal components of fetal HR fluctuation.

Animals↗

PubMed2003

Contribution of the fetal baroreceptor reflex to the low frequency component of fetal heart rate fluctuations.

OBJECTIVE: The objective of this study was to examine whether the fetal baroreceptor reflex contributed to the low frequency component (LF: 0.025-0.125 cycles/beat) of fetal heart rate fluctuations. METHODS: Sheep fetuses in late gestation with normoxemia were used. The baroreceptor function was expressed as the baroreceptor reflex sensitivity (BRS) based on the change of the R-R interval in response to the elevation of blood pressure by noradrenaline (Nor-Ad). A frequency analysis was conducted by the autoregression method on heart rate fluctuations and blood pressure fluctuations in 300 stable heart beats immediately before the Nor-Ad test. The gain and the coherence from blood pressure LF to heart rate LF were calculated. The correlations between the BRS and the power values of heart rate LF, blood pressure LF, and the gain or the coherence were examined. RESULTS: The BRS and the gain showed a positive correlation (p < 0.01). There was a negative correlation between the heart rate LF and the BRS, and between the blood pressure LF and the BRS (p < 0.01, p < 0.005). CONCLUSIONS: This study showed that fetal BRS was involved in the change of LF in fetal heart rate fluctuation. Baroreceptor function should be considered when examining the change of LF domain in fetal heart beat fluctuation.

Animals↗