Jean-Claude Veille

Effects of estrogen on nitric oxide biosynthesis and vasorelaxant activity in sheep uterine and renal arteries in vitro

OBJECTIVES Our purpose was to determine whether estrogen alters the relaxation responses to bradykinin and superoxide dismutase of the uterine and renal arteries and to determine the role of nitric oxide in that response. STUDY DESIGN Ten nulliparous, ovariectomized nonpregnant sheep received either estradiol-17beta or vehicle solution. In vitro studies evaluating vasorelaxation were done with either bradykinin or superoxide dismutase. The nitric oxide inhibitor nomega-nitro-L-arginine methyl ester was used to determine the role of nitric oxide in this process. Nitric oxide synthase activity was assessed by measuring citrulline generation. RESULTS We found a dose dependency of relaxation to bradykinin and superoxide dismutase. Estrogen enhanced this response in uterine arteries. Estrogen increased citrulline generation in uterine but not renal arteries. Nomega-nitro-L-arginine methyl ester blocked relaxation responses and citrulline generation in both arteries. CONCLUSION In nonpregnant sheep we found that nitric oxide release and nitric oxide synthase activity is enhanced by estrogen in the uterine arteries but not in the renal arteries. Increases in nitric oxide synthase activity may be important in the hyperemic response of the uterus during estrus.

Peripartum cardiomyopathy: summary of an international survey on peripartum cardiomyopathy.

OBJECTIVE The aim of this survey was to assess the evaluation, management, and future recommendations of patients with the diagnosis of peripartum cardiomyopathy and to evaluate the interest in the creation of a prospective database regarding this rare disorder. STUDY DESIGN A total of 116 surveys were sent to major teaching institutions in the United States (including Puerto Rico), Canada, Crete, and South Korea after a national conference held at the National Institutes of Health regarding peripartum cardiomyopathy. This was an open-ended survey containing 17 specific questions regarding this disorder and its management. RESULTS A total of 78 (67%) maternal-fetal specialists responded to the survey. Diuretics and digoxin were used as first-line treatment for this disorder. Only 6% used angiotensin-converting enzyme inhibitors during pregnancy. Fifty-eight percent of the perinatologists (58%) recommended either intrauterine contraceptive devices or foam and condoms, whereas oral contraceptives (progesterone-only pill or estrogen-progesterone mix) were recommended in 23% and 41%, respectively. Sixty-six percent (66%) of the respondents would recommend future pregnancy if ventricular function returned to normal. CONCLUSIONS Fundamental clinical and basic research is lacking regarding this rare but potentially devastating disorder. Major teaching institutions do not have significant numbers of patients with this disorder to provide concrete recommendations, and starting a database will be useful in the gathering of important epidemiologic information. A secondary aim of such a registry would be to establish a repository for tissue and blood samples to answer basic mechanistic questions about this disorder.

Quantitative assessment of human fetal renal blood flow

OBJECTIVE Our purpose was to longitudinally quantify human fetal renal blood flow. STUDY DESIGN Twenty-two normal fetuses underwent a color-pulsed Doppler evaluation of the renal artery. The Doppler waveforms were digitized to assess the velocity-time integral. The size of the vessel was determined during systole with color high-resolution two-dimensional ultrasonography. Renal blood flow was estimated by multiplying the time-velocity integral (i.e., area under the curve) by the area of the renal artery. The combined cardiac output was calculated by adding right and left inflow Doppler-derived volumes. RESULTS Renal artery size, peak flow velocity, time-velocity integral, and renal blood flow significantly increased with advancing gestational age. The resistivity indexes, such as the systolic/diastolic ratio or the Pourcelot index of the fetal renal artery, did not significantly change with advancing gestational age. The pulsatility index, however, was correlated with gestational age. The percentage of the combined cardiac output to the fetal kidney remained constant throughout gestation. CONCLUSIONS Color pulsed Doppler can be used to visualize small and deep vascular structures in the human fetus. Renal blood flow increased with advancing gestational age. This increase seems to be related to the increase in the combined cardiac output.

Fetal renal pulsed Doppler waveform in prolonged pregnancies

OBJECTIVE Our purpose was to determine Doppler waveforms of the fetal human renal artery in prolonged pregnancy in the presence or absence of oligohydramnios. STUDY DESIGN Fifty patients at or after 40 weeks were studied. Ultrasonography was performed to determine the amniotic fluid index by the four-quadrants technique. Two groups of patients were obtained on the basis of the amniotic fluid index. Group 1 had an amniotic fluid index > 5 (normal) (n = 33); group 2 had amniotic fluid index < or = 5 (oligohydramnios) (n = 17). Umbilical artery and fetal renal pulsed Doppler waveforms were determined and analyzed. The fetal renal artery systolic-to-diastolic ratio of the two groups was compared. RESULTS Fetuses with a low amniotic fluid index had a significantly higher ratio. A significant negative correlation coefficient between amniotic fluid index and fetal renal systolic/diastolic ratio was found (r = -0.435 and p < 0.01). CONCLUSIONS In prolonged pregnancies there is a significant relationship between the amniotic fluid index and the fetal renal systolic/diastolic ratio. In pregnancies associated with oligohydramnios the systolic/diastolic ratio is significantly higher than in those with normal amniotic fluid volume. These data suggest that intrarenal flow in prolonged pregnancies complicated with oligohydramnios is significantly different.

Longitudinal quantitation of middle cerebral artery blood flow in normal human fetuses

OBJECTIVES We attempted to quantify noninvasively blood flow of the middle cerebral artery in human fetuses during five distinct periods. STUDY DESIGN Twenty normal fetuses had color pulsed Doppler ultrasonography of the middle cerebral artery. A total of 68 studies were successfully done and are reported. The Doppler sample was placed as parallel to the direction of the vessel flow as possible. All waveforms were recorded on a strip chart at a preset speed of 100 mm/sec. Six Doppler waveforms were digitized for the time velocity integral (area under the curve is equal to time velocity integral) and averaged. Middle cerebral blood flow was obtained by multiplying the time velocity integral of the Doppler curve by the cross-sectional area of the vessel. The combined cardiac output was obtained by adding the right and left ventricular outputs, which were obtained by multiplying the time velocity integrals by the area of the corresponding annuli. Analysis of variance for repeated measurements was used to determine significance. RESULTS The diameter of the middle cerebral artery, the time velocity integral, and the peak flow velocity of the Doppler waveform increased significantly with advancing gestational age. Blood flow to the middle cerebral artery ranged from 23 ml/min at 19 weeks to 133 ml/min at term. Resistivity index values were not correlated with advancing gestational age. The percent of the cardiac output to one of the two middle cerebral arteries remained constant throughout gestation with a range between 3% and 7%. CONCLUSIONS (1) Time velocity integral, peak flow velocity, diameter, and blood flow of the middle cerebral artery increased significantly with gestational age; (2) the percent of the total cardiac output to the middle cerebral artery does not significantly change with gestational age.

M-mode echocardiographic evaluation of fetal and infant hearts : Longitudinal follow-up study from intrauterine life to year one

OBJECTIVE Our purpose was to evaluate cardiac variables, including right and left end-diastolic and end-systolic dimensions by use of M-mode echocardiography during fetal, neonatal (transitional), and infancy periods to understand hemodynamic adaptation during these periods. STUDY DESIGN Fifty-three fetuses were enrolled in this study. Echocardiography evaluations were started as early as the sixteenth week of gestation and were repeated every 4 to 6 weeks until term, on postnatal days 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastolic and end-systolic measurements were made according to published standards. Mean and SEM for each of the end-diastolic and end-systolic measurements were calculated for each of 11 study periods. Data were analyzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t tests were used for significance. RESULTS Left ventricular end-diastolic and end-systolic correlated positively with advancing age (R2 = 0.93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R2 = = 0.361, p < 0.05), and right ventricular end-diastolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.0001). Heart rate significantly decreased with advancing age (p < 0.001), whereas ejection fraction for either the right or the left ventricle did not change significantly with advancing age. CONCLUSION This suggests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions without having to increase contractility reserve.

Effects of maternal administration of 3% carbon dioxide on umbilical artery and fetal renal and middle cerebral artery Doppler waveforms

OBJECTIVE The null hypothesis is that umbilical, middle cerebral, and renal artery pulsed Doppler velocity waveforms in the normal term fetus may be affected during short-term maternal inhalation of 3% carbon dioxide gas mixture. STUDY DESIGN Seventy-two observations were made on 14 term fetuses before and during maternal 3% carbon dioxide gas mixture inhalation. The umbilical, middle cerebral, and renal arteries of these fetuses were sampled with pulsed Doppler velocity waveforms and recorded on a strip chart at a preset speed of 50 mm/sec. Doppler waveforms were analyzed for differences in the systolic peak to end-diastolic velocity ratio for these three vascular beds. Peak flow velocity and time velocity integral were also analyzed for the cerebral and renal vascular beds. The data were analyzed with the paired t test. RESULTS A significant decrease in the systolic-to-diastolic-velocity ratio of the middle cerebral artery occurred with 3% carbon dioxide inhalation (p < 0.02). The other vascular beds had no demonstrable change. CONCLUSION Transient maternal breathing of 3% carbon dioxide gas mixture selectively causes a decrease in resistance in the fetal cerebral circulation.

Sargassum fusiforme Fraction is a Potent and Specific Inhibitor of HIV-1 Fusion and Reverse Transcriptase

Sargassum fusiforme (Harvey) Setchell has been shown to be a highly effective inhibitor of HIV-1 infection. To identify its mechanism of action, we performed bioactivity-guided fractionation on Sargassum fusiforme mixture. Here, we report isolation of a bioactive fraction SP4-2 (S. fusiforme), which at 8 μg/ml inhibited HIV-1 infection by 86.9%, with IC50 value of 3.7 μg. That represents 230-fold enhancement of antiretroviral potency as compared to the whole extract. Inhibition was mediated against both CXCR4 (X4) and CCR5 (R5) tropic HIV-1. Specifically, 10 μg/ml SP4-2 blocked HIV-1 fusion and entry by 53%. This effect was reversed by interaction of SP4-2 with sCD4, suggesting that S. fusiforme inhibits HIV-1 infection by blocking CD4 receptor, which also explained observed inhibition of both X4 and R5-tropic HIV-1. SP4-2 also inhibited HIV-1 replication after virus entry, by directly inhibiting HIV-1 reverse transcriptase (RT) in a dose dependent manner by up to 79%. We conclude that the SP4-2 fraction contains at least two distinct and biologically active molecules, one that inhibits HIV-1 fusion by interacting with CD4 receptor, and another that directly inhibits HIV-1 RT. We propose that S. fusiforme is a lead candidate for anti-HIV-1 drug development.

Hyperemic response of the brachial artery during the second half of pregnancy.

Objective: To determine if women who developed preeclampsia had measurable differences in the vascular response postrelease of a 1-minute blood flow occlusion. Methods: A total of 33 nulliparous patients were enrolled in this study during the second half of the pregnancy. All had baseline Doppler flow velocities while resting in the left lateral decubitus. Subsequently, a blood pressure cuff was inflated for 60 seconds in the forearm so as to occlude blood flow. Doppler waveforms were analyzed immediately after the release of the blood pressure cuff and on a single beat occurring at 15 second intervals for a total of five reading. After a rest period, patients were asked to squeeze a handheld manometer at maximum strength as long as possible. Doppler waveforms were analyzed as above. The Doppler waveforms of all enrolled patients who subsequently developed preeclampsia any time after the study were compared to those who remained normotensive. Results: 1) The “hyperemic response” that occurred immediately after release of the blood pressure occlusion of the forearm was significantly different between patients who subsequently developed preeclampsia compared with those who remained normotensive, 2) the hyperemic response that occurred after the isometric handgrip exercise was not significantly different between the two groups, and 3) sensitivity, specificity, and negative predictive values were high, but positive predictive values were low. Conclusion: There was a significant difference in the hyperemic response of the brachial artery to a short period of ischemia of the foream (blood pressure occlusion) between normotensive patients and a group of patients who subsequently developed preeclampsia.

Validation of noninvasive fetal renal artery flow measurement by pulsed Doppler in the lamb

OBJECTIVE Our objective was to evaluate the accuracy of quantitative measurement of blood flow of the left renal artery in the fetal lamb by means of range-gated, two-dimensional pulsed Doppler ultrasonography. STUDY DESIGN Doppler measurements were compared with invasive measurements obtained with a perivascular flow probe (Transonic) placed on the fetal renal artery. Renal blood flow was manipulated acutely either by volume expansion or depletion or by means of pharmacologic agents. With each manipulation values of the left fetal renal artery blood flow were obtained with both methods. The size of the fetal renal artery was determined by postmortem examination. RESULTS A total of 36 paired flow measurements were obtained on five fetuses. One fetus had only Transonic determination of renal blood flow. Pulsed Doppler ultrasonography blood flow and transit-time ultrasonography blood flow estimations were correlated (F = 82.4, R2 = 0.73, p < 0.001). CONCLUSION This study suggests that two-dimensional pulsed Doppler can reliably estimate renal blood flow in the fetal lamb.