The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Giancarlo Pennati - One of the best experts on this subject based on the ideXlab platform.
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Doppler Investigation in Intrauterine Growth Restriction—From Qualitative Indices to Flow Measurements
Annals of the New York Academy of Sciences, 2020Co-Authors: Enrico Ferrazzi, Maria Bellotti, Henry L. Galan, Giancarlo Pennati, Maddalena Bozzo, Serena Rigano, Frederick C. BattagliaAbstract:: In 1997 we started a collaboration among three groups, combining our experience with Doppler examination of the human Fetus, Blood flow studies on fetal lamb, and mathematical modeling of human circulation. In preliminary investigations on fetal lambs, the same Doppler method designed for the human Fetus was used to measure venous Blood flow in the umbilical veins of seven fetal lambs. Doppler measurements and diffusion technique groups for umbilical venous flow were 210.8 ± 18.8 and 205.7 ± 38.5 ml/min/kg, respectively (p= 0.881). In human pregnancy the interobserver variabilities for the vein diameter, mean velocity, and absolute umbilical venous Blood were 2.9%, 7.9%, and 12.7%, respectively. A cross-sectional study allowed us to establish normal reference values. Venous Blood flow/kg of estimated fetal weight showed a nonsignificant linear reduction with gestational age, from 128.7 ml/min/kg at 20 weeks to 104.2 ml/min/kg at 38 weeks. In a series of 37 growth-restricted Fetuses, the UV flow per kilogram was significantly lower in the more severe growth-restricted Fetuses (abdominal circumference below the second percentile and abnormal umbilical arterial p.i.) than in normal comparable Fetuses (p < 0.001). In a series of 140 normal Fetuses, we calculated that the absolute Blood flow rate in the ductus venosus (DV) increases significantly with advancing gestational age from 20 to 38 weeks of gestation (from 23.2 ± 9.6 ml/min to 43.5 ± 21.5 ml/min). This means that the percentage of umbilical Blood flow shunted through the DV decreases significantly during gestation (from 50% at midgestation to 20% at 38 weeks). In a series of 45 growthrestricted Fetuses, delivered because of nonreactive fetal heart rate (group 2) and for other reasons but still with a normal heart rate pattern (group 1), we measured the ductal inlet diameter. In these Fetuses, the diameters at the ductal isthmus, normalized for the dimension of the abdominal circumference (inlet diameter/abdominal circumference), were significantly larger (group 1 = 6.8 ± 2.3; group 29.4 ± 2.8) than in the control group (6.1 ± 0.3). This means that in this subset of Fetuses the amount of Blood shunted can be increased as a compensatory mechanism.
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Blood flow through the ductus venosus in human Fetus calculation using doppler velocimetry and computational findings
Ultrasound in Medicine and Biology, 1998Co-Authors: Giancarlo Pennati, Maddalena Bozzo, M Bellotti, E Ferrazzi, G Pardi, R FumeroAbstract:Abstract The present study was performed to assess a new method to calculate the Blood flow rate through the ductus venosus (DV) in normal human Fetuses using available echo-Doppler data. Color Doppler sonographic unit was used to study DV flow in 26 normal Fetuses between 20 and 36 wk of gestation. Maximal velocity flow tracings and vessel diameters were obtained at the isthmic and the outlet portion of the DV. Time-averaged velocities in the DV were measured from the recorded tracings. The velocity distribution in the two investigated cross-sectional areas of the DV was evaluated by means of computational model simulations and the velocity shape coefficients h in and h out , ( i.e., the ratios between the maximal and mean spatial velocities) were calculated as a function of vessel geometry. These values allowed us to convert maximal Doppler velocities into mean spatial velocities for each Fetus. Blood flow rate was evaluated both at the isthmus and at the outlet of the vessel by means of two formulae based on the ultrasonographic measures and the results of the computational model. The value of the DV Blood flow rate was calculated as the average between the results provided by the two formulae. The velocity distributions both at the isthmus ( h in =0.677±0.040) and the outlet ( h out =0.374±0.072) of the ductus are skewed toward the inner wall. Ductus geometry, i.e., the isthmic/outlet diameter ratio, affects the shape of the velocity profiles in the vessel, particularly that at the outlet. The coefficients of variation for repeated measurements of the ductal diameters were 9.5 ± 7.7% and 6.7 ± 4.9% at the isthmus and the outlet, respectively. The two formulae gave values statistically identical for the time-average Blood flow rate (36.3 ± 22.1 vs. 39.4 ± 24.0 mL/min; R = 0.946, p = NS). The mean percent difference between the results of the two formulae was 7.1%. Thus, in human Fetuses, the use of the two formulae based on both Doppler data and computational model simulations makes it possible to calculate the ductal flow rate. When the difference between the calculations of the two formulae exceeds the 30% of their average value, it is convenient to adopt the flow rate value calculated at the isthmus instead of the average of the two measures. The measurements at the outlet of the ductus were more difficult to obtain, and the spatial velocity profile at the outlet depends more on the DV anatomy.
R Fumero - One of the best experts on this subject based on the ideXlab platform.
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Blood flow through the ductus venosus in human Fetus calculation using doppler velocimetry and computational findings
Ultrasound in Medicine and Biology, 1998Co-Authors: Giancarlo Pennati, Maddalena Bozzo, M Bellotti, E Ferrazzi, G Pardi, R FumeroAbstract:Abstract The present study was performed to assess a new method to calculate the Blood flow rate through the ductus venosus (DV) in normal human Fetuses using available echo-Doppler data. Color Doppler sonographic unit was used to study DV flow in 26 normal Fetuses between 20 and 36 wk of gestation. Maximal velocity flow tracings and vessel diameters were obtained at the isthmic and the outlet portion of the DV. Time-averaged velocities in the DV were measured from the recorded tracings. The velocity distribution in the two investigated cross-sectional areas of the DV was evaluated by means of computational model simulations and the velocity shape coefficients h in and h out , ( i.e., the ratios between the maximal and mean spatial velocities) were calculated as a function of vessel geometry. These values allowed us to convert maximal Doppler velocities into mean spatial velocities for each Fetus. Blood flow rate was evaluated both at the isthmus and at the outlet of the vessel by means of two formulae based on the ultrasonographic measures and the results of the computational model. The value of the DV Blood flow rate was calculated as the average between the results provided by the two formulae. The velocity distributions both at the isthmus ( h in =0.677±0.040) and the outlet ( h out =0.374±0.072) of the ductus are skewed toward the inner wall. Ductus geometry, i.e., the isthmic/outlet diameter ratio, affects the shape of the velocity profiles in the vessel, particularly that at the outlet. The coefficients of variation for repeated measurements of the ductal diameters were 9.5 ± 7.7% and 6.7 ± 4.9% at the isthmus and the outlet, respectively. The two formulae gave values statistically identical for the time-average Blood flow rate (36.3 ± 22.1 vs. 39.4 ± 24.0 mL/min; R = 0.946, p = NS). The mean percent difference between the results of the two formulae was 7.1%. Thus, in human Fetuses, the use of the two formulae based on both Doppler data and computational model simulations makes it possible to calculate the ductal flow rate. When the difference between the calculations of the two formulae exceeds the 30% of their average value, it is convenient to adopt the flow rate value calculated at the isthmus instead of the average of the two measures. The measurements at the outlet of the ductus were more difficult to obtain, and the spatial velocity profile at the outlet depends more on the DV anatomy.
Maddalena Bozzo - One of the best experts on this subject based on the ideXlab platform.
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Doppler Investigation in Intrauterine Growth Restriction—From Qualitative Indices to Flow Measurements
Annals of the New York Academy of Sciences, 2020Co-Authors: Enrico Ferrazzi, Maria Bellotti, Henry L. Galan, Giancarlo Pennati, Maddalena Bozzo, Serena Rigano, Frederick C. BattagliaAbstract:: In 1997 we started a collaboration among three groups, combining our experience with Doppler examination of the human Fetus, Blood flow studies on fetal lamb, and mathematical modeling of human circulation. In preliminary investigations on fetal lambs, the same Doppler method designed for the human Fetus was used to measure venous Blood flow in the umbilical veins of seven fetal lambs. Doppler measurements and diffusion technique groups for umbilical venous flow were 210.8 ± 18.8 and 205.7 ± 38.5 ml/min/kg, respectively (p= 0.881). In human pregnancy the interobserver variabilities for the vein diameter, mean velocity, and absolute umbilical venous Blood were 2.9%, 7.9%, and 12.7%, respectively. A cross-sectional study allowed us to establish normal reference values. Venous Blood flow/kg of estimated fetal weight showed a nonsignificant linear reduction with gestational age, from 128.7 ml/min/kg at 20 weeks to 104.2 ml/min/kg at 38 weeks. In a series of 37 growth-restricted Fetuses, the UV flow per kilogram was significantly lower in the more severe growth-restricted Fetuses (abdominal circumference below the second percentile and abnormal umbilical arterial p.i.) than in normal comparable Fetuses (p < 0.001). In a series of 140 normal Fetuses, we calculated that the absolute Blood flow rate in the ductus venosus (DV) increases significantly with advancing gestational age from 20 to 38 weeks of gestation (from 23.2 ± 9.6 ml/min to 43.5 ± 21.5 ml/min). This means that the percentage of umbilical Blood flow shunted through the DV decreases significantly during gestation (from 50% at midgestation to 20% at 38 weeks). In a series of 45 growthrestricted Fetuses, delivered because of nonreactive fetal heart rate (group 2) and for other reasons but still with a normal heart rate pattern (group 1), we measured the ductal inlet diameter. In these Fetuses, the diameters at the ductal isthmus, normalized for the dimension of the abdominal circumference (inlet diameter/abdominal circumference), were significantly larger (group 1 = 6.8 ± 2.3; group 29.4 ± 2.8) than in the control group (6.1 ± 0.3). This means that in this subset of Fetuses the amount of Blood shunted can be increased as a compensatory mechanism.
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Blood flow through the ductus venosus in human Fetus calculation using doppler velocimetry and computational findings
Ultrasound in Medicine and Biology, 1998Co-Authors: Giancarlo Pennati, Maddalena Bozzo, M Bellotti, E Ferrazzi, G Pardi, R FumeroAbstract:Abstract The present study was performed to assess a new method to calculate the Blood flow rate through the ductus venosus (DV) in normal human Fetuses using available echo-Doppler data. Color Doppler sonographic unit was used to study DV flow in 26 normal Fetuses between 20 and 36 wk of gestation. Maximal velocity flow tracings and vessel diameters were obtained at the isthmic and the outlet portion of the DV. Time-averaged velocities in the DV were measured from the recorded tracings. The velocity distribution in the two investigated cross-sectional areas of the DV was evaluated by means of computational model simulations and the velocity shape coefficients h in and h out , ( i.e., the ratios between the maximal and mean spatial velocities) were calculated as a function of vessel geometry. These values allowed us to convert maximal Doppler velocities into mean spatial velocities for each Fetus. Blood flow rate was evaluated both at the isthmus and at the outlet of the vessel by means of two formulae based on the ultrasonographic measures and the results of the computational model. The value of the DV Blood flow rate was calculated as the average between the results provided by the two formulae. The velocity distributions both at the isthmus ( h in =0.677±0.040) and the outlet ( h out =0.374±0.072) of the ductus are skewed toward the inner wall. Ductus geometry, i.e., the isthmic/outlet diameter ratio, affects the shape of the velocity profiles in the vessel, particularly that at the outlet. The coefficients of variation for repeated measurements of the ductal diameters were 9.5 ± 7.7% and 6.7 ± 4.9% at the isthmus and the outlet, respectively. The two formulae gave values statistically identical for the time-average Blood flow rate (36.3 ± 22.1 vs. 39.4 ± 24.0 mL/min; R = 0.946, p = NS). The mean percent difference between the results of the two formulae was 7.1%. Thus, in human Fetuses, the use of the two formulae based on both Doppler data and computational model simulations makes it possible to calculate the ductal flow rate. When the difference between the calculations of the two formulae exceeds the 30% of their average value, it is convenient to adopt the flow rate value calculated at the isthmus instead of the average of the two measures. The measurements at the outlet of the ductus were more difficult to obtain, and the spatial velocity profile at the outlet depends more on the DV anatomy.
Warren R. Selman - One of the best experts on this subject based on the ideXlab platform.
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Changing Metabolic and Energy Profiles in Fetal, Neonatal, and Adult Rat Brain
Metabolic Brain Disease, 2003Co-Authors: W. David Lust, Svetlana Pundik, Jennifer Zechel, Yinong Zhou, Marek Buczek, Warren R. SelmanAbstract:The regional energy status and the availability of metabolic substrates during brain development are important, since a variety of fetal metabolic insults have been increasingly implicated in the evolution of neonatal brain disorders. The response of the brain to a metabolic insult is determined, in large part, by the ability to utilize the various substrates for intermediary metabolism in order to maintain energy stores within the tissue. To ascertain if metabolic conditions of the fetal brain make it more or less vulnerable to a stress, the high-energy phosphates and glucose-related compounds were examined in five regions of the embryonic day 18 (E-18) fetal brain. Glucose and glycogen levels in the E-18 fetal brain were generally higher in the cerebellum and its neuroepithelium than in the hippocampus, cerebral cortex, and its neuroepithelium. Regional lactate and high-energy phosphate concentrations were essentially the same in the five regions. Subsequently, the metabolic profile was examined in the cerebral cortex and striatum from E-18, postpartum day 7 (P-7) and adult rats. At the various stages of development, there were only minimal differences in the high-energy phosphate levels in the striatum and cortex. Glucose levels, the primary substrate in the adult brain, were essentially unchanged throughout development. In contrast, lactate was significantly elevated by 6- and 2-fold over those in the adult brain in the E-18 and P-7 striatum and cortex, respectively. Another alternative substrate, β-hydroxybutyrate, was also significantly elevated at E-18 and increased more than 2-fold at P-7, but was barely detectable in the adult cortex and striatum. Finally, glucose and lactate levels were examined in cerebrospinal fluid, Blood, and brain from the E-18 brain to determine if a gradient among the compartments exists. The levels of both lactate and glucose exhibited a concentration gradient in the E-18 Fetus: Blood > cerebrospinal fluid > brain parenchyma. The results indicate that energy state in the fetal brain is comparable to that in the neonates and the adults, but that the availability of alternative substrates for intermediary metabolism change markedly with development. The age-dependent substrate specificity for intermediary metabolism could affect the response of the fetal brain to a metabolic insult.
Kozinets Gi - One of the best experts on this subject based on the ideXlab platform.
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The stability of cell composition of Fetus Blood in norm and under hypoferric anemia
Klinicheskaia laboratornaia diagnostika, 2013Co-Authors: Shmarov Da, Krekhnov Bv, Blbulyan Ak, Kozinets GiAbstract:The article deals with indicators of cell composition of umbilical Blood (Fetus Blood) in case of normal pregnancy (n = 38) and hypoferric anemia of light degree (n = 14)10 the hematologic analyzer of medium class was applied. The parameters of erythrocytes of Fetus Blood in case of hypoferric anemia of light degree were sufficiently stable and had no differences with normal values both in mean values and variability. The variety of adaptive index of Fetus Blood (Garkavi index) was significantly higher in case of hypoferric anemia as compared with normal values. This occurrence testifies higher stability of indicators of adaptation in case of moderate ferric deficiency. The study results testify the informativity of applied approach related to assessment of stability of cell composition of Fetus Blood.