1,027 research outputs found
Fetal growth restriction is associated with prioritization of umbilical blood flow to left hepatic lobe, at the expense of the right lobe
No full textEighty to 85% of the venous perfusion to the fetal liver is from the umbilical vein, the rest from the portal vein. Umbilical venous flow to the liver is essential for intrauterine growth, and is impaired in placental insufficiency. We hypothesized that in growth-restricted fetuses portal blood flow compensates for insufficient umbilical blood flow to the liver. In 29 fetuses with fetal growth restriction (estimated fetal weight < or =5th percentile), we used ultrasound to measure blood flows in the umbilical vein, ductus venosus, left portal vein, and main portal stem. Compared with normal fetuses, both absolute and normalized total venous liver blood flows were reduced in growth-restricted fetuses, related to the degree of placental compromise and equally affecting both liver lobes. However, portal replaced umbilical flow to the right lobe, in a manner graded according to placental vascular resistance; in extreme cases, the right lobe received no umbilical perfusion. In fetal growth restriction, the liver suffers from venous hypoperfusion, and portal blood partially replaces umbilical flow to the right lobe; this will result in right liver lobe hypoxemia. This striking prioritization in nutrient delivery of left over right lobes suggests an adaptive response to poor placental perfusion that may have functional consequence
Longitudinal study of umbilical and portal venous blood flow to the fetal liver: low pregnancy weight gain is associated with preferential supply to the fetal left liver lobe
No full textRecent data suggest that umbilical venous perfusion of the fetal liver has an important influence on fetal growth and postnatal liver function, and that maternal factors in late pregnancy modify this circulation. In a longitudinal study of 160 low-risk pregnancies, we determined how umbilical and portal venous blood flows to the fetal liver changed during gestation, and examined the hypothesis that maternal body mass index and pregnancy weight gain influenced fetal liver blood flows. We measured blood flows in the umbilical and portal veins, left portal branch, and ductus venosus using ultrasound. Normalizing for estimated fetal weight, fetal liver total venous blood flow fell from 84 to 57 mL. min(-1). kg(-1) during 21-39 wk of gestation; toward term the portal contribution increased (from 14 to 20%) and the umbilical contribution fell, whereas distribution between the left and right liver lobes was stable, 60%/40%. Greater flow of nutrient-rich umbilical venous blood to the liver was associated with higher birth weight and neonatal ponderal index. Maternal body mass index was not related to fetal liver blood flows, but low pregnancy weight gain strongly influenced flow distribution between the right and left liver lobes, sparing the left lobe and increasing the difference between lobes by 16%
Venous liver blood flow and regulation of human fetal growth: evidence from macrosomic fetuses
No full textOBJECTIVE: Experimental studies show that fetal liver venous perfusionis a determinant for growth in utero. Here we explore the relationshipbetween fetal venous blood flow to the liver and macrosomia.STUDY DESIGN: From diameter and blood flow velocity measurements,we derived liver venous blood flow in a longitudinal ultrasoundstudy of 25 macrosomic fetuses of nondiabetic mothers during the secondhalf of pregnancy.RESULTS: Compared with appropriately growing fetuses, macrosomicfetuses directed more umbilical blood to the liver tissue, with correspondinglyless contribution from the portal circulation when normalizedfor fetal weight. Whereas total venous liver blood flow showed nolate gestation rise in the reference population, it continued to increase inmacrosomic fetuses and was accompanied by greater fetal weight.CONCLUSION: The direct relationship between venous liver blood flowand macrosomia in the fetus supports the concept that intrauterinegrowth is linked to the amount and distributional pattern of venous liverperfusion
Redistribution pattern of fetal liver circulation in intrauterine growth restriction
No full textObjectiveFetal liver blood supply is an important determinant of fetal growth and adaptation. Most fetal liver blood supply is from the umbilical vein, but the portal vein contributes 14-20% and studies of low-risk pregnancies suggest the splanchnic arteries are also involved in the homeostasis of fetal liver perfusion. Here we determine the circulatory pattern of the fetal liver in intrauterine growth restriction (IUGR). Design. Cross-sectional study. Population. Thirty-one IUGR fetuses (estimated fetal weight <5th centile). Methods Pulsatility index (PI) measurements of the umbilical, middle cerebral, splenic, hepatic, and superior mesenteric arteries were compared with a reference population and related to umbilical venous flow, umbilico-caval pressure gradient (assessed by ductus venosus peak velocity) and venous distribution within the liver (assessed by flow velocity in the left portal vein). ResultsThirteen of 31 IUGR fetuses had umbilical artery PI > 97.5 centile and 13 showed a middle cerebral artery brain-sparing pattern (PI Z-score < - 2). In IUGR, umbilical venous flow was lower and less umbilical blood was distributed to the right liver lobe, while the umbilico-caval pressure gradient was kept normal. The hepatic and splenic arteries, but not the superior mesenteric artery, had low PI compared with the reference population. ConclusionsIUGR fetuses with increased or normal umbilical artery PI maintained venous perfusion pressure to the liver while distributing less umbilical blood to the right liver lobe. They showed regional splanchnic arterial redistribution with low splenic and hepatic artery PI, implying increased portal venous flow and direct arterial contribution to hepatic perfusion, respectively
Altered development of fetal liver perfusion in pregnancies with pregestational diabetes
No full text
Background Pregestational diabetes is associated with fetal macrosomia, and umbilical perfusion of the fetal liver has a role in regulating fetal growth. We therefore hypothesized that pregestational diabetes alters fetal liver blood flow depending on degree of glycemic control. Methods In a prospective study, 49 women with pregestational diabetes underwent monthly ultrasound examinations during 24-36 gestational weeks. Blood flow was determined in the umbilical vein, ductus venosus and portal vein, and blood velocity was measured in the left portal vein, the latter reflecting the watershed between splanchnic and umbilical flow. The measurements were compared with reference values by z-score statistics, and the effect of HbA
1c
assessed. Results The umbilical venous flow to the liver (z-score 0.36, p = 0.002), total venous liver flow (z-score 0.51, p<0.001) and left portal vein blood velocity (z-score 0.64, p<0.001), were higher in the study group. Normalized portal venous flow was lower (z-score -0.42, p = 0.002), and normalized total venous liver flow tended to be lower after 30 gestational weeks (z-score -0.54, p = 0.047) in the diabetic pregnancies compared with reference values from a low-risk population. The left portal vein blood velocity was positively, and the portal fraction of total venous liver flow negatively correlated with first trimester HbA
1C
. Conclusions In spite of increased umbilical blood distribution to the fetal liver, graded according to glycemic control, the total venous liver flow did not match third trimester fetal growth in pregnancies with pregestational diabetes, thus contributing towards increased perinatal risks and possibly altered liver function with long-term metabolic consequences.
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Fetal superior mesenteric artery: longitudinal reference ranges and evidence of regulatory link to portal liver circulation
No full textObjective: To establish longitudinal reference ranges for the fetal superior mesenteric artery (SMA) flow
velocity and pulsatility index (PISMA). Also to examine the hemodynamic relationship to venous liver
perfusion and umbilical flow distribution in the liver, to other splanchnic arteries, and more generally to the
middle cerebral and umbilical artery.
Methods: Prospective longitudinal study of 161 low-risk pregnancies using Doppler recordings including the
SMA, repeated on 3–5 occasions at 3–5 weekly intervals. Umbilical venous flow was estimated, blood velocity
in the shunt ductus venosus represented umbilico-caval (i.e. porto-caval) pressure gradient, and left portal
vein blood velocity represented umbilical distribution within the liver. The correlation between PISMA and the
splenic and hepatic artery PI were analysed (PISA and PIHA), and the association to middle cerebral and
umbilical artery PI (PIMCA and PIUA) assessed.
Results: Reference ranges for the SMA for gestational weeks 21–39 were based on 589 observations. Low
impedance in the SMA (i.e. low PISMA) was associated with low umbilical flow and porto-caval pressure
gradient (i.e. b10th centile), and high distribution of umbilical flow to the right lobe (i.e. left portal vein blood
velocity N90th centile). PISMA correlated weakly with PISA and PIHA (r=0.30, 95%CI 0.22–0.37, and r=0.39, 95%
CI 0.27–0.51, respectively). PISMA was positively associated with PIMCA and PIUA.
Conclusion: We have provided longitudinal reference ranges for fetal SMA flow velocity and PI, and shown
that the SMA, which perfuses the fetal gut, is also involved in the regulation of the liver perfusion
Commentary. Students Offer Innovative Ideas to Stimulate Maine\u27s Economy
No full textConclusions students reached when researching ways to stimulate Maine\u27s economy are presented. The project was part of a macroeconomics class assignment taught by the author, Tove Rasmussen, at the University of Southern Maine
Disputable Issues in the Russian History of the 16th Century
No full textKnud Rasmussen (1930–1985) was a famous Danish historian, Professor at Institute of Slavic Studies at University of Copenhagen, specialist in medieval Russia, author of a dozen of scientific monographs published in large editions including in Russian. In 1973, he defended his thesis titled “The Livonian crisis of 1554–1561”. According to the list of works published by J. Lind, 13 publications are devoted to the epoch of Ivan the Terrible. This article, published for the first time, is presented in the form of a report at the conference in Hungary. The scientist consistently outlined the main tasks and problems related to the study of Russian history abroad, in particular, in Denmark. He told what plan was built for the team of Danish historians who decided in the early 1970s to prepare a textbook on Russian history in the form of a problem historiographic course for Danish students, and how this plan was implemented. The study of works on Russian history and their systematization helped the team of Danish historians, which included K. Rasmussen, develop a special historiographic method and its principles, which led to developing understanding of the problematic historical field as a whole and placing individual research in it. As a result, a multivolume manual was written; by the time of K. Rasmussen’s speech, 3 volumes were published, covering the period of Russian history from the 17th to the 20th century inclusive. K. Rasmussen worked on preparing a volume on the Russian history of the 16th century. In the second part of his speech (article), the author shared his thoughts on the chosen approach to the assessment of historiography and spoke about the content of this volume, where he outlined the controversial problem of enslaving peasants, discussions on the reasons for backwardness of Russian cities as the basis of Moscow defeats in Livonia, possible ways of Russian revival, on the state and its institutions and on the development of historical events in the field of domestic policy. This volume was published after the death of the author in the same year: Rasmussen Knud. Ruslands historie i det 16. Arhundrede: En forsknings-og kildeoversigt. Kobenhavn, 1985. 161 s. Bibliography about K. Rasmussen: Lind J. Creative Way Knud Rasmussen (on the 10th anniversary of his death) // Archeographic Yearbook for 1995. – Moscow : Nauka, 1995. – P. 160–165; Lind J. H. Knud Rasmussen in memoriam // Jacob Ulfeld. Travel to Russia. – M. : Languages of Slavic culture, 2002. – Р. 17–25; Vozgrin V. E. Knud Rasmussen and Zans Bagger – Danish historians of Russia // Proceedings of the Department of the History of New and Newest Times of St. Petersburg State University. – 2016. – № 16 (2). – Р. 205–219.
The abstract is prepared by Candidate of Sciences (History), Associate Professor N.V. Rybalko
Om medier, verdier og moral
No full textTerje Rasmussen Mediesamfunnets moral. Oslo: Pax forlag, 2001
The Public Market as an Engine for Economic Revival
No full textJohn Rasmussen discusses the integral role of public markets in the economic benefit of their home cities. In the author’s words, “viable cities have viable public markets”. The author uses his professional experience as a real estate appraiser as well as case studies in this article. Conference paper; originally published in Western Reserve Studies Symposium (17th:2002 : Cleveland, Ohio)
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