The effect of litter size on placental blood flow and placental calcium transfer in the multifoetate guinea-pig

1978 ◽  
Vol 39 (2) ◽  
pp. 347-356 ◽  
Author(s):  
H. W. Symonds ◽  
R. H. Bubar ◽  
W. CRACKEL ◽  
A. R. Twardock
Keyword(s):  
Blood Flow ◽  
Litter Size ◽  
Flow Rate ◽  
Transfer Rate ◽  
Placental Tissue ◽  
Blood Flow Rate ◽  
Maternal Plasma ◽  
Placental Blood ◽  
The Mean ◽  
Placental Blood Flow

1. Placental blood flow rate and calcium transfer rate were measured at 61 d of pregnancy in guinea-pigs carrying between one and eight foetuses.2. Placental blood flow rate was significantly correlated with foetal weight. Ca transfer rate was related to placental size. Irrespective of litter size the mean amount of Ca transferred across a placenta was between 0.22 and 0.34 mg/h per g placental tissue.3. It was concluded that there was a limit to the rate of transfer which was produced by a combination of limitations in placental blood flow rate, maternal plasma Ca concentration and placental tissue transfer capacity.

scholarly journals Evaluation of hemodynamic impact of absorbable sutures in native arteriovenous fistulas: A retrospective study

2019 ◽  
Vol 43 (1) ◽  
pp. 58-61
Author(s):  
Savino Occhionorelli ◽  
Fabio Fabbian ◽  
Yuri Battaglia ◽  
Tommaso Miccoli ◽  
Dario Andreotti ◽  
...  
Keyword(s):  
Blood Flow ◽  
Arteriovenous Fistula ◽  
Flow Rate ◽  
Neointimal Hyperplasia ◽  
Blood Flow Rate ◽  
Absorbable Suture ◽  
Absorbable Sutures ◽  
The Mean ◽  
Fistula Maturation ◽  
Arteriovenous Fistula Maturation

One of the major causes of arteriovenous fistula failure is the venous stenosis due to aggressive neointimal hyperplasia. The aim of the study was to assess the arteriovenous fistula maturation comparing absorbable sutures and non-absorbable ones in native vessels. Surgeries performed during a period of 24 months by a single team of expert surgeons were evaluated. Surgeries that met the inclusion criteria, namely, age ⩾ 18 years and radio-cephalic arteriovenous fistula, were considered. According to type of suture, patients were classified as Max group (absorbable suture) and Prol group (non-absorbable). Data pertaining to 70 patients were collected; 51% were men and the mean age was 73 ± 12 years. In Max group, an increasing blood flow was observed during the first 4 weeks without post-operative complications. In Prol group, six patients had thrombosis that resulted in vascular access failure. After the first week, the duplex Doppler ultrasound of both groups showed a regular arteriovenous fistula maturation, with an increase of blood flow rate. Although pre-operative post-tourniquet mean vein diameters of Max group were not adequate, the mean vein diameter and mean blood flow rate increased after 4 weeks, respectively. On the contrary, in Prol group, mean vein diameters and blood flow rate decreased. The maturation of arteriovenous fistula and its functional performance were not altered by the type of suture (absorbable/non-absorbable). Absorbable sutures were associated with good results considering arteriovenous fistula maturation.

scholarly journals Placental Transfer of Lactate, Glucose and 2-deoxyglucose in Control and Diabetic Wistar Rats

2001 ◽  
Vol 2 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Chris R. Thomas ◽  
Beryl B. Oon ◽  
Clara Lowy
Keyword(s):  
Blood Flow ◽  
Wistar Rats ◽  
Placental Transfer ◽  
Maternal Plasma ◽  
Diabetic Group ◽  
Control Group ◽  
Placental Blood ◽  
Lactate Levels ◽  
Placental Blood Flow

Placental transfer of lactate, glucose and 2-deoxyglucose was examined employing thein situperfused placenta. Control and streptozotocin induced diabetic Wistar rats were infused with U-14C]-glucose and [3H]-2-deoxyglucose (2DG). The fetal side of the placenta was perfuseci with a cell free medium and glucose uptake was calculated in the adjacent fetuses. Despite the 5-fold higher maternal plasma glucose concentration in the diabetic dams the calculated fetal glucose metabolic index was not significantly different between the 2 groups. Placental blood flow was reduced in the diabetic animals compared with controls but reduction of transfer of [U-14C]-glucose and [3H]-2-deoxyglucose and endogenously derived [14C]-Lactate to the fetal compartment, could not be accounted for by reduced placental blood flow alone. There was no significant net production or uptake of lactate into the perfusion medium that had perfused the fetal side of the placenta in either group. The plasma lactate levels in the fetuses adjacent to the perfused placenta were found to be higher than in the maternal plasma and significantly higher in the fetuses of the diabetic group compared with control group. In this model thein situperfused placenta does not secrete significant quantities of lactate into the fetal compartment in either the control or diabetic group.

Chronic alterations in ovine maternal corticosteroid levels influence uterine blood flow and placental and fetal growth

2005 ◽  
Vol 288 (1) ◽  
pp. R54-R61 ◽  
Author(s):  
Ellen Jensen ◽  
Charles E. Wood ◽  
Maureen Keller-Wood
Keyword(s):  
Blood Flow ◽  
Plasma Cortisol ◽  
Somatic Growth ◽  
Maternal Plasma ◽  
Control Group ◽  
Uterine Blood Flow ◽  
Arterial Blood ◽  
Placental Blood ◽  
Low Cortisol ◽  
Placental Blood Flow

Previous work from this laboratory demonstrated that the elevation of maternal plasma corticosteroid concentrations during pregnancy is important for the support of fetal development. Reducing ovine maternal plasma cortisol concentrations to nonpregnant levels stimulates homeostatic responses that defend fetal blood volume. The present study was designed to test the hypothesis that chronic decreases or increases in maternal plasma cortisol concentration alter uterine and placental blood flow and morphology. Three groups of pregnant ewes and their fetuses were chronically catheterized and studied: ewes infused with cortisol (1 mg·kg−1·day−1; high cortisol), ewes adrenalectomized and underreplaced with cortisol (0.5 mg·kg−1·day−1; low cortisol), and control ewes. The normal increment in uterine blood flow between 120 and 130 days was eliminated in the low-cortisol ewes; conversely, uterine blood flow was increased in the high-cortisol group compared with the control group. Fetal arterial blood pressure was increased in the high-cortisol group compared with controls, but there was no increase in fetal arterial pressure from 120 to 130 days of gestation in the low-cortisol group. The fetuses of both low-cortisol and high-cortisol groups had altered placental morphology, with increased proportions of type B placentomes, and overall reduced fetal placental blood flow. The rate of fetal somatic growth was impaired in both low-cortisol and high-cortisol groups compared with the fetuses in the intact group. The results of this study demonstrate that maternal plasma cortisol during pregnancy is an important contributor to the maternal environment supporting optimal conditions for fetal homeostasis and somatic growth.

scholarly journals P1367THE RELATIONSHIP OF SERUM PHOSPHORUS LEVEL AND ARTERIOVENOUS FISTULA DYSFUNCTION IN MAINTENANCE HEMODIALYSIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Hyung-Jong Kim ◽  
Mi Jung Lee
Keyword(s):  
Blood Flow ◽  
Risk Factor ◽  
Arteriovenous Fistula ◽  
Flow Rate ◽  
Vascular Access ◽  
Univariate Analysis ◽  
Blood Flow Rate ◽  
Dialysis Unit ◽  
The Mean ◽  
The Impact

Abstract Background and Aims It is known that maintenance of function of arteriovenous fistula (AVF) is very important in the management of hemodialysis (HD) patients. Therefore, identifying a risk factor for decreased vascular access flow has a clinical relevance in real world practice. Although hyperphosphatemia plays a crucial role in the pathogenesis of vascular calcification, there is lack of studies evaluating the effect of hyperphosphatemia on AVF. This study investigated the impact of serum phosphorous (P) on vascular access flow in HD patients. Method Sixty-two maintenance HD patients who visited dialysis unit of Bundang CHA Medical Center from November 2016 to December 2017 were included in this study. Serum P levels were determined every month and time-averaged serum P was calculated. All patients had left arm AVF (side to side anastomosis) and vascular access flow was assessed by Transonic HD 03. Decreased vascular access flow was defined as less than 600 mL/min. Results The mean age was 57.9 ± 12.1 years, 32 patients (51.6%) were men. The mean serum P levels were 5.1 ± 1.1 mg/dL and the vascular access flow was 1,071.4 ± 504.2 mL/min. Decreased vascular access flow was observed in 14 of 62 patients (22.6%). In univariate analysis, higher serum P was significantly associated with decreased vascular access flow (odds ratio [OR]=2.089, 95% confidence interval [CI]=1.159-3.766, P=0.014). But there was no significant association of dialysis blood flow rate, ejection fraction on echocardiography and serum calcium (Ca) levels with vascular access flow. Multivariable analysis indicated that higher serum P was independently associated with greater risk of decreased vascular access flow (OR=4.012, 95% CI=1.651-9.711, P=0.002). Old age, reduced EF, low dialysis blood flow rate and higher serum Ca was not associated with vascular access flow. Conclusion This study demonstrated that higher serum P was the independent risk factor for decreased vascular access flow in maintenance HD patients. Serial monitoring of serum P may be helpful to stratify the risk of vascular access dysfunction in these patients.

The Effect of Furosemide on the Intrarenal Blood Flow Distribution in the Dog

1972 ◽  
Vol 50 (8) ◽  
pp. 774-783 ◽  
Author(s):  
Serge Carrière ◽  
Michel Desrosiers ◽  
Jacques Friborg ◽  
Michèle Gagnan Brunette
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Urine Volume ◽  
Flow Distribution ◽  
Blood Flow Rate ◽  
Initial Distribution ◽  
Blood Flow Distribution ◽  
Intrarenal Blood Flow ◽  
Femoral Blood ◽  
Furosemide Administration

Furosemide (40 μg/min) was perfused directly into the renal artery of dogs in whom the femoral blood pressure was reduced (80 mm Hg) by aortic clamping above the renal arteries. This maneuver, which does not influence the intrarenal blood flow distribution, produced significant decreases of the urine volume, natriuresis, Ccreat, and CPAH, and prevented the marked diuresis normally produced by furosemide. Therefore the chances that systemic physiological changes occurred, secondary to large fluid movements, were minimized. In those conditions, however, furosemide produced a significant increase of the urine output and sodium excretion in the experimental kidney whereas Ccreat and CPAH were not affected. The outer cortical blood flow rate (ml/100 g-min) was modified neither by aortic constriction (562 ± 68 versus 569 ± 83) nor by the subsequent administration of furosemide (424 ± 70). The blood flow rate of the outer medulla in these three conditions remained unchanged (147 ± 52 versus 171 ± 44 versus 159 ± 54). The initial distribution of the radioactivity in each compartment remained comparable in the three conditions. In parallel with the results from the krypton-85 disappearance curves, the autoradiograms, silicone rubber casts, and EPAH did not suggest any change in the renal blood flow distribution secondary to furosemide administration.

scholarly journals Non-invasive evaluation of placental blood flow: lessons from animal models

Reproduction ◽  
2017 ◽  
Vol 153 (3) ◽  
pp. R85-R96 ◽  
Author(s):  
E Mourier ◽  
A Tarrade ◽  
J Duan ◽  
C Richard ◽  
C Bertholdt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Animal Models ◽  
Ultrasound Contrast Agents ◽  
Valuable Insight ◽  
Non Invasive ◽  
Placental Blood ◽  
2D And 3D ◽  
Reliable Methods ◽  
Placental Blood Flow ◽  
Invasive Evaluation

In human obstetrics, placental vascularisation impairment is frequent as well as linked to severe pathological events (preeclampsia and intrauterine growth restriction), and there is a need for reliable methods allowing non-invasive evaluation of placental blood flow. Uteroplacental vascularisation is complex, and animal models are essential for the technical development and safety assessment of these imaging tools for human clinical use; however, these techniques can also be applied in the veterinary context. This paper reviews how ultrasound-based imaging methods such as 2D and 3D Doppler can provide valuable insight for the exploration of placental blood flow both in humans and animals and how new approaches such as the use of ultrasound contrast agents or ultrafast Doppler may allow to discriminate between maternal (non-pulsatile) and foetal (pulsatile) blood flow in the placenta. Finally, functional magnetic resonance imaging could also be used to evaluate placental blood flow, as indicated by studies in animal models, but its safety in human pregnancy still requires to be confirmed.

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