TRANSFER OF WATER AND SOLUTES ACROSS THE PLACENTA

PEDIATRICS ◽  
1960 ◽  
Vol 25 (1) ◽  
pp. 1-1
Keyword(s):  
Osmotic Pressure ◽  
Fetal Development ◽  
General Area ◽  
Placental Barrier ◽  
Two Sides

BOTH the pediatrician and the obstetrician need to know what influences various events during fetal development have on the performance of the infant after birth. It would be desirable to have more of the studies in this general area appear in pediatric journals to emphasize its importance to pediatricians. An example is the matter of the forces which govern the movement of water across the placenta. In general, this problem has been studied by determining the concentration of total solute, or what is more commonly termed the total osmotic pressure, of the plasma on the two sides of the placental barrier.

Placental Transfer of Calcium and Strontium in the Rat and Rabbit

1957 ◽  
Vol 189 (1) ◽  
pp. 91-97 ◽  
Author(s):  
R. H. Wasserman ◽  
C. L. Comar ◽  
M. M. Nold ◽  
F. W. Lengemann
Keyword(s):  
Steady State ◽  
Urinary Excretion ◽  
Fetal Development ◽  
Placental Transfer ◽  
Maternal Diet ◽  
Late Pregnancy ◽  
Placental Barrier ◽  
Tracer Techniques ◽  
Comparative Metabolism ◽  
Differential Movement

The comparative metabolism of calcium and strontium during fetal development was investigated in rats and rabbits using double tracer techniques. In general, the placental transfer from dam to fetus of strontium was about one-half that of calcium; the site of discrimination was the placental barrier. The major discrimination occurred in movement of Ca* and Sr* from dam to fetus, with little or no differential movement from fetus to dam. Under steady state conditions in the rat the relative Sr*/Ca* ratios in the fetus, maternal skeleton and diet were 0.17, 0.28 and 1, respectively. The over-all discrimination of 0.17 between fetus and diet resulted from absorption (0.42), urinary excretion (0.63) and placental transfer (0.65). In the rat it was estimated that 92% of the fetal calcium had originated from the maternal diet. In the rabbit during late pregnancy, it was determined that about 24 mg of calcium/fetus/day moved across the placenta as compared with a need of about 13 mg for fetal development.

scholarly journals THE COLLOIDAL BEHAVIOR OF PROTEINS

1921 ◽  
Vol 3 (4) ◽  
pp. 557-564 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Aqueous Solution ◽  
Osmotic Pressure ◽  
Chloride Solution ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Preliminary Note ◽  
Hydrogen Ion Concentration ◽  
Chloride Solutions ◽  
The Difference ◽  
Two Sides

1. It is well known that neutral salts depress the osmotic pressure, swelling, and viscosity of protein-acid salts. Measurements of the P.D. between gelatin chloride solutions contained in a collodion bag and an outside aqueous solution show that the salt depresses the P.D. in the same proportion as it depresses the osmotic pressure of the gelatin chloride solution. 2. Measurements of the hydrogen ion concentration inside the gelatin chloride solution and in the outside aqueous solution show that the difference in pH of the two solutions allows us to calculate the P.D. quantitatively on the basis of the Nernst formula See PDF for Equation if we assume that the P.D. is due to a difference in the hydrogen ion concentration on the two sides of the membrane. 3. This difference in pH inside minus pH outside solution seems to be the consequence of the Donnan membrane equilibrium, which only supposes that one of the ions in solution cannot diffuse through the membrane. It is immaterial for this equilibrium whether the non-diffusible ion is a crystalloid or a colloid. 4. When acid is added to isoelectric gelatin the osmotic pressure rises at first with increasing hydrogen ion concentration, reaches a maximum at pH 3.5, and then falls again with further fall of the pH. It is shown that the P.D. of the gelatin chloride solution shows the same variation with the pH (except that it reaches its maximum at pH of about 3.9) and that the P.D. can be calculated from the difference of pH inside minus pH outside on the basis of Nernst's formula. 5. It was found in preceding papers that the osmotic pressure of gelatin sulfate solutions is only about one-half of that of gelatin chloride or gelatin phosphate solutions of the same pH and the same concentration of originally isoelectric gelatin; and that the osmotic pressure of gelatin oxalate solutions is almost but not quite the same as that of the gelatin chloride solutions of the same pH and concentration of originally isoelectric gelatin. It was found that the curves for the values for P.D. of these four gelatin salts are parallel to the curves of their osmotic pressure and that the values for pH inside minus pH outside multiplied by 58 give approximately the millivolts of these P.D. In this preliminary note only the influence of the concentration of the hydrogen ions on the P.D. has been taken into consideration. In the fuller paper, which is to follow, the possible influence of the concentration of the anions on this quantity will have to be discussed.

scholarly journals Contribution of the oxidative and nitrosative stresses to the development of placental malaria and the consequences for the fetus

2020 ◽  
Vol 12 (9) ◽  
pp. e3784
Author(s):  
Kassyo Lenno Sousa Dantas ◽  
Anna Beatriz da Silva Sousa Mota ◽  
Cristiane Santos Silva e Silva Figueiredo ◽  
Michael Ranniery Garcia Ribeiro ◽  
Adriana dos Santos Oliveira ◽  
...  
Keyword(s):  
Fetal Development ◽  
Cell Structure ◽  
Placental Malaria ◽  
Host Cells ◽  
Placental Barrier ◽  
Cytokines And Chemokines ◽  
Blood Microcirculation ◽  
Infected Cells ◽  
Placental Invasion

Objective: To describe the role of oxidative/nitrosative stresses in the pathogenesis of placental malaria and complications for the fetus. Bibliographic review: Placental malaria results from the sequestration of erythrocytes infected by Plasmodium falciparum in the blood microcirculation of the placental interventional spaces, leading to the infiltration of activated leukocytes in these sites, with subsequent production of cytokines and chemokines. These mediators, associated with phagocytosis of parasites and infected cells, activate the oxidative/nitrosative stresses pathways, producing free radicals and oxidation/nitration molecules, which act by attacking compounds of the cell structure of both the parasite and the host cells, causing damage to the integrity of the placental barrier and leading to insufficiency of the placenta to support fetal development. Final considerations: Therefore, we conclude that the immune response and oxidative/nitrosative stresses play an important role not only in the defense of the patient (reducing parasitaemia), but also in the progression of the disease and placental invasion, leading to serious changes and complications to the fetus.

Asymmetrical transfer of inert hydrophilic solutes across rat placenta

1993 ◽  
Vol 265 (3) ◽  
pp. R670-R675
Author(s):  
J. Stulc ◽  
B. Stulcova
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Active Transport ◽  
Free Water ◽  
Volume Flow ◽  
Placental Barrier ◽  
Pentobarbital Anesthesia ◽  
Hydrostatic Pressure Gradient ◽  
Hydrophilic Solutes

Transfer of [14C]mannitol, 51Cr-labeled EDTA, and [14C]-inulin from mother to fetus and from fetus to mother was measured in rats under pentobarbital anesthesia. The clearance of the three substances from the mother to fetus (Kmf) was 2.69 +/- 0.38, 1.93 +/- 0.73, and 0.47 +/- 0.14 microliter/min (means +/- SE), respectively, and the clearance from fetus to mother (Kfm) was 5.97, 6.66, and 4.95 microliters/min, respectively (the SE could not be estimated). Kfm appears to be consistently higher than Kmf by an almost constant value of approximately 4 microliters/min. To explain this a hypothesis was proposed according to which volume flow circulates across the placenta. Solute-free water is driven transcellularly across the placental barrier from the maternal to the fetal side by a difference of osmotic pressure created by active transport of some solutes (mainly Na+) to the fetus. Water together with all solutes dissolved returns from fetus to mother by filtration through wide extracellular channels in the placenta down a hydrostatic pressure gradient.

Structural and Functional Developmental Perspectives of the Placental Barrier and Its Role in the Fetal Development During the First and Second Trimesters

2016 ◽  
pp. 441-455
Author(s):  
Priyodarshi Sengupta ◽  
Biplabendu Talukdar ◽  
Indranil Roy ◽  
Santanu Tripathi ◽  
Nandita Bose ◽  
...  
Keyword(s):  
Fetal Development ◽  
Placental Barrier

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

The Eleventh Circuit Holds that Agreements in which Pharmaceutical Companies Pay Generic Companies Not to Compete May be Valid

2004 ◽  
Vol 32 (1) ◽  
pp. 181-184
Author(s):  
Amy Garrigues
Keyword(s):  
Pharmaceutical Companies ◽  
Court Decisions ◽  
Patent Holder ◽  
Trial Court ◽  
Court Of Appeals ◽  
The Us ◽  
Antitrust Laws ◽  
Per Se ◽  
Appeals Court ◽  
Two Sides

On September 15, 2003, the US. Court of Appeals for the Eleventh Circuit held that agreements between pharmaceutical and generic companies not to compete are not per se unlawful if these agreements do not expand the existing exclusionary right of a patent. The Valley DrugCo.v.Geneva Pharmaceuticals decision emphasizes that the nature of a patent gives the patent holder exclusive rights, and if an agreement merely confirms that exclusivity, then it is not per se unlawful. With this holding, the appeals court reversed the decision of the trial court, which held that agreements under which competitors are paid to stay out of the market are per se violations of the antitrust laws. An examination of the Valley Drugtrial and appeals court decisions sheds light on the two sides of an emerging legal debate concerning the validity of pay-not-to-compete agreements, and more broadly, on the appropriate balance between the seemingly competing interests of patent and antitrust laws.

378: 14-3-3 Expression Patterns in the Human Kidney: From Fetal Development to the Adult State to Malignant Transformation

2005 ◽  
Vol 173 (4S) ◽  
pp. 103-103
Author(s):  
Adam G. Baseman ◽  
Andrew J. Kirsch ◽  
Fray F. Marshall ◽  
Haiyen E. Zhau ◽  
Leland W.K. Chung ◽  
...  
Keyword(s):  
Malignant Transformation ◽  
Fetal Development ◽  
Expression Patterns ◽  
Human Kidney

The Two Sides of Temporal Orienting

2010 ◽  
Vol 57 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Ángel Correa ◽  
Paola Cappucci ◽  
Anna C. Nobre ◽  
Juan Lupiáñez
Keyword(s):  
Executive Control ◽  
Stroop Effect ◽  
Traffic Situation ◽  
Target Onset ◽  
Stimulus Features ◽  
Two Sides ◽  
Spatial Stroop Effect ◽  
Probable Interval ◽  
Spatial Stroop ◽  
Temporal Orienting

Would it be helpful to inform a driver about when a conflicting traffic situation is going to occur? We tested whether temporal orienting of attention could enhance executive control to select among conflicting stimuli and responses. Temporal orienting was induced by presenting explicit cues predicting the most probable interval for target onset, which could be short (400 ms) or long (1,300 ms). Executive control was measured both by flanker and Simon tasks involving conflict between incompatible responses and by the spatial Stroop task involving conflict between perceptual stimulus features. The results showed that temporal orienting facilitated the resolution of perceptual conflict by reducing the spatial Stroop effect, whereas it interfered with the resolution of response conflict by increasing flanker and Simon effects. Such opposite effects suggest that temporal orienting of attention modulates executive control through dissociable mechanisms, depending on whether the competition between conflicting representations is located at perceptual or response levels.

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