scholarly journals Measuring osmosis and hemolysis of red blood cells

2017 ◽  
Vol 41 (2) ◽  
pp. 298-305 ◽  
Author(s):  
Lauren K. Goodhead ◽  
Frances M. MacMillan
Keyword(s):  
Cell Membrane ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Cells ◽  
Clinical Importance ◽  
Bathing Solution ◽  
Animal Blood ◽  
Composition And Structure ◽  
Clinical Scenarios ◽  
Tissue Fluids

Since the discovery of the composition and structure of the mammalian cell membrane, biologists have had a clearer understanding of how substances enter and exit the cell’s interior. The selectively permeable nature of the cell membrane allows the movement of some solutes and prevents the movement of others. This has important consequences for cell volume and the integrity of the cell and, as a result, is of utmost clinical importance, for example in the administration of isotonic intravenous infusions. The concepts of osmolarity and tonicity are often confused by students as impermeant isosmotic solutes such as NaCl are also isotonic; however, isosmotic solutes such as urea are actually hypotonic due to the permeant nature of the membrane. By placing red blood cells in solutions of differing osmolarities and tonicities, this experiment demonstrates the effects of osmosis and the resultant changes in cell volume. Using hemoglobin standard solutions, where known concentrations of hemoglobin are produced, the proportion of hemolysis and the effect of this on resultant hematocrit can be estimated. No change in cell volume occurs in isotonic NaCl, and, by placing blood cells in hypotonic NaCl, incomplete hemolysis occurs. By changing the bathing solution to either distilled water or isosmotic urea, complete hemolysis occurs due to their hypotonic effects. With the use of animal blood in this practical, students gain useful experience in handling tissue fluids and calculating dilutions and can appreciate the science behind clinical scenarios.

Colloid osmotic pressure changes of dog's blood exposed to different mixtures of CO2 and air

1978 ◽  
Vol 44 (2) ◽  
pp. 254-257 ◽  
Author(s):  
Y. Kakiuchi ◽  
A. B. DuBois ◽  
D. Gorenberg
Keyword(s):  
Red Blood Cells ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Blood Cells ◽  
Freezing Point ◽  
Colloid Osmotic Pressure ◽  
Red Cell ◽  
Freezing Point Depression ◽  
Pressure Changes ◽  
Different Levels

Hansen's membrane manometer method for measuring plasma colloid osmotic pressure was used to obtain the osmolality changes of dogs breathing different levels of CO2. Osmotic pressure was converted to osmolality by calibration of the manometer with saline and plasma, using freezing point depression osmometry. The addition of 10 vol% of CO2 to tonometered blood caused about a 2.0 mosmol/kg H2O increase of osmolality, or 1.2% increase of red blood cell volume. The swelling of the red blood cells was probably due to osmosis caused by Cl- exchanged for the HCO3- which was produced rapidly by carbonic anhydrase present in the red blood cells. The change in colloid osmotic pressure accompanying a change in co2 tension was measured on blood obtained from dogs breathing different CO2 mixtures. It was approximately 0.14 mosmol/kg H2O per Torr Pco2. The corresponding change in red cell volume could not be calculated from this because water can exchange between the plasma and tissues.

scholarly journals Volume regulation by flounder red blood cells in anisotonic media

1977 ◽  
Vol 69 (5) ◽  
pp. 537-552 ◽  
Author(s):  
PM Cala
Keyword(s):  
Red Blood Cells ◽  
Cell Volume ◽  
Water Flow ◽  
Blood Cells ◽  
Volume Regulation ◽  
Control Cell ◽  
Regulatory Volume Decrease ◽  
Electrochemical Gradient ◽  
Osmotic Swelling ◽  
Inorganic Cation

The nucleated high K, low Na red blood cells of the winter flounder demonstrated a volume regulatory response subsequent to osmotic swelling or shrinkage. During volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation after osmotic swelling is referred to as regulatory volume decrease (RVD) and was characterized by net K and water loss. Since the electrochemical gradient for K is directed out of the cell there is no need to invoke active processes to explain RVD. When osmotically shrunken, the flounder erythrocyte demonstrated a regulatory volume increase (RVI) back toward control cell volume. The water movements characteristic of RVI were a consequence of net cellular NaCl and KCl uptake with Na accounting for 75 percent of the increase in intracellular cation content. Since the Na electrochemical gradient is directed into the cell, net Na uptake was the result of Na flux via dissipative pathways. The addition of 10(-4)M ouabain to suspensions of flounder erythrocytes was without effect upon net water movements during volume regulation. The presence of ouabain did however lead to a decreased ration of intracellular K:Na. Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na and K fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage. In addition, the Na and K flux rate through both pump and leak pathways decreased in a parallel fashion as cell volume was regulated. Taken as a whole, the Na and K movements through the flounder erythrocyte membrane demonstrated a functional dependence during volume regulation.

scholarly journals Impact of parity and gestational age of mothers with hypertension on birth weight, red blood cells and mode of delivery of their babies

1970 ◽  
Vol 19 (4) ◽  
pp. 3038-3044
Author(s):  
Helen Chioma Okoye ◽  
Chilota Chibuife Efobi ◽  
Josephat Maduabuchi Chinawa ◽  
Odutola Israel Odetunde ◽  
Awoere Tamunosiki Chinawa ◽  
...  
Keyword(s):  
Birth Weight ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Gestational Age ◽  
Packed Cell Volume ◽  
Blood Cells ◽  
Mode Of Delivery ◽  
Poor Correlation ◽  
Hypertensive Group ◽  
The Impact

Background: Maternal factors are determinants of birth outcome which includes birth weight, haematological indices and mode of delivery of their babies.Objectives: To determine the impact of parity and gestational age of hypertensive mothers on some neonatal variables.Methods: A hospital based cross-sectional study of measurement of neonatal variables (birth weight, red blood cells and mode of delivery) among hypertensive mothers and their controls was conducted over a period of six months. Data were analyzed using the Statistical Package for Social Sciences program (SPSS), version 20.Results: There were statistically significant differences in means between the neonates of the hypertensive group and non-hypertensive group for maternal age (t =1.61, p = 0.002), baby weight (t =2.87, p < 0.001), haemoglobin (Hb) (t =4.65, p = 0.010) and packed cell volume (PCV) (t =4.75, p = 0.009), but none for gravidity (t =1.95, p = 0.927)For all subjects, there was poor correlation between gestational age and variables; birth weight , haemoglobin (Hb), packed cell volume (PCV), nucleated red blood cell (nRBC) and parity. Likewise, parity poorly correlated with variables; age, birth weight, Hb, PCV, and nRBC. There was a statistically significant association between mode of delivery and hypertension (χ2 =53.082, p <0.001) but none with having a family history of hypertension (χ2 =1.13, p = 0.287).Conclusion: Parity and gestational age of mothers with hypertension have no impact on birth weight and red cells when compared with their non-hypertensive counterparts. However, mothers of babies delivered by elective and emergency caesarean section were about 2-3 times more likely to be hypertensive than those that delivered through spontaneous vertex delivery.Keywords: Hypertension; neonate; gestational age; parity.

Urea alters set point volume for K-Cl cotransport, Na-H exchange, and Ca-Na exchange in dog red blood cells

1993 ◽  
Vol 265 (2) ◽  
pp. C447-C452 ◽  
Author(s):  
J. C. Parker
Keyword(s):  
Red Blood Cells ◽  
Cell Volume ◽  
Okadaic Acid ◽  
Blood Cells ◽  
Regulatory System ◽  
Set Point ◽  
Volume Sensor

Urea equilibrates rapidly across the red blood cells of mammals. It was speculated that urea might affect the cell volume sensor by virtue of its properties as a protein perturbant. At concentrations of 0.1-0.6 M, urea caused a decrease in the set points for shrinkage-induced Na-H exchange, swelling-induced K-Cl cotransport, and swelling-induced Ca-Na exchange of dog red blood cells. Okadaic acid opposed the action of urea on all three pathways. The effects were reversible and not due to cyanate. Formamide and acetamide had actions similar to urea but not as potent. Equimolar concentrations of methanol had no effect. The coordinated influence of urea on three separate volume-activated transporters suggests that it acts on a mutual regulatory system that senses and transduces volume stimuli.

Splenic red cell sequestration and blood volume measurements in conscious pigs

1985 ◽  
Vol 248 (3) ◽  
pp. R293-R301 ◽  
Author(s):  
J. P. Hannon ◽  
C. A. Bossone ◽  
W. G. Rodkey
Keyword(s):  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Volume ◽  
Plasma Volume ◽  
Blood Cells ◽  
Physical Restraint ◽  
Red Cell ◽  
Red Cell Volume ◽  
Epinephrine Injection ◽  
Volume Measurements

When estimated by the dilution of 51Cr-labeled red blood cells under nearly basal conditions, immature splenectomized pigs (n = 20) had a circulating red cell volume of 17.8 +/- 1.64 (SD) ml/kg. At an assumed body-to-large vessel hematocrit (BH:LH) ratio of 0.9, plasma volume was 49.6 +/- 3.12 ml/kg and blood volume 67.3 +/- 3.67 ml/kg. Sham-operated pigs (n = 20) had a circulating red cell volume of 16.2 +/- 1.39 ml/kg, a plasma volume of 51.1 +/- 3.42 ml/kg, and blood volume of 67.2 +/- 4.12 ml/kg. Kinetic analysis of early 51Cr loss from the circulating blood of the sham-operated pigs indicated a splenic red cell sequestration of 4.5 +/- 0.89 ml/kg and a t1/2 of 9.76 +/- 1.93 min for splenic red cell turnover. Epinephrine injection (n = 6) and physical restraint (n = 8) caused rapid mobilization of splenic red blood cells in sham-operated pigs. Volume estimates in splenectomized pigs (n = 7) based on simultaneous dilutions of 51Cr-labeled red blood cells and 125I-labeled bovine albumin gave circulating red cell, plasma, and blood volumes of 18.4 +/- 2.46, 60.7 +/- 4.01, and 79.0 +/- 3.51 ml/kg, respectively, and a BH:LH ratio of 0.756 +/- 0.029. The latter value may have reflected an overestimation of plasma volume by the 125I-labeled albumin procedure.

Sign in / Sign up

Export Citation Format

Share Document