Red Cell Filterability Research Articles

1269 POSSIBLE RELATIONSHIP BETWEEN MATERNAL ANESTHESIA AND NEONATAL JAUNDICE: EFFECT IN VITRO OF ANESTHETICS ON THE NEONATAL RED CELL

Neonatal jaundice has been correlated with use of anesthetics in the mother. These membrane-active agents cross the placenta & lead to measurable blood levels in the newborn. We investigated the effect in vitro of 3 commonly used agents on filterability of neonatal red cells (RBC). Cord blood was obtained from 10 infants whose mothers had received no medication or anesthetics prior to or during labor. RBC were washed and resuspended to a hematocrit of 5% in pH 7.4 Kreb's phosphate buffer, & incubated for ½ hour at 37°C with either buffer or anesthetic agent (1 or 2 μg/ml). Filterability was tested using a modification of Teitel's method. For the 3 agents tested, no significant difference was seen in T1/2 at the 2 concentrations tested. At both 1&2 μg/ml, the T½ of bupivicaine-treated RBC was significantly prolonged when compared with buffer-treated RBC. These results complement available clinical information linking the use of bupivicaine with neonatal jaundice, and suggest that this agent may be adversely affecting the deformability of neonatal RBC, leading to premature red cell destruction.

Effects of vitamin E and iron deficiency on filterability of rat red blood cells (RBC)

Experimental nutritional deficiencies of vitamin E and iron both decrease the filterability of rat red blood cells incubated in vitro but by two completely different mechanisms. The decreased filterability of red cells from vitamin E-deficient rats was accompanied by a discocyte/spherocyte transition and crosslinking of membrane proteins, whereas the decreased filterability of red cells from iron-deficient rats was not associated with any shape change or protein crosslinking. Nutritional deficiencies may provide useful approaches for studying the general problem of red cell deformability.

Red cell filterability in diabetes.

A negative pressure red cell filteration technique using polycarbonate sieve (Nuclepore) was devised for the observation of red cell filterability (RCF) in diabetes. A significant increase of HbA1 was suggested to be closely correlated to the decrease of RCF. A greater decrease of RCF was observed in diabetics with advanced retinopathy. The increased 2,3-DPG of red cells has been observed in diabetes, but P50 changed much less than might be expected. Improved RCF was observed when Pentoxifylline was added into red cell suspensions. This suggests that Pentoxifylline will have a good effect on microcirculation where impared circulation is observed.

Increase in red cell filterability after incubation with oxpentifylline.

Red cells from patients with various diseases known to decrease red cell filterability were washed and incubated in oxpentifylline suspended in buffered saline. An improvement of red cell filterability could be observed which was independent of the aetiology of red cell rigidity. The improvement was related to the initial degree of abnormality. No change was observed in normal cells or cells more than 4 hours old.

Pharmacological influences of pentoxifylline on red cell filterability and 2-3 diphosphoglycerate.

The diabetic's impairment of the red cell filterability is all the more important if the diabetic subject is suffering from an acute and progressive lower limb arteriopathy. Red cell 2-3 diphosphoglycerate (2-3 DPG) increases when red cell filterability decreases among these patients. Pentoxifylline (i.v. 600 mg per day) produces a rapid initial improvement of red cell filterability and then increases red cell 2-3 DPG level.

The effects of Arvin and surgery on red cell filterability

Arovin (ancrod) treatment is generally recognized to lower fibrinogen levels and is sometimes used to decrease plasma and whole blood viscosity. The fall in fibrinogen is accompanied by a rise in fibrinogen degradation products (FDP), but none of the other clotting factors is affected. This study shows that patients undergoing surgery with subsequent Arvin treatment decrease their red cell filterability (RCF), and that this drop cannot be explained by either the surgical intervention, a direct effect of Arvin on the red cells, or the lowered fibrinogen levels. However the decrease of RCF does correlate with the rise in FDP.

Red cell filterability and metabolic state in diabetic subjects with macro-angiopathy.

In twenty control subjects, twenty diabetic patients without macro-angiopathy and forty diabetic patients with an acute and severe arteriopathy of lower limbs, we studied the red cell filterability (TFE) on total blood, the 2-3 diphosphoglycerate level (2-3 DPG) and the Adenosine Triphosphate level (ATP). The diabetic's impairement of the red cell filterability and ATP level are all the more important than the subject is suffering from an acute arteriopathy of lower limbs. For the same subjects, we notice that the 2-3 DPG level increases significantly. The filterability is related to the ATP red cell concentration. An ATP depletion produces an increase membrane rigidity and a minor filterability. These findings strongly suggest a relation that can exist between the red cell metabolic state and filterability in diabetic population with or without macroangiopathy.

Filterability and cerebro-vascular thrombosis. Study on the mechanism.

The filterability of red cells was altered in 100 patients with CVA. This disorder appeared to be correlated with risk factors and haemostatic disturbances. The mechanism which links thrombosis with the filterability disorder, mainly depended upon a plasmatic factor. This factor disappeared after the red cells were carefully washed. The hypothesis of products originating from the thrombotic areas amd vasculo-endothelial lesions (mainly fibrin-related products) was supported.

Red blood cell filterability in non-diabetic patients with chronic occlusive arterial disease.

One-hundred and fifty non-diabetic patients with stage II chronic occlusive arterial disease (COAD), were tested for red blood cell filterability (RBF). At the same time, glycaemia, uricaemia, plasma cholesterol and triglycerides, fibrinogen, haematocrit, and white blood cells (granulocytes and lymphocytes) count, mean corpuscular volume, were measured. Thirty healthy people, tested for the same biological parameters, were used as controls. RBF was performed, using the Reid & Dormandy technique, with the same batch of filters (Nuclepore 5 micrometer, No. 54 A8 A25) for patients and controls. Filtration time was expressed in s.ml-1. Values obtained in patients (41.967 +/- 0.889) were significantly different (P less than 0.005) from controls (32.1 +/- 1.329). RBF alteration was correlated (P less than 0.05) with white blood cells count, haematocrit and plasma fibrinogen values. No correlation was observed with other biological parameters.

Filterability and vascular disease--I. Red cell filterability in diabetes mellitus: its relation to other methods of measuring deformability and to blood viscosity.

Erythrocyte deformability, blood viscosity and other rheological variables were measured in 30 diabetics and 28 normal control subjects. Measurements of red cell rheology were made simultaneously by filtration of whole blood, centrifugation and viscometry of packed red cells. The diabetics showed a significant reduction of erythrocyte deformability measured by filtration, an increase in flexibility measured by centrifugation and values similar to normals for viscometry of packed red cells. Plasma viscosity but not whole blood viscosity (shear rates 23 and 230 s-1) was increased in the diabetics. Erythrocyte flexibility as measured by centrifugation was significantly related to blood viscosity and plasma fibrinogen and glucose in the diabetics, however, neither filtration nor viscometry of packed red cells correlated with other rheological variables. It seems likely that multiple rheological abnormalities are present in diabetes mellitus. Conclusions about erythrocyte rheology in particular will depend critically on the methodology used.

Red cell filterability and chronic renal failure.

Filterability has been studied during chronic renal failure (with creatinin level above 350 mumol/l); red cells were washed thrice with 9 g/l NaCl or 40 g/l human serum albumin), adjusted to give a PCV of 0.3 and filtered on polycarbonate sieves with pore sizes of 5 micrometer. In the uremic patients groups, the results are heterogeneous and show a significant reduction of the red cell filterability. The filtration time is not well correlated with the degree of uraemia but with the haemoglobin level.

Filterability and vascular disease--II. Red cell filterability after myocardial infarction.

Red cell filterability was measured in 51 patients after proven myocardial infarction. The filterability index (FI) falls to a minimum 7-16 h after the onset of symptoms. This early minimum value is a very good indicator of the patients' subsequent clinical course. The results of three different types of experiments all suggested that the changes in FI were principally due to a change in the plasma secondarily affecting the red cells.

Crosslinking of membrane proteins in red blood cells from vitamin E-deficient lead-poisoned rats

Red blood cells from vitamin E-deficient rats lose their filterability after incubation in vitro and concurrent lead poisoning of the rats accelerates this decline. This decreased red cell filterability is associated with an increased crosslinking of red cell membrane proteins. Previous reports by others suggested an association between red cell glutathione levels and filterability, but we found no such association in red cells treated with N-ethylmaleimide. Increased aggregation of red cell membrane proteins may play a role in the discocyte/ spherocyte shape change that accounts for the impaired filterability of red blood cells from vitamin E-deficient lead-poisoned rats.

Red blood cell filterability and occlusive arterial disease.

In 1976 Ehrly and co-workers as well as Reid and co-workers investigated the filterability of blood from patients with chronic occlusive vascular diseases. Using micropore filters there was a markedly reduced filterability in spite of differences in the filterability techniques as filter type, hydrostatic pressure and others.The results were explained by an increased ridgidity of red cells which increase the resistance to flow through the filter pores. These findings where discussed as one of the pathophysiological mechanisms of chronic occlusive arterial diseases, but brought up a number of questions such as the mechanism of the reduced filterability and the significance of an impaired deformability of red cells in vivo. Another question is if the impaired filterability of blood is the cause or the consequence of the underlying disease.If we consider the red cell deformability to be an important factor for the pathophysiology of vascular diseases, it seems clear that not only the mechanical property of the less deformable red cell in the capillary will be most important, but also rigid red cell as a cause for an inhomogenous blood flow in the microcirculation (microcirculatory blood maldistribution).From the therapeutic point of view it seems important to know the mechanism which leads to an impaired flexibility of red cells, so, for example, a low ATP-content in the cells, hypermolarity or acidosis of blood.In vitro tests, like filtration of patients blood through micropore filters, may indicate the value of drugs said to improve the deformability of red cells. More sophisticated methods like the measurement of the oxygen tension of the muscle tissue can give us an answer as to whether an improvement of the deformability of red cells also leads to an improvement of the tissue supply.

Forces between membranes approaching contact

Cell stickiness to surfaces is recognized as an important concern in tests of red cell filterability. Many forces need to be considered in order to think about the sources of cell sticking. As cell membranes are brought together they experience successively the domination of several classes of forces van der Waals attraction, electrostatic repulsion, hydration repulsion, and specific charge-charge interactions at contact. The behaviour of each of these forces is described in the context of red cell adhesion.

Red cell filterability

Red cell filterability

Erythrocyte filterability in the burned patient

Red blood cell filterability was measured in a group of 6 simultaneously, severely burned patients. The mean filterability time was prolonged in the burn patients (25·0 ± 16·9) when compared with the normal for our laboratory (4·0 ± 1·0), indicating a decrease in deformability of the red cell. Except for a low red cell potassium and high white blood count, this could not be correlated with other serum or erythrocyte biochemical and physical characteristics studied. With adequate resuscitation it returned to normal in three days. The physiological implications are unknown.

The functional significance of red cell deformability and its significance in burns

Decreased red cell filtrability is often found after burning injury and a humoral mechanism is probably involved. The implications of lowered cell deformability in the lowered supply of oxygen to the burn wound are stressed. Stasis predisposes the red cell to ultimate destruction and possible therapeutic measures to prevent the loss of cell membrane elasticity are suggested.

Red cell filtration by paper filters.

A method for the assessment of red cell filterability with paper filters is described. Two milliliters of a washed red cell suspension with a hematocrit of 50% was filtered through a filter paper cone in a glass funnel and the filtration half-time (FT1/2) was measured. The filter papers were calibrated by previous measurement of the filtration time for the suspending solution, the calibration time (CT). A linear correlation between CT and FT1/2 was found for individual red cell suspensions (p less than 0.001) as well as for a normal population (p less than 0.001). Consequently, the index FT1/2/CT should represent a more reproducible parameter than FT1/2 and experimentally this appears to be the case. In fact, elimination of erratic values in a normal population was realized. Furthermore, discrimination between normal and abnormal values was improved and the coefficient of variation of single measurements passed from 28.4 to 9.4%. The reproducibility and reliability of this extremely simple method are therefore decisively enhanced without complication of the procedure.

Water movement in red cells from burned patients. Its relationship to sodium retention and red cell filtrability

Nine burned patients were investigated. Urinary sodium retention was associated with low red cell water and reduced red cell filtrability. The red cells from patients who recovered lost less water than normal cells when suspended in hypertonic NaCl solution but the proportionality of water loss or gain found for normal cells was maintained. The red cells from fatally burned patients lost proportional behaviour in hypertonic or hypotonic media. The abnormalities are not related to the area of the burn and may be the result of varying therapy. The monitoring of red cell water and water movement under tonicity stress is a convenient measure of the metabolic state of the cell.