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Biomedical subjects

C R Valeri

Publications and source records attributed to C R Valeri.

At least 289 records · Page 16Linked to original sources
PubMed1978

Enhanced red cell oxygen transport in a pregnant woman with hemoglobin SD disease.

An anemic pregnant black primigravida with hemoglobin SD disease was studied throughout pregnancy and parturition. Hemoglobin SD disease was established by agar gel electrophoresis at pH 6.2. The patient carried to term a healthy femlae infant, an unusual occurrence in a patient homozygous for hemoglobin SD disease. The increase in the red cell concentration of 2,3 disphosphoglycerate (2,3 DPG) of 18--21 micrometer/g Hb (normal 12 +/- 2 micrometer/g Hb) was associated with a decrease in red cell oxygen affinity. The patient's in vitro P50 value ranged between 35 and 45 mm Hg (normal 28 +/- 1 mmHg). The function of red cells with increased 2,3 DPG levels and decreased affinity for oxygen in a pregnant woman with hemoglobin SD disease is discussed.

Adult↗
PubMed1977

Myocardial depression during sepsis.

The cardiac response to volume loading was evaluated in fifty severely septic patients. After a rapid infusion of albumin or whole blood the cardiac index (CI) and left ventricular stroke work index (LVSWI) were recorded as the pulmonary arterial wedge pressure (PAWP) increased. Initial values of PAWP, CI, and LVSWI were similar in both the nineteen surviving and thirty-one nonsurviving patients. Surviving patients, however, demonstrated greater increases in CI and LVSWI as PAWP rose. Nearly half of both patient groups developed decreases in CI and LVSWI as the PAWP continued to increase. These downslopes occurred at relatively low PAWP and are taken as evidence of an abnormality of myocardial function in both survivors and nonsurvivors. The lower upslope of the performance curves in nonsurvivors indicates myocardial depression or a negative inotropic effect. Cardiac ischemia, acute respiratory failure, and high affinity red cells were found to diminish the cardiac response to volume loading, whereas hepatic and renal failure were associated with a good CI and LVSWI response.

Blood Pressure↗
PubMed1977

Polybrene neutralization as a means of monitoring heparin therapy for extracoporeal cirulation.

Dose-response effects of heparin and protamine in 34 adult patients undergoing cardiac operations were monitored by an in vitro analysis utilizing hexadimetharine bromide (Polybrene) neutralization. Heparin administered prior to cannulation for cardiopulmonary bypass in a dose of 3.0 mg (300 units) per kilogram of body weight, and 1.5 mg (150 units) per kilogram for each subsequent hour of bypass, routinely produced circulating heparin concentrations greater than 1.0 units per milliliter of plasma. A protamine dose equal to 80% of the total number of milligrams of heparin given resulted in no detectable plasma heparin in 23 of the 34 patients one-half hour after administration. No patient required protamine in an amount greater than the total number of milligrams in the heparin dose to achieve heparin neutralization. Modest postoperative chest tube drainage (mean, 784 ml in 48 hours) in these patients provides clinical support for low-dose protamine administration for heparin neutralization at the conclusion of cardiopulmonary bypass.

Adult↗
PubMed1977

Physiologic effects of normal-or low-oxygen-affinity red cells in hypoxic baboons.

Baboons were bled one-third their red cell mass and were given homologous transfusions of red blood cells to restore the red cell volume. One group of baboons received red blood cells with a normal 2,3-diphosphoglycerate 2,3-DPG) level and normal affinity for oxygen, and in this group the 2,3-DPG level after transfusion was normal. The other group received red blood cells with a 160% of normal 2,3-DPG level and decreased affinity for oxygen, and in this group the 2,3-DPG level after transfusion was 125% of normal. In both groups of baboons, the inspired oxygen concentration was lowered and arterial PO2 tension was maintained at 55-60 mmHg for 2 h after transfusion. During the hypoxic state, systemic oxygen extraction was similar in the two groups, whereas oxygen saturation was lower in the high 2,3-DPG group than in the control animals. Cardiac output was significantly reduced 30 min after the arterial PO2 was restored to normal. These data indicate that red blood cells with decreased affinity for oxygen maintained satisfactory oxygen delivery to tissue during hypoxia.

Animals↗
PubMed1977

Current concepts of blood transfusion.

Extensive research into the physiology of red blood cells and platelets has shown that it is more advantageous to separate blood into its components than to store it as whole blood. After the red blood cells and platelets have reached the restricted period of storage in the liquid state, they can be freeze-preserved and stored for prolonged periods. Plasma can be frozen for future use or can be fractionated into the various stable components. The use of a combination of liquid-preservation and freeze-preservation methods affords a more efficient use of the limited supply of available blood.

Blood Platelets↗
PubMed1976

Citrate anticoagulation and cell washing for intraoperative autotransfusion in the baboon.

Extracorporeal citrate was used for anticoagulation during autotransfusion of baboons. A cell-washing plasmaphoresis procedure was added in one group of animals in order to remove activated clotting materials. Both groups became hypocoagulable, but the cell-washed group had less evidence of disseminated intravascular coagulation as well as lower plasma hemoglobin levels. Citrate anticoagulation plus cell washing is a potential alternative to heparinization for autotransfusion.

Animals↗
PubMed1976

The effect of cryogenic storage on human erythrocyte membrane proteins as determined by polyacrylamide-gel electrophoresis.

A study was conducted to determine the effects of freezing on the major membrane proteins of isolated human erythrocyte membranes. Membranes in low or normal ionic strength medium were frozen at slow or fast freezing rates. The membrane protein composition and elution of proteins from the membranes were studied utilizing polyacrylamide-gel electrophoresis in a sodium dodecyl sulfate or an acetic acid-urea-phenol solvent system. Neither a change in the composition of the membrane proteins nor any elution of membrane protein during freezing and thawing was observed. The data indicate that any human erythrocyte membrane damage during freezing and thawing was not related to a change in major membrane protein composition. Human red cell membranes were stable at --80 or --196degreesC in the absence of a cryoprotective agent.

Blood Preservation↗
PubMed1976

The effects of acute bleeding on acid-base balance erythropoietin (Ep) production and in vivo P50 in the rat.

The mechanism of erythropoietin (Ep) production after acute haemorrhage has been thought to be due to a reduction in blood volume and tissue perfusion leading to tissue hypoxia. In the present study we have evaluated the effect of acute haemorrhage in the rat on the acid-base status, the red cell affinity for oxygen in vivo, and Ep production. Within a few hours after acute blood loss there was a respiratory alkalosis with an increase in blood pH, a decrease in pCO2 and an increase in the red cell affinity of Hb for oxygen in vivo that was temporally related to an increase in Ep production. Within 24 h after the acute haemorrhage, the blood pH AND PCO2, red cell affinity for oxygen in vivo, and Ep level returned towards normal. The decrease in in vivo red cell affinity for oxygen was associated with an increase in red cell 2,3-DPG levels and a decrease in Ep production.

Acid-Base Imbalance↗
PubMed1976

Cryobiology overview of red cell preservation: achievements and prospective.

Preserved red cells are transfused to improve the delivery of oxygen to tissue. The preserved red cells must circulate to increase the red cell volume and improve the oxygen carrying capacity. The correlation between oxygen transport function and the red cell 2,3 DPG level has been known since 1967. but it was only recently that the importance of the oxygen delivering capacity of transfused red cells during the immediate posttransfusion period became apparent. Red cells with low 2,3 DPG levels and increased affinity for oxygen will increase cardiac output and/or decrease venous pO2 for at least 4 hours after transfusion. Oxygen transport function is maintained longer in red cells stored in CPD than in ACD-stored red cells. Supplementation of CPD red cells with inosine, ascorbate; dihydroxyacetone and other substances helps to maintain the oxygen transport function during storage at 4 C. Liquid-stored red clls can be biochemically modified before freeze-preservation to increase the 2,3 DPG levels to to 1-1/2 to 2 times normal; these red cells have decreased oxygen affinity. The red cells have acceptable posttransfusion survival and improved oxygen releasing capacity for at least 72 hours after transfusion. The well-being of certain patients may be placed in jeopardy of they are given preserved red cells with increased affinity for oxygen. The patient may not be able to meet the accompanying demand for increased blood flow, and the venous-capillary oxygen tension may fall to a critical level. Clearly, patients in hemorrhagic and septic shock, those subjected to extracorporeal circulation during cardiac surgery, and anemic patients with myocardial or cerebrovascular insufficiency are best treated with red cells that have 150% normal 2,3 DPG levels.

Adenosine Triphosphate↗
PubMed1975

Physiologic effects of hyperventilation and phlebotomy in baboons: systemic and cerebral oxygen extraction.

Eighteen anesthetized baboons were studied to determine the effects of passive hyperventilation and phlebotomy on oxygen transport. After 1 hour of hyperventilation a significant increase in the red cell affinity for oxygen occurred in vivo. This was not associated with any significant changes in cardiac output, oxygen consumption, or in lactic acid production. There was a 40% decrease in cerebral blood flow, a 10 mm Hg decrease in the pulmonary artery Po2 level, and a 17 mm Hg decrease in the jugular venous Po2 level. After 1 hour of hyperventilation, the plasma inorganic phosphorus level decreased significantly, the red cell ATP level decreased slightly, and the red cell 2. 3 DPG level increased significantly, indicating that inorganic phosphorus had been removed from the blood during hyperventilation. Passive hyperventilation was maintained, and the baboons were bled 32% of their red cell volume. The blood volume was partially restored with nonbuffered isotonic saline. One hour after the phlebotomy and volume restoration (2 hours of hyperventilation) there were no changes in oxygen consumption, cardiac output, cerebral blood flow, or blood lactate levels, but the pulmonary artery Po2 level was decreased by 15 mm Hg, and the jugular venous Po2 level was decreased by 20 mm Hg. Systemic oxygen consumption was not affected by the significant decrease in pulmonary artery Po2.

Animals↗
PubMed1975

Physiologic effects of transfusing red blood cells with high or low affinity for oxygen to passively hyperventilated, anemic baboons: systemic and cerebral oxygen extraction.

Anemic, passively hyperventilated baboons were given preserved red blood cells either with increased or with slightly reduced affinity for oxygen to restore the red cell volume. In the high affinity group there was a 50% increase in cerebral blood flow immediately after the transfusion, but there was no significant change in the low affinity group. The cardiac output decreased slightly in the low affinity group, and increased slightly but insignificantly in the high affinity group. Two hours after transfusion the cerebral blood flow had returned to normal in the high affinity group. In both groups there was a decrease in arterial blood pH and an increase in Po2 in blood from the pulmonary artery and the jugular vein after transfusion. A 40% restoration of the 2,3 DPG level occurred within 4 hours of the transfusion of red cells with high affinity for oxygen, and this rapid increase was associated with increases in blood pH and inorganic phosphorus levels. Preserved red cells with high affinity for oxygen and low 2, 3 DPG levels significantly increased the cerebral circulation during the 2-hour posttransfusion period. These findings lend support to the recommendation that preserved red cells with normal or elevated 2,3 DPG levels be administered to patients in hemorrhagic or septic shock, and to patients subjected to extracorporeal circulation during cardiac surgery in order to lessen the demand for increased blood flow and to ensure adequate tissue oxygenation during the postoperative period.

Anemia↗
PubMed1975

Improved myocardial performance following high 2-3 diphosphoglycerate red cell transfusions.

Twenty-two matched coronary bypass surgery (CABS) patients were randomly divided into two groups; 11 patients in the control group received CPD-stored or fresh blood (mean age, 5.5 days) containing 70 percent of normal 2-3 diphosphoglycerate (2-3 DPG) and 11 patients received 2-3 DPG-enriched previously frozen, washed, concentrated red cells (2-3 DPG 150 percent of normal). Coming off cardiopulmonary bypass, when given a volume load, the high 2-3 DPG patients had a significant increase in cardiac index (2.95 L. per minute vs. 2.18 L. per minute, p smaller than 0.001) at similar filling pressures. At this time body oxygen consumption, in vivo P50, red cell 2-3 DPG, and arterial-venous oxygen content difference were all increased, but P minus vo2 was normal. Improved oxygen delivery occurred without decreasing mixed venous oxygen tension. The results suggest that, with volume loading, function in the heart with coronary artery disease is limited in part by available oxygen. By decreasing oxygen affinity for hemoglobin by altering red blood cells biochemically, myocardial performance can be improved safely.

Blood Transfusion↗
PubMed1975

The determination of leukocyte phagocytic oxidase activity by measurement of the initial rate of stimulated oxygen consumption.

A method for the estimation of leukocyte phagocytic oxidase activity is described, which is based upon the polarographic measurement of the initial rate of oxygen consumption of peripheral blood leukocyte suspensions during maximally active phagocytosis. Mean values are presented for 22 normal donors, and the effects of centrifugal force, serial washing, temperature of storage, and the presence of platelets in the incubation mixture are described and discussed.

Blood Platelets↗
PubMed1975

The effects of Staphylococcus aureus and Klebsiella pneumoniae peritonitis in mice exposed to normal and hypoxic conditions on red cell oxygen transport function.

Normal mice exposed to 10% oxygen concentration developed a slight but statistically significant decrease in blood pH and a slight statistically insignificant decrease in red cell 2,3-DPG. Mice that were infected intraperitoneally with Staphylococcus aureus or Klebsiella pneumoniae and exposed to 20% oxygen developed acidosis, hemoconcentration, and decreased red cell 2,3-DPG levels. When mice with acute bacterial peritonitis were exposed to 10% oxygen concentration they likewise developed significant acidosis and hemoconcentration, but their reduction in red cell 2,3-DPG was not as great as that in the similarly infected mice exposed to 20% oxygen concentration.

Animals↗