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Biomedical subjects

C R Valeri

Publications and source records attributed to C R Valeri.

At least 271 records · Page 15Linked to original sources
PubMed1980

Is respiratory failure a consequence of blood transfusion?

The pulmonary entrapment of microaggregates, platelets, and white cells in stored blood is thought to contribute to abnormalities in lung function. Washing of red cells removes these potentially damaging elements. This prospective, randomized, double-blind study compares the pulmonary function of patients undergoing abdominal aortic aneurysmectomy who received either washed or unwashed red cell concentrates. Both groups received equivalent volumes of blood, albumin, and balanced salt solution duing surgery. Postoperatively, no differences were observed in the physiologic shunt, QS/QT, pulmonary artery pressure, pulmonary vascular resistance, or effective dynamic compliance. The cardiac index at equivalent left ventricular filling pressures was the same. The results indicate that it is unlikely that microaggregates or other formed elements in stored blood lead to compromised pulmonary function.

Aged↗
PubMed1980

Measuring percent oxygen saturation of hemoglobin, percent carboxyhemoglobin and methemoglobin, and concentrations of total hemoglobin and oxygen in blood of man, dog, and baboon.

We used an automated four-wavelength spectrometer to measure the concentration of total hemoglobin, percent oxyhemoglobin, carboxyhemoglobin, and methemoglobin, and concentration of oxygen bound to hemoglobin in the blood of humans, dogs, and baboons under clinical and various experimental conditions. Measurements of total hemoglobin and methemoglobin with this simple method were comparable to those with standard spectrometric procedures. Carboxyhemoglobin measurements were comparable to those made with gas chromatography, and measurements of oxygen content were comparable to those made with the galvanic cell method. The new instrument is as accurate as the comparison methods used to evaluate it in all parameters, is reliable, and measurements take only 63 s per sample. In addition, it requires minimal operator training, infrequent need for calibration, and no sample preparation.

Animals↗
PubMed1980

Antibody inhibition of polymorphonuclear phagocytosis. Dissociation of bacterial attachment and bacterial killing.

The inhibition of killing of Staphylococcus aureus 502A by PMNs treated with the IgG fraction of serum from a group of patients with demonstrable leukocyte antibodies was investigated. The uptake of opsonized thymidine-labeled S. aureus 502A by PMNs treated with allogeneic antibody was essentially unimpaired, despite significantly decreased killing. The findings were similar to bacteria opsonized by serum complement or bacteria opsonized with specific lapine antibody. An increased proportion of PMN-bound bacteria susceptible to lysis by lysostaphin indicated a reduced rate of translocation of bacteria from the surface of allogeneic antibody-treated PMNs. Antibody did not stimulate the basal oxidative metabolism, but the oxidative metabolism of antibody-treated PMNs during phagocytosis was increased. Although the precise mechanism of inhibition of PMN killing by antibody is uncertain, the data suggest that the impairment of bacterial killing by PMNs treated with allogeneic leukocyte antibody is associated with inefficient translocation of bacteria into phagolysosomes rather than by interference with the binding of bacteria to specific PMN opsonic receptors.

Antibodies, Bacterial↗
PubMed1980

Temperature effects on shape and function of human granulocytes.

Scanning microscopic and functional studies were made of granulocytes isolated from CPD anticoagulated whole blood by counterflow centrifugation in a Beckman JE-6 rotor. The collection buffer was phosphate (20 mM) buffered saline (280 mOsM) with glucose (29 mM) and human serum albumin (1.2% w/v). The final suspension contained less than 2% mononuclear cells and 5% red cells. Incubation and fixation at various temperatures revealed two distinct temperature dependent shape transformations. At 22, 37, 40 and 45 degrees C granulocytes were ameboid with extensive highly textured veils. These smoothed progressively, bullae and blebs formed, and membranes peeled finally leaving nonfunctional spheres with smooth surfaces. At 4 degrees C, granulocytes were irregular spheres, less rugose but with numerous microvilli and nodules. Veiling was absent. Phagocytosis, initially low, progressively declined over 48 h while cell surfaces become smooth. Some formed blebs, but all terminated as nonfunctional spheres with untextured surfaces containing occasional large single holes. Cellular stability estimated from changes in volume distributions, and phagocytosis by microfluorescence measurements of yeast and latex particle ingestion were also temperature dependent and paralleled the shape progressions. It is concluded that at body (37 degrees C) or fever (40 degrees C) temperatures, granulocytes have dynamic membrane surfaces characterized by extensive veiling and high function. At 4 degrees C they are relatively inactive spheres devoid of pseudopodia or veils, yet functional at slow rates.

Cell Membrane↗
PubMed1979

Cytotaxins after the sedimentation behavior of human granulocytes.

Human granulocytes from the peripheral blood of healthy donors were subjected to transient gravity sedimentation analysis in Ficoll density gradient columns (37 degrees C) containing different concentrations of Escherichia coli endotoxin-activated serum and medium 199. A dramatic serum concentration-dependent dispersion of the cells based on changes in sedimentation velocity was observed as a function of time, using a new optical scanning instrument. The phenomenon was virtually abolished in the presence of cytochalasin B, a known inhibitor of cellular chemotaxis. The width (second statistical moment) of the sedimenting cell distribution increased in a sigmoid fashion as a function of time regardless of cytotaxin concentration. This indicates that a slow and nonlinear response of the granulocytes to the cytotaxins occurs. This new kinetic method should be useful in examining an alternate manifestation of the chemoresponsiveness of phagocytic cells and of cell interactions in general.

Bacterial Toxins↗
PubMed1979

Intrapulmonary clotting and fibrinolysis during abdominal aortic aneurysm surgery.

Intravascular clotting and fibrinolysis (C and F) are events which often accompany major surgical trauma. Their role in inducing cardiopulmonary failure is debated and prompted this study of 13 patients undergoing elective AAA. Following intubation, anesthesia and pressure breathing fibrinolytic activity (FA) in arterial blood exceeded that in mixed venous blood (p < 0.001) indicating pulmonary secretion of proteolytic activity. Fibrinogen, plasminogen and fibrin degradation products (FDPs) were normal. During surgery, fibrinogen and plasminogen fell (p < 0.001) while nonplasmin mediated FA and FDPs rose (p < .001). Despite heparinization (5000 U IV) aortic clamping (avg 56 min) led to evidence of C and F within the lungs. Arterial fibrinogen was 33.2 mg/ml lower than mixed venous blood (p < 0.01) and plasminogen was 0.47 Sherry units lower (p < 0.001). Soluble fibrin monomer appeared in arterial blood (p < 0.01). At the same time nonplasmin mediated FA was consumed within the lungs (p < 0.01) and FDPs were produced (44.6 microg/ml higher in arterial blood, p < 0.001). Similar changes were noted after aortic declamping. The transient 5.3 ml/cm H(2)0 fall in dynamic compliance was unrelated to C and F. Pulmonary vascular resistance and arterial pressure were unchanged. During wound closure intrapulmonary C and F ceased. Postoperatively (6 h), the physiologic shunt of 15.1% was similar to tbe preoperative value of 13.3%. All C and F factors returned to normal except FDPs which remained elevated. An average of 0.2 U blood was given prior to aortic clamping and 3.1 U during clamping. Neither the volume nor the type of blood (7 patients received washed RBCs) influenced pulmonary C and F. The results show that pressure breathing will alter pulmonary metabolism from clearance to secretion of fibrinolytic activity. Surgery leads to systemic C and F while intrapulmonary C and F is triggered by aortic clamping despite IV heparin. Delayed functional consequences of C and F are possible. Immediate postoperative effects are not apparent.

Aorta, Abdominal↗
PubMed1979

"The colouring substance of blood.".

Over a century ago, Stokes wrote on the oxidation and reduction of "the colouring substance of the blood." The mechanisms that govern the binding of oxygen to hemoglobin have been defined in even greater detail and higher orders of accuracy, even to the ends of the oxyhemoglobin dissociation curve. The Bohr effect has ceased to be a reduction in the affinity of hemoglobin for oxygen due to an increasing hydrogen ion concentration and according to a mere logarithmic equilibration constant. The constant has become a variable, subject to the interactions of temperature, carbon dioxide, organic phosphate, and ionic concentrations. This interdependence of so many variables has rendered the once inaccurate, but precise prediction of the effect of tht, well beyond the means of the average physician managing the treatment of a sick patient.

Biological Transport↗
PubMed1979

In vitro measurement of P50--the pH correction, and use of frozen red blood cells as controls.

The Unicam Spectrophotometer, the IL 282 CO-Oximeter, and the Hemoscan were used to measure the in vitro P50 using 1, 20--45, and 50% hematocrit values of red blood cells suspended in autologous plasma or phosphate buffered saline at pH of 6.7--7.7. The relation between pH and P50 was a linear correlation for washed red blood cells by all three methods whereas the relation between pH and P50 was a log correlation for red blood cells in plasma. Multiple units of red blood cells with low 2,3 diphosphoglycerate (2,3 DPG) and increased affinity for oxygen, with normal 2,3 DPG and normal affinity for oxygen, and above normal 2,3 DPG and decreased affinity for oxygen, were frozen in 10 ml aliquots with 40% w/v glycerol and maintained at -80 degrees C. One tube of each level of 2.3 DPG was thawed, washed, and suspended in buffer daily to yield P50 values of 17.5 +/- 0.67, 29.7 +/- 0.92, or 41.2 +/- 0.72 torr at pH 7.2 in order to have a control of both instrumentation and personnel.

Diphosphoglyceric Acids↗
PubMed1979

Importance of oxygen transport in clinical medicine.

One or more of the several components of the oxygen transport system may function abnormally in critical illness. Arterial hypoxemia is an important feature of acute respiratory failure. Its prominence may obscure other limitations in oxygen availability such as low cardiac output, anemia, or an increased red cell affinity state. These several components of the oxygen transport system can be influenced by therapeutic maneuvers, but the result may not necessarily be a net benefit. For example, red blood cell transfusion therapy may correct anemia, but increase the red blood cell affinity state so as to adversely affect cardiac function. Treatment programs require consideration of the interaction of these several variables affecting oxygen transport.

Aged↗
PubMed1979

Human red blood cells with normal or improved oxygen transport function prepared and frozen in the primary polyvinyl chloride plastic blood collection container.

This is a report a a new system for freezing human red blood cells in the same polyvinyl chloride plastic container in which the blood is collected and separated into components. This polyvinyl chloride plastic collection bag with integrally attached transfer packs for blood collection, component separation, red blood cell biochemical modification, freezing, storage, and post-thaw dilution before washing, represents a major advancement in the freeze-preservation process. The label with the donor's blood type and identification number affixed to the bag at the time of collection remains in place throughout the freezing and thawing process. The transfused red blood cells are of superior quality, and the processing cost is less than with other methods of freeze-preservation. There is a lower risk of contamination with these red blood cells because manipulation of the product is kept at a minimum. "Rejuvenation", a bioengineering process by which outdated red blood cells can be salvaged, can be incorporated into the preservation process using one of the attached transfer packs of the primary collection bag. This process has been introduced as a possible means of alleviating the dramatic blood shortages which occur periodically. Red blood cells may also be "rejuvenated" after storage in the liquid state to increase their 2,3 DPG and ATP levels to 150 to 200% of normal, and these red blood cells with improved oxygen transport function have been administered to anemic patients with and without cardiopulmonary insufficiency, patients undergoing cardiopulmonary bypass and treatment with hypothermia during cardiac surgery, and in instances where nonhemolytic transfusion reactions might be expected.

Adenosine Triphosphate↗
PubMed1978

Transfusion of 2,3 DPG-enriched red blood cells to improve cardiac function.

Attempts were made to enhance oxygen availability in patients undergoing coronary artery bypass operations by transfusing red blood cells enriched in 2,3 diphosphoglycerate (2,3 DPG) to 150% of normal. In this study of 22 patients, 11 received red blood cells with high 2,3 DPG levels and 11 received red blood cells with 70% of normal 2,3 DPG levels (control). Immediately following cardiopulmonary bypass the 11 patients who received high 2,3 DPG red blood cells had a P50 value of 31.6 mm Hg; the value in control patients was 28.3 mm Hg (p less than 0.05). Oxygen consumption values were 135 and 106 ml/min/m2, respectively (p less than 0.05). Mixed venous oxygen tensions were similar in the two groups, but the arteriovenous content difference was higher in the high 2,3 DPG group (p less than 0.05). Cardiac indices increased significantly in response to a fluid load in the high 2,3 DPG group compared with controls at comparable filling pressures. We believe the improved myocardial performance in response to a fluid challenge is a result of increased oxygen availability.

Blood Transfusion↗
PubMed1978

Red cell 2,3-diphosphoglycerate and oxygen affinity of hemoglobin in patients with thyroid disorders.

We measured red blood cell 2,3-diphosphoglycerate (2,3-DPG), adenosine triphosphate (ATP), and the P50 value in vitro of the oxyhemoglobin dissociation curve, which is the oxygen tension at half saturation of hemoglobin, in order to quantitate red blood cell oxygen transport function in individuals who were diagnosed as hypothyroid, euthyroid, or hyperthyroid based on measurements of thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), and their clinical status. Hypothyroid (mean T4 2.8 microgram/dl, T3 49 ng/dl, TSH 37 microU/ml) and hyperthyroid (mean T4 14 microgram/dl, T3 271 ng/dl, TSH less than 0.7 microU/ml) patients had normal red cell 2,3-DPG and ATP levels and normal P50 values in vitro. The known changes in oxygen consumption produced by alterations in thyroid hormone levels in patients with hypothyroidism or hyperthyroidism did not affect red blood cell oxygen transport function.

Diphosphoglyceric Acids↗