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Biomedical subjects

C R Valeri

Publications and source records attributed to C R Valeri.

At least 253 records · Page 14Linked to original sources
PubMed1981

Alternative complement pathway-dependent ingestion of fluolite particles by human granulocytes.

Fluorescent particles (Fluolite) with an average size of 0.1 micrometers were ingested by human granulocytes after incubation in fresh normal human serum (NHS). Ingestion was assessed by visual counting in a fluorescent microscope of cells containing particles. Ingestion required fresh normal serum and did not occur when serum was heated for 30 min at 50 degrees C or in the presence of ethylenediaminetetraacetic acid (EDTA). It did not occur in serum genetically deficient in C3b inactivator or in C3. Phagocytic activity was restored to C3-deficient serum by purified human C3 and to heat inactivated serum by purified factor B. Opsonic activity was present in NHS containing 5 mM Mg++ and 10 mM ethyleneglycoltetraacetic acid (EGTA) and in human serum genetically deficient in human C components C2 and C5. Agammaglobulinemic sera had normal opsonic activity. Opsonization of particles in this system is mediated through the alternative pathway of C activation, and its measurement serves as a simple quantitative functional assay for this system.

Complement Activation↗
PubMed1981

Liquid preservation of baboon red blood cells in acid-citrate-dextrose or citrate-phosphate-dextrose anticoagulant: effects of washing liquid-stored red blood cells.

Autologous baboon RBC stored at 4 C in acid-citrate-dextrose (ACD) or in citrate-phosphate-dextrose (CPD) for 3 weeks after collection had 24-hour 51Cr posttransfusion survival values of about 77%. When 20-day-old ACD and CPD baboon RBC were washed and then stored at 4 C for 24 hours before autotransfusion, the 24-hour 51Cr posttransfusion survival values were about 81%. These values were similar to those seen in studies of human RBC preserved in an identical manner. Our results indicated that the baboon can be used to evaluate RBC preservation techniques before human volunteers are studied.

Animals↗
PubMed1981

Measurement of red blood cell volume, plasma volume, and total blood volume in baboons.

Red blood cell volume was measured directly in baboons by infusion of 51Cr-labeled autologous RBC, and was indirectly estimated from the plasma volume measured with 125I-labeled albumin and the total body hematocrit. The total body hematocrit was calculated from the peripheral venous hematocrit multiplied by a correction factor; for nonanemic baboons the correction factor was 0.87, and for anemic baboons, 0.75. Within 2 weeks after the phlebotomy (150 ml of blood), the baboon's RBC volume was restored to normal. Posttransfusion survival of baboon RBC can be measured accurately in nonanemic baboons; the preserved RBC can be labeled with 51Cr and the RBC volume of the baboon can be measured indirectly from the plasma volume measured with 125I-labeled albumin and the total body hematocrit.

Animals↗
PubMed1981

51Cr and DF32P labeling of human blood cells in leukocyte-rich plasma.

Cell-rich plasma from human peripheral blood was labeled with disodium chromate (51Cr) and diisopropylfluorophosphate (DF32P), and the uptake and distribution of the radionuclides by granulocytes, lymphocytes, monocytes, and erythrocytes were studied. Velocity sedimentation through a 1-2% albumin gradient and electrophoresis in a Ficoll-sucrose gradient demonstrated that granulocytes migrated the fastest, followed by monocytes, and then by the mixture of lymphocyte-red cell populations. Monocytes accumulated four to five times as much 51Cr as the other leukocytes or the red blood cells. Erythrocytes showed a greater uptake of 51Cr than did granulocytes or lymphocytes. Granulocytes were preferentially labeled in vitro by DF32P, and the uptake of DF32P by lymphocytes was about one-third that by granulocytes. No measurable DF32P labeling of monocytes and only slight labeling of erythrocytes was observed by liquid scintillation counting of the labeled cells. These data have implications in the interpretation of in vivo survival studies of radiolabeled leukocytes.

Blood Cells↗
PubMed1981

Freeze-preserved baboon red blood cells: effects of biochemical modification and perfusion in vitro.

Nonrejuvenated and rejuvenated baboon RBC were freeze-preserved with 40% (w/v) glycerol at -80 C. To prepare rejuvenated RBC, a 50-ml solution containing pyruvate, inosine, glucose, phosphate, and adenine was used and RBC were incubated with this solution before glycerolization and freezing. Appropriate steps were taken to minimize osmotic damage to the RBC during glycerolization and deglycerolization. Nonrejuvenated and rejuvenated cryopreserved RBC had freeze-thaw recovery values of 98%, freeze-thaw-wash recovery values of 92%, and 24-hour post-transfusion survival values of 85%. Some units of cryopreserved RBC were autotransfused after thawing, washing, and storage at 4 C for 24 hours. Other units were perfused in vitro before autotransfusion. After 24 hours of postwash storage, the RBC were concentrated by centrifugation and suspended in a plasma protein fraction and/or an electrolyte solution, and then were exposed to extracorporeal perfusion. Serious adverse effects were not observed on posttransfusion survival, function, or hemolysis in nonrejuvenated or rejuvenated baboon RBC as a result of perfusion in vitro.

2,3-Diphosphoglycerate↗
PubMed1980

Nuclear magnetic resonance studies of blood platelets.

Blood platelets contain membrane-enclosed granules which have inside them high concentrations of 5-hydroxytryptamine (serotonin) along with adenine nucleotides and divalent metal ions. 19F n.m.r. of fluorinated serotonin incorporated into the granules of both human and pig intact platelets has shown that the motional state of the serotonin is restricted. Comparison with 31P n.m.r. experiments indicates that this restriction of motion is a consequence of high molecular weight aggregates formed by the adenine nucleotides and metal ions, and that it varies with the species from which the platelets are obtained. In the case of human platelet granules, at least, these high molecular weight aggregates are present in the absence as well as in the presence of serotonin. The biological significance of these data is briefly discussed.

Adenine Nucleotides↗
PubMed1980

Flow disturbance at the distal end-to-side anastomosis. Effect of patency of the proximal outflow segment and angle of anastomosis.

We investigated the flow disturbance that occurs at the distal end-to-side anastomosis. Clear plastic model end-to-side anastomoses were constructed with inlet angles of 15 degrees and 45 degrees. Flow patterns were visualized with steady and pulsatile flow using a dye-injection technique. Multiple lateral pressure measurements were made in the region of the anastomosis. A laser Doppler anemometer was used to measure near-wall velocity. Flow disturbance was minimal when the inlet angle was low and the proximal outflow segment occluded. Patency of the proximal outflow segment or a high inlet angle may result in areas of boundary-layer separation, with corresponding adverse pressure gradients at the anastomosis. These separation regions are characterized by low near-wall velocity, which may contribute to anastomotic hyperplasia.

Blood Circulation↗
PubMed1980

Gravity sedimentation analysis of human blood leukocytes.

A new method of sedimentation analysis of human blood leukocytes is described. Platelets, lymphocytes, monocytes, and polymorphonuclear cells isolated from normal human peripheral blood have been analyzed alone and in mixture by gravity sedimentation, employing a computerized scanning instrument. All four classes could be clearly resolved from each other exhibiting sedimentation velocities of 0.06 +/- 0.00, 1.04 +/- 0.11, 1.27 +/- 0.15 and 1.89 +/- 0.21 x 10(-4) cm/s, respectively, at 37 degrees C in a 2.5--6.25% Ficoll gradient in Medium 199. Less than 10(6) cells can be used for analysis. Possible applications of the method are discussed.

Blood Platelets↗
PubMed1980

Improved oxygen delivery to the myocardium during hypothermia by perfusion with 2,3 DPG-enriched red blood cells.

The oxygen affinity of red cells increases stepwise with temperature reductions below 37 degrees C. In vitro studies demonstrated that biochemically modified red cells with increased 2,3 diphosphoglycerate (2,3 DPG) (150% and 250% of normal) exhibited significantly less oxygen affinity at 24 degrees C than did unmodified cells. At 15 degrees C, significant attenuation of affinity was observed with 250%, but not 150%, of normal 2,3 DPG cells. Measurements made of isolated fibrillating dog hearts during perfusion at 24 degrees C alternately with unmodified (80% of normal 2,3 DPG) and modified (300% of normal 2,3 DPG) red cells demonstrated significantly greater oxygen consumption, higher coronary sinus partial pressures of oxygen and carbon dioxide, higher in vitro P50 values, and lower arterial and coronary sinus lactate levels during perfusion with modified as compared with unmodified cells. This evidence, indicating improved oxygen delivery to hypothermic dog hearts by red cells with 300% of normal 2,3 DPG activity, suggests that high 2,3 DPG cells might protect myocardial tissue in patients undergoing hypothermic cardiac operation.

Animals↗
PubMed1980

Comparative evaluation of new fine-screen filters: effects on blood flow rate and microaggregate removal.

Fine-screen filters were studied in a simulated clinical situation wherein ten units of outdated concentrated erythrocytes were rapidly transfused per filter to determine flow rates and effectivenesses of debris removal. Preliminary studies to evaluate flow rates with outdated whole blood indicated that the Bentley PFF-100, Fenwal 4C9003, and Biotest MF-10 fine-screen filters allowed flow rates sufficient to justify further detailed testing. For comparative purposes, the filter the authors have used clinically, the Pall Ultipor 40-micrometers filter, was studied again. As many as ten units of outdated, concentrated erythrocytes (hematocrits 75--85 per cent) were infused through each of the fine-screen filters at 300 torr pressure. All filters (except one of five Pall filters) accepted all ten units. The Bentley PFF-100 filter allowed the highest flow rates, such that the tenth unit of erythrocytes required 5 +/- 3 min (1 SD) to pass the filter. The Biotest MF-10, Bentley PFF-100 and Fenwal 4C9003 filters retained more debris/g erythrocytes, decreased screen filtration pressure, and eliminated more particulate matter (as determined by Coulter counter testing) than did the Pall Ultipor filter. When three or more units of blood are transfused, any of the four filters tested is cost-effective when compared with the current 170-micrometer standard transfusion filter.

Blood Flow Velocity↗
PubMed1980

A primate model for the study of the interaction of 111In-labeled baboon platelets with Dacron arterial prostheses.

This paper presents early experience with a primate model for the noninvasive study of the interaction of circulating platelets with healing arterial prostheses. These experiments demonstrate that baboon platelets can be isolated and labeled with 111Indium with high efficiency using a sterile technique. Platelets subjected to this process have a linear life span similar to that of 51Chromium-labeled baboon platelets. The high energy gamma emission of 111Indium oxine allows for external scanning using a standard gamma camera. The small quantity of 111Indium-labeled platelets in the region of the graft can be discriminated from the surrounding blood vessel and quantitated by gamma camera imaging and computer analysis. There was a significant increase in the platelet deposition on prosthetic surfaces observed 5--48 hours after graft implantation and injection of 111Indium-labeled autologous platelets.

Animals↗