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Biomedical subjects

J J Vecchione

Publications and source records attributed to J J Vecchione.

At least 19 recordsLinked to original sources
PubMed1991

Detection of intracoronary fibrin degradation after coronary balloon angioplasty.

Intracoronary thrombus formation may be involved in the pathogenesis of arterial closure after coronary angioplasty and may contribute to restenosis. It is hypothesized that, unlike markers of platelet activation and fibrin formation, D-dimer, a product of plasmin-mediated proteolysis of cross-linked fibrin, is not subject to significant catheter-induced artifact and could be used to study intracoronary fibrin degradation during angioplasty. No significant difference in D-dimer levels was noted in serial plasma samples obtained from an 8Fr arterial sheath and the wire lumen of an angioplasty balloon catheter, indicating that sampling through the catheter lumen did not induce artifactual D-dimer elevations. Translesion (proximal and distal to the lesion) coronary blood samples were collected in 31 patients undergoing elective coronary angioplasty pretreated with aspirin, dipyridamole and heparin. In 20 of those in whom translesion coronary samples for plasma D-dimer levels (mean +/- standard deviation) were collected before balloon dilation, there was no evidence of ongoing intracoronary fibrinolysis (proximal D-dimer levels, 289 +/- 145 ng/ml; distal, 299 +/- 156 ng/ml; difference not significant). After coronary angioplasty (n = 31), there was a relatively small, but significant (p less than 0.001) increase (45 +/- 71 ng/ml) in translesional D-dimer levels (proximal, 396 +/- 223 ng/ml; distal, 441 +/- 257 ng/ml). The results from this study suggest (1) D-dimer levels are not subject to significant catheter-induced artifact and may be useful for assessment of intracoronary fibrin metabolism, and (2) intracoronary degradation of fibrin can be detected after (but not before) routine coronary angioplasty despite pretreatment with antithrombotic therapy, presumably in response to balloon-induced arterial injury and fibrin formation.

Aged↗
PubMed1986

Cryopreservation of dog platelets with dimethyl sulfoxide: therapeutic effectiveness of cryopreserved platelets in the treatment of thrombocytopenic dogs, and the effect of platelet storage at -80 degrees C.

Dog platelets were frozen with 6% dimethyl sulfoxide at 2-3 degrees C per minute in a -80 degrees C mechanical freezer. The frozen platelets were stored at -80 degrees C for as long as 39 months. After storage at -80 degrees C for less than 1 year, platelet in vitro freeze-thaw-wash recovery values were 70%, and in vivo survival values 1 to 2 hr after transfusion were 40% those of fresh platelets. After 2 years or longer storage, in vitro freeze-thaw-wash recovery values were 60%, and in vivo survival values 1 to 2 hr after transfusion were 20% those of fresh platelets. These results indicate that significant deterioration of the dog platelets occurred between the first and second year of storage at -80 degrees C. Platelets that were stored frozen at -80 degrees C for less than 1 year and washed before transfusion into lethally irradiated thrombocytopenic dogs were hemostatically effective.

Animals↗
PubMed1982

Cryopreservation of platelets isolated with the IBM 2997 blood cell separator: a rapid and simplified approach.

The equivalent of 5-7 units of platelets, isolated from a single donor with the IBM Blood Cell Processor 2997 using a dual stage separation chamber, was frozen with the cryoprotectant dimethylsulfoxide (DMSO). The DMSO-saline solution was added directly to the platelets, and the platelets were frozen in a polyvinyl chloride plastic bag by storage in a -80 degrees C mechanical freezer. Washing the thawed platelets with a phosphate-buffered sodium chloride-dextrose solution, pH of 5.0, removed about 95% of the DMSO. In vitro freeze-thaw-wash recovery was 80%, and in vivo 51Cr platelet recovery was 31%. Platelet dense body granules were well maintained after freezing, thawing, and washing. This is a safe and effective method of platelet cryopreservation which can be performed in less time than other currently used methods.

Adolescent↗
PubMed1981

Studies on the in vivo elution of 51Cr from baboon red blood cells.

Four anticoagulant solutions were added to baboon red blood cells prior to labeling with 51Cr to determine how each would influence the distribution of 51Cr within the red blood cells, the loss of 51Cr from the red blood cells after transfusion, and the calculated red cell survival value. The 51Cr label was detected in the hemoglobin and in the low molecular weight compounds within the red blood cells. The elution of 51Cr from labeled baboon red blood cells following transfusion could not be explained by the distribution of 51Cr between hemoglobin and low molecular weight compounds within the red blood cells.

Animals↗
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

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

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↗
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↗
PubMedDate not supplied

Liquid and freeze-preservation of dog red blood cells.

After storage in the liquid state at 4 C for up to three weeks, washing with sodium chloride solutions, and storage in a sodium chloride-glucose-phosphate solution for 24 hours at 4 C, dog red blood cells had excellent post-transfusion survival. After freeze-preservation with 40% W/V glycerol at -80 C or with 20% W/V glycerol at -150 C, thawing, washing with sodium chloride solutions, and storage in a sodium chloride-glucose-phosphate solution for 24 hours at 4 C, dog red blood cells had satisfactory recovery values in vitro, acceptable 24-hour post-transfusion survival and long-term survival values, and normal oxygen transport function. Controlled addition and removal of the cryoprotectant, glycerol, helped reduce the amount of osmotic damage to the red blood cells and enhanced freeze-preservation. Osmotic damage can also be prevented by warming the dog blood to a temperature of 22 +/- 2 C prior to centrifugation to concentrate the red blood cells and remove the plasma. This step enhances removal of the cold agglutinins. Another processing step used by the authors was to add a sodium chloride solution to the dog red blood cells before adding the glycerol solution in order to eliminate rouleaux formation.

Animals↗