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Biomedical subjects

G Moroff

Publications and source records attributed to G Moroff.

At least 37 records · Page 2Linked to original sources
PubMed1994

Storage of apheresis platelets after gamma radiation.

BACKGROUND: There are conflicting data on the effect of irradiation and subsequent storage on the quality of platelet components. STUDY DESIGN AND METHODS: The retention of platelet properties during storage of gamma-irradiated apheresis suspensions was studied in 22 apheresis components obtained on a cell separator with a specialized centrifugation chamber. Immediately after collection, each suspension was divided equally into two 1-L polyolefin containers. On Day 1 (n = 12) and Day 3 (n = 10) one of each pair of suspension containers was gamma radiated with 2500 cGy. All platelet suspensions were stored for 5 days at 20 to 24 degrees C. Samples were drawn on Day 5 from each of the 22 pairs of containers for evaluation of an array of in vitro properties. Samples were taken from 10 pairs of containers for platelet labeling with either 51Cr or 111In for subsequent transfusion and concurrent in vivo measurement of recovery and survival. Posttransfusion samples were drawn after 24 hours for ex vivo whole blood aggregation. RESULTS: Comparable in vitro and in vivo properties were measured in irradiated and control platelets, whether irradiation was performed on Day 1 or Day 3. The mean +/- 1 SD in vivo recovery and survival time for controls and platelets irradiated on Day 1 was 52 +/- 14 percent and 146 +/- 34 hours and 51 +/- 7 percent and 147 +/- 36 hours, respectively. For Day 3 irradiation, the values were 46 +/- 12 percent and 150 +/- 60 hours and 47 +/- 9 percent and 151 +/- 53 hours, respectively. A small, but measurable adverse effect of irradiation on ex vivo platelet aggregation was present. CONCLUSION: These data indicate that storage of apheresis platelets after gamma radiation is without clinically significant, demonstrably adverse effects on platelet quality.

Blood Platelets↗
PubMed1993

Assessment of the hemostatic effectiveness of human platelets treated with aminomethyltrimethyl psoralen and UV A light using a rabbit ear bleeding time technique.

The photochemical aminomethyltrimethyl psoralen (AMT), in conjunction with UV A light (UVA), has been shown to inactivate human immunodeficiency virus-1 and model viruses in platelet suspensions under conditions that have only a minimal effect on in vitro platelet properties. A rabbit ear bleeding time technique was used to assess the hemostatic effectiveness of human platelet suspensions treated with AMT/UVA. New Zealand White rabbits were made thrombocytopenic by a combination of irradiation and heterologous antirabbit platelet antiserum. Reticuloendothelial function in these rabbits was suppressed by the intravenous administration of ethyl palmitate. The hemostatic function of 1- and 5-day-old human platelet suspensions (14.5% plasma) that had been treated on day 1 with 40 micrograms/mL AMT and 24 kJ/m2 UVA (1 x UVA) was evaluated by measuring microvascular bleeding times after a standard incision. Comparable bleeding times were observed after infusion with both control and AMT/UVA-treated platelets stored for either 1 or 5 days. With the transfusion of AMT/1 x UVA-treated platelets stored for 5 days, the mean (+/- SD) bleeding time was 156.3 +/- 39.2 seconds (n = 10). With untreated platelets (no AMT/no UVA), stored for 5 days, the mean bleeding time was 189.2 +/- 36.4 seconds (n = 10). Neither AMT nor 1 x UVA treatment alone influenced the observed bleeding times. In contrast, the hemostatic effectiveness of human platelet suspensions was diminished if they were exposed to three times the standard UVA dose (72 kJ/m2) on day 1 and stored for 4 more days, regardless of whether AMT was present, with the mean bleeding time increasing to 442.2 +/- 122.6 seconds (n = 15, AMT present) or 396.0 +/- 45.9 seconds (n = 10, AMT absent). These results are consistent with data obtained from in vitro studies and indicate that virucidal AMT/1 x UVA treatment does not influence platelet hemostatic function. However, the final conditions to achieve these results must be carefully controlled.

Animals↗
PubMed1993

Storage of pools of six and eight platelet concentrates.

Platelet concentrates (PCs) prepared from units of whole blood are routinely stored singly at 20 to 24 degrees C and pooled prior to transfusion. Studies have been conducted to evaluate the in vitro properties of pools of six (n = 19) and eight (n = 17) ABO-identical PCs after storage, with comparative studies involving single units (n = 33). The pools were prepared using the sterile connecting device. One-day-old and 3-day-old PCs were pooled and stored for a total of 5 days in a container system consisting of two 1000-mL polyolefin containers. The pooled platelet suspension was divided approximately equally between the two containers. The platelet count was reduced by less than 5 percent during storage of the pools, which is similar to the reduction found with storage of control units of single PCs. The volume loss due to pooling was 9.6 +/- 1.9 percent (mean +/- 1 SD). The pH of the PC pools was approximately 7.0 after 5 days of storage, with no pool having a pH below 6.2. In vitro platelet properties, such as morphology score, extent of shape change induced by ADP, total ATP, aggregation response to ADP and collagen, response to hypotonic stress, lactate dehydrogenase discharge, and beta-thromboglobulin release, were similar for pools and control single PCs. In addition, comparable low levels of thymidine uptake were detected in the mononuclear leukocyte fraction of pooled and unpooled PCs that were stored for 5 days at 20 to 24 degrees C, which indicates that the mixing of lymphocytes in the pool did not stimulate in vitro immunologic reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1992

Leukocyte reduction in blood component therapy.

PURPOSE: To review methods of preventing or minimizing the adverse effects associated with the transfusion of passenger leukocytes present in cellular blood components and to define groups of patients who are at risk for adverse effects. DATA SOURCES: English-language articles on transfusion medicine. STUDY SELECTION: Original reports describing the pathogenesis of leukocyte-induced adverse effects in transfusion recipients and the influence of leukocyte-reduced blood components on these effects. DATA EXTRACTION: Evaluation of the diagnosis, transfusion history, and treatment of the study patients; the methods and results of leukocyte reduction; and specific outcomes, including development of alloimmunization to leukocytes, febrile reactions to transfusion, and platelet refractoriness. DATA SYNTHESIS: Passenger leukocytes are the chief cause of alloimmunization to human leukocyte antigen (HLA) and leukocyte-specific antigens in transfusion recipients. Alloimmunization may result in febrile transfusion reactions, platelet refractoriness, and acute lung injury. Leukocytes are also the vector for transfusion-associated cytomegalovirus infection. Technologic advances in the leukocyte reduction of cellular blood components have made it possible to reduce the number of leukocytes to fewer than 10(7) per transfusion. Findings suggest that the use of leukocyte-reduced cellular blood components may minimize or prevent recurrent febrile reactions and alloimmunization to leukocyte antigens. Cytomegalovirus may not be transmitted by blood components containing fewer than 10(7) leukocytes. CONCLUSIONS: Leukocyte reduction in red blood cell and platelet transfusions using third-generation filters is indicated for selected patients who are likely to receive long-term transfusion support, to prevent recurrent febrile reactions and to prevent or delay alloimmunization to leukocyte antigens. Leukocyte-depleted transfusions may also be indicated to delay or prevent refractoriness to platelet transfusion.

Blood Component Transfusion↗
PubMed1992

Selection of platelets for refractory patients by HLA matching and prospective crossmatching.

A multi-site clinical study compared platelets chosen for refractory patients by prospective platelet crossmatching using stored donor platelets and HLA-based selection. Seventy-three patients who were refractory to random-donor platelets received two plateletpheresis components, one chosen by HLA-based criteria and the other by crossmatching. Patients were carefully evaluated to exclude nonimmune factors that could adversely affect transfusion results. Each of the five study sites used a crossmatch procedure with which it had experience. Results from this study indicate the following: 1) The overall rate of successful transfusion was similar when an HLA-based method of donor selection that includes all grades of matching and mismatching was compared to a crossmatch-based method of donor selection. 2) HLA-based selection that restricts recipients to grade A and BU matches was superior to a selection method based upon crossmatching alone. Donor selection based on HLA matching (grades A or BU) was also superior to selection based on any degree of HLA mismatching (grades BX, C, or D). 3) Selection of donors based on HLA-cross-reactive groups (defined by in vitro serologic crossreactivity) was no more successful than that based on grade C and D mismatches and was no more successful than selection by crossmatching alone. 4) Lymphocytotoxic and platelet antibodies were not detected in many of the enrolled patients, even though patients demonstrating nonimmune factors were eliminated from the study. It can be concluded that HLA-compatible (grades A and BU) platelets provide optimal support for refractory patients, but that crossmatch-selected platelets are acceptable as an alternative component.

Adult↗
PubMed1992

Factors influencing virus inactivation and retention of platelet properties following treatment with aminomethyltrimethylpsoralen and ultraviolet A light.

A wide variety of viruses are inactivated by psoralen compounds in the presence of ultraviolet A light (UVA). Use of aminomethyltrimethylpsoralen (AMT) and UVA is being evaluated as a method to inactivate viruses that may be present in platelet suspensions prepared for transfusion. Studies have been conducted to assess how variation in various environmental parameters influences the extent of viral inactivation and the retention of platelet properties. Most notably, it was determined that increasing levels of plasma progressively inhibited the inactivation of model viruses. As a result, experiments were routinely conducted at a plasma level of approximately 14.5%, using 40 micrograms/ml AMT, which was determined to be optimal when using this reduced plasma level. The reduced plasma level was achieved by dilution with a nonplasma medium that has been shown to be satisfactory for storage of platelets. Under these conditions, about 5 logs of vesicular stomatitis virus (VSV), pseudorabies, and phi 6 inactivation were achieved. Variation of platelet and leukocyte counts, within normal levels, had a minimal effect on extent of viral inactivation. Although oxygen level (mean levels, 97.9 mm Hg versus 19.2 mm Hg) had only a small influence on viral inactivation with 2.4, 4.8, and 7.2 J/cm2 of UVA (equivalent to 1-3 minutes of exposure), in vitro platelet properties, such as medium pH, morphology characteristics, and aggregation response, were better retained with a longer exposure time at the reduced oxygen level. With normal oxygen (97.9 mm Hg), platelet properties declined substantially relative to untreated controls (no UVA, no AMT) on exposure to 4.8 J/cm2. Our studies have identified two sets of conditions that provide about 5 logs of virus inactivation without extensively altering platelet in vitro properties.

Blood↗
PubMed1991

Concepts about current conditions for the preparation and storage of platelets.

Substantial experimentation over the last 20 years has led to the conditions that are currently used to prepare and store platelets. Although platelet rich plasma is used in most instances to prepare platelet concentrates, there may be some benefit associated with the use of buffy coats as the source component. Extension of the maximum allowable storage time for platelets to 5 days has been possible as a result of defining the conditions which allow for the better retention of platelet properties. Storage temperature, permeability of the storage container, volume of platelet suspension, and the need to agitate platelets have been identified as key parameters that maintain platelet viability and functional properties. Storage in the 20 to 24 degrees C range prevents a reduction in posttransfusion viability that occurs when platelets are maintained at lower temperatures. Adequate influx of oxygen through container walls to support platelet metabolism and, to a lesser degree, adequate efflux of produced carbon dioxide are essential for maintaining pH levels, a key parameter that also influences posttransfusion viability. Permeability is influenced by container size and material, by use of a satisfactory volume of plasma and by agitating the container. Although platelet concentrates prepared from whole blood have been primarily used to delineate appropriate storage conditions, they also apply to platelets harvested by aphersis technology. Storage under currently used conditions, although providing products with acceptable clinical efficacy, is associated with a reduction in viability and functional characteristics. The development of storage media, specific for platelets, may minimize the occurrence of deleterious changes.

Anticoagulants↗
PubMed1990

The maintenance of platelet properties upon limited discontinuation of agitation during storage.

Platelet concentrates are routinely stored with continuous agitation but may need to be maintained without agitation for substantial time periods. Studies were conducted in vitro to assess the retention of platelet properties after the discontinuation of agitation. Platelets were maintained without agitation in an insulated cardboard container. In one study, platelet concentrates were kept at 20 to 24 degrees C for the entire 24-hour period. In another study, they were kept at 37 degrees C for 6 hours with subsequent storage at ambient room temperature for the remainder of the 24-hour holding period. Under the simulated shipping conditions, discontinuation of agitation for 24 hours between Days 2 and 3 of a 7-day storage period minimally influenced the maintenance of a series of in vitro platelet properties. The maintenance of platelet concentrates at 20 to 24 degrees C, sitting undisturbed on a bench top for 9 hours, after storage for 6 days with continuous agitation, also had no damaging influence.

Blood Platelets↗
PubMed1990

Storage of ADSOL-preserved red cells at 2.5 and 5.5 degrees C: comparable retention of in vitro properties.

Previous studies with CPDA-1 and Nutricel preserving solutions indicated that red cell properties were affected by small differences in storage temperature. The influence of a 3 degrees C differential on the preservation of the in vitro properties of ADSOL-preserved (AS-1) red blood cells was investigated in a paired study. AS-1 red blood cells were stored at 2.5 and 5.5 degrees C for 42 days. Extent of hemolysis, glucose consumption and pH levels were comparable at the two storage temperatures. Lactate levels were slightly, but significantly higher at 5.5 degrees C. ATP levels were slightly but significantly higher at 2.5 degrees C, only during the later part of the storage period. 2.3-DPG levels were slightly better retained at 2.5 degrees C after 7 days of storage. Holding units of whole blood for either 1 or 8 h at ambient temperature after phlebotomy prior to processing did not influence the types of temperature-dependent changes. The differences as a function of storage temperature were small and appear to be of no practical importance in connection with the storage of AS-1 red blood cells.

2,3-Diphosphoglycerate↗
PubMed1990

Resistance of platelet proteins to effects of ionizing radiation.

Gamma irradiation of blood components prevents lymphocyte-induced graft-versus-host disease after transfusion in immunocompromised individuals. In this report we demonstrate the resistance of blood platelet proteins to gamma radiation-induced protein cleavage and aggregate formation when platelet concentrates were treated with a dose of 5000 rad. Results of one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total platelet protein and cytoskeletal protein preparations indicate that platelet proteins are neither cleaved nor cross-linked under these conditions of irradiation. These results support those of a previous study that documented the lack of any adverse effect of 5000 rad gamma radiation on in vitro platelet properties.

Blood Platelets↗
PubMed1989

Properties of platelet concentrates prepared after extended whole blood holding time.

Extension of the maximum holding time for whole blood collected into a CPD-ADSOL system from 6 to 8 hours at ambient temperature under conditions that cause the temperature of the blood to decrease to 20 to 24 degrees C would facilitate the preparation of platelet concentrates (PCs). In this study, the properties of CPD-PCs prepared and stored for 5 days in PL-732 containers after various initial holding periods were assessed in two laboratories, designated Laboratory A and Laboratory B. Laboratory A found higher platelet-rich plasma (PRP) volumes (276 +/- 25 vs. 249 +/- 19 mL) and platelet yields (76 +/- 18 vs. 66 +/- 18 x 10(9) platelets) with 8-hour holds (n = 10) than with 1- to 2-hour holds (n = 10), although only the difference in PRP volumes was significant (p less than 0.05). No significant difference was observed in autologous in vivo recovery (54 +/- 11 vs. 47 +/- 9%) or survival (167 +/- 37 vs. 170 +/- 25 hrs), as calculated by gamma function using 111In as radiolabel. Laboratory B also found higher PRP volumes (304 +/- 31 vs. 279 +/- 37 mL) and platelet yields with 8-hour holds (n = 12) than with a 6-hour holds (n = 10) (88 +/- 26 vs. 77 +/- 27 x 10(9) platelets). No significant differences were found in morphology score, the extent of release of beta-thromboglobulin, the discharge of lactate dehydrogenase, or hypotonic shock response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1986

Effect of forskolin on the maintenance of platelet properties during storage.

During storage of platelet concentrates under routine blood banking conditions a gradual increase takes place in the degree of platelet activation. Studies were designed to determine whether the addition of forskolin, a direct activator of platelet adenylate cyclase and inhibitor of platelet activation, could reduce some of the deleterious changes occurring during a 10-day storage period at 20 degrees to 24 degrees C. Forskolin was added to the platelet-rich plasma before preparation of the platelet concentrates. Dose-effect studies in which 0.5, 5, and 50 mumol/L forskolin were compared indicated that 5 mumol/L forskolin was the optimal concentration for the reduction of platelet activation over this period as assessed by measuring the release of beta-thromboglobulin and the formation of thromboxane B2. It was determined that cyclic adenosine monophosphate levels were increased approximately fourfold by 5 mumol/L forskolin and maintained at a high level for at least the first 48 hours. These results show that the presence of forskolin inhibits the activation of platelets during storage.

Blood Platelets↗
PubMed1985

Effects of storage conditions on platelet cytoskeletal proteins.

The platelet cytoskeleton is a major determinant of platelet morphology and function. Changes in the protein composition of the cytoskeleton were studied during storage of platelets at 20 degrees to 24 degrees C under blood banking conditions. Cytoskeletons were prepared by extraction of washed platelets with the detergent Triton X-100 and then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In addition to the three major proteins visible with Coomassie blue staining--actin, myosin, and actin-binding protein--silver staining revealed other proteins associated with the cytoskeletons of freshly collected and stored platelets. The resting platelet cytoskeleton contained 8% to 10% of the total platelet protein and approximately 50% of the total actin. During storage of platelet concentrates for up to five days in the PL 732 container, proteins of 50,000 to 55,000 and 90,000 mol wt were increasingly incorporated into the Triton-insoluble fraction, whereas the amounts of cytoskeleton-associated actin-binding protein, myosin, and actin were maintained at levels present in fresh platelets. Storage of platelets under conditions that allowed the reduction of platelet concentration pH to nearly 6.0 resulted in a marked decrease in the amounts of the major proteins of the cytoskeleton. The loss of specific proteins from platelets stored for extended periods with reduced pH, accompanied by the appearance of lower molecular weight proteins in the cytoskeleton, suggests that extensive proteolysis may occur under certain storage conditions. These data show that the conditions employed for storage of platelet concentrates influence the protein composition of the cytoskeleton and the total protein content of the platelet.

Blood Banks↗
PubMed1982

Factors influencing changes in pH during storage of platelet concentrates at 20-24 degree C.

The magnitude of the pH change during platelet concentrate storage at 20-24 degree C in polyvinyl chloride containers is not determined solely by platelet count per cubic millimeter of plasma, since a wide variation in pH was observed with similar platelet concentrations. In modified platelet concentrates having lost through centrifugation 3-15% of total platelets and 61-92% of residual leukocytes, the pH was maintained at substantially higher levels than in the paired control platelet concentrates. Leukocyte levels do not appear to determine the magnitude of the pH fall. Continuous oxygen utilization is needed if the pH is to be maintained near 7.0. However, oxygen tension per se is not the factor which influences the extent of pH change. It has been concluded that a specific platelet subpopulation comprising a small proportion of the total platelets in concentrates and having an enhanced capacity to form lactate may be responsible for a major part of the pH reduction which occurs during storage of many platelet concentrates.

Antimycin A↗
PubMed1979

Influence of glygerol on ATP and 2,3-DPG levels of human erythrocytes.

Glycerolization of freshly collected human erythrocytes leads to a reduction in ATP levels which return to their original values following deglycerolization. The reduction in ATP levels is largely prevented by pyruvate but not by inosine and glucose, singly or in combination. This implies that the ATP lesion associated with glycerolization reflects mainly a decrease in the NAD/NADH ratio and accordingly a reduced glyceraldehyde-3-phosphate dehydrogenase activity. 2,3-DPG levels were not influenced by glycerolization and deglycerolization. Erythrocytes depleted of ATP in the presence of glycerol can have their ATP levels repleted by either pyruvate or inosine, but require the presence of both compounds for maintenance during a post-rejuvenation incubation period. This indicates that the prolonged presence of glycerol influences both the NAD/NADH ratio and the carbon-containing intermediates of glycolysis. Glycerol did not influence ATP repletion of erythrocytes stored at 4 degrees C for 20 days by inosine in combination with pyruvate, but substantially decreased the repletion of their 2,3-DPG levels.

Adenosine Triphosphate↗