Interesting but unclear.
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Blood Transfusion↗
Biomedical subjects
R F Reiss
Publications and source records attributed to R F Reiss.
Metabolism of prostacyclin by 9-hydroxyprostaglandin dehydrogenase in human platelets. Formation of a potent inhibitor of platelet aggregation and enzyme purification.
We have reported the identification of a metabolite of prostacyclin (PGI2) in the liver, 6-keto-PGE1, a substance having similar potency to PGI2 in its vascular and antiaggregative actions but differing in its greater stability. Either PGI2 or its inactive hydrolysis product, 6-keto-PGF1 alpha, can be enzymically transformed via the 9-hydroxyprostaglandin dehydrogenase pathway to 6-keto-PGE1. In this study, we demonstrated 9-OH prostaglandin dehydrogenase activity in the cytoplasmic fraction of human platelets by measuring the release of 3H from positin 9 using [9-3H]PGI2 and [9-3H]6-keto-PGF1 alpha as substrates. The enzyme was further purified by DEAE-cellulose, followed by Sephadex G-200, and finally by isoelectric focusing. The enzyme was found to have a pH optimum of 8.5 to 9.0 and an isoelectric point of 5.0. The molecular weight was estimated to be 60,000 by sodium dodecyl sulfate-gel electrophoresis. Enzymic activity was time- and concentration-dependent and required NAD+ as a cofactor. The activity of the purified enzyme was further confirmed by using a more stable form of PGI2, the methyl ester. Incubation of [11-3H]PGI2 methyl ester with the purified enzyme resulted in formation of [11-3H]6-keto-PGE1 methyl ester, which also inhibited platelet aggregation. Thus, 9-hydroxyprostaglandin dehydrogenase in platelets could be a major enzymic pathway for the transformation of PGI2, and perhaps 6-keto-PGF1 alpha, to 6-keto-PGE1. The possibility that the effects of prostacyclin on platelet aggregation are related to conversion to the biologically active metabolite, 6-keto-PGE1, should be considered.
Alprostadil↗
Cardiopulmonary bypass. Associated hemostatic abnormalities.
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Adult↗
Redistribution of platelets during discontinous flow platelet pheresis.
Greater numbers of platelets are recovered during discontinuous flow centrifugation than can be simply accounted for by the decrease in total circulating platelets in the donor. There is a linear relationship between the logarithm of the circulating platelet count and the number of plateletpheresis bowls filled. The disappearance of platelets from the peripheral circulation occurs at a greater rate in splenectomized donors than in normal donors, and the rate of platelet disappearance in normal donors is less than what would be expected if there were no in vivo platelet storage pools. The data suggest the redistribution of platelets from the spleen in normal donors during the time course of the procedure.
Blood Platelets↗
An improved method for the quantitation of A2 hemoglobin utilizing cellulose acetate electrophoresis and densitometry.
An improved method of A2 quantitation by cellulose acetate electrophoresis is describes. Densitometry is performed on uncleared membranes. The height of the peak obtained for the A2 band is compared with a standard curve derived from peaks obtained by serial dilutions of hemoglobin. Noral A2 hemoglobin as measured by this method is 2.55 percent plus or minus 0.60 (2 S.D.). Twenty patients samples were run in parallel with a column chromatographic method. Eight samples were found to contain elevated A2 levels by the column method. The same eight samples were correctly identified by the electrophoretic technic.
Blood Protein Electrophoresis↗
Malignant blue nevus. Occurrence with aggressive behavior.
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Head and Neck Neoplasms↗
Effect of counselling rejected blood donors to seek health care.
The appropriate public health role of a blood bank has not been completely defined. An evaluation of verbal counselling as an incentive for rejected blood donors to seek follow-up medical care was undertaken. Two groups, deferred from donating blood because of low hematocrits, were compared in terms of compliance rate (percentage seeking medical care). The first group, comprising 60 individuals deferred in a traditional manner with either a brief written or verbal statement, had a compliance rate of 25%. In the second group, comprising 61 individuals to whom additional counselling was offered, 79% requested such counselling. A compliance of 60% was found among those counselled, and an overall compliance rate of 54% was noted in the group as a whole. The more than doubling of the compliance rate indicates that a blood bank can effectively encourage deferred donors, most of whom are asymptomatic, to seek health care.
Adolescent↗
Platelets and factor VIII as functions of blood collection time.
Plasma and platelet concentrates were prepared from whole blood collected in less than eight minutes, and from blood collected in 8 to 12 minutes. Comparison was made between the two collection groups of Factor VIII activity in fresh plasma, and of Factor VIII activity in fresh frozen plasma. Using the rank sum test, no significant difference was found between Factor VIII activities in either fresh or fresh frozen plasma. The number of platelets in concentrates prepared from blood collected in less than eight minutes were compared with those in concentrates from blood collected in 8 to 12 minutes. Mean numbers of platelets were 6.89 x 10(10) and 7.12 x 10(10),respectively. No significant difference was found between the two groups when compared by the rank sum test, or the "t" test. Current guidelines recommending maximum eight-minute collection for component preparation may be inappropriately restrictive.
Blood Cell Count↗
Statewide support of thrombocytopenic patients with ABO matched single donor platelets.
Use of ABO matched, HLA nonmatched platelet units obtained from single donors by pheresis, using the Haemonetics 30 Cell Separator, has a lowered hepatitis risk, and possibly delays the onset of the refractory state. Pheresis also offers a method of obtaining HLA matched platelets for the already refractory patient. A mean of 4.2 X 10(11) platelets are collected in about 1 1/2 hours. ABO matched, HLA nonmatched platelets produced corrected increments of more than 2500/mm3 per 7 X 10(10) platelets infused in 67 per cent of transfusions to nonselected recipients. The procedure is simple, safe, and requires little time. It is a worthwhile large-scale program for a regional blood center to undertake in order to provide optimal therapy for thrombocytopenic patients.
ABO Blood-Group System↗
Optimizing recovery of platelets in platelet rich plasma by the simplex strategy.
A Simplex is an empirical, geometric feedback strategy which progressively programs a series of experiments according to the results of the preceeding experiments. It leads to definition of conditions which maximize or minimize the result of experiments in two or more variables. When applied to study a laboratory method it dictates simultaneous variation of the conditions of an experiment, differing from the usual approach in which variables are altered sequentially and arbitrarily. A two variable Simplex (force and duration of centrifugation) has been applied to maximize platelet recovery in platelet rich plasma (PRP). The technique of Simplex is described. Maximal recovery of platelets in PRP was reached by centrifugation at 2160 X g for 2.7 minutes. To confirm the correctness of this result, platelet concentrates were prepared from PRP's separated by three different methods: 1) conditions determined by Simplex, 2) American National Red Cross recommended method (2820 X g for two minutes), and 3) Canadian Red Cross recommended method (995 X g for nine minutes). Mean recovery of 78 per cent was obtained by Simplex, significantly higher than 61 per cent with the American National Red Cross method (p greater than .005) and higher than 69 per cent with the Canadian Red Cross method. Simplex strategy is recommended as a simple, powerful technique for determining optimal experimental or laboratory conditions.
Blood Banks↗
Microaggregate content and flow rates of packed red blood cells.
Platelet rich red cells (PRRC) and platelet poor red cells (PPRC) are both prepared in the course of red cell production. PRRC tend to have a higher hematocrit (82 +/- 7) than PPRC (77 +/- 5), (p less than .001). There are more microaggregates present in PRRC (2.48 +/- 1.41 gm) than in PPRC (1.46 +/- 0.61 gm), (p less than .001). The infusion rate for PRRC was 4.0 X 1.8 ml/minute, and this was significantly smaller than for PPRC which was 9.7 +/- 1.7 m/minute, (p less than .001). This compares to a rate for whole blood of 32.8 ml/minute. The difference in flow rate of the two types of red blood cells is in part due to a difference in viscosity, but more inportantly due to a difference in microaggregate content. Flow rate is normalized for both types of packed cells by the addition of 100 to 150 ml of saline, while infusion time is normalized by the addition of only 50 to 100 ml of saline to the packed cell units.
Blood Flow Velocity↗
Therapeutic plateletpheresis in thombocythemia.
Patients with myeloproliferative thrombocythemia have usually been managed with chemotherapy. Generally, removal of platelets from such patients has been performed intermittently to lower the platelet mass rapidly when neurologic or hemorrhagic complications were manifest or concurrently with the initiation of chemotherapy. A platelet count of 1,000,000/microliter or less was maintained by the use of repeated plateletpheresis over a period of three months in a patient with essential thrombocythemia, who had frequent syncopal episodes. A second patient with secondary thrombocytosis, who sustained two cerebrovascular accidents, underwent intermittent plateletpheresis over a 22-day period until her underlying disorder improved. It is concluded from the experience, combined with that of others, that plateletpheresis is not only a life-saving procedure in an acute episode but may also be used to maintain a lowered platelet count over a prolonged period in selected patients with primary thrombocythemia, in whom chemotherapy cannot be undertaken, and in symptomatic patients with secondary thrombocythemia.
Adult↗
Dose-response and time-response study of erythrocytosis in rats after intrarenal injection of nickel subsulfide.
Erythrocytosis was induced in Fischer rats by intrarenal (ir) injection of nickel subsulfide (Ni3S2) in dosages ranging from 0.6 to 10 mg per rat. Measurements of blood packed cell volume (PCV) became increased by one month after ir injection of Ni3S2; reached maximum values at approximately two months; and gradually returned to control values by seven months. The duration and magnitude of erythrocytosis were related to the dosage of Ni3S2. Increases in hemoglobin concentrations and erythrocyte counts (RBC) in Ni3S2-treated rats were consistently proportional to blood PCV values. Blood hemoglobin concentration was 24.9 +/- 1.2 g per dl at two months after bilateral ir injection of Ni3S2 (10 MG PER RAT), VERSUs 15.8 +/- 0.5 g per dl in saline-injected controls (P less than 0.001). No significant changes occurred in leukocyte or platelet counts of Ni3S2-treated rats. Autopsy of rats killed two months after ir injection of Ni3S2 showed marked erythroid hyperplasia of bone marrow and fibrotic needle tracts in renal parenchyma with localized deposits of particles of Ni3S2. In contrast to the erythrocytosis induced by ir injection of Ni3S2, administration of Ni3S2 by intramuscular (im) injection (10 mg per rat) had no significant effect upon blood PCV, RBC or hemoglobin values or upon morphology of bone marrow.
Animals↗
Elution of filtered granulocytes for transfusion.
Functional and clinical transfusion studies were carried out on granulocytes eluted from nylon filters using ACD Saline solutions and 20% CPD Plasma ACD Saline solutions. Although the average volume of blood and total number of granulocytes filtered were the same, the yield of granulocytes eluted form the filters was 20% greater when 20% CPD plasma was in the eluting solution. Function studies indicated that while the antibacterial capacity of the saline eluted granulocytes was equivalent to that of plasma eluted cells, chemotactic activity was markedly reduced after 24 hours storage in the saline eluted cells. Clinical studies post transfusion also suggest better response from plasma eluted granulocytes.
Blood Bactericidal Activity↗