Platelet transfusion: a clinical practice guideline from the AABB

BACKGROUND: The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients. METHODS: These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. RECOMMENDATION 1: The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 2: The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence). RECOMMENDATION 3: The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 4: The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 5: The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 6: The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).(AU)

Delayed intravascular haemolysis following multiple asymptomatic ABO-incompatible red blood cell transfusions in a patient with hepatic failure.

ABO-incompatible red blood cell (RBC) transfusions have rarely been associated with delayed haemolysis. However, we report the case of a 75-year-old man (blood type O) with hepatic disease, who received 5 units of incompatible type B RBCs over 8 days. The patient did not develop symptomatic or biochemical evidence of haemolysis until 7-8 days after the first incompatible RBC unit. The patient had a low anti-B antibody titre (1 : 64) prior to the first transfusion. The onset of haemolysis was temporally associated with an increase in anti-B and the infusion of fresh-frozen plasma. In conclusion, a patient with hepatic failure experienced a delayed haemolytic transfusion reaction after receiving multiple ABO-incompatible RBC transfusions that were initially well-tolerated. We speculate that the delayed haemolysis may have resulted from an anamnestic antibody response to the initial incompatible transfusion, or possibly as a result of the transfusion of fresh-frozen plasma, which might have repleted low complement levels.

Intensive medical management of ureteral calculi.

OBJECTIVES: To compare two treatment regimens in patients with ureteral calculi. One regimen (control arm) used routine drugs, and the second regimen (treatment arm) used the same routine drugs plus uncommonly used drugs. METHODS: Between February and October 1998, 70 consecutive patients were evaluated for symptomatic ureteral calculi. Thirty-five patients were randomized to a control arm and received ketorolac, oxycodone, and acetaminophen combination tablets and prochlorperazine suppositories. Thirty-five patients were randomized to the treatment arm and received the same medications plus nifedipine XL, prednisone, and trimethoprim/sulfa combination tablets and plain acetaminophen. Stone passage rates, work days lost, emergency room visits, surgical interventions, and possible side effects of the drugs were recorded. RESULTS: The treatment arm (addition of nifedipine XL, prednisone, trimethoprim/sulfa, and plain acetaminophen) had higher (86% versus 56%) stone passage rates and fewer lost work days (mean 1.76 versus 4.9), emergency room visits (1 versus 4), and surgical interventions (2 versus 15). Both arms exhibited similar potential drug side effects. CONCLUSIONS: The addition of a calcium channel blocking agent, steroids, antibiotics, and more acetaminophen effected a higher stone passage rate and fewer lost work days, emergency room visits, and surgical interventions.

New generation dopaminergic agents. 1. Discovery of a novel scaffold which embraces the D2 agonist pharmacophore. Structure-activity relationships of a series of 2-(aminomethyl)chromans.

A series of 2-(aminomethyl)chromans (2-AMCs) was synthesized and evaluated for their affinity and selectivity for both the high- and low-affinity agonist states (D2High and D2Low, respectively) of the dopamine (DA) D2 receptor. The 7-hydroxy-2-(aminomethyl)chroman moiety was observed to be the primary D2 agonist pharmacophore. The 2-methylchroman moiety was discovered to be an entirely novel scaffold which could be used to access the D2 agonist pharmacophore. Attaching various simple alkyl and arylalkyl side chains to the 7-hydroxy 2-AMC nucleus had significant effects on selectivity for the D2High receptor vs the 5HT1A and alpha 1 receptors. A novel DA partial agonist, (R)-(-)-2-(benzylamino)methyl)chroman-7-ol [R-(-)-35c], was identified as having the highest affinity and best selectivity for the D2High receptor vs the alpha 1 and 5HT1A receptors. Several regions of the 2-AMC nucleus were modified and recognized as potential sites to modulate the level of intrinsic activity. The global minimum conformer of the 7-hydroxy-2-AMC moiety was identified as fulfilling the McDermed model D2 agonist pharmacophoric criteria and was proposed as the D2 receptor-bound conformation. Structure-activity relationships gained from these studies have aided in the synthesis of D2 partial agonists of varying intrinsic activity levels. These agents should be of therapeutic value in treating disorders resulting from hypo- and hyperdopaminergic activity, without the side effects associated with complete D2 agonism or antagonism.

Cytokine generation in stored, white cell-reduced, and bacterially contaminated units of red cells.

BACKGROUND: Proinflammatory cytokines were measured in the supernatant portion of stored, bacterially contaminated, and/or white cell (WBC)-reduced units of red cells (RBCs). Previous studies from this laboratory and others have shown that cytokines are generated in platelet concentrates during storage. This earlier work has been expanded to the study of stored RBCs. STUDY DESIGN AND METHODS: Units of AS-1 RBCs (n = 10 non-WBC-reduced; n = 10 WBC-reduced) were obtained from a regional blood center, and each was split on Day 3 of storage into three equal portions by sterile techniques. One portion was kept sterile (control), and the other two were inoculated with Yersinia enterocolitica and Staphylococcus aureus, respectively, at 1 to 3 colony-forming units per mL. The RBCs were stored at 1 to 6 degrees C for 42 days. Sequential samples were taken during storage and assayed for interleukin 8 (IL-8), interleukin 1 beta (IL-1 beta), interleukin 6, WBC count, and bacteria count. For the WBC-reduced group (n = 10), WBC removal was done by filtration on Day 3 of storage, before bacterial inoculation. RESULTS: IL-8 was detected in the supernatant portion of all 42-day-old, non-WBC-reduced (mean WBCs = 4760 +/- 3870/microL) units of AS-1 RBCs at levels ranging from 63 to 1610 pg per mL. By contrast, at 2 to 3 days of storage, lower levels of IL-8 (range, 0-280 pg/mL) were detected in the same units. IL-8 levels increased progressively during storage in most (7/10) units. The highest mean levels of IL-8 were reached by outdate at Day 42. Y. enterocolitica-contaminated units had statistically higher levels of IL-8, with a range of 170 to 2100 pg per mL, by 42 days of storage. S. aureus grew poorly in stored units of RBCs and failed to further stimulate cytokine production. No WBC-reduced unit (mean WBCs = 0.5 +/- 0.6/microL), even when contaminated with bacteria, had more than 260 pg per mL of IL-8. Although IL-1 beta was not detected in any unit of RBCs at 3 days of storage, it increased to low levels (5-13 pg/mL) in all units tested at 42 days. Interleukin 6 was not detected in any unit at any storage time. CONCLUSION: IL-8 and IL-1 beta accumulated in the supernatants of stored RBCs despite cold storage conditions. IL-8 reached levels > 1000 pg per mL in the supernatants of some RBC units. IL-1 beta increased to significant but low levels (< 13 pg/mL). WBC filtration early in storage prevented the accumulation of IL-8. The physiologic significance to transfusion recipients of IL-8 in RBC supernatants is currently unknown and deserves further investigation.

Cytokine generation in stored platelet concentrates.

BACKGROUND: Cytokines, because of the nature of their immunoinflammatory actions, are potential mediators of the symptom complex of nonhemolytic transfusion reactions. One possible source of cytokines in the transfusion setting is the stored blood component itself. STUDY DESIGN AND METHODS: To test this possibility, the plasma portion of stored platelet concentrates (PCs) was assayed for the presence of interleukins 1 beta (IL-1 beta), 6 (IL-6), and 8 (IL-8) and tumor necrosis factor alpha (TNF-alpha). Samples were taken from PCs obtained from the inventory of a regional blood center (n = 120; 30 each of 2-, 3-, 4-, and 5-day-old units). RESULTS: Detectable levels of IL-8 were measured in 59 percent of the PCs sampled, ranging from 30 percent of the 2-day-old units to 83 percent of the 5-day-old units. The median IL-8 concentration ranged from undetectable levels in 2-day-old units up to 1100 pg per mL in 5-day-old units. The mean IL-8 concentration in 5-day-old units, 11,600 pg per mL, was 100 times the mean for 2-day-old units, which was 116 pg per mL (p < 0.0001). The highest levels of IL-8, 50,000 to 200,000 pg per mL, in general were found in units with the longest storage times and highest white cell counts. Sequential sampling of 17 individual PCs over 7 days of storage confirmed that IL-8 increases progressively with increasing storage time. Parallel, but smaller, increases in IL-1 beta were observed in those units with high IL-8 concentrations. TNF-alpha was detected in 3 (10%) of 30 five-day-old PCs, but never exceeded 55 pg per mL in any unit tested. IL-6 at levels of 740 and 508 pg per mL was detected in two 5-day-old units with high white cell counts of 9500 and 14,800 per microL, respectively, but not in 21 additional units tested with white cells < or = 9200 per microL or storage time of < or = 2 days. White cell reduction by third-generation filters on Day 1 of platelet storage prevented the generation of IL-8 and IL-1 beta to Day 5 of storage. CONCLUSION: Although IL-8 achieved levels in some units of PCs that appear capable of causing physiologic changes, the potential adverse effect on transfusion recipients of the infusion of cytokines in PCs remains to be investigated.

In vitro comparison of heated saline-blood admixture with a heat exchanger for rapid warming of red blood cells.

We compared the rapidity of rewarming and infusing red blood cells (RBCs) mixed with 24 degrees C, 50 degrees C, and 60 degrees C saline with the rapidity of administering undiluted RBCs through a heat exchanger. We measured flow rate, final temperature, and hemolysis in matched 41-45-day-old pooled AS-1 RBCs infused through high-flow tubing via a 14-gauge catheter under the influence of gravity. Undiluted RBCs were tested as controls. The final temperature of the 60 degrees C admixture technique was lower than that with the heat exchanger (28.5 +/- 0.2 degrees C vs. 32.7 +/- 0.2 degrees C), but the flow rate was higher (258 +/- 8 mL/min vs. 61 +/- 4 mL/min). Admixture with 60 degrees C saline resulted in no increase in hemolysis. This technique appears to be a simple, inexpensive method for rapid rewarming and infusion of RBCs and may be valuable for administration of RBCs simultaneously through multiple sites during resuscitation.

2-Phenyl-2-(1-hydroxycycloalkyl)ethylamine derivatives: synthesis and antidepressant activity.

A series of 2-phenyl-2-(1-hydroxycycloalkyl)ethylamine derivatives was examined for the ability to inhibit both rat brain imipramine receptor binding and the synaptosomal uptake of norepinephrine (NE) and serotonin (5-HT). Neurotransmitter uptake inhibition was highest for a subset of 2-phenyl-2-(1-hydroxycyclohexyl)dimethylethylamines in which the aryl ring has a halogen or methoxy substituent at the 3- and/or 4-positions. Potential antidepressant activity in this subset was assayed in three rodent models--the antagonism of reserpine-induced hypothermia, the antagonism of histamine-induced ACTH release, and the ability to reduce noradrenergic responsiveness in the rat pineal gland. An acute effect seen in the rat pineal gland with several analogues, including 1-[1-(3,4-dichlorophenyl)-2-(dimethylamino)ethyl]cyclohexanol (23) and 1-[2-(dimethylamino)-1)-(4-methoxyphenyl)ethyl]cyclohexanol (4), was taken as a possible correlate of a rapid onset of antidepressant activity. Compound 4 (venlafaxine) is presently undergoing clinical evaluation.

Relative mitogenic activities of various estrogens and antiestrogens.

The abilities of a variety of estrogens and antiestrogens to stimulate DNA synthesis in the prepuberal rat uterus were compared. One microgram of each compound was administered in vivo via a single intraperitoneal injection. DNA synthesis was assayed in vitro in isolated nuclei 24 h later. The relative mitogenicities of the steroidal estrogens were: 16 alpha-E2 less than 17 alpha-E2 = E3 = 16-EpiE3 less than 16 beta-E2 = 17 beta-E2. The potencies of several nonsteroidal estrogens were also tested. Indenestrol A was as potent at 17 beta-E2, whereas indanestrol and dimethylstilbestrol had weaker activities. The antiestrogens, nafoxidine and 4-hydroxytamoxifen, were both potent stimulators of DNA synthesis. The abilities of an estrogen to stimulate increases in uterine wet weight, DNA polymerase alpha activities, and DNA synthesis in uterine nuclei 24 h after injection were closely correlated. Because the magnitude of the stimulation of DNA synthesis was greatest, its measurement is the most sensitive of these assays of uterotrophic activity.

Storage of pooled platelet concentrates. In vitro and in vivo analysis.

The use of sterile connecting devices will permit up to 5-day storage of pooled platelet concentrates (PCs). However, there are no data evaluating long-term storage of PCs pooled from multiple donors. Four units of ABO-compatible or -incompatible PCs were pooled and stored in single 300-ml PL-732 storage bags for up to 5 days. Results of in vitro assays showed acceptable storage values regardless of the ABO types in the pool. Pool pH on Day 5 was 6.83 +/- 0.3 (mean +/- 1 SD). The in vitro storage characteristics were comparable to those of unpooled age-matched platelets reported previously from our laboratory. For in vivo studies, 4-unit pools of ABO-compatible random-donor PCs stored for up to 96 hours in 1000-ml PL-732 bags were transfused into patients who were thrombocytopenic due to bone marrow failure, and the correct count increments (CCI) were determined. In vivo results showed a mean 1-hour CCI of 11,368 +/- 5824 for the pooled stored platelets and 7819 +/- 5189 for unpooled controls (p greater than 0.05). To evaluate the possibility that passenger lymphocytes in the concentrates would generate mixed lymphocyte reactions (MLR) in the pooling bag during storage, lymphocytes were studied over 5 days of storage by the use of monoclonal antibodies against activated T-cell markers and by 3H thymidine uptake. Results failed to show evidence of either the generation of activated T-cell markers or the uptake of 3H thymidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Piezoelectric properties and temperature stability of poly(vinylidene fluoride-trifluorethylene) copolymers.

Piezoelectric measurements were made on several copolymers of vinylidene fluoride and trifluorethylene having a vinylidene fluoride concentration in the range of 65-70%. The hydrostatic g constant showed only a slight dependence on pressure, and pressures up to 35 MPa caused no apparent loss of the piezoelectric activity. A significant increase in the value of the hydrostatic g constant was observed both at temperatures above and considerably below the room temperature. The anomalous result obtained upon cooling below the room temperature can be attributed to the glass transition temperature of the trifluoroethylene comonomer. Temperature aging studies were performed at high temperatures using films of these copolymers. A significant loss of piezoelectric activity occurred after long-time exposure. Isothermal studies at various aging temperatures revealed that this decay continued over a long time span. The aging behavior characteristically followed a linear dependence on the logarithm of aging time.

Structure and function of the pS2 gene and estrogen receptor in human breast cancer cells.

The role of estrogen in the growth of human breast cancers has been investigated at two levels. First, we have studied the pS2 gene, whose transcription is stimulated by estrogen in the human breast cancer cell line, MCF-7. The pS2 gene product is a small, secreted polypeptide currently of unknown function, but with structural features similar to some growth factors. The expression of the pS2 gene has so far been detected only in MCF-7 cells and some breast cancer biopsies. Preliminary studies indicate that pS2 is a potential marker for hormone-dependent breast cancer. Ongoing studies will continue to focus on the implicated role of pS2 in the estrogen-mediated growth of breast cancers and its possible use as a marker for estrogen-dependent tumors. Second, we have analyzed the structure and function of the human ER. The receptor stimulates pS2 gene transcription by interacting with an ERE in the 5'-flanking region of that gene. A mutational analysis of the receptor protein has localized a DNA-binding domain, which determines target gene specificity, and a hormone-binding domain. These domains appear to be the only two regions of the receptor which are absolutely required for the transcription-activating function of the ER in transfection assays with reporter plasmids. The N-terminal region of the protein (regions A and B), which is necessary for increasing the efficiency of gene expression using the pS2 ERE, but not a vitellogenin ERE, may also play a role in transcription activation. Further progress in the characterization of the ER functional domains will require studies on target genes in a more physiological chromatin environment, as well as detailed physical analyses of receptor structure.

Functional domains of the human estrogen receptor.

Two domains of the human estrogen receptor, responsible for hormone binding (region E) and tight nuclear binding (region C), are essential for the receptor to activate efficiently the transcription of estrogen-responsive genes. Region D, which joins the DNA- and hormone-binding domains, can be altered without affecting activation. Deletion of the N-terminal domain (region A/B) has no effect on activation of a reporter gene containing a vitellogenin estrogen-responsive element (ERE) and the HSV-tk promoter, whereas it severely impairs activation of the human pS2 gene promoter. Deletion of most or all of the hormone-binding domain leads to only about 5% constitutive transcriptional activity, yet these mutants appear to bind efficiently to an ERE in vivo. Apparently, region C recognizes the ERE of target genes, and the hormone-binding domain plays an essential role for efficient activation of transcription.

Introduction of estrogen-responsiveness into mammalian cell lines.

We introduced estrogen responsiveness as a new characteristic into rat hepatoma, mouse Ltk- and human HeLatk-cells by transfecting the human estrogen receptor (ER) cDNA. To measure the estrogen response we used Xenopus vitellogenin gene A2 constructs linked to the bacterial CAT gene. Transient cotransfections of the ER cDNA and the vitellogenin gene-CAT constructs containing the estrogen responsive element (ERE) lead to a hormone dependent induction of CAT activity whereas cotransfected vitellogenin gene constructs lacking the ERE are not inducible. Stable transfections of ER cDNA into Ltk- cells give rise to cell clones that are estrogen responsive as shown by transfection of various vitellogenin gene-CAT constructs. These results prove that the transfected ER is biologically active and is sufficient to make a cell estrogen responsive.

Relationship of estrogen receptors and protein synthesis to the mitogenic effect of estrogens.

1,3,5(10)-Estratriene-3,16 alpha-diol (16 alpha-E2) is an estrogen which is ineffective in stimulating DNA synthesis in the prepuberal rat uterus when administered to rats in a single injection in doses up to at least 5 micrograms. However, it acquires the same high mitogenic potency as 1,3,5(10)-estratriene-3,17 beta-diol (17 beta-E2) if a 5-micrograms dose is administered over a 12-h period via sequential injections of 1 microgram each at 3-h intervals. In an attempt to explain this phenomenon we have found that the ability of an estrogen to maintain a stimulated rate of protein synthesis for 12 h correlates directly with its ability to stimulate DNA synthesis. A single injection of 16 alpha-E2 stimulates protein synthesis at 4 h to a degree comparable to 17 beta-E2. By 12 h when the effect of 17 beta-E2 is maximal, the effect of one injection of 16 alpha-E2 has diminished to control levels. However, if 16 alpha-E2 is administered via sequential injections at 3-h intervals, protein synthesis at 12 h is stimulated to the same extent achieved by a single injection of 17 beta-E2. We also have examined the fate of estrogen receptors in relationship to these changes in protein and DNA synthesis. The effects of a single injection of 16 alpha-E2 differ in four respects from those of 17 beta-E2: 1) the retention of receptors in the nuclear form is shorter; 2) replenishment of receptors to the cytosolic form is more rapid and greater than 80% complete within 3 h; 3) fewer receptors are processed, i.e. the loss of receptors detectable by exchange assay is smaller; and 4) the overshoot in receptor replenishment 24 h after an injection is smaller. Overall, the stimulation of DNA synthesis is positively related to the rate of protein synthesis 12 h after an injection of estrogen, the retention of receptors in the nuclear form, and the amount of receptor processing.

Estrogen-stimulated deoxyribonucleic acid synthesis: a ratchet model for the prereplicative period.

Multiple injections of a short acting estrogen, 1,3,5(10)-estratriene-3,16 alpha-diol (16 alpha-E2), have been used to analyze the lag or prereplicative period of approximately 12 h, which precedes the onset of estrogen-stimulated DNA synthesis. A single injection of 1.0 microgram 16 alpha-E2, which itself does not stimulate DNA synthesis, shortened by 3-4 h the lag period between subsequently administered estrogen and the initiation of DNA synthesis. This lag-shortening effect of 16 alpha-E2 was stable for 24 h, but had decayed by 36 h. One or two additional injections of 16 alpha-E2 given sequentially at 3-h intervals each further shortened the lag period but to a lesser extent than the first injection. The results indicate that estrogen induces the accumulation of relatively stable cell changes which are required for the onset of DNA synthesis. The prolonged estrogen requirement during the lag period is not truly discontinuous as previously suggested but rather can be satisfied by discontinuous pulses of estrogen in a ratchet-like fashion because of the stability of their effects.

Direct mitogenic effect of estrogen on the prepuberal rat uterus: studies on isolated nuclei.

Isolated uterine nuclei incorporate [3H]deoxythymidine-5'-triphosphate into acid-precipitable material for 60 min. The rate and extent of incorporation is markedly enhanced by prior treatment of rats with estradiol-17 beta. This stimulation is dose dependent and follows a time course which parallels that which is observed in intact uteri. The maximum response occurs 24 h after an injection of estradiol-17 beta when the DNA synthesis rate has shown an 8.5 +/- 0.9-fold average stimulation over 34 experiments. When a small dose of estradiol-17 beta was injected directly into one uterine horn, DNA synthesis was stimulated in nuclei isolated from that horn but not in nuclei from the vehicle-injected contralateral horn. This suggests that the mitogenic effect of estrogen is direct and not mediated by systemic factors. As shown by diethylaminoethyl-cellulose chromatography and inhibition studies with N-ethylmaleimide and 2':3'-dioxythymidine-5'-triphosphate, the uterine nuclei contain both DNA polymerases alpha and beta; however, alpha-polymerase alone appears to be responsible for the estrogen-stimulated DNA synthesis. When soluble DNA polymerase alpha-activity and endogenous DNA synthesis rates were simultaneously measured, both were found to be initially stimulated between 12 and 15 h after an injection of estradiol-17 beta. However, because the fold-stimulation of alpha-polymerase activity was only half that of DNA synthesis, it appears that DNA synthesis is not merely a simple function of polymerase activity.