Flow cytometric analysis of platelet function in stored platelet concentrates.

Platelet activation occurs during the collection, processing and storage of platelet concentrates. The effect of the platelet activation on the functional state of stored platelets remains however undefined. We employed flow cytometric analysis to evaluate the extent of platelet activation and the physiological response to thrombin stimulation of platelets stored for up to five days under routine blood bank conditions. Platelet surface expression of the activation markers CD62 and CD63 was examined, along with modulation of platelet membrane glycoproteins (GP) Ib and IIbIIIa. Platelet dense granule content was determined using a mepacrine uptake assay and the extent of platelet microparticle generation was quantified. Thirteen random-donor platelet concentrates prepared under routine conditions by a platelet-rich-plasma protocol were examined. Platelets were found to be activated following preparation on day 1. Although a gradual increase was seen with increasing storage time, this was not statistically significant for CD62 or CD63 expression, GPIIbIIIa or GPIb modulation or dense granule release; the generation of platelet microparticles did, however, increase with increasing storage time. The characteristic increase in surface expression of CD62, CD63 and GPIIbIIIa and decrease in GPIb and dense granule content in response to thrombin stimulation was observed with all concentrates, but these measures of platelet functional reserve showed decreasing platelet function with increasing storage time. The results indicate that platelets are activated by day 1, likely as a consequence of manipulation during collection and processing, but are not further progressively activated with increasing storage time; they do, however, become relatively hypofunctional with increasing storage.

Effects of a 5-lipoxygenase inhibitor, ABT-761, on exercise-induced bronchoconstriction and urinary LTE4 in asthmatic patients.

The novel 5-lipoxygenase (5-LO) inhibitor, ABT-761, was investigated for its effect on exercise-induced bronchoconstriction in asthmatic subjects. The relationship between 5-LO inhibition and effects on the response of the airways to exercise was examined. In a double-blind, randomized, crossover clinical trial, 10 patients with mild to moderate persistent asthma (who exhibited a fall in forced expiratory volume in one second (FEV1) > or = 20% following standardized exercise challenge) received 200 mg ABT-761 or matched placebo, orally, 5 h prior to exercise on two study days, 7-10 days apart. Lung function, urinary leukotriene E4 (LTE4) and ex vivo calcium ionophore-stimulated LTB4 release in whole blood were measured prior to dosing, prior to exercise and at various time points up to 4 h post-exercise. The mean (SD) maximal percentage fall in FEV1 after exercise was 27.1 (12)% on placebo and 19.9 (10)% on ABT-761 days, respectively (p<0.05). Post-exercise fall in FEV1 was significantly attenuated at 5, 10, 15 and 30 min after exercise and the mean area under curve, representing the overall effect of exercise from 0-45 min post-challenge, was also significantly attenuated by ABT-761 (p<0.001). Ex vivo LTB4 release was inhibited by more than 80% throughout the 4 h post-exercise period, indicating that 5-LO was extensively inhibited at all time points. Urinary LTE4 in the post-exercise period was significantly lower after ABT-761 day than after placebo (40.1 (17.6) versus 89.8 (58.2) pg x mg creatinine(-1); p<0.05). Inhibition of LTB4 release in ABT-761-treated patients correlated positively with the attenuation of post-exercise FEV1 decline (r=0.711; p<0.05). We conclude that ABT-761 is effective in suppressing exercise-induced bronchoconstriction and that this protection is related quantitatively to the degree of 5-lipoxygenase inhibition.

Preoperative autologous blood deposition in support of gynaecological repair procedures.

Autologous blood transfusion was evaluated in gynaecological repair procedures including abdominal/ vaginal hysterectomy with vaginal repair, post-hysterectomy vaginal suspension and fixation, uni/bilateral salpingo-oophorectomy with vaginal colpopexy and sling procedures. A total of 247 autologous units were collected from 95 patients at the regional blood centre with 1-3 units (mean 2-6 units) deposition from each patient. One hundred and ninety of all collected units were transfused (collection/transfusion ratio = 1.3). Of these patients, 86 (90.5%) received autologous blood; 12 (13%) being transfused with 1 unit, 44 (46%) with 2 units and 30 (32%) with 3 units. Two of these patients received additional homologous blood. The average preoperative haemoglobin level was 119 g L-1 and average post-operative haemoglobin level was 105 gL-1. The post-operative Hb level was used as a retrospective indicator for the requirement for blood transfusion. The results show that overall 75% of patients had post-operative haemoglobin levels < or = 110 and 33% of patients with Hb levels < 100, respectively. These results suggest that preoperative autologous blood deposition may be appropriate in the patients undergoing reconstructive gynaecological repair procedures since there was a high rate of usage of autologous blood and low post-operative haemoglobin in a significant proportion of patients.

A survey of red cell use in 45 hospitals in central Ontario, Canada.

BACKGROUND: The purpose of this survey was to establish baseline information on blood component use in relation to patient diagnoses, procedures, and demographics and to identify patterns of blood use that may be used for blood program planning and transfusion audits. STUDY DESIGN AND METHODS: A cross-sectional survey of the transfusion of blood components in teaching and nonteaching hospitals in central Ontario between September 1991 and August 1992 was carried out. Coders of hospital medical records routinely record demographics, procedures, diagnoses, and other relevant information. A protocol was created by which medical records coders could add the components transfused to the discharge abstract for this study. Red cell use is reported here. RESULTS: Of the 61 hospitals invited to participate, from which 547,279 patients were discharged during the 12-month period of the study, 45 (74%) agreed to participate. Information was collected on 439,373 discharged patients. Of these, 26,611 (6.1%) received at least 1 unit of red cells. Of a total of 101,116 red cell units transfused, more than 74 percent were used in patients discharged with neoplasms, gastrointestinal diseases, circulatory system diseases, and trauma. High-transfusion-use procedures included operations and procedures on the digestive and cardiovascular systems, diagnostic and therapeutic procedures, musculoskeletal system, and hemic or lymphatic system procedures. CONCLUSION: This survey provides baseline blood transfusion information for a specific period that can help determine the need for hospital audits and maximum surgical blood-order schedule guideline reviews. This information is relevant to current recommendations to reduce patient's exposure to blood components. These transfusion data will assist in blood program planning based on known disease trends, demographics, and population changes.

Hematopoietic progenitor cells are resistant to dimethyl sulfoxide toxicity.

BACKGROUND: A direct chemical toxicity of dimethyl sulfoxide (DMSO) to hematopoietic progenitor cells has been suggested. However, a recent study failed to corroborate these earlier findings. Thus, a series of experiments was undertaken to address this issue. STUDY DESIGN AND METHODS: Bone marrow was collected from 18 donors and cryopreserved with 10 percent (vol/vol) DMSO. Aliquots of frozen bone marrow were thawed, diluted with ACD-A to 8 percent (vol/vol) DMSO, and allowed to remain in DMSO for up to 2 hours before mononuclear cells were plated for colony-forming assays. After 14 days in culture, burst-forming units-erythroid, colony-forming units--granulocyte/macrophage, and colony-forming units--granulocyte/erythrocyte/macrophage/megakaryocyte colonies were enumerated. RESULTS: There was no significant difference (p > 0.5) seen in colony formation over the 2-hour exposure to DMSO. CONCLUSION: These results support and extend a previous study that bone marrow hematopoietic progenitor cells, including burst-forming units--erythroid, colony-forming units--granulocyte/macrophage, and colony-forming units--granulocyte/erythrocyte/macrophage/megakaryocyte are resistant to any toxic effects of 8- to 10-percent (vol/vol) DMSO during at least 2 hours of DMSO exposure.

Comparison of a transfusion preparation of newly formed red cells and standard washed red cell transfusions in patients with homozygous beta-thalassemia.

BACKGROUND: Previous studies of transfusions of newly formed red cells (neocytes) demonstrated modest extensions of transfusion interval in patients with homozygous beta-thalassemia. STUDY DESIGN AND METHODS: The clinical benefits of a new system of neocyte preparation (Neocel, Cutter Biological, Berkeley, CA), reported to combine ease of preparation with reduction in the transfusion requirements of thalassemia patients, were evaluated. Sixteen thalassemic patients who had undergone splenectomy received eight consecutive, standard, automated, washed red cell transfusions (standard transfusions), followed by eight transfusions with the neocyte preparation (neocyte transfusions). In each arm of the study, mean pretransfusion hemoglobin and mean red cell mass transfused were carefully controlled and were similar. RESULTS: A significant (p < 0.0001) extension of transfusion interval was observed in patients receiving neocyte transfusions (mean +/- SD; 38.7 +/- 34 days; range, 35.0-44.5), over that in those receiving standard transfusions (32.9 +/- 2.5 days; range, 29.6-38.5). The mean prolongation of transfusion interval by neocyte transfusion corresponded to a mean reduction of 25 mL in packed red cells transfused per kg of body weight per patient per year and a mean reduction in transfused iron of 15 percent per year per patient. During neocyte transfusions, blood preparation costs were considerably increased and donor exposure was significantly (p < 0.0005) higher than during the standard transfusion period. CONCLUSION: These data demonstrate that extension of the transfusion interval, and reduction in transfused iron, may be achieved in thalassemic patients by use of the Neocel system. These benefits are achieved, however, with substantial increases in donor exposure and in component preparation costs.

Anti-HCV in post-transfusion hepatitis: deductions from a prospective study.

Stored sera from 52 patients who developed post-transfusion hepatitis (PTH) during a prospective study of PTH in Toronto in 1984/85, sera from 111 donors whose blood was transfused into these patients and sera from 50 patients with chronic active hepatitis with a remote history of blood transfusion were tested for anti-HCV. In patients with PTH seroconversion occurred relatively early. Ten converted in less than 14 weeks after transfusion. Only three of the 34 patients (9%) whose hepatitis resolved developed anti-HCV compared to 11 of 18 (61%) whose hepatitis became chronic. Patients who seroconverted had higher alanine aminotransferase (ALT) values during the phase of acute hepatitis than those who did not seroconvert. Most of the patients who developed PTH received blood that was negative for anti-HCV. Four donors whose blood was positive for anti-HCV transmitted hepatitis. Three of the patients developed anti-HCV and chronic hepatitis. One of the recipients did not seroconvert and the hepatitis resolved. Forty-two of the 50 patients (84%) with chronic hepatitis and a remote history of blood transfusion were positive for anti-HCV. We conclude that anti-HCV-positive donors may transmit hepatitis C; that if anti-HCV is diagnostic of hepatitis C, most cases of acute PTH are either not due to hepatitis C or may represent cases of hepatitis C in which the anti-HCV test was undetectable. On the other hand, most cases of PTH which progress to chronic hepatitis are caused by HCV.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a confidential method of excluding blood donors exposed to human immunodeficiency virus: studies on hepatitis and cytomegalovirus markers.

A confidential self-administered questionnaire was given to all blood donors prior to donation (n = 95,917). The questionnaire describes groups at increased risk of acquired immunodeficiency syndrome (AIDS) and requires the donor to designate his blood either for laboratory purposes or for transfusion. In a previous communication, we reported that donors in the former group had a much higher prevalence of antibody to human immunodeficiency virus (HIV) than age, sex and clinic matched controls or a group of "miscellaneous" donors who did not fill out the form properly. In this communication, we report results of tests for other viral markers performed on the three designation groups, namely laboratory-designated, miscellaneous and controls. We found that the former two groups had a higher prevalence of antibody to hepatitis B surface antigen (anti-HBs), hepatitis B core antigen (anti-HBc) and cytomegalovirus (anti-CMV) than controls, but there were no differences in alanine aminotransferase (ALT) levels among the groups. In addition, the laboratory-designated group had a higher prevalence of hepatitis B surface antigen (HBsAg) than the general donor population. These data indicate that a questionnaire designed to ascertain AIDS high-risk donors is valuable in excluding donors who may be carriers of other viruses as well.

Evaluation of a confidential method of excluding blood donors exposed to human immunodeficiency virus.

A confidential self-administered questionnaire was given to all donors prior to blood donation (n = 95,917). The questionnaire describes acquired immunodeficiency syndrome (AIDS) high-risk groups and requires the donor to designate his blood for either laboratory purposes or for transfusion. Six-hundred and twenty-seven people (0.65%; 78% men) designated their blood for laboratory purposes. In addition to routine enzyme-linked immunoassay (EIA) screening for human immunodeficiency virus (HIV) antibody, all units from the latter group of donors were tested by Western blot (WB) irrespective of the EIA result. An equal number of donor units was selected from those designating their blood for transfusion (age, sex and clinic matched) and these too were tested by WB irrespective of the EIA result. We found that donors designating their blood for laboratory purposes had a 10 times (vs transfusion-designated controls) to 100 times (vs general donor population) greater exposure to HIV. In the laboratory-designated group, an EIA negative donor was WB positive, yielding an estimated EIA false-negative rate of 16 per million. A confidential questionnaire, as described, is a valuable adjunct in ascertaining high-risk blood donors.