Implementation of buffy-coat-derived pooled platelet concentrates for internal quality control of light transmission aggregometry: a proof of concept study

Essentials In platelet function testing, standardized internal controls (IQC) are not commercially provided. Platelet function testing was performed daily on aliquoted pooled platelet concentrates. Pooled platelet concentrates showed stability for control purposes from Monday to Friday. Pooled platelet concentrates provide the necessary steadiness to serve as IQC material.

SUMMARY

Background Standardized commercially available control material for internal quality control (IQC) of light transmission aggregometry (LTA) is still lacking. Moreover, the availability of normal blood donors to provide fresh platelets is difficult in small laboratories, where 'volunteers' may be in short supply. Objectives To evaluate the implementation of buffy-coat-derived pooled platelet concentrates (PCs) for IQC material for LTA. Methods We used buffy-coat-derived pooled PCs from the blood bank as IQC material for LTA. On each weekend one PC was prepared (> 200 mL) and aliquoted from the original storage bag on a daily basis in four baby bags (40-50 mL), which were delivered from Monday to Friday to our laboratory. The IQC measurements of at least 85 work-weeks (from Monday to Friday) were evaluated with this new IQC material. LTA was performed on a four-channel Chronolog 700 Aggregometer (Chronolog Corporation, Havertown, PA, USA) (agonists: collagen, adenosine diphosphate [ADP], arachidonic acid [AA] and thrombin receptor activator peptide-6 [TRAP-6]). Results The medians of platelet aggregation from IQC measurements with collagen, ADP and AA from Monday to Friday were 68.0-59.5, 3.0-2.0 and 51.0-50.0%, respectively, and the mean of platelet aggregation with TRAP-6 was 71.2-66.4%. Conclusions Buffy-coat-derived pooled PCs serve as a reliable and robust IQC material for LTA measurements and would be beneficial for the whole laboratory procedure and employees' safety.

Autologous blood donation for surgery in inflammatory bowel disease--a report of six cases

BACKGROUND

Surgery in inflammatory bowel disease (IBD) is frequently associated with need for perioperative blood transfusions carrying the potential risk of infection. Autologous blood donation is often limited by IBD-associated anemia which is reversible by intravenous iron and erythropoietin. We therefore tested the feasibility of autologous blood donation in IBD.

METHODS

Six patients (five Crohn's disease, one ulcerative colitis) with indication for elective bowel resection were treated after informed consent was obtained. Two to four blood donations were scheduled during four weeks prior to surgery. Once a week 350-450 ml of blood were collected from patients with a hemoglobin level above 11.0 g/dl. After each donation 200 mg of iron saccharate diluted in 0.9% saline were given to all patients intravenously as substitute for donation-related iron loss. Patients with preexisting anemia or C-reactive protein above 2.0 mg/dl received concomitant erythropoietin.

RESULTS

The scheduled number of packed red cells was donated successfully by four patients. Due to low hemoglobin levels two patients donated one unit less than intended. Four patients received autologous blood transfusions intra- or postoperatively. No patient needed homologous blood. No serious adverse events were observed during blood donations, perioperatively, and during the one year follow-up period.

CONCLUSION

Preoperative autologous blood donation is save and feasible in IBD patients with elective bowel resection.

Increase in endogenous thrombopoietin in healthy donors after automated plateletpheresis

BACKGROUND

Thrombopoietin (TPO) is a key cytokine involved in the regulation of megakaryocytopoiesis and platelet production. The aim of the present study was to test whether platelet donation is associated with changes in the serum TPO levels in healthy donors undergoing plateletpheresis.

STUDY DESIGN AND METHODS

The study group consisted of 23 healthy donors undergoing single-donor plateletpheresis for the first time. Serum TPO levels and platelet counts were determined before platelet collection, at the end of apheresis, and for 4 days thereafter. Serum TPO levels were determined by a TPO-specific enzyme-linked immunosorbent assay.

RESULTS

In relationship to platelet donation, serum TPO levels showed a temporary increase from baseline levels of 69.2 +/- 7.1 pg per mL to 117 +/- 6.8 pg per mL 2 days after plateletpheresis (p < 0.05). Further evaluation revealed a decline in serum TPO levels as platelet counts increased. Female donors showed a delayed normalization of circulating platelet numbers and serum TPO levels as compared to male donors. There was no significant correlation between serum TPO levels and the absolute platelet number during normalization of the donors' platelet counts after plateletpheresis.

CONCLUSION

Single-donor plateletpheresis results in a temporary increase in serum TPO levels in healthy platelet donors, which may be part of a compensatory response-boosting megakaryocytopoiesis after platelet collection.

[Evoked response audiometry of the guinea pig before and after drop in hearing induced by furosemid (author's transl)]

Using particular surface electrodes evoked response audiometry (ERA) can be applied to small laboratory animals without any sedation or anaesthesia. In addition to other methods we have studied in this way the influence of extreme doses of Furosemid on the guinea pig inner ear. 6-20 mg Furosemid per 100 g of bodyweight (about 100 times the human therapy dose) were applicated i.v. within 5 min resulting in a drop of hearing immediately. For the anaesthesized animal the cochlear microphonic potentials (CM) decrease simultaneously, indicating Furosemid to act at the inner ear itself. By both methods recovery of inner ear function is seen to start about 10 min later according to the little biological half life of Furosemid. As being restricted in respect of time for the CM-measurements we are sure about reversibility only by the ERA-method.