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Biomedical subjects

N M Heddle

Publications and source records attributed to N M Heddle.

26 records · Page 2Linked to original sources
PubMed1992

An animal model of allogeneic donor platelet refractoriness: the effect of the time of leukodepletion.

Approximately 50% of multi-transfused individuals become refractory to random donor platelets. Recent clinical data suggest that those patients receiving leukocyte-depleted blood products are less likely to become refractory to random donor platelets than recipients of non-leukocyte-depleted products. Leukocyte depletion can be performed immediately after collection of a unit of whole blood before its storage (prestorage leukodepletion) or just before the transfusion of the blood product to a recipient, after its storage (poststorage leukodepletion). However, the most appropriate time for the leukodepletion of blood products has not been established. The present study was undertaken to establish an animal model of allogeneic platelet refractoriness, and to compare the effect of prestorage and poststorage leukodepletion on the frequency of refractoriness to allogeneic donor platelets. In this model, two strains of rabbits were used: California Black rabbits were used as blood donors, while New Zealand White rabbits were used as recipients. Eight weekly infusions of nonleukodepleted allogeneic fresh blood resulted in an allogeneic platelet refractory rate of 91.2% (31/34). The prestorage leukodepletion of the donor blood was associated with a significantly higher allogeneic platelet survival and lower refractory rate (33.3%) to allogeneic platelets than poststorage leukodepletion (66.7%). Furthermore, the data suggest that cell-free plasma products are capable of inducing refractoriness to allogeneic donor platelets; the stored plasma having a greater likelihood of inducing such refractoriness than fresh plasma. Thus, these data provide evidence that the prestorage leukodepletion of allogeneic donor blood is associated with a lower frequency of refractoriness and better allogeneic platelet survival than poststorage leukodepletion.

Animals↗
PubMed1992

A randomized trial on the efficacy of an autologous blood drainage and transfusion device in patients undergoing elective knee arthroplasty.

The purpose of the study reported here was the determination of the efficacy of a postoperative autologous blood drainage and transfusion device in reducing allogeneic red cell requirements in patients undergoing elective knee arthroplasty. The study was a randomized controlled trial with adult patients undergoing unilateral elective arthroplastic knee surgery. Patients underwent suction drainage, attached to an autologous blood drainage and transfusion device, or standard suction drainage. Allogeneic red cells were given according to strict transfusion guidelines based on blood loss and postoperative hemoglobin values. Outcome measures included the mean number of allogeneic red cell concentrates required and the number of patients in each group who required no transfusion. Patients assigned to standard suction drainage had a mean allogeneic red cell utilization of 1.2 units (SD 1.0), as compared to a mean of 0.4 units (SD 0.8) in the group undergoing drainage with the autologous blood drainage and transfusion device (p = 0.0007). The percentage of patients not requiring allogeneic red cells was significantly higher in the latter group (74.3% vs. 32.5%; p = 0.002). The postoperative drainage and transfusion device was efficacious in reducing the amount of allogeneic red cells required by patients undergoing knee arthroplasty, and its use resulted in a 42 percent reduction in the number of patients requiring allogeneic transfusion.

Blood Transfusion, Autologous↗
PubMed1992

A prospective study to determine the safety of omitting the antiglobulin crossmatch from pretransfusion testing.

Transfusion medicine laboratories routinely perform a series of pretransfusion serological tests including: ABO grouping, Rh typing, and investigation of the recipient's serum to detect antibodies against blood group antigens (antibody screen). As a final check, most laboratories also perform a crossmatch in which the recipient's serum is incubated with the donor's red cells followed by the addition of an antiglobulin reagent (antiglobulin crossmatch). The need for the antiglobulin crossmatch when the antibody screen is negative has been questioned because there are few antibodies that are detected by this test. Such antibodies are usually directed against low incidence antigens that are not expressed on the screening cells and in many cases the clinical importance of these antibodies is uncertain. For these reasons, we performed a prospective study in which patients requiring red cell transfusion had a group and screen performed. If the antibody screen was negative the antiglobulin crossmatch was omitted. Following the transfusion of the blood, the antiglobulin crossmatch was performed to look for any potential incompatibility. All patients were monitored both serologically and clinically. Over the 2-year interval of the study 9128 patients were entered. There were 8936 patients (97.9%) with a negative antibody screen and 26.9% (2404 patients) were transfused a total of 10,899 red cell concentrates. The antiglobulin crossmatch performed after the transfusion indicated that 168 red cell concentrates (1.5%) would have been incompatible if the antiglobulin crossmatch had been performed pretransfusion. These 168 red cell concentrates were transfused to 119 patients during 130 transfusion episodes (defined as all transfusions administered within 24 h). Of the 130 transfusion episodes, 79.2% (103/130) were false positive laboratory results. There were 27 transfusion episodes where the antiglobulin crossmatch on blood transfused was positive due to an IgG antibody. Even though these transfused red cell concentrates were designated incompatible by the antiglobulin crossmatch, none of the patients receiving this blood had clinical or serological evidence of haemolysis. We concluded that the antiglobulin phase of the crossmatch can be omitted from pretransfusion testing without putting patients at risk.

Blood Component Transfusion↗
PubMed1991

Searching the scientific literature.

This article reviews three strategies for reviewing the available literature to identify relevant articles. The use of Index Medicus/Medline, Science Citation Index/SciSearch and Exerpta Medica/EMBASE is discussed, using a sample question to illustrate the process.

Canada↗
PubMed1989

Acute paroxysmal cold hemoglobinuria.

Over eighty years have passed since Donath and Landsteiner identified the syndrome of PCH and reported an in vitro test for its diagnosis. The accuracy of their observations, and the usefulness of the DL procedure has persisted. PCH has been investigated over the years providing further information regarding antibody specificity and serological characteristics. However, the etiology of the syndrome remains to be elucidated. PCH, which was once thought to be rare and associated primarily with congenital syphilis, is not encountered as one of the most common causes of acute transient hemolytic anemia in young children.

Acute Disease↗
PubMed1985

Association of renal failure with Lewis incompatibility after allogeneic bone marrow transplantation.

The cause of the renal failure that occurs in approximately 20 percent of patients following allogeneic bone marrow transplantation is poorly understood. A patient is described in whom acute renal failure occurred one week after allogeneic bone marrow transplantation. The onset of the renal failure was associated with the demonstration of anti-Lewis antibodies in the patient's serum, which could only have been derived from donor lymphocytes. Recovery of renal function coincided with the disappearance of the Lewis antibody. It is postulated that Lewis incompatibility between graft and host tissue may have contributed to the renal failure in this patient and that incompatibility associated with determinants present on renal cells may account for other instances of acute renal failure following allogeneic bone marrow transplantation.

Acute Kidney Injury↗
PubMedDate not supplied

Hypergammaglobulinemia can be associated with a positive direct antiglobulin test, a nonreactive eluate, and no evidence of hemolysis.

To determine the cause of a positive direct antiglobulin test (DAT), blood banks routinely perform serologic tests on eluates prepared from DAT-positive red cells. Negative eluates traditionally have been suspected to be associated with drug reactions. This report confirms that the most frequent cause of a positive DAT and a nonreactive eluate is hypergammaglobulinemia. The results of 74 patient samples with positive DATs were analyzed retrospectively. Eluates prepared from the red cells of 54 patients (72.9%) reacted; eluates from 20 patients (27.1%) did not react. This latter group had identical serologic and clinical findings, suggesting that they made up a homogeneous group. In particular, the patients had a positive DAT, a negative indirect antiglobulin test, and a negative eluate; an increased serum concentration of IgG; and no evidence of hemolysis. In a subsequent study, DATs were performed prospectively on red cells from 44 consecutive patients with elevated serum IgG levels. The serum IgG concentration was highest in the three patients whose red cells had a positive DAT. The DAT also became positive in two patients treated with high-dose intravenous gammaglobulin (IV IgG). These studies indicate that a negative eluate from red cells with a positive DAT, a common serologic finding, is often caused by hypergammaglobulinemia. The authors postulate that IgG binds nonspecifically to the red cells because of the hypergammaglobulinemia.

Coombs Test↗