ABO-immune complex formation and impact on platelet function, red cell structural integrity and haemostasis: an in vitro model of ABO non-identical transfusion.

BACKGROUND: Transfusion of ABO non-identical platelets has been associated with fatal haemolytic reactions, increased red cell transfusion needs and other adverse effects, but the practice of ABO matching in platelet transfusion is controversial. Immune complexes can be formed from the anti-A and/or anti-B antibodies and ABO soluble antigen(s) present in donor and recipient plasma after ABO non-identical transfusions. We hypothesized that these immune complexes affect recipient red cell structural integrity, platelet function and haemostasis. STUDY DESIGN AND METHODS: Haemolysis, platelet function and haemostatic function were assessed before and after incubation of recipient red cells, platelets and whole blood with normal saline controls, ABO-identical plasma controls or in vitro-generated ABO-immune complexes. RESULTS: ABO-immune complexes caused significantly increased haemolysis (P < 0·001), inhibition of platelet function (P = 0·001) and disruption of clot formation kinetics (P < 0·005) in both group A and O recipient samples. CONCLUSIONS: Substantial changes in platelet function, red cell integrity and haemostasis occur after in vitro exposure to immune complexes. These in vitro findings may explain, in part, previously observed associations of ABO non-identical platelet transfusions with adverse effects including increased red cell transfusion needs, organ failure and mortality.

Inhibition of HIV-1 protease: the rigidity perspective.

MOTIVATION: HIV-1 protease is a key drug target due to its role in the life cycle of the HIV-1 virus. Rigidity analysis using the software First is a computationally inexpensive method for inferring functional information from protein crystal structures. We evaluate the rigidity of 206 high-resolution (2 Å or better) X-ray crystal structures of HIV-1 protease and compare the effects of different inhibitors binding to the enzyme. RESULTS: Inhibitor binding has little effect on the overall rigidity of the protein homodimer, including the rigidity of the active site. The principal effect of inhibitor binding on rigidity is to constrain the flexibility of the ß-hairpin flaps, which move to allow access to the active site of the enzyme. We show that commercially available antiviral drugs which target HIV-1 protease can be divided into two classes, those which significantly affect flap rigidity and those which do not. The non-peptidic inhibitor tipranavir is distinctive in its consistently strong effect on flap rigidity. CONTACT: jack.heal@warwick.ac.uk; r.roemer@warwick.ac.uk SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The development of a model for in vitro testing of femoral stems in impaction bone grafting.

Comprehension of the biomechanical behaviour of orthopaedic implants is essential. This paper describes the development of an in vitro model to investigate the behaviour of femoral implants in the revision setting. The development of a femoral model and a bone graft substitute is described. The properties of human, bovine, ovine morselized bone graft, and a graft substitute were compared. On measuring hoop strain after impaction bone grafting there was no significant difference between the ovine bone graft and graft substitute with the size 1 Exeter stem. The results suggest that this bone graft substitute is a viable alternative for in vitro testing. The authors recommend the use of the graft substitute and the femoral model to predict femoral stem biomechanics.

Reproducibility of the Gartland classification for supracondylar humeral fractures in children.

PURPOSE: To evaluate the intra- and inter-observer reproducibility of the Gartland radiographic classification for supracondylar humeral fractures in children. METHODS: Anteroposterior and lateral radiographs of 50 supracondylar humeral fractures in children were graded on 2 separate occasions by 4 orthopaedic surgeons according to the Wilkins modification of the Gartland classification. Data were analysed by calculating the Kappa values for intra- and inter-observer agreement to indicate the reproducibility of the classification. RESULTS: There was moderate inter-observer agreement, except for poor agreement over type I fractures. Type II fractures only showed fair to moderate agreement. Type III fractures and the flexion group showed good to very good agreement. Intra-observer agreement was good to very good. CONCLUSION: Surgeons should treat paediatric supracondylar humeral fractures based on an assessment of the degree of displacement rather than by employing the Gartland classification.

Extracting the tip of a fractured DHS wire from the hip joint.

Dynamic Hip Screw fixation is a very commonly performed operation, but one not without complications (1-3). To stabilise the fixation the guide wire can be advanced into the subchondral bone. An unusual complication of this, and one not previously documented in the literature, is that the tip of the guide wire can fracture. We describe a simple method of removing the tip of the guide wire.

What would Karl Landsteiner do? The ABO blood group and stem cell transplantation.

ABO blood group antigens, of great importance in transplantation and transfusion, are present on virtually all cells, as well as in soluble form in plasma and body fluids. Naturally occurring plasma IgM and IgG antibodies against these antigens are ubiquitous. Nonetheless, the ABO blood group system is widely ignored by many transfusion services, except for purposes of red cell transfusion. We implemented a policy of transfusing only ABO identical platelets and red cells in patients undergoing stem cell transplantation or treatment for hematologic malignancies. Major bleeding episodes have occurred in about 5% of patients undergoing induction therapy for acute leukemia as compared with 15-20% in the literature. Overall survival times appear to be superior to that in historical cohorts. In 2002-2004, treatment-related mortality at 100 days in our Blood and Marrow Transplant Unit was 0.7% for autologous transplants (n=148), 13% for sibling allogeneic transplants (n=110), and 24% (n=62) for matched unrelated allogeneic transplants, suggesting that our approach is safe. We speculate that more rigorous efforts on the part of transfusion services to provide ABO identical blood components, and to remove incompatible supernatant plasma, when necessary, might yield reduced morbidity and mortality in patients undergoing stem cell transplantation.

Bacterial contamination of surgical gloves by water droplets spilt after scrubbing.

Wound infection and deep sepsis can have disastrous consequences, particularly in orthopaedic surgery. Strict protocols, ultra-clean air, prophylactic antibiotics, and impervious gowns and drapes, have all been shown to diminish wound infection. However it remains a common and significant problem. The water droplets spilt from the surgeons hands after meticulous scrubbing with povidone iodine were cultured. The permeability of the surgical glove packaging to Gram-positive bacteria was also investigated. The water droplets from the surgeon's arms contained environmental and potentially pathogenic bacteria including a micrococcus, a coliform and coagulase-negative staphylococci. The paper packaging for the range of sterile surgical gloves tested was discovered to be permeable to Gram-positive bacteria. In conclusion accidental water droplet contamination of surgical gloves is a potential source of infection. Alternative recommendations are made.

Bacterial strike-through of re-usable surgical drapes: the effect of different wetting agents.

Wound contamination and the resultant postoperative infection is a major problem in all forms of surgery. Air contamination, gloves, surgical instruments and drapes have all been investigated as sources of wound contamination. We investigated the effect of different wetting agents on strike-through rate of bacteria through re-usable polyester/cotton surgical drapes using a newly described method. Within 30 min bacterial strike-through of dry surgical drapes occurs. Wetting drapes with blood or normal saline enhances the strike-through rate of bacteria. Wetting drapes with iodine or chlorhexidine diminishes, but does not stop, bacterial strike-through. The use of re-usable polyester/cotton drapes is a potential source of wound contamination especially when wetted with blood or normal saline.

Kinemax total knee arthroplasty: trial by template.

A retrospective radiologic study of Kinemax total knee arthroplasty templates is presented to establish their accuracy. The preoperative and postoperative radiographs of 49 Kinemax total knee arthroplasties were assessed using the Kinemax template. The size of the actual component used was compared with that predicted from the preoperative and postoperative radiographs. The preoperative radiograph template was accurate in 57% of cases, but the postoperative radiograph template was accurate in only 41%. Preoperative radiologic templating is of questionable benefit as part of preoperative management for patients undergoing Kinemax total knee arthroplasty.

WBC-reduced blood transfusions and clinical outcome in children with acute lymphoid leukemia.

BACKGROUND: WBC reduction offers a variety of benefits to patients requiring multiple transfusions during induction therapy for childhood acute lymphoid leukemia (ALL), including reductions in febrile transfusion reactions, HLA alloimmunization, and CMV transmission. One potential benefit is a reduction in the deleterious effects of transfusion immunomodulation. In the surgical setting, transfusion immunomodulation has been linked to increases in postoperative infections and decreases in host cellular immunity that are mitigated by WBC reduction of transfused blood. STUDY DESIGN AND METHODS: A retrospective review was conducted of the medical records of 68 consecutive children undergoing induction therapy for newly diagnosed ALL from 1988 through 1995, a period whose midpoint is 1991, the year WBC reduction was introduced in this hospital. RESULTS: WBC reduction of platelet and RBC transfusions was associated with fewer days with fever (mean, 5.7 days [no WBC reduction] and 2.1 days [WBC reduction]; p = 0.012) and days with positive microbial cultures (mean, 1.5 [no WBC reduction] and 0.71 [WBC reduction]; p = 0.0055). There were more high-risk ALL patients in the group receiving WBC-reduced transfusions. CONCLUSION: Allogeneic WBCs in transfused blood may cause impairment of host defenses against microbial infection during induction therapy for childhood ALL.

Association of ABO-mismatched platelet transfusions with morbidity and mortality in cardiac surgery.

BACKGROUND: The transfusion of ABO-mismatched platelets has been associated with increased morbidity and mortality during induction therapy for acute leukemia and allogeneic progenitor cell transplantation. STUDY DESIGN AND METHODS: Reported here is a cohort study of 153 patients undergoing primary coronary artery bypass graft or coronary valve replacement surgery by two surgeons in one institution during 1997 and 1998. All statistics employed nonparametric two-sided tests (Mann-Whitney; Fisher's exact test). RESULTS: Patients receiving at least one ABO-mismatched pool of platelets had a significantly longer hospital stay, more days of fever, greater total hospital charges, and more RBC transfusions. Mortality, hours in the intensive care unit, days on antibiotics, and numbers of platelet transfusions were also greater in recipients of ABO-mismatched platelets, but these differences were of less statistical significance. When the analysis was restricted to the 139 patients who received no more than two pools of platelets, the trends for increased morbidity and mortality (8.6% vs. 1.9%; p = 0.10) in recipients of ABO-mismatched platelets persisted. The number of RBC transfusions required in this latter cohort was 50 percent greater (mean, 6.1 vs. 9.2; p = 0.02), despite the fact that the number of platelet transfusions given was similar (mean, 1.2 vs. 1.3 pools; p = 0.22). CONCLUSIONS: ABO-mismatched platelet transfusions are associated with unfavorable outcomes in cardiac surgery, a relationship that remains unexplained. As this association has been found in three cohort studies in various clinical settings, further investigation of this association is warranted.

Platelet washing to prevent recurrent febrile reactions to leucocyte-reduced transfusions.

Symptoms of fever and/or rigours after transfusion continue to occur commonly in patients receiving platelets leucocyte-reduced after storage. A cohort of 24 consecutive patients who had experienced severe or repeated febrile nonhaemolytic reactions to post-storage leucocyte-reduced platelet transfusions were treated with saline-washed, post-storage leucocyte-reduced platelets. The frequency of reactions declined from 20% of transfusions (n = 191) to 0.6% (n = 331) after instituting saline-washed, post-storage leucocyte-reduced platelet transfusions. These results support the hypothesis that substances present in the supernatant of stored platelet concentrates mediate febrile nonhaemolytic transfusion reactions, and provide one strategy for preventing their occurrence.

What do trainees think about advanced trauma life support (ATLS)?

Advanced trauma life support (ATLS) has become a desirable or even essential part of training for many surgeons and anaesthetists, but aspects of the ATLS course have attracted criticism. In the absence of published data on the views of trainees, this study sought their opinions in a structured questionnaire, which was completed by trainees in accident and emergency (A & E) (26), anaesthetic (82), general surgical (26), orthopaedic (42) and other (5) posts in different hospitals (response rate 66%). Of the trainees, 78% had done an ATLS course and, of these, 83% considered ATLS a 'major advantage' or 'essential' for practising their proposed specialty--100% for A & E, 94% for orthopaedics, 92% for general surgery, and 75% for anaesthetics. ATLS was considered a major curriculum vitae (CV) advantage by 94%, 85%, 50%, and 45%, respectively. Over 90% had positive attitudes towards ATLS, and 74% selected 'genuine improvement of management of trauma patients' as the most important reason for doing the course: 93% thought ATLS saved lives. Of the respondents, 83% thought that all existing consultants dealing with trauma patients should have done the course, and 41% thought it offered major advantages to doctors not involved in trauma. Funding problems for ATLS courses had been experienced by 14% trainees. This survey has shown that most trainees view ATLS positively. They believe that it provides genuine practical benefit for patients, and very few regard ATLS primarily as a career advantage or mandate.

Mortality risks, costs, and decision making in transfusion medicine.

Traditional quality-adjusted life year (QALY) cost analysis is complex and assigns arbitrary dollar values to catastrophic outcomes such as death. Analysis of transfusion medicine technologies by an alternative approach that focuses on costs to avoid fatal outcomes might be a useful adjunct to QALY analysis for allocating limited financial resources. We estimated the cost per death averted for the following interventions: apheresis platelets vs random platelets, solvent detergent-treated plasma vs untreated plasma, and leukocyte-reduced vs unmodified transfusions in cardiac surgery. As a control, similar data were calculated for current donor viral testing. The estimated incremental costs per death avoided were as follows: single-donor apheresis platelets, $15 million; solvent detergent plasma, $17 million; leukocyte-reduced transfusions in cardiac surgery, $11,000; HIV-1 antibody testing, $22,000; and HIV-1 antigen testing, $3.9 million. The estimated number of deaths averted per year in our hospital were as follows: apheresis platelets, 0.1; solvent detergent plasma, 0.044; leukocyte-reduced transfusions, 14; HIV-1 antibody testing, 6.0; and HIV-1 antigen testing, 0.033. HIV-1 antibody testing and leukocyte-reduced transfusions in cardiac surgery are comparably cost-efficient means of averting mortality in patients receiving transfusions. Solvent detergent plasma and apheresis platelets are comparatively expensive approaches to reducing mortality from transfusion complications.

A search within the IL-1 type I receptor reveals a peptide with hydropathic complementarity to the IL-1beta trigger loop which binds to IL-1 and inhibits in vitro responses.

In previous research, we were able to demonstrate that a seven amino acid residue peptide (VITFFSL), designed as an antisense peptide of the beta-bulge trigger loop region of interleukin 1beta (IL-1beta) (QGEESND; residues 48-54 [mature protein sequence]), was able to interact with IL-1 specifically and inhibit the response to IL-1 in an in vitro bioassay. The evidence was consistent with a specific interaction ocurring between antisense peptide and the trigger loop region. On the basis that antisense peptides are able to interact with their corresponding sense peptide sequences as a result of their mutually complementary hydropathic profiles (Fassina G., Verdoliva, A., Cassani, G., Melli, M., 1994. Binding of type I IL-1 receptor fragment 151-162 to IL-1. Growth Factors 10, 99-106; Maier, C.C., Moseley, H.N.B., Zhou, S., Whitaker, J.N., Blalock, J.E., 1994. Indentification of interactive determinants on idiotypic-anti-idiotypic antibodies through comparison of their hydropathic profiles. Immunomethods 5, 107-113), we devised a computer program (FINDH) to search the amino acid residue sequence of interleukin-1 type 1 receptor (IL-1 R1) for peptide motifs possessing hydropathic complementarity to the trigger loop sequence. The most complementary "best-fit peptide" motif (LITVLNI) was located in the third extracellular domain of IL-1 R1. A best-fit peptide corresponding to this motif was synthesised and found to bind to IL-1beta as well as inhibit the response to IL-1 in two independent in vitro bioassays (monitoring IL-1 dependent serum amyloid A synthesis and IL-1 dependent alkaline phosphatase activity, respectively). A second peptide motif (VIEFITL) was identified and the corresponding peptide synthesised along with a reordered version (LTILINV) of the best fit peptide. Both failed to bind measurably with IL-1beta or inhibit the response to IL-1 in the two bioassays. This best fit peptide behaved very similarly, in terms of IL-1 binding and inhibition behaviour, to the original trigger loop antisense peptide. Reference to the recently released X-ray crystal structure of IL-1beta and the IL1-R1 extracellular domain shows that the best fit peptide motif in IL-1 R1 is not apparantly interacting with the IL-1 trigger loop, although both are close in space. The intriguing possibility exists that the best fit peptide motif could represent an alternative site for IL-1beta receptor interaction which has not thus far been identified.