DNA analysis in disputed parentage: the occurrence of two apparently false exclusions of paternity, both at short tandem repeat (STR) loci, in the one child.

In cases of disputed paternity investigated by DNA analysis, it is generally accepted that at least two independent exclusions be observed before concluding that a putative father is not the biological father of the child. We report here a case in which two apparent exclusions of paternity were obtained (at the loci FESFPS and TPOX), from a total of nineteen loci examined (short tandem repeats, AMFLPs, DQA1, Polymarkers). The combined paternity index of the other seventeen loci, and of two multilocus probes (33.15 and 33.6) would exceed twenty-eight trillion to one. In the absence of any alternative putative father (including close relatives of the man tested), we concluded that the most likely explanation for these results was that the putative father was indeed the biological father, but that two independent mutations had occurred in either the ovum and/or spermatozoon. We have altered our internal laboratory criterion for exclusion of paternity to require exclusions in three independent loci.

Transfusion of frozen thawed blood stored at -20 degrees C to -25 degrees C.

OBJECTIVE: To determine the clinical efficacy of transfusion of frozen-thawed (FT) red cells using a 5-bag system for freezing (at -20 degrees C to -25 degrees C), storage and reconstitution. DESIGN: A prospective, controlled, non-randomised clinical trial was undertaken with two groups of orthopaedic surgical patients. Nine patients received FT homologous blood and a control group of 10 patients received homologous blood stored in liquid form at 4 degrees C. Five transfusion-dependent patients with medical conditions were also studied. OUTCOME: Thirty-three FT units were transfused without incident to 14 patients. In addition to clinical assessment, haematological and biochemical parameters were monitored after transfusion. There were no clinical side effects and laboratory data were consistent with those after recent surgery or for pre-existing medical conditions and subsequent blood transfusion. On the practical side certain technical difficulties were encountered which improved with experience. CONCLUSIONS: One of the major advantages of the system is the 35-day shelf-life at 4 degrees C after reconstitution. This system has potential for pre-deposit autologous collection, especially where large volume replacement may be required.

Donor blood frozen and stored between -20 degrees C and -25 degrees C with 35-day post-thaw shelf life.

With standard blood bank facilities and interconnected plastic bags donor erythrocytes can be frozen and stored in commercial freezers at temperatures of -20 degrees to -25 degrees C for at least 6 months. The cryoprotectant, a mixture of glycerol and dextrose, is washed off in a closed-circuit system. After being thawed and reconstituted with an additive solution, the pack of red cells can be stored in liquid form for up to 35 days at 4 degrees-6 degrees C. The system lends itself to routine clinical blood transfusion practice.

A case of polyagglutination with features of Th and Tk activation associated with an acquired B antigen.

A case is reported of polyagglutination with features of both Tk and Th activation associated with an acquired B antigen. Reactions with polybrene, Glycine soja, and Bandeiraea simplicifolia II indicated the presence of Tk activation. However, the reactivity of the patient's erythrocytes with Arachis hypogoea was greatly reduced by treatment with ficin, indicating the concomitant presence of Th activation.

The serological investigation of red cell incompatible transfusion reactions.

The hospital blood bank plays a key role in the diagnosis of acute transfusion reactions involving red cell incompatibility. This paper discusses the interpretation of the serological tests performed by the laboratory. Because red cell incompatible transfusion reactions occur so infrequently it is difficult to accumulate practical experience in their laboratory presentation and this paper describes several of the pitfalls that may be encountered when laboratory findings deviate from classical descriptions. These include the absence of a positive direct antiglobulin test (Coombs) or an incompatible crossmatch, the absence of any apparent discrepancy between the pre- and post-transfusion specimens in cases of ABO incompatibility, the differentiation of auto-immune haemolytic anaemia from delayed transfusion reactions and the assessment of the clinical significance of any blood group antibodies that may be detected.