Influence of a 12-hour, 22 degrees C holding period for buffy coats on the preparation of platelet concentrates stored in plasma.

BACKGROUND: The preparation of platelet concentrates (PCs) from buffy coats (BCs) stored at room temperature is controversial, because of the strong metabolic activity of cells in BCs and the possible detrimental effect of neutrophil enzymes on platelets when the holding time before separation is prolonged. Despite good in vitro and in vivo behavior of BC-PCs stored in synthetic solution, little is known of the quality of BC-PCs stored in plasma. STUDY DESIGN AND METHODS: Comparison was made of PCs prepared from BCs held at 22 degrees C for 3 hours (3-hour BC-PCs) or overnight (12-hour BC-PCs) and stored in plasma. Platelet and white cell counts, pH, response to osmotic shock, and morphologic scores were determined on 20 PCs of each type. The decrease in dense granule and alpha granule content, a marker of platelet activation, were estimated by mepacrine counting and beta-thromboglobulin measurement, respectively (n = 8-10). Platelet function was studied in terms of aggregation and thromboxane production in response to various concentrations of collagen and thrombin (n = 8-17). PCs prepared from unstored BCs (n = 15) and from BCs held for 90 minutes (n = 15) were used as controls. RESULTS: Platelet yield was increased from 53 +/- 10 percent of donated platelets to 73 +/- 4 percent by increasing the BC holding time from 0 to 90 minutes to 3 hours (p < 0.001). Similar yields (7.8 +/- 1.8 vs. 7.9 +/- 2 x 10(10) platelets) and white cell contamination (0.9 +/- 0.8 vs. 1.0 +/- 0.9 x 10(7)) were obtained with 3-hour and 12-hour BC-PCs. At the end of the storage period (Day 5), all variables known to correlate with platelet survival in vivo were well maintained in both 3-hour and 12-hour BC-PCs: pH > or = 6.9, response to osmotic shock > or = 70 percent, and morphology scores always > or = 240. During storage, the dense granule content decreased moderately (30% after 5 days), whatever the conditions. By contrast, the total platelet beta-thromboglobulin content was better preserved in 12-hour BC-PCs than in 3-hour BC-PCs (p < 0.04). No significant differences were observed in collagen-induced aggregation and thromboxane production in the two PC preparations. However, aggregation responses to thrombin were higher in 12-hour BC-PCs on Day 5 of storage (p < 0.01). CONCLUSION: BCs can be held at 22 degrees C for up to 12 hours, with no detrimental effect on the quality of PCs stored for up to 5 days in plasma. Such a holding time might help overcome logistic problems in blood banks.

[Anti-HBc in blood donors. Distribution by sex and age classes]. / Anticorps anti-HBc chez les donneurs de sang. Répartition par sexes et classes d'âge.

Among the 21,341 blood donors who gave their blood in 1990, 638 were anti-HBc positive. There is a significant difference between men and women who are 18 to 22 years old and those who are more than 50 years old. In the first case, this difference can be referred to the heterogeneity of the male population and in the second case, to the aftermath of military campaigns.

[Flow cytometric analysis of cellular DNA content in Barret's esophagus. A study of 66 cases]. / Analyse du contenu cellulaire en ADN par cytométrie en flux dans les endobrachyoesophages. Etude de 66 cas.

Dysplasia is the only marker for malignant potential in Barrett's esophagus. The histologic interpretation of dysplasia is sometimes difficult, particularly when attempting to distinguish dysplastic changes from those of a regenerating and inflammatory mucosa. In order to find an objective marker to identify patients with high risk of malignant transformation, the authors evaluated 497 biopsies from 66 patients with Barrett's esophagus with flow cytometry. The aim of the study was to correlate DNA content and proliferative abnormalities with histology. All biopsies classified histologically as negative for dysplasia had a diploid DNA content. The percentage of biopsies with an aneuploid DNA content increased with the histologic grade of dysplasia: 2 percent of indefinite dysplasia, 11 percent of low grade dysplasia, 44 percent of high grade dysplasia and 78 percent of biopsy specimens with cancer biopsies were aneuploid. Mean S and G2M fractions of diploid biopsy specimens increased with the severity of histologic changes. The S and G2M fraction threshold values that could differentiate patients that were negative for dysplasia from those with high grade dysplasia or cancer were 9 percent and 6 percent, respectively. Aneuploidy or G2M fraction greater than 6 percent was the best discriminating criteria between those two distinct groups of patients. All 6 patients with high grade dysplasia or cancer had aneuploid cell populations or increased G2M fraction, whereas none of the 35 patients whose biopsies were histologically negative for dysplasia had evidence of genomic instability or increased G2M fraction. Flow cytometric abnormalities were found in 10 out of 25 patients whose biopsies were classified as indefinite for dysplasia or low grade dysplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

[Direct diagnosis of predominant mutation delta F508 associated with the mucoviscidosis gene]. / Diagnostic direct de la mutation majoritaire delta F508 associée au gène de la mucoviscidose.

The cystic fibrosis locus was mapped on the long arm of the chromosome 7 in 1985. It has recently been cloned and a three base pair deletion has been recognized as the mutation associated with the majority of CF chromosomes (delta F508). CF haplotypes previously defined with tightly associated DNA markers were analysed using PCR (Polymerase Chain Reaction) and allele specific oligonucleotides to determine the presence or absence of this mutation. This mutation was found on 80% of our CF chromosomes and associated predominantly with the B haplotypes. The detection of this mutation is now a major improvement for carrier detection and prenatal diagnosis of the disease.

[Autosomal dominant polycystic kidney and genetic markers of chromosome 16]. / Polykystose rénale autosomique dominante et marqueurs génétiques du chromosome 16.

The mutation for autosomal dominant polycystic kidney disease (APKD) has been mapped by linkage analysis on the distal part of the short arm of chromosome 16. We present in this study the results of linkage analysis using the two most tightly linked DNA markers (3'HVR and 24-1) in 183 members of 14 families of a same ethnic origin. We have constructed haplotypes using these two polymorphic probes, and compared the frequency of these on the normal and the affected chromosome. No evidence of linkage heterogeneity was found in our population.

[Mucoviscidosis: current diagnostic possibilities. Applications in perinatology]. / Mucoviscidose: de nouvelles possibilités diagnostiques. Applications en anténatalogie.

The gene of cystic fibrosis is localised on the long arm of chromosome 7. DNA probes placed close to the gene enable a study of restriction polymorphism to follow the transmission of the gene in index families. It is now possible to counsel those families, who already have an affected child, with an early antenatal diagnosis at ten weeks after the last period. In our personal experience, based on a study of the genotype of 48 families, 70% were informative when they were studied by two probes corresponding to the local pJ3.11 and met. When the latter probes Km19-XV2c were studied concurrently useful information was achieved in 96%. DNA analysis non enables the detection of the chromosome carrying the deleterious gene in practically every family where there is a child suffering from the disease.

HLA class II genes polymorphism in DR4 giant cell arteritis patients.

We have previously reported a significant increase of HLA-DR4 antigen frequency in giant cell arteritis (GCA). This finding suggested an important role of immunogenetic factors in this syndrome. Recent data suggest that inherited susceptibility to several autoimmune diseases was associated with specific DR4 associated DQ beta alleles. DNAs from 27 DR4 positive patients with GCA were digested with Taq I and Bam HI, analysed on 0.7% agarose gel and hybridized with DR beta, DQ alpha and DQ beta probes. DR beta hybridization produced no variant detectable within DR4. DQ beta probe confirmed two clusters among DR4 associated DQW3 alleles: DQW 3.1 (Bam HI 360 Kb) and DQw 3.2 (Taq I 1.9 Kb and Bam HI 11 Kb). Among our 27 DR4 positive patients, 34% were DQW 3.1 and 66% were DQW 3.2. These frequencies are the same as those observed in healthy controls.

[Approaching the gene of mucoviscidosis. New data]. / Approche du gène de la mucoviscidose. Nouvelles données.

We used 5 polymorphic probes strongly linked to the gene of cystic fibrosis (CF) to perform the genotypical study of 48 families with at least one child presenting with the disease. The last Km19 and XV2c probes showed a very important linkage imbalance with the CF gene (allele 2 = 6.6 kb of Km19/Pstl, chi 2 = 56; allele 1 = 2.1 kb of XV2c/Taql, chi 2 = 21). These two markers define a B haplotype which confers a relative risk of 55 to be gene carrier. From these data, the predictive value for an individual presenting with this haplotype to be heterozygous was computed to be 1/5. Presently, the risk of 1/20 for a randomized subject to be gene-carrier should be reexamined after study of this genotype. These results are very important practically, as they modify the classical data of genetic counselling concerning cystic fibrosis for the couples with a risk higher than 1/4.

[Molecular biology and mucoviscidosis. Brest experience in 1987]. / Biologie moléculaire et mucoviscidose. Expérience brestoise en 1987.

The gene for cystic fibrosis is located on the long arm of chromosome 7 at 7q31. The close linkage between the disease locus and several DNA markers allowed a study of the DNA restriction polymorphism pattern in 30 Breton families. The frequency of the haplotypes indicated by the probes pJ 3.11, met H and met D was established reaching a 66.6% informativity for the families studies. The complete informativity of a family allows for detection of heterozygous brothers and sisters, uncles and aunts and for antenatal screening on trophoblast biopsies in case of further pregnancies.

[Post-transfusion malaria. Partial statistical data. Preventive approach to detecting blood donors at risk]. / Paludisme post-transfusionnel. Données statistiques partielles. Approche prophylactique par le dépistage des donneurs de sang à risque.

The authors demonstrate the reality of post-transfusion malaria, define the plasmodial species involved, and insist on the responsibility of Plasmodium falciparum in the occurrence of major complications. A prophylactic approach is proposed, by researching anti-malarial antibodies in donors at risk. An I. F. A. (Indirect Immunofluorescence Assay) is performed (Falciparum Spot I. F., Bio-Mérieux, Lyon, France). The screening procedure relies heavily on medical history taking, but subsequent results are satisfying; moreover it seems they could be bettered by using specific monoclonal antibodies.

[Prevention of post-transfusional malaria]. / Prévention du paludisme post-transfusionnel.

The Authors report the results over a four year-period of their protocol for the detection of blood donors at risk of harboring Plasmodium Falciparum and thence transmitting post-transfusional malaria. This protocol is based on donor questioning and antibody detection by an immunofluorescence assay. It has led to exclude from the direct transfusional network 0,41% of the draws, but then 1032 units have been reintegrated in the inventory without provoking any reported incident. A short study of the geographic origins of the infections confirms the World Health Organization (W.H.O.) data and allows to insist on high risk areas and even reveals previously unsuspected ones. As long as there is no available automated method, and, foremost, no direct parasitemia-detecting assay, this low-cost protocol seems satisfying.

[The micro-computer card. Possible applications to transfusion from A to Z]. / La carte à micro-calculateur. Applications possibles à la transfusion de A à Z.

Following characteristics of micro-computer cards: inaccessibility to selected secret information; strong resistance to aggressive external agents; impossibility of altering stored data without destroying it; instant reading and reproduction by authorized services; make them a perfect material for building up individual records of civil and biological data. Their application to blood transfusion allows increased safety not only for blood donation registrations, but above all when transfusion takes place; they may also be used as credit cards for health expenditures. They consequently serve as real LIFE cards.

[Practical impact of instructions concerning AIDS]. / Impact pratique des instructions concernant le SIDA.

Following an inquiry to determine what measures has been taken since january 1984 in French Blood Centers to avoid transmission of AIDS by blood, answers from 49 % of the centers, representing 75 % of the blood collection in France were analyzed. Due to the absence of a biological marker, only information given to blood donors, unpaid in France, permitting spontaneous autoexclusion had been used to screen donors in blood center. Direct questioning of donor for risk factors before taking blood raised numerous problems in donors of whole blood, but could be satisfactorily implemented in cytapheresis and plasmapheresis donors mainly because of closer human contact between volunteers and the medical staff.

Screening blood donors for Plasmodium falciparum malariae. Application of ready-to-use homologous antigens.

Prevention of post-transfusion malaria remains a worrying problem. Until now it was very difficult to obtain homologous antigens, and immunologic methods used to detect malaria were expensive. We tested the ready-to-use Plasmodium falciparum prepared slides using the IFA (indirect fluorescent antibody) test on 866 selected potentially dangerous donors and known malaria cases. We found that it is a simple, quick, reliable and inexpensive method that can be easily used by blood banks and improve blood transfusion safety.

[Identification of blood donors capable of transmitting P. falciparum. Use of homologous antigenic preparations ready for use]. / Dépistage des donneurs de sang susceptibles de transmettre P. falciparum. Utilisation de préparations d'antigènes homologues prêts à l'emploi.

The smears of P. falciparum parasited blood ready to be employed, that we have tested in indirect immunofluorescence to detect blood donors who can be at the origin of post transfusional paludism, seem to offer a very important progress to us for the improvement of transfusion security. Their routine use can be recommended because their easy way of using allows their adoption by very many transfusion centers.