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Biomedical subjects

F Guignier

Publications and source records attributed to F Guignier.

30 records · Page 2Linked to original sources
PubMed1989

[Leukocyte removal in a closed system of human red-cell concentrates: a technic coupled with the automated extraction of the buffy coat using a sterile connector from a filtration kit].

A technique, integrally run in a closed system, for leucocyte depletion of human red cell concentrates is described. It associates two complementary processes: buffy-coat removal and filtration. The first step is carried out with an automated system for blood component preparation (Compomat, NPBI); its efficiency is improved by a custom made blood collection set with ACD anticoagulant solution in the primary bag. The second step is simplified by a filtration kit requiring only one sterile connection for operation (SCD 312, Dupont de Nemours) and allowing a standardised rinsing of the filter. Quality control of 33 units so prepared shows principally: --an intensive leuko-depletion (4 logs) enabling leukocyte contamination to be kept below 10(6) per unit; --a moderate red cells loss (15 ml for the first step and 20 ml for the second one). This technique provides a permanently available and very pure blood component. Moreover it offers new potential for standardisation and mastery of quality control.

Blood Cell Count↗
PubMed1989

[Viability of human red blood cells preserved for 35 days after leukocyte depletion (in vitro study)].

24 leukocyte poor red cells concentrates (L.P.R.C.) were prepared by sterile connection of a leucocyte filter between the primary bag and the SAGM bag of a blood unit after centrifugation. Their quality was followed up to 42 days by means of a panel of tests including, ATP and 2,3-DPG levels, hemolysis, plasma potassium, lactate and glucose, and counts of the microaggregates. 24 standard units acted as a control group. Results showed better preservation of LPRC and especially less hemolysis, higher ATP levels and at least equal oxyphoric capacity (explored by 2,3-DPG). Microaggregate formation was dramatically reduced and bacteriologic checks (48 at day 25 and 48 at day 42) were all negative. Leucocyte depletion appears as a new way to improve functionality of erythrocytes during storage in the SAGM medium. 35 days shelf life will allow this blood product to be more available and its preparation more standardised.

2,3-Diphosphoglycerate↗
PubMed1988

Comparison between a solid-phase low-ionic-strength solution antiglobulin test and conventional low-ionic-strength antiglobulin test: assessment for the screening of antierythrocyte antibodies.

A solid-phase low-ionic strength salt antiglobulin test (LISS-SPAT) has been developed using a microplate coated with dried sera as a solid phase. Before coating, the in vitro C3d fragment generation was activated by adding heat-aggregated immunoglobulin. The LISS-SPAT was compared with low-ionic strength conventional antiglobulin test (LISS-AGT) and also with a test using polybrene or papain microplates. When detecting the IgG and IgM antierythrocyte antibodies the reaction was developed in the same way in LISS-SPAT and LISS-AGT. In routine work, the LISS-SPAT provides a fast, reliable, handy and inexpensive screening of antibodies. This method appears to be an additional method to the papain and polybrene tests in microplates.

Blood Group Antigens↗
PubMed1985

Outbreak of respiratory syncytial virus in France.

A report is given of an outbreak of respiratory syncytial virus infection in a neonatal unit in France. Twenty-three of 32 infants were infected (72%) despite infection control procedures. Prophylactic administration of non-specific gamma globulins was associated with a significant decrease in infection rate (p less than 0.05). The administration of transfer factor to infected infants was also associated with a significantly lower rate of severe respiratory diseases (p less than 0.05).

Disease Outbreaks↗
PubMed1983

[Computerization of a bank of platelets with HLA phenotype and preserved at -196 degrees C].

In order to complete the logistics of the unit cytapheresis, we have developed a decision helping system which rests upon the computer management of -196 degrees C cryopreserved HLA type platelets. The hardware used is a micro-computer equipped with two floppy disks and a printer. Two files have been created: namely "Product" and "Patient". Data relating to 800 platelet concentrates may be recorded on a floppy disk. The software which has been developed has several functions: 1 - The input of the parameters of a HLA type concentrate with the possibility of reservation for the given recipient; 2 - The print out of the bank's stock; 3 - The selection and the reservation of HLA matched platelets according to the recipient; 4 - The print out of concentrates allocated to each patient, it is possible to thaw out chosen platelet concentrate and a thawing report is printed out, thus enabling one to locate the concentrate in the bank. Thanks to this "aid in decision making", the management of - 196 degrees C cryopreserved HLA type platelets may be carried out. The proposed software allows an one line answer for any emergency transfusion case. Considering the recipient HLA typing the suitable best match platelet concentrates are instantly transfused or save.

Blood Transfusion↗
PubMed1977

[Radioimmunologic determination of the thyrotropin releasing hormone].

We describe the preliminary steps for a radio-immunoassay of Thyrotropin Releasing Hormone (TRH). Rabbit antiserum at dilution 1 : 10 000 is used with radioiodinated TRH (125I). We are able to assay from 5 to 1 000 pg unlabeled TRH with an intraassay reporducibility varying from 7 to 4 % and the lowest detectable amount in this system is 10 pg TRH. TRH mean and standard deviation in normal subjects are 136,9 and 25,3 pg/ml.

Female↗
PubMedDate not supplied

Induction of tissue factor expression on human umbilical vein endothelial cells by cell-specific HLA class I antibody: preliminary data.

Donor-specific antibodies may play an important role in the development of chronic allograft rejection process. However, the mechanisms leading to intimal vascular proliferation and fibrosis remain poorly understood. The aim of this study was to examine whether donor-specific HLA antibodies induce overexpression of tissue factor (TF) by endothelial cells. HLA typed human umbilical vein endothelial cells (HUVEC) were incubated for 1 to 12 hours with LPS (10 microg/mL), and increasing concentrations (1 to 500 microg/mL) of anti-HLA A1 antibody specific for an antigen expressed by HUVEC and of an anti-HLA A2 antibody for which A2 was not expressed by the HUVEC. Expression of TF mRNA transcripts was quantified using real time Q-RT PCR and TF activity was tested in cell lysates of cultured HUVEC using a chromogenic TF activity assay. HUVEC-specific anti-HLA A1 antibody at low concentrations (10 microg/mL) induced both a significant increase of TF mRNA transcripts after 1 hour of incubation and TF activity after 3 hours incubation compared to incubation with medium alone or with the nonspecific anti-HLA A2 antibody (n = 4 for all experiments, P < .05). These data show for the first time that specific anti-HLA antibody can induce overexpression of TF on endothelial cells. TF, a transmembrane glycoprotein involved not only in the onset of the coagulation cascade, but also in cell proliferation and anti-apoptotic processes, may play a role in the development of alloantibody-induced chronic rejection.

Endothelium, Vascular↗
PubMedDate not supplied

[Assessment and value of the polybrene microplate test for study and identification of irregular anti-erythrocyte antibodies].

We have adapted Lalezari's manual polybrene test for use with microplate technology for screening and identification of anti-erythrocytes antibodies with a view to future automation. The technical conditions have been standardized, firstly by using a programmable centrifuge and a sequential shaking, secondly by using a preservative medium for panel after dispensing onto microplates. This methodology has been run in parallel with papain test and LIS indirect antiglobulin test: 7,000 screenings have been performed and their results are considered here. Our results are comparable to those described for automatic and manual techniques. The polybrene-microplate test affords a fast, reliable, handy and inexpensive means of screening and identification for irregular antibodies. It appears as an additional method for enzymatic tests in microplate. An antiglobulin test can be carried out after negative tests.

Antibodies↗