A flexible RF applicator for heating viscous lossy products such as foods.

A helical RF industrial applicator was evaluated for heating minced meat flowing in a hollow tube. Heating was homogeneous inside the product, although the product was highly lossy due to its high electric conductivity. The homogeneity was much better than could be obtained with microwave heating. A high power density, up to 5 kW/liter, can be deposited inside the product with 95% efficiency.

[Seroprevalence of hepatitis C antibodies among blood donors. Study of second generation ELISA and RIBA tests and surrogate markers]. / Séroprévalence des anticorps contre le virus de l'hépatite c chez les donneurs de sang. Etude des tests ELISA et RIBA de 2e génération et des marqueurs indirects.

Between March and November 1991, prevalence of hepatitis C antibodies was evaluated in 60,960 blood donors from the North-East of France. Using a second generation ELISA, 424 donors (0.69%) were reactive, with no significant difference between males (0.69%) and females (0.70%). Among these 424 donors, respectively 137 (32.3%), 86 (20.3%) and 201 (47.4%) were reactive, indeterminate or nonreactive by a second generation RIBA (RIBA-2) (Recombinant Immunoblot Assay). Donors with a high ELISA ratio (> or = 4) were significantly more likely to have a reactive RIBA-2. Of the 1906 donors with anti-HBc positivity (3.12%), 44 had a reactive ELISA; of these, respectively 27, 12 and 5 had a reactive, indeterminate and nonreactive RIBA. Of the 1201 donors (1.97%) with increased serum ALAT (alanine-amino-transferase) levels (> or = 2N), 42 had a positive ELISA; of these, respectively 35, 2 and 5 had a reactive, indeterminate and nonreactive RIBA. Of the 54 donors with both indirect markers, nine had a reactive ELISA; the same nine donors had a reactive RIBA. These data show that donors with both surrogate markers and a reactive ELISA are very likely to have a positive RIBA. Seventy-seven (18.16%) of the 424 donors with a reactive ELISA had at least one surrogate marker; 67 of these donors (30.04%) were among the 223 donors with a reactive ELISA and a reactive or indeterminate RIBA.

The in vitro effect of amodiaquine on bone marrow granulocyte-macrophage progenitor cells from normal subjects.

Amodiaquine is used for antimalarial prophylaxis and treatment and has been associated with neutropenia and agranulocytosis in man. The effect of the drug on the in vitro growth of bone marrow human myeloid progenitor cells (GM-CFU) was tested using the soft agar culture technique: 42 haematologically normal subjects were studied and it was found that amodiaquine, at concentrations tested in vitro (0.005, 0.05 and 0.5 micrograms.ml-1), had no quantitative effect on the colony and cluster growth. Our results argue against direct toxicity of the drug on GM-CFU. Therefore, in cases of amodiaquine-associated neutropenia, alternative mechanisms should be considered: a abnormally sensitive GM-CFU; b) toxic effect of metabolites such as desethyl-amodiaquine; c) immune-mediated toxicity.

Serum and erythrocyte ferritin in regular blood donors.

This study evaluated 217 regular blood donors, with the aim of measuring their iron stores and recording the influence of donation frequency. In the population studied, 10% of men and 15% of women showed reduced iron stores of the erythropoietic marrow (erythrocyte ferritin less than the normal range) and 64% of the population showed a latent deficiency in iron (serum ferritin values less than the reference values). An increase in donation frequency was followed by an important decrease in serum ferritin concentration. Blood haemoglobin levels were inferior to control limits in 4% of men and 15% of women, measurements of haemoglobin being the legal screening test performed at the time of donation. However, this test gives a late indication of an already established iron deficiency and should be replaced by the determination of serum ferritin in order to avoid the possible appearance of iron deficiency. Erythrocyte ferritin is another late indicator of iron depletion and hence is of little interest for the control of blood donors.

[Serum antibodies against hepatitis C: study of 4,100 blood donors from the northeast of France]. / Anticorps sériques contre le virus de l'hépatite C: étude de 4,100 donneurs de sang du nord-est de la France.

Between June 1989 and February 1990 the prevalence of antibodies to hepatitis C virus (anti-HCV) was studied in blood donations from 4,100 donors tested in north east France. 37 samples were found reactive for anti-HCV (prevalence of anti-HCV: 0.90%) without any significant difference in sex (males: 0.94%; females: 0.87%) and age distributions. 178 (4.34%) of the 4,100 donors were found anti-HBc positive, 5 of these donors being anti-HCV positive (13.51% of all anti-HCV positive donors). 52 donors (1.27%) had raised alanine aminotransferase (ALT) levels (greater than or equal to 2 N: 2 times the M +/- 2 SD value): 3 were found anti-HCV positive (8.11% of all anti-HCV positive donors). Association of the 2 surrogate markers is poorly sensitive since it detects only 8 (21.62%; males: 4, females: 4) of all anti-HCV positive donors. Furthermore, it appears weekly specific since it discards 230 blood samples of which 222 (96.52%) were anti-HCV negative. The 2 surrogate markers are complementary to one another and none of the anti-HCV positive donors had both anti-HBc antibodies and raised ALT. The mean ALT level is significantly higher in anti-HCV positive donors as compared to seronegative (M +/- 1 SD: 51 +/- 82 U/l versus 24 +/- 17 U/l). In anti-HCV positive donors, a marginal (r = 0.34) though statistically significant (p less than 0.05) positive correlation was found between ALT level and anti-HCV ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

'Eccentriplate': a new centrifugal plate for platelet concentrates.

The evaluation of Dideco's Double Ring reveals a sensitive improvement on the Single Ring. This system provides a platelet concentrate of over 4x 10(11) platelets in 75 minutes. It is reasonable to envisage yet shorter and more efficient processes, as suggested by VALBONESI et al. However, considering the platelet transfusion requirements, it would be interesting to have a plastic 5-day preservation closed system.

[Determination of C3a and C5a in hemapheresis procedures]. / Evaluation du C3a et du C5a dans les procédures d'hémaphérèse.

Study of the interface between blood and artificial surfaces reveals numerous undesirable reactions. For example, the formation of biologically active peptides, C3a and C5a (anaphylatoxins), is a result of complement activation via the alternative pathway. It cannot be denied that the reinjection of large quantities of these molecules could be at the origin of serious side effects. We report herein the anaphylatoxin levels found with 9 hemapheresis procedures (4 plasma filtration membranes, 3 systems for platelet collection, 2 plasma treatment techniques (dextran sulfate cellulose column and cascade filtration)). All the filtration procedures generated very high levels of anaphylatoxins, especially C3a. In contrast, the centrifugation systems produced lower levels. However, considerable amounts of C3a were found with the Cobe Spectra and V50 Haemonetics blood cell separators. The anaphylatoxins generated by the primary filter were partially retained by the dextran sulfate column. These high toxin levels enable an assessment of the degree of hemo-incompatibility of these systems. However, it remains difficult to evaluate whether these anaphylatoxins are dangerous or not.

[Efficacy of 2 cholesterol apheresis systems]. / Efficacité de deux systèmes d'épuration du cholestérol.

A new generation of techniques can be applied to the selective removal of some well-defined molecules from plasma. This is the field of plasma treatment. We investigated the selective removal of LDL cholesterol, by double filtration and dextran sulfate cellulose column plasmapheresis, from 3 to 4 liters of plasma from 4 hypercholesterolemic patients. The extraction rate of Apo A1 lipoprotein in dextran sulfate was less than 25% and Apo B was between 50 and 90%. Cascade filtration gave an extraction rate for Apo A1 between 25 and 50%; the extraction rate for Apo B was about the same as that found using the dextran sulfate procedure. Both techniques decreased the concentrations of coagulation factors (V, VIII and fibrinogen). In conclusion, we obtained good removal of LDL cholesterol with both systems. Dextran sulfate (from Kaneka) was more selective but very expansive. However, we observed side effects with this product that probably result from the release of dextran sulfate from the column.

[Epidemiologic study of HIV serology in blood donors from 5 departments in northeastern France (1985-1989)]. / Etude épidémiologique de la sérologie VIH des donneurs de sang dans cinq départements du nord-est de la France (1985-1989).

Between July 1985 and June 1989, the prevalence of HIV antibody was studied in 503,019 blood donations tested in 5 administrative areas ("departments") of north east France: 91 seropositive donations (donors) were detected (prevalence: 0.18%). The prevalence was 0.41% in 1985, 0.22% in 1986, 0.14% in 1987, 0.10% in 1988 and 0.11% in 1989: in each year, it was found lower than the national prevalence. 14 (15.4%) of the 91 seropositive donors were females, and the prevalences of HIV antibody in blood donations from female and male donors were 0.07% and 0.26% respectively. All seropositive donors were younger than 50 and 83 (91.2%) younger than 40. The prevalence of HIV antibody was higher in blood units at first donation (occasional donors) as compared with blood units collected from regular donors (0.60% versus 0.09%). The prevalence of HIV antibody was higher in blood donations from military donors as compared with donations from civilian donors (0.49% versus 0.07% in 1987, 1988 and 1989). Most seropositive military donors were young male recruits of the national armed forces conscription system. We believe that these recruits are subjects with risk factors which must be taken into account for the determination of national blood supply policies.

Analysis of blood CD4+ and CD8+ T-lymphocyte subsets with monoclonal antibodies. Comparison of the Genetic Systems CD4/CD antigen typing kit with conventional indirect immunofluorescence microscopy and the automated Technicon-H1 Enzyme Immunoassay (EIA).

The Genetic Systems Technique (GS: direct immunofluorescence microscopy with ethidium bromide counterstaining of nuclei) was tested for quantitative analysis of T-lymphocyte subsets in human peripheral blood. The monoclonal antibodies anti-CD4 and anti-CD8 were used for detection of T-helper and T-suppressor cells respectively and the results compared to those obtained by conventional indirect immunofluorescence microscopy and the Technicon Enzyme Immunoassay (EIA) with automated reading. The GS technique provided results correlating well with both indirect immunofluorescence and EIA techniques. Moreover, this method has two advantages: it is less time-consuming than the indirect immunofluorescence microscopy and necessitates less expensive and more commonly available equipment than the automated EIA technique.

Toxicity of HPA-23 (ammonium-21-tungsto-9-antimoniate) for normal human myeloid progenitor cells (GM-CFU) in vitro.

HPA-23 is a competitive inhibitor of the RNA-dependent DNA polymerase (reverse transcriptase) of the human immunodeficiency virus (HIV). It may therefore potentially benefit patients with HIV infection. This study aimed at defining the haematopoietic toxicity of this drug and particularly its effects on the normal human granulocyte-macrophage progenitor cells (GM-CFU). Our in vitro studies, in semi-solid agar, have shown an inhibitory effect of increasing concentrations of HPA-23 on colony and cluster formation. This effect is probably dose-dependent. An almost complete inhibition of colony formation was observed at doses of more than 20 micrograms/ml. Regarding cluster formation, a similar although much more progressive inhibitory effect was found. Our experimental data should be extrapolated with caution to clinical situations. However, they must be kept in mind for optimal design of HPA-23 therapy in HIV infected patients.

Amodiaquine-induced agranulocytosis: report of a case with in vitro studies of granulocyte-macrophage progenitor cells.

We report a case of amodiaquine-induced agranulocytosis in a 60-year-old woman. Four months after the agranulocytosis episode we investigated the effect of the drug using in vitro agar culture techniques. Amodiaquine at increasing concentrations (0.005, 0.05 and 0.5 microgram/ml) displayed an inhibitory effect, probably dose-dependent, on the growth of the patient's bone marrow GM-CFU colonies in the absence of autologous serum. In contrast, no effect was found on the colony and cluster growth of bone marrow samples from 13 healthy controls. Though it has been shown in several cases that amodiaquine-induced agranulocytosis occurs via immune-mediated mechanisms, our data are in support of a direct toxic effect of the drug on abnormally sensitive myeloid progenitor cells.