Food experience on the predatory behavior of the ant Myrmica rubra towards a specialist moth, Acrolepiopsis assectella.

Entomophagous insects are often repelled by the secondary compounds of the plants eaten by their prey. These compounds, therefore, take on a defensive role for the phytophagous species that sequester them. Given that numerous entomophagous species are capable of learning, the effects on the foraging behavior of a repeated experience were investigated in the predatory ant Myrmica rubra. The sulfur amino acids methyl-cysteine sulfoxide (MCSO) and propyl-cysteine sulfoxide (PCSO) produced by Allium plants were identified in caterpillars of the leek moth Acrolepiopsis assectella. Three behavioral studies were carried out, with or without prior familiarization with caterpillars reared either on leek or on an artificial diet containing no Allium compounds. In choice tests with the two types of caterpillars, unfamiliarized ants displayed a preference for caterpillars reared on the artificial diet, but this preference disappeared or was reversed in both young and old ants after familiarization.

A case of chronic myelomonocytic leukaemia and factor XI deficiency with a circulating anticoagulant.

Inhibitors against factor XI (FXI) have been frequently described in patients who acquired inhibitors (due to auto-immune disorders, malignancies or infections), but less often in those with a congenital deficiency of this factor, who had received plasma infusions. The present report concerns one such inhibitor found in the plasma of a patient with chronic myelomonocytic leukaemia and infected by B19 parvovirus, who was neither a heterozygote nor a homozygote for FXI deficiency, and who had no bleeding tendency despite a very low FXI level. Taking this case into account, we discuss and present the clinical and biological features of acquired FXI deficiency caused by an inhibitor.

A cellular model for drug interactions on hematopoiesis: the use of human umbilical cord blood progenitors as a model for the study of drug-related myelosuppression of normal hematopoiesis.

A cellular model of hematopoiesis which would be more convenient than bone marrow (BM) progenitors and directly relevant to human pathology is needed in order to investigate xenobiotic toxicity. Human umbilical cord blood (HCB), previously shown to be able to repopulate BM, provides a powerful in vitro model of normal human hematopoiesis. In order to validate the use of normal HCB progenitors as targets for dose-related myelosuppression, we used clonogenic assays and expansion in a liquid culture of progenitor-enriched cell suspensions from HCB. A series of 8 reference molecules, doxorubicin, cytosine-arabinoside, 5-fluorouracil, 3'-azido-3'-deoxythymidine, acetylsalicylic acid, sodium valproate and two cephalosporin antibiotics, were tested. In vitro 50% inhibition concentrations (IC50) were compared to those observed or reported with BM progenitors, and to the values of plasma concentrations from treated patients. HCB progenitors as in vitro targets for cytotoxic molecules were easy to access and handle, and their use was sensitive, specific and reproducible. They gave results similar to BM progenitors and allowed a qualitative approach to cellular metabolism and toxicity using morphological, flow cytometric and chromatographic methods.

[Importance of flow cytometry in the detection of anti-erythrocyte autoantibodies]. / Intérêt de la cytométrie en flux dans la détection des auto-anticorps anti-érythrocytaires.

Coombs test and flow cytometry have been compared in terms of specificity and sensibility in a population of hospitalized patients, for whom a Coombs test had been required. The Coombs test seems more sensible than flow cytometry to detect red cell-bound IgG. For a given patient and over the time, flow cytometry seems better correlated with the severity of haemolysis if erythrocytes are strongly sensitized by IgG. The results of flow cytometric analysis, in percentage of sensitized erythrocytes, do not allow to define a sensibilization threshold for haemolysis prediction. Flow cytometric analysis would be more sensible than Coombs test in the detection of red cell-bound C3d, but these cases are not associated with autoimmune haemolytic anemia. Direct Coombs test should remain the diagnostic test of autoimmune haemolytic anemia.

Evaluation of a high-performance thin-layer chromatographic technique for the determination of salbutamol serum levels in clinical trials.

Salbutamol concentrations were determined by high-performance thin-layer chromatography in the sera of two sets of ten volunteers at hourly intervals for 6 h after taking one 8-mg slow-release tablet. The influence of time lapse in processing of serum samples, i.e. centrifugation, extraction and chromatography, was studied. A statistical significant instability of salbutamol in the sera of patients was found which was not present in standard drug-free serum samples spiked with salbutamol and used for construction of standard curves.

Inhaled and oral salbutamol: how effective in the prophylaxis of asthma?

Inhaled and oral salbutamol were compared in 12 asthmatic patients for prophylaxis in antigen-induced asthma. The patients were pretreated with 0.2- and 1.0-mg doses of inhaled salbutamol and with the standard oral 4- and 8-mg slow-release (SR) salbutamol preparations. Bronchodilatation was monitored over the ensuing 3 h and protection against antigen challenge at the end of the period. On each study day the degree of baseline airway hyperreactivity was determined by histamine challenge. Precautions were taken during the antigen challenge to ensure a reproducible response. Blood levels of salbutamol were monitored at hourly intervals for the 3 h after treatment and during the asthmatic reaction subsequent to challenge. Both the 0.2- and 1.0-mg inhalations caused immediate bronchodilation as compared to a placebo (p less than 0.05), but only the 1.0-mg dose protected subjects against antigen challenge (p less than 0.05). In comparison to the placebo, no bronchodilatation was achieved with the standard 4-mg oral preparation in spite of measurable blood levels, nor were the patients protected against antigen challenge at 3 h after pretreatment. However, the 8-mg SR salbutamol caused significant bronchodilatation within 2 h and suppressed antigen challenge responses as compared to placebo (p less than 0.05). It can be concluded that doses of inhaled salbutamol higher than the conventional 0.2- or the standard 4-mg oral preparations are required to protect asthmatics against inadvertent antigen exposure. In patients who are unable to use inhalers effectively, the SR preparation can be considered as an alternative.

[Drug-induced thrombopenias and neutropenias. An in vitro study by the indirect immunofluorescence test]. / Thrombopénies et neutropénies induites par des médicaments. Etude in vitro par le test d'immunofluorescence indirecte.

The sera from 38 patients with suspected drug-induced thrombocytopenia (22) or neutropenia (16) were tested with the indirect immunofluorescence test on platelets or granulocytes for the presence of drug-dependent antibodies. Three drug-induced antibodies with reactivity against platelets and 5 with reactivity against granulocytes were detected. In 3 sera antibodies were found which reacted already with target cells without adding the drug to the test system. These data show that drug-induced blood dyscrasias often have an immunological cause and that in vitro tests can be helpful in detecting the responsible drug. Different mechanisms can be involved. In many sera circulating antibodies were not found, but an immunological mechanism is likely to be involved in some of these cytopenias: the antibody could be entirely absorbed by the target cells, a metabolite of the drug could be the immunogen and finally the test may not be sensitive enough.

[Effect of in vitro carbamylation of erythrocytes on their rheological properties]. / Effet de la carbamylation "in vitro" des érythrocytes sur leurs propriétés rhéologiques.

In order to assess the role of carbamylation of erythrocyte proteins in the modification of rheological parameters of red blood cells observed in uremic patients, and in vitro carbamylation of erythrocytes and hemoglobin was carried out using sodium cyanate. The carbamylation of hemoglobin was determined by observation of the increase of HbA1 fraction. The deformability of erythrocytes and the viscosity of erythrocyte suspensions and of hemolysate were measured. The results showed an increase in the deformability of red blood cells and a decrease in the viscosity of hemoglobin as the carbamylation increased. This is attributed to a decrease of hemoglobin viscosity and to a modification of the electric charge of the membrane. These results show that the reduced erythrocyte deformability observed in patients with renal failure is not due to erythrocyte protein carbamylation.

Morphologic and phenotypic heterogeneity of two cases of translocation t(4;11) acute leukemia.

The morphological, ultrastructural, and immunological characteristics of two cases of acute leukemia with t(4;11) (q21;q23) were studied. The blasts from both cases were initially classified as L1 lymphoblasts. Ultrastructural examination indicated a heterogenous blast population in both cases, with some regular lymphoblast-like cells, and others exhibiting nuclear irregularity, small bundles of microfilaments, or large inclusions. In one case at diagnosis, fresh cells expressed B-associated and a myeloid antigen (B4 and 1G10). At the second relapse, the cells from this patient expressed another myeloid-associated antigen, LFA1 molecule, recognized by the monoclonal antibody M232 (CD18). At the end of clinical evolution, a further myeloid antigen was expressed (OKM1), while 8% peroxidase were noted. The other case was studied at diagnosis only and did not express any myeloid marker but expressed the B-associated B4 antigen. Furthermore, the case that exhibited a phenotypic transformation, was noted to show a chromosomal clonal evolution not described so far in other reported cases of t(4;11) acute leukemia. A dual lymphoid-myeloid nature of t(4;11) acute leukemia has been widely discussed. One of the cases reported here supports this hypothesis while the other does not. We would like to underline the possibility of heterogeneity of a case at presentation and transformation to a myeloid phenotype through clonal evolution.