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Biomedical subjects

F Lejeune

Publications and source records attributed to F Lejeune.

At least 127 records · Page 7Linked to original sources
PubMed1988

[Peroxidase deficiency in eosinophils: an optical and electron microscopy cytologic study apropos of a case].

A case of eosinophil peroxidase deficiency (EPO), discovered using an automated differential leukocyte cell counter, was studied using optical and ultrastructural cytologic methods. The blood and bone marrow eosinophilic cells had an abnormal ultrastructural aspect with important modifications of the specific granule matrix. No peroxidase activity could be revealed in these cells using optical or ultrastructural techniques. The mechanism and significance of this anomaly raise the question of the physiological function of this enzyme.

Adult↗
PubMed1987

Subrenal capsule assay for fresh human tumors in immunocompetent mice; an inappropriate technique for non-small cell lung cancer.

The subrenal capsule assay (SRA) seems to present some difficulties for the evaluation of the chemosensitivity of antineoplastic agents against fresh tumor xenografts. A study was therefore carried out to verify whether two different xenografts would behave in a similar way. Tumors such as melanoma provided adequate homogeneous material for this technique, while non-small cell lung carcinoma (NSCLC) were heterogeneous since the 1 mm3 specimen grafted under the renal capsule usually contained diffuse areas of necrosis and of infection. Furthermore, a large proportion of the grafted specimens, 257 out of 298, did not contain any tumor at all on microscopic examination even when they showed macroscopic growth. Added to these discrepancies, a random microscopic analysis of 180 adjacent fragments of NSCLC and melanomas demonstrated that the variability of heterogeneous tumors precludes any meaningful comparison between homologous tumor tissues designed to be grafted on treated and on control mice. The anti-inflammatory effect of chemotherapeutic drugs on the host's reaction to the graft is probably responsible for the differences between the macroscopic growth results observed in pieces grafted to both treated and control mice: however, it could not be simulated by hydrocortisone (HC) under our experimental conditions. This allows us to conclude that fresh tumors from NSCLC cannot be used in SRA.

Animals↗
PubMed1987

[The Schilling test in Biermer's disease, problems of false negative reactions. Apropos of a case].

A case of pernicious anemia in a 30 years old men is described. This disease was typical for the hematologic, immunologic and medullary patterns, for his evolution, but the Schilling test, a dual tracer method, did not confirm the diagnosis. The contradictory of this result can be explained wether by the bias of the test itself, or by the intestinal malabsorption due to the vitamin B12 deficiency, or by other factors like bacterial overgrowth state (associated in the pernicious anemia) and a high level of antibodies to intrinsic factor.

Adult↗
PubMed1987

Expression of blood group A antigen during erythroid differentiation in A1 and A2 subjects.

The expression of blood group A antigen on marrow and blood cells from A1 and A2 subjects was investigated by the binding of Helix pomatia and Dolichos biflorus lectins using immunofluorescence. These two lectins stained BFU-E-derived colonies from A subjects in the early days of culture before the expression of glycophorin. The erythroid origin of these cells was ascertained by the coexpression of two other very early erythroid markers. In bone marrow, the ultrastructural immunogold method revealed that the entire erythroid lineage including proerythroblasts was labeled by HPA, whereas no staining was observed on granulomonocytic cells including myeloblasts. Platelets from A subjects were HPA-labeled and so were platelets from an O subject preincubated in A plasma. Megakaryocytes obtained in CFU-MK-derived colonies were weakly and heterogeneously labeled by the HPA lectin. Cultures from A1 and A2 subjects were the reflection of the genetic differences only when investigations were performed on mature erythroblasts. In contrast, the great majority of immature erythroblasts both from A2 and A1 subjects were equally labeled by both lectins; during further erythroid maturation, binding of both lectins markedly diminished only on A2 erythroblasts. When marrow erythroblasts were investigated at electron microscopic level, heterogeneity of labeling among all stages of maturation was clearly observed in A2 subjects, with staining stronger on immature than on mature erythroblasts. Therefore, the genetic differences between A1 and A2 subjects are revealed during terminal erythroid differentiation.

ABO Blood-Group System↗
PubMed1985

[Alder's anomaly in mucopolysaccharidosis type VI. Cytological, cytochemical and ultrastructural study].

A cytological study of the blood and bone marrow of a child with mucopolysaccharidosis with Alder's anomaly was analysed at the optical and ultrastructural level. Morphological abnormalities of the blood and bone marrow leucocytes are defined; cytochemical and cytoenzymological abnormalities are indicated, allowing a differential diagnosis with "toxic granulations". The ultrastructural patterns of the storage cells are described compared to descriptions in the literature and the question of their mastocytic or macrophagic filiation is discussed.

Bone Marrow↗
PubMed1984

Chemosensitivity of human melanoma xenografts in immunocompetent mice and its histological evaluation.

In the subrenal capsule assay, the immuno-competent mice used have a host immune response to the graft which may introduce a bias in the determination of tumour size. A study was therefore conducted to verify the quality of the correlation that could exist between "macroscopical" and "microscopical" evaluation. A histological study of 12 different tumours treated with cis-Pt, L-PAM, DTIC, vindesine, BCNU or TGU demonstrated that a cellular host immune response was observed in 11 out of the 12 control groups and was uneven in the treated groups. The "microscopical" and "macroscopical" evaluations of tumour-take were 100 and 95% respectively. Although there was a fair correlation between the "microscopic" and "macroscopic" parameters, tumour variations in absence of host reaction--which reflect pure chemosensitivity of the treated tissue--could be measured in 50% of the cases. It was possible to determine a base-line for rejection of the test results when the control group showed a decrease in mean tumour size exceeding 20% of its initial size on day 0. If the decrease is less than 20%, then the histological evaluation appears to be of considerable additional value.

Animals↗
PubMed1984

Production of the effector molecule thymidine by human lung alveolar macrophages.

Cultured human alveolar macrophages (HAM phi) were found to produce soluble factors which inhibit tritiated thymidine [( 3H]-TdR) incorporation into tumour cells in vitro. We present evidence that thymidine (TdR) can be detected in HAM phi culture supernatants by thin-layer chromatography. Moreover, TdR secretion by HAM phi is an active process. Using [6-14C]-orotic acid as an early precursor to TdR and [3H]-TMP as the phosphorylation product, we were able to show that cultured HAM phi transformed them into labelled TdR. The very efficient thin-layer chromatography of the labelled metabolites was backed up by high-pressure liquid chromatography of nucleotides. HAM phi produce TdR by de novo synthesis and dephosphorylation. This phenomenon is due to the lack of thymidine kinase in normal mature macrophages. Since TdR, in high concentrations, can inhibit DNA synthesis through the 'TdR blockade' phenomenon, it is suggested that TdR secretion by HAM phi is a mechanism of non-specific modulation of tumour cell growth but highly restricted to the immediate macrophage microenvironment in vivo. The effectiveness of the thymidine gradient may thus be quite narrow, but is worthy of interest.

Animals↗
PubMed1984

[Malignant lymphoma initially of the buttocks: possible role of repeated intramuscular injections].

The authors report the case of a patient who received intramuscular injections of bismuth and penicilline for three consecutive years. Twenty-five years later, a lymphoma of the right buttock developed. The tumor was treated with radiotherapy and remained localized for two years. It then diffused to lungs, maxilla and skin. The occurrence of a lymphoma in muscles is thought to be exceptionnal. It has been suggested that lymphomas may develop at the site of silicone injections or of protracted infections. Fibrosarcomas have been reported after intramuscular injections of iron. The observations may suggest that the muscular lymphoma observed in our patient may have been related to the injections of bismuth performed twenty-five years earlier.

Aged↗
PubMed1983

[Chronic lymphoid leukemia followed by acute monocytic leukemia].

A 62 year old patient with CLL treated by alkylating drugs for more than three years, underwent acute leukaemia (AL). The clinical particularities of the onset and course of this AL, the cytological, cytoenzymological and ultrastructural characteristics of the blasts are discussed in order to find a relation between the two hemopathies. A possible drug-induced etiology of this AL is proposed.

Antineoplastic Agents↗
PubMed1982

Comparison and evaluation of different methods for alpha-MSH labelling.

We have studied the behaviour of 125I-labelled alpha-MSH under different experimental conditions. Until now, the chloramine T method had been used by most investigators with variable results. We have tested three other labelling techniques based on 125I mild oxidation: (1) an enzymatic method with lactoperoxidase, (2) a sparingly soluble chloramine method (T.D.G.U.) and (3) modified chloramine T procedure, 'the iodine volatilization method'. Labelled hormone obtained after each kind of iodination was assayed for immunoreactivity. In addition, time course degradation was measured by classical RIA incubation procedures. Charcoal-dextran was used to separate bound and free antigen. We have found chloramine T-iodinated alpha-MSH to be significantly more damaged than preparations obtained by other methods and to be less stable when stored at -18 degrees C. No differences were found between the differently labelled 125I-labelled alpha-MSH fresh preparations in binding to surface receptors of human melanoma cell lines in culture.

Animals↗