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Biomedical subjects

G Le Roux

Publications and source records attributed to G Le Roux.

At least 19 recordsLinked to original sources
PubMed2002

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.

Allium↗
PubMed2000

Human CDK10 gene isoforms.

The CDK10/PISSLRE gene has been shown to encode two different CDK-like putative kinases. The function(s) of the gene products are unknown, although a role at the G2/M transition has been suggested. We characterised two novel cDNAs. CDK10 mRNA quantity was not found to be correlated with cell proliferation status in HeLa or WI38 cell cultures or in human tissues. Relative levels of the four CDK10 isoforms were studied by RT-PCR, of which three were principally expressed. The two initially cloned isoforms predominated in human tissues, except in brain and muscle. Relative isoform levels did not vary during the cell cycle in culture, except when cells entered into the cell cycle. Finally, the predominant isoforms were shown to have different translation initiation sites and to have different subcellular distribution, due to an alternatively spliced nuclear localisation signal.

Amino Acid Sequence↗
PubMed2000

Successful treatment of thymoma-associated pure red cell aplasia with intravenous immunoglobulins.

Repeated cycles of intravenous immunoglobulins (IVIG) have been reported to be successful in a few patients with idiopathic pure red cell aplasia (PRCA) or associated with another pathology. The efficacy of this treatment for PRCA with thymoma has not been reported previously. We describe here the case of a 75-yr-old man who presented with PRCA associated with a benign thymoma. After failure of thymectomy, corticosteroids and octreotide, a complete durable remission was obtained after a single 5-d cycle of IVIG.

Adrenal Cortex Hormones↗
PubMed1999

[Evaluation of erythrocyte concentrate prescription in a university hospital center].

This prospective study, based on declaratory data, evaluates the appropriateness of red blood cell transfusion prescriptions in a university hospital. Local recommendations written after data collection and the analysis of prescriptions using a blinded method limited the bias related to the declaratory data. The results show that the rate of unjustified prescriptions is 4.2% (95% CI: 2.2%; 6.2%). This rate is statistically (P = 0.032) lower in the department of surgery (1.3%) than in the department of medicine (5.7%). This rate tends to decrease according to the experience of the prescriber (P = 0.06) and varies significantly according to the hemoglobin levels (P = 0.03). The logistic regression, integrating these three parameters, confirms that only the hemoglobin level is significantly related (P < 0.003) to the appropriateness of RBC transfusions. This study also highlights problems not linked to prescriptions, and the hospital created a quality assurance program as a result.

Anemia↗
PubMed1999

Accelerated telomere shortening and telomerase activation in Fanconi's anaemia.

Fanconi's anaemia (FA) is an autosomal recessive disorder characterized by progressive bone marrow failure that often evolves towards acute leukaemia. FA also belongs to a group of chromosome instability diseases. Because telomeres are directly involved in chromosomal stability and in cell proliferation capacity, we examined telomere metabolism in peripheral blood mononuclear cells (PBMC). Telomere length was significantly shorter in 54 FA patient samples, compared to 51 controls (P<0.0001). In addition, mean telomere terminal restriction fragment lengths (TRF) in nine heterozygous patient samples did not differ from those of controls. In 14 samples from FA patients with severe aplastic anaemia (SFA), telomere length was significantly shorter than in 22 samples of age-matched FA patients with moderate haematological abnormalities (NSFA) (P<0.001). However, no correlation was found between TRF length and the presence of bone marrow clonal abnormalities in 16 additional, separately analysed, patient samples. Sequential measurement of TRF in six FA patients showed an accelerated rate of telomere shortening. Accordingly, telomere shortening rate was inversely correlated with clinical status. Telomerase, the enzyme that counteracts telomere shortening, was 4.8-fold more active in 25 FA patients than in 15 age-matched healthy controls. A model for the FA disease process is proposed.

Adolescent↗
PubMed1999

67Ga scintigraphy in B-cell non-Hodgkin's lymphoma: correlation of 67Ga uptake with histology and transferrin receptor expression.

UNLABELLED: 67Ga scintigraphy is routinely used in the management of non-Hodgkin's lymphomas (NHLs), but the heterogeneity of 67Ga uptake in the different NHL histological subtypes has not been clearly explained. The transferrin receptors (TfR/CD71) play an important role in the mechanisms of 67Ga uptake by tumor cells. However, the relationship between the 67Ga uptake in NHL and the TfR/CD71 expression in lymphomatous cells remains to be defined. The aim of this study was to determine the intensity of 67Ga uptake in different histological subtypes of B-cell NHL (B-NHL) and to compare this uptake with the expression of TfR/CD71 on lymphomatous cells. METHODS: 67Ga scintigraphy of 47 patients having histologically proven lymphomas was investigated. 67Ga uptake was semiquantitatively evaluated in regions of interest and was reported as 67Ga uptake index (GaUI). In all cases, biopsies were reviewed for classification of NHL. The expression of TfR/CD71 was determined on frozen sections and was semiquantitatively evaluated. The relationships between GaUI, histology and TfR/CD71 were investigated. RESULTS: The values of GaUI were significantly related to the different histological subtypes analyzed (P = 0.0007) and to the presence of a large cells component, thus demonstrating that 67Ga uptake rose with the grade of lymphoma. Moreover, the values of GaUI and TfR/CD71 were closely related in the tested cases (P = 0.0059). CONCLUSION: There were three factors influencing 67Ga uptake in NHL: histology, TfR/CD71 expression and the presence of a large cells component. This justifies the usefulness of 67Ga scintigraphy in staging the TfR/CD71-positive lymphomas.

Adolescent↗
PubMed1997

PML/RAR alpha rearrangement in acute promyelocytic leukaemia with t(1;17) elucidated using fluorescence in situ hybridization.

Acute promyelocytic leukaemia (APL) is characterized by t(15;17)(q22;q21) which results in the formation of two chimaeric genes, PML/RAR alpha and RAR alpha/PML, thought to play a role in leukaemogenesis. We report a case of a patient with APL apparently lacking the t(15;17) but with t(1;17) translocation identified by fluorescence in situ hybridization (FISH). Chromosome 15 seemed intact but PML/RAR alpha fusion transcript was detected by molecular analysis. The patient achieved complete remission with all-trans retinoic acid treatment associated with chemotherapy. This case illustrates the usefulness of combined cytogenetics, FISH and molecular biology in cases with no evident t(15;17) to predict response to treatment.

Chromosomes, Human, Pair 1↗
PubMed1994

D-dimer levels in the cerebrospinal fluid: a marker of central nervous system involvement in neoplastic disease.

D-dimer assay was performed on 145 cerebrospinal fluid (CSF) samples from patients with or without neoplastic diseases. Levels of D-dimers were significantly higher in carcinoma and lymphoid malignancies with clinical or biological evidence of central nervous system (CNS) involvement than in diseases without such complications. In one patient, serial determinations of D-dimers were well correlated with the appearance and disappearance of CNS involvement. Although this test is not specific for neoplastic affections, our data suggest that the measurement of D-dimers in CSF may be useful in the diagnosis of CNS involvement of neoplastic cells and in monitoring intrathecal therapy in patients with lymphoma, acute lymphoblastic leukaemia or carcinoma. In this study, the D-dimer assay was also positive in some non neoplastic diseases, but failed to differentiate subarachnoid haemorrhage from traumatic lumbar puncture.

Adult↗
PubMed1992

Haemostasis at high altitude.

Haemostasis has been studied by several authors during exposure to altitude hypoxia. On acute induction to hypoxia, platelet count, platelet aggregability and bleeding time are normal; an increase of thromboxane released from platelets and of prostacyclin, released from endothelial cells is observed; coagulation factors are unchanged except of F. VIII which is increased; modified antithrombin III (ATm) are normal; fibrinopeptide A is increased in subjects with pulmonary edema and fibrinolytic activity after venous occlusion is normal. In chronic hypoxia, during a stay at 6542 m (Mt. Sajama), we found in 7 subjects an important increase in D. Dimer (p < 0.001) that seems to correspond to an activation of coagulation and a decrease of F. VIII R. Cof/F. VIII R. Ag ratio which suggests an endothelial cell damage.

Altitude Sickness↗
PubMed1991

[Platelet hyperaggregation induced by low molecular weight heparin in adult respiratory distress syndrome].

A case is reported of a 68-year-old woman admitted to the intensive care unit with an adult respiratory distress syndrome (ARDS) due to accidental poisoning with anhydrous phthalic acid. She was given prophylactic low molecular weight heparin (Fraxiparine). During the period of intensive care (mechanical ventilation with positive end-expiratory pressure), the patient experienced a stroke from which she recovered only partially. During pleurectomy for persistent pneumothorax, a lung biopsy was carried out. It confirmed the diagnosis of ARDS and recognized multiple pulmonary arterial thrombi. Because of these two thrombotic phenomena, a coagulation defect was searched for. Platelet aggregation tests were all positive with heparin and two low molecular weight fractions. The patient recovered remarkably once she was no longer given Fraxiparine, being extubated nine days afterwards. Six months after discharge, the patient's platelets still aggregated with heparin. The possible mechanism was a heparin-platelet-endothelium complex. It is noteworthy that, in this case, no thrombocytopaenia was found. It may have been countered by thrombocytosis, induced by cellular factors released during ARDS.

Aged↗
PubMed1989

Activated partial thromboplastin time performed on capillary blood.

Activated partial thromboplastin time is one of the most frequently used assay in haemostasis investigation, but sampling of venous blood is often difficult in newborns (as well as some adult patients). We analysed a method described by Zondag et al [9] performed on capillary blood samples. We studied normal adults and newborns, patients with liver diseases, and those receiving therapy with vitamin K antagonists and heparin. Capillary assay was correlated with venous blood in normal subjects, in patients with liver diseases and during therapy by vitamin K antagonists. However results both in newborns and adults during heparin therapy were not accurate.

Adolescent↗
PubMed1988

[Venous thrombosis in the brain and upper limbs associated with thrombopenia induced by pentosan polysulfate].

The authors report a new observation of thrombocytopenia thrombosis syndrome induced by a synthetic heparinoid: pentosan polysulfate and presenting with dural sinus thrombosis. This syndrome was aggravated by standard heparin therapy. Thrombocytopenia was due to an immunological mechanism and preceded thrombotic phenomena, so emphasizing the need for platelet counts in all patients considered for heparin or synthetic heparinoid therapy.

Adult↗