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Biomedical subjects

J Louis

Publications and source records attributed to J Louis.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Importance of progress achieved in fundamental biomedical sciences, especially in immunology, for the design of new vaccines].

The identification of the type of immune response which leads to the elimination of a pathogen by infected hosts is an important step in the design of a new vaccine. The progress made during recent years in basic immunology and molecular biology offers rational means by which to select the type of immune response elicited by a vaccine. In this brief communication the applicability of discoveries in basic immunology to the design of new vaccines is discussed.

Allergy and Immunology↗
PubMed1996

Methods for simultaneous interphase in situ hybridization and nuclear antigen immunocytochemistry in T47-D cells.

Procedures that combine immunocytochemistry (ICC) and in situ hybridization (ISH) techniques are now used to investigate phenotype/genotype relationships in the same cells. In this report we describe three rapid procedures for simultaneous detection of a nuclear antigen, progesterone receptors (PR), and the centromeric region of chromosome 11 (to which the human PR gene has been assigned) in T47-D cells. Proteins were stained by precipitates of horseradish peroxidase-diaminobenzidine (PO-DAB, brown color), alkaline phosphatase-Fast Red (APase-Fast Red, red color) or alkaline phosphatase-nitroblue tetrazolium-X-phosphate (APase-NBT-X-Phosphate, blue color) respectively. To obtain a suitable contrast for the two labels, we detected DNA on PO-DAB and APase-NBT-X-phosphate-immunostained cells with interphasic fluorescent in situ hybridization (FISH). By contrast, we combined the APase-Fast Red ICC with an immunocytochemical ISH using alkaline phosphatase-NBT-X-phosphate detection. Only the procedure combining APase-NBT-X-phosphate ICC and FISH ensures optimal visualization of both the PR content and the number of chromosome 11. This method easily provides simultaneous localization of DNA and protein targets in the same cells and should be applicable to many other situations.

Antigens, Nuclear↗
PubMed1995

Postinfectious purpura fulminans caused by an autoantibody directed against protein S.

OBJECTIVE: To determine the mechanism responsible for idiopathic purpura fulminans, we investigated the procoagulant and anticoagulant pathways in five consecutive patients, four after varicella, and the fifth after a nonspecific infection. METHODS: Procoagulant and anticoagulant factors, including protein C, protein S, and antithrombin III, were measured by quantitative or functional assays. Anti-protein S autoantibodies were identified by dot blotting and Western blotting, and quantified serially by enzyme-linked immunosorbent assay. Clinical and laboratory data were collated retrospectively. RESULTS: In each case the disease began 7 to 10 days after the onset of the precipitating infection, with rapidly progressive purpura leading to extensive areas of skin necrosis. The illness was complicated by impaired perfusion of limbs or digits (two patients), peripheral gangrene resulting in an above-knee amputation (one patient), and major organ dysfunction caused by thromboembolic phenomena involving the lungs (two patients), the heart (one patient), or the kidneys (one patient). Protein S levels were virtually undetectable at the time of admission and failed to respond to infusions of fresh frozen plasma, despite correction of other procoagulant and anticoagulant factors. All five children had anti-protein S IgM and IgG autoantibodies, which persisted for less than 3 months after admission. Decline in the anti-protein S IgG antibody concentration was associated with normalization of the plasma protein S levels. CONCLUSIONS: Autoimmune protein S deficiency may be a common mechanism causing postinfectious idiopathic purpura fulminans. Recognition of the pathophysiologic mechanism may provide a rational basis for treatment. Immediate heparinization, infusions of fresh frozen plasma, and, in cases complicated by major vessel thrombosis, the use of tissue-type plasminogen activator may limit thromboembolic complications.

Acute Disease↗
PubMed1995

Infection of human and murine macrophages with Leishmania major is associated with early parasite heat shock protein synthesis but fails to induce a host cell stress response.

Heat shock/stress proteins (HSP) represent the most conserved proteins expressed in prokaryotes and eukaryotes. These constitutive and inducible proteins function as molecular chaperones and are part of virulence factors. They participate in self/non-self discrimination and may protect phagocytes from the toxic effects of the reactive oxygen species generated by these cells during bacterial phagocytosis and infection. In this study, we investigated the early stress response of host cells [either human alveolar macrophages (AM) or murine peritoneal macrophages (PM)] during infection by an obligate intracellular parasite (Leishmania major), which lives within phagolysosomes. Immunoblotting with specific antibodies demonstrated that L. major had no effect on host stress protein synthesis, but synthesized high levels of its own stress proteins within AM and PM. The lack of induction of a host cell stress response may relate to the failure of L. major to activate the respiratory burst in these cells, whereas the upshift of L. major HSP within macrophages is part of an adaptive response of the parasite to the host.

Animals↗
PubMed1995

Progesterone receptor heterogeneity in MCF-7 cell subclones is related to clonal origin and kinetics data.

Heterogeneity of progesterone receptor (PR) expression in MCF-7 cells is generally attributed to the coexistence of several sublines, each possessing different stages of differentiation. One hypothesis is that the variation of PR distribution relates to the genotype cell heritage and cell cycle phases. The aim of this study was to demonstrate the implication of cell subclones in PR heterogeneity. MCF-7 cell line subclones were obtained initially by the limit dilution method on microscopic slides. On these slides PR was assessed by immunofluorescence. 20 of the subclones were PR-negative, 10 were positive with varying degrees of PR expression. As these cell populations arose from a single cell, they can be considered as monoclonal. These results show that PR heterogeneity (positive vs. negative clones) is based on a clonal origin and could be genotypically explained. In a second experiment four PR-positive MCF-7 cell subclones were maintained in continuous culture and studied. On each one a triple fluorescent staining (PR, Ki-67 antigen and DNA) was performed and the reactions were quantified by videofluoro microscopy. These results demonstrated that a relation between cell PR content and cell cycle stages exists in these four subclones. Cells in G0 express only little PR; PR level increases during the S phase to reach a maximum in the G2 phase; after mitosis PR level decreases with cell division and degradation may occur in G1: PR level reaches a minimum in late G1 and in the early S phase. The doubling times of the different MCF-7 subclones shows that those that are rapidly cycling were preferentially PR-positive, whereas slowly cycling MCF-7 subclones were PR-negative. We conclude that in MCF-7 cells some subclones are able or not able to synthesize PR; PR content is directly dependent on cell cycle phase and population doubling time.

Breast Neoplasms↗
PubMed1994

Mouse mammary tumor virus superantigens and murine autoimmune gastritis.

BACKGROUND/AIMS: Neonatal thymectomy induces autoimmune gastritis in BALB/c (minor lymphocyte-stimulating antigen [Mls]-1b) mice, whereas DBA/2 (Mls-1a) mice are resistant. Resistance has been linked to the Mls-1a locus, which encodes a retroviral superantigen, and to superantigen reactive T cells that express V beta 6+ T-cell receptors. V beta 6+ T cells are known to be deleted in mice expressing Mls-1a superantigens. METHODS: Neonatal thymectomized BALB/c and Mls-1a congenic BALB.D2.Mls-1a mice were analyzed to examine directly the role of Mls-1a self-superantigens and V beta 6+ T cells in autoimmune gastritis. RESULTS: Autoimmune gastritis was detected in thymectomized BALB.D2.Mls-1a mice with high incidence. Autoantibodies to the gastric H+,K(+)-adenosine triphosphatase were present independent of the Mls phenotype in sera of gastritic mice. Severe gastritis had already appeared 1 month after thymectomy in BALB.D2.Mls-1a mice. V beta 6+ T cells were deleted in the stomach lymph nodes of 1-month-old gastritic BALB.D2.Mls-1a mice but could be detected by immunocytochemistry in the stomach lesions. CONCLUSIONS: Endogenous Mls-1a self-superantigens and Mls-1a reactive V beta 6+ T cells are not involved in resistance to autoimmune gastritis in BALB.D2 mice.

Animals↗
PubMed1994

Narcolepsy in children.

The clinical and polygraphic characteristics of narcolepsy in children were established on the analysis of 97 reported cases in children (including 12 personal cases). In idiopathic narcolepsies (77 cases) narcoleptic attacks occurred in 97% of the cases, cataplexy in 80.5%, hypnagogic hallucination in 39% and sleep paralysis in 29%; 13% of the children had the tetrad; dyssomnia was a prominent feature. Polygraphic data showed no significant differences between adults and children. In symptomatic narcolepsies (20 cases): cataplexy was the prominent feature occurring in 95% of the cases, 26% of the children had status cataplecticus; in these narcoleptic-cataplectic syndromes there was often an absence of polygraphic evidence of narcolepsy. Symptomatic narcolepsy should be suspected in cases where narcolepsy is detected in preteenage children, where cataplectic attacks are abnormally frequent, where there is an absence of polygraphic evidence of classical narcolepsy (although this criterion may not apply in the case of younger children) or where human leukocyte antigen typing for DR2 is negative. An association with a Niemann-Pick disease type C was found in 12 out of the 20 symptomatic cases, this association merits further study.

Catalepsy↗
PubMed1994

The value of DNA image cytometry for the cytological diagnosis of well-differentiated breast carcinomas and benign lesions.

Cytological evaluation of breast diseases can lead to false diagnosis if benign lesions show epithelial atypia or if carcinomas are orthoplasic and well differentiated. In order to determine the potential usefulness of image cytometry for discrimination between benign and malignant breast lesions, we studied 120 Feulgen-stained imprints, half from benign lesions with epithelial atypia and half from well-differentiated carcinomas and determined values of parameters expressing DNA content, morphometry and chromatin texture. Twenty-five out of the 60 carcinoma imprints were found to be DNA-aneuploid and could thus be easily distinguished from benign imprints, as, in our and other authors' experiences, aneuploidy very rarely occurs in benign breast lesions. When the remaining 35 carcinoma imprints were compared with 38 benign lesion imprints, randomly selected from the 60 cases studied, only four cases were misclassified after a linear discriminant analysis; the most discriminant parameters were those expressing the heterogeneity of DNA content and the chromatin texture. Thus, in cases where cytological diagnosis is difficult, image analysis of Feulgen-stained imprints may be a very useful tool for correctly discriminating benign from malignant cases.

Aneuploidy↗
PubMed1993

Characterization of host CD4+ T lymphocytes in mice neonatally tolerized to alloantigens.

BALB/c mice injected at birth with semi-allogeneic F1 spleen cells become tolerant to alloantigens as shown by their CTL unresponsiveness to the corresponding alloantigen and the persistence of donor F1 cells into the BALB/c host. Moreover, these mice develop a transient systemic lupus erythematosis-like autoimmune syndrome characterized by splenomegaly, glomerulonephritis, thrombocytopenia and abnormal serological findings, such as several autoantibodies and IgG1 hypergammaglobulinemia. Recent studies done in our laboratory have shown that donor F1 B cells persisting in the host are responsible for the production of autoantibodies and must be activated in vivo by the host CD4+ T lymphocytes in a MHC class II-restricted fashion. In the present work, we have focused our attention on the ability of splenic CD4+ T cells recovered at different periods from BALB/c mice injected at birth with (CBA/Ca x BALB.Ighb) F1 spleen cells to interact with and activate F1 semi-allogeneic spleen cells in vitro. We show that (i) only CD4+ T cells from 2- and 3-week-old tolerant BALB/c mice preferentially produce IL-4 and IL-5 in response to a F1 semi-allogeneic in vitro stimulation, (ii) CD4+ T cells purified from 3-week-old tolerant BALB/c mice are able to induce in vitro IgG and IgM production by F1 B cells. Taken together, these results strongly suggest that host CD4+ T cells, belonging to the TH2 subset progressively lose their reactivity towards the F1 semi-allogeneic persistent B cells, reaching a state of unresponsiveness that correlates with the disappearance of serum autoantibodies and autoimmune pathology.

Animals↗
PubMed1993

Self-monitoring of blood glucose and insulin dose alteration in type 1 diabetes mellitus.

The purpose of this study was to evaluate the relationship between proper use of self-monitoring of blood glucose (SMBG) including knowledge and application of specific algorithms and metabolic control in a group of randomly selected insulin-dependent diabetic patients. We studied 80 patients responding to the following criteria: intensive conventional insulin therapy and SMBG for at least 6 months using a reflectance meter, and previous 5-day hospital education period. The practical knowledge of the guidelines was evaluated by a questionnaire simulating 8 metabolic situations. A computer analysis of the SMBG data for the 3 months preceding the study allowed us to evaluate patient compliance with SMBG (number of blood glucose determinations) and patients' application of the guidelines (percentage of insulin doses modified according to the guidelines). Fifty-nine patients (79%) were compliant with SMBG and had better metabolic control than the non-compliers (HbA1c: 6.7 +/- 1.1% vs. 7.5 +/- 1.9, P < 0.05). Twenty-eight out of the 59 compliant subjects had good knowledge of the guidelines but without patent improvement of glycemic control. Seventeen of these 28 correctly used the algorithms to modify insulin dosage; their HbA1c levels were lower than those of the 11 patients who did not use the algorithms (6.1 +/- 0.9 vs. 7.1 +/- 0.9%, P < 0.05). The percentage of insulin dose modification consistent with the guidelines and the level of HbA1c was negatively correlated in the good-knowledge group. The conclusion is that good metabolic control is linked not only with the degree of knowledge but also with the application of this knowledge.

Adolescent↗
PubMed1993

Leishmania major infection in BALB/c mice: protection or exacerbation by treatment with different doses of BCG.

The effect of live bacillus Calmette-Guérin (BCG), administered intraperitoneally to BALB/c mice, upon the development of lesions induced by subcutaneous infection with Leishmania major was examined. Lesions in mice given 10(7) BCG colony-forming units (CFU) 9 days before challenge with L. major were less severe and contained significantly fewer parasites than those of similarly infected control mice not given BCG. This effect of treatment with high doses of BCG upon the development of leishmanial lesions was observed using L. major promastigotes and amastigotes, whether or not 10(6) live BCG was included in the parasite inoculum. Lesions in mice given 5 x 10(4) BCG CFU 14 days before infection with L. major contained significantly fewer parasites than those of control mice not given BCG. Mice treated with low doses of BCG and infected with an L. major inoculum also comprising BCG exhibited larger lesions that contained more parasites. Interestingly, compared to naive mice infected with L. major, infection of naive mice with L. major mixed with live BCG consistently led to the development of more severe lesions that contained higher numbers of parasites. No correlation was found between the effect of BCG on the development of lesions induced by L. major and the amounts of IFN gamma, IL5 and TNF produced after in vitro antigenic challenge of either draining lymph node or spleen cells, the antigenic challenge being either live BCG or live L. major.

Animals↗
PubMed1993

[Usefulness of cytoprognostic classification combined with histoprognostic classification in breast cancer].

Histopathological grading according to Scarff Bloom Richardson can provide powerful prognostic information. However one criticism of this system is that 60% of patients cluster in grade 2 with no clear separation of good versus bad prognosis. In an effort to solve this problem we propose to add cytological grading performed on fine needle aspirates or imprints. Indeed histological grade 2 (H2) group can be subdivided into 2 groups according to cytological grading: cytological grade 2 (C2) and grade 3 (C3). Analysis of cytometrical and proliferative features shows that H2 C3 tumors are closer from H3 C3 than from H2 C2 tumors. So, using morphological evaluation, we propose to classify breast carcinoma into 2 groups: 1 group associating histological grade 1 tumors and histological grade 2, cytological grade 2 tumors; group 2, associating histological grade 3 tumors and histological grade 2, cytological grade 3 tumors.

Breast Neoplasms↗
PubMed1993

DNA image cytometry of bladder tumours: comparison of washings and tumour imprints from 61 patients.

Cellular DNA cytometry is commonly used to assess the prognosis of bladder tumours. Measurements are made mainly on voided urine or irrigation fluids by flow or image cytometry. In order to determine whether this material is really representative of the bladder tumour, we compared DNA assessments of bladder washings and tumour imprints from the same patients using image cytometry on Feulgen-stained preparations. DNA aneuploidy was found in 41.0% of the washings, 42.6% of the imprints and 49.2% of the patients if both samples were considered. If DNA histograms are classified into three groups (diploid, diploid+aneuploid, aneuploid), a 70% concordance rate is obtained between washings and imprints. In 15% of the cases, an aneuploid population was found in both samples, but in different proportions. In the latter 15%, an aneuploid population was found in one sample but not in the other; this discrepancy, which is probably due to poor tumour exfoliation or to tumour heterogeneity, is of clinical significance since it indicates the importance of making DNA assessments on both washings and cells directly obtained from the tumour.

Adult↗
PubMed1992

Ontogenesis of nocturnal organization of sleep spindles: a longitudinal study during the first 6 months of life.

Ontogenesis of sleep spindles was studied on overnight longitudinal recordings in 12 full-term infants at 1.5-3-4.5 and 6 months of life. Six parameters (density, duration, frequency, amplitude, asymmetry and asynchrony) were analyzed during both slow wave sleep (SII and delta) and during 5 periods of the night. Results show a significant increase of most parameters between 1.5 and 3 months of age. All spindle patterns developed quite rapidly during the first 3 months of infancy, possibly reflecting developmental changes in thalamo-cortical structures and maturation of the physiological system that produces spindles. The density of 12-14 Hz spindle frequency was higher in stage II when compared to stage delta, as in adults. Our data confirm previous reports on spindle ontogenesis and give a more complete aspect of this ontogenesis in relation to sleep development. Three months of age appeared to be a turning point in maturational processes and might reflect changes in central nervous system activity and behavior which take place during that period. Sleep spindle evolution seems to be an accurate reflection of the slow wave sleep (SWS) development, and our results are discussed in terms of the developmental aspect of SWS production and characterization of sleep stages in young infants. Concordance between quantitative aspects and nocturnal organization leads us to consider that the individualization of slow wave sleep (SWS) in infants occurs from 4.5 months of life.

Aging↗
PubMed1992

Leishmania major: differential regulation of the surface metalloprotease in amastigote and promastigote stages.

During its life cycle, the protozoan parasite Leishmania major alternates from an intracellular amastigote form in the mammalian host to a flagellated promastigote form in the insect vector. The expression of the surface metalloprotease (PSP) during differentiation in vitro was investigated by Western and Northern blots, by immunoprecipitation of cells metabolically labeled with [35S]methionine or labeled at the surface with radioactive iodine, and by quantification of the proteolytic activity in substrate-containing polyacrylamide gels. We report that the surface metalloprotease is down-regulated at both the mRNA and the protein level in amastigotes, where it represents less than 1% of the equivalent proteolytic activity detected in promastigotes. A significant amount of mRNA is detected 4 hr after the onset of differentiation. The expression of the protease begins at that time and reaches steady state 8 hr later. The synthesis of PSP precedes the complete morphological differentiation to the promastigote stage and the appearance of the lipophosphoglycan, another major promastigote surface component. In contrast to PSP, a family of mercaptoethanol-activated proteases present in the amastigote exists only at a reduced level in the promastigote. The confinement of the surface metalloprotease to the insect stage of the parasite suggests that it has no physiological function in the parasitism maintenance of mammalian host macrophages.

Animals↗
PubMed1991

Establishment of resistance to Leishmania major infection in susceptible BALB/c mice requires parasite-specific CD8+ T cells.

Although CD4+ T cells are generally accepted to be responsible for the determination of resistance to infection in experimental murine cutaneous leishmaniasis, a contribution of CD8+ lymphocytes to immunity can be demonstrated under certain well-defined conditions. Normally highly susceptible BALB/c mice can be rendered resistant to infection with Leishmania major promastigotes by a single injection of monoclonal anti-CD4 antibodies at the beginning of infection. Mice treated in such a way can heal their primary cutaneous lesions and acquire immunity to subsequent challenge infection. Both the resolution of the primary infection and the induced state of immunity to reinfection in these mice is shown to be dependent upon the anti-leishmanial effector functions of CD8+ T cells. Furthermore, in contrast to control infected BALB/c mice, which are unable to mount a delayed-type hypersensitivity (DTH) response to viable parasites, mice cured as a result of treatment with anti-CD4 antibodies in vivo exhibit a strong DTH response, which can be significantly reduced by injection of either anti-CD4 or anti-CD8 monoclonal antibodies prior to antigenic challenge with viable promastigotes. Moreover, increased numbers of specific CD8+ T cells, able to transfer Leishmania-specific DTH responses, were found in lymphoid organs of BALB/c mice rendered resistant to infection by immunointervention with anti-CD4 monoclonal antibodies at the beginning of infection. Neutralization in vivo of interleukin 4 during the course of infection in BALB/c mice also enables these otherwise susceptible mice to resolve their cutaneous lesions and to decrease the parasite burden in infected tissues. CD8+ T cells are required for both of these beneficial effects. Taken together, these results indicate that in the immune BALB/c mouse, as in the normally resistant CBA mouse, CD8+ lymphocytes are involved in the elimination of L. major and in the establishment and maintenance of immunity against infection with this parasite.

Animals↗
PubMed1991

Image cytometry of progesterone receptor expression during the cell cycle in the MCF-7 cell line.

Progesterone receptors (PR) appear to be distributed in a heterogeneous way in mammary tumor cells. The study presented here was designed to examine if heterogeneity of PR expression is cell-cycle dependent. Immunofluorescence techniques were used to label PR on the MCF-7 human breast cancer cell line and image cytometry was used to analyze the PR expression during G0 (Ki-67 antigen-negative cells), G1, S, and G2/M cell-cycle phases. A second PR, BrdU, and DNA analysis was performed to study PR expression in the S-phase (BrdU-positive cells). Our results show that PR synthesis occurs preferentially during the G0-G1 transition and that PR levels are constant during the G1-G2 transition. The PR expression appears to be cell-cycle related and may therefore explain the heterogeneity of PR expression. However, the possibility that PR heterogeneity may be linked to the existence of PR-negative subclones cannot be ruled out.

Breast Neoplasms↗