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Biomedical subjects

M Michel

Publications and source records attributed to M Michel.

At least 37 records · Page 2Linked to original sources
PubMed2003

[Recurrent Kikuchi's disease in a patient with discoid lupus].

INTRODUCTION: Histiocytic necrotizing lymphadenitis, also called Kikuchi-Fujimoto's disease (KD), usually occurs in young women and is characterized by localized lymphadenitis (mostly cervical) usually associated with fever. Diagnosis relies on histopathological and immunohistochemical analysis of involved lymph node. KD is considered to be the clinical expression of an inadequate immunological reaction, resulting in a self-limited hyperstimulation of the lymphoid tissue, trigerred by an antigenic infectious stimulation. The clinical course is usually benign with a spontaneous remission of symptoms. Recurrence is very rarely observed. KD may be associated with systemic lupus erythematosus, whereas the association with chronic discoid lupus has only been rarely reported. EXEGESIS: We report a case of KD recurrence, 9 years after the initial diagnosis, in a young eurasian woman, with a chronic discoid lupus erythematosus. CONCLUSION: KD is a benign disease with a spontaneously good outcome. Recurrence may rarely occur many years after the initial diagnosis but needs a new histopathological confirmation. Systemic or even cutaneous lupus erythematosus may be associated with KD. Although unfrequent, this association suggests that both diseases could share a common pathogenesis.

Adult↗
PubMed2003

Multiple sclerosis-associated retrovirus particles cause T lymphocyte-dependent death with brain hemorrhage in humanized SCID mice model.

A retroviral element (multiple sclerosis-associated retrovirus, MSRV) defining a family of genetically inherited endogenous retroviruses (human endogenous retrovirus type W, HERV-W) has been characterized in cell cultures from patients with multiple sclerosis. Recently, MSRV retroviral particles or the envelope recombinant protein were shown to display superantigen activity in vitro, but no animal model has yet been set up for studying the pathogenicity of this retrovirus. In the present study, the pathogenicity of different sources of MSRV retroviral particles has been evaluated in a hybrid animal model: severe combined immunodeficiency (SCID) mice grafted with human lymphocytes and injected intraperitoneally with MSRV virion or mock controls. MSRV-injected mice presented with acute neurological symptoms and died within 5 to 10 days post injection. Necropsy revealed disseminated and major brain hemorrhages, whereas control animals did not show abnormalities (P <.001). In ill animals, reverse transcriptase-polymerase chain reaction (RT-PCR) analyses showed circulating MSRV RNA in serum, whereas overexpression of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma was evidenced in spleen RNA. Neuropathological examination confirmed that hemorrhages occurred prior to death in multifocal areas of brain parenchyma and meninges. Further series addressed the question of immune-mediated pathogenicity, by inoculating virion to SCID mice grafted with total and T lymphocyte-depleted cells in parallel: dramatic and statistically significant reduction in the number of affected mice was observed in T-depleted series (P <.001). This in vivo study suggests that MSRV retroviral particles from MS cultures have potent immunopathogenic properties mediated by T cells compatible with the previously reported superantigen activity in vitro, which appear to be mediated by an overexpression of proinflammatory cytokines.

Animals↗
PubMed2002

[Characteristics of autoimmune hemolytic anemia in adults: retrospective analysis of 83 cases].

PURPOSE: To describe the main characteristics and outcome of adult's acquired immune hemolytic anemias (AIHA). To analyse the relevance of the complementary tests performed for the search of an underlying disease. METHODS: Retrospective (1980-2000) monocentric study. INCLUSION CRITERIA: age above 16, AIHA defined by an hemoglobin level below 12 g/dl in men and 11 g/dl in women, with hemolysis and/or a positive direct Coombs test and/or the presence of cold agglutinins (threshold 1/500) and/or in the absence of any other cause. RESULTS: Eighty three patients included (56 women and 27 men), with a mean age of 56 years (+/- 22) at AIHA onset including: 72 patients (87%) with warm antibody AIHA and 11 (13%) with cold agglutinin disease. The mean follow-up was 48 months (median 22 months). Among the 72 patients with warm antibody AIHA, the specificity of autoantibodies was: IgG + complement (43%), IgG (32%) or complement alone (25%); cold agglutinins (titre from 1/60 to 1/512) were detected in 15 (20%) of the patients. Antinuclear antibodies were detected (threshold: 1/80) in 33% of the cases. Hypogammaglobulinemia on serum protein electrophoresis (SPE) was significantively associated with the presence of an underlying non-Hogkin lymphoma (NHL). The CT-scan of the the chest and abdomen which was performed in 50% of the patients, showed abnormalities other than a spleen enlargement in 25% of the cases. The medullar biopsy (MB) was abnormal in 7 of 26 cases (27%) but lead by itself to the diagnosis of NHL in a single case. Thrirty seven (51%) of warm antibody AIHA cases were finally considered to be "secondary" to an underlying disease namely: NHLs (n = 14), Hogkin's disease (n = 1) connective tissue disease (CTD) (n = 14), drug-induced AIHA (n = 3), miscellaneous (n = 5). In 6 out of 14 cases (43%) of NHL's associated AIHA, the onset of AIHA precedes the NHL from 22 to 66 months. The response rates to different therapeutic regimens did not significatively differ when "secondary" and "idiopathic" AIHA were compared. Overall, 13 patients (15.6%) died mainly from infectious complications (n = 5) or an underlying NHL (n = 5). CONCLUSIONS: In more than half of the cases AIHA are associated with an underlying disease and AIHA may precede the onset of a NHL for a long period. In the absence of a clinically apparent underlying disorder, testing for the presence of antinuclear antibodies, a SPE and a CT-scan must be systematic. Conversely, if no abnormalities are found, the relevance of a systematic MB at AIHA onset seems very low.

Adult↗
PubMed2002

Enteral nutrition in French institutionalized patients: a multicentric study.

BACKGROUND: No previous studies have demonstrated either a nutritional improvement, or a survival benefit from tube placement in an institutionalized population. OBJECTIVE: The aim of this study was to determine current indications for tube feeding in French geriatric centers and to evaluate clinical outcome and mortality rates in these frail very old patients. DESIGN: Between November 1, 2000 and April 31, 2001, we prospectively recruited all hospitalized or institutionalized patients who received enteral nutrition (EN) in 7 Departments of Geriatric Medicine in France. Nutritional parameters and main indications of EN were recorded at the time of feeding tube placement. Pneumonia and mortality rates were observed over a period of one year. RESULTS: 57 patients of mean age 81.6 7.8 yrs underwent placement of a feeding tube. Mean BMI value was 20.7 4.8 and mean serum albumin level 26.1 6.1 g/L. The most frequent indications for EN included stoke (39%) and other neurologic diseases (42%). Fourteen patients (25%) died within 30 days, and 27 (47%) died over the 12-month follow-up period. During the first month, an episode of pneumonia was noted in 26 cases (55%). CONCLUSION: The similarity between rates of early mortality reported in our study and those reported in several previous studies involving younger, ambulatory subjects is surprising because we might expect poorer survival in our frail elderly patients. We can think that French geriatric teams have changed their attitudes toward EN in recent years, EN being less frequently used in patients with advanced dementia and at the end-stage of life.

Journal Article↗
PubMed2001

Multiple sclerosis retrovirus particles and recombinant envelope trigger an abnormal immune response in vitro, by inducing polyclonal Vbeta16 T-lymphocyte activation.

A retroviral element (MSRV) defining a family of genetically inherited endogenous retroviruses (HERV-W) has recently been characterized in cell cultures from patients with multiple sclerosis (MS). To address the possible relationship with MS, direct detection of circulating virion RNA was proposed but revealed technically difficult to perform in standardized conditions, in the face of multiple endogenous HERV-W copies. A parallel approach has evaluated MSRV potential pathogenicity in relation to characteristic features of multiple sclerosis, in particular, T-lymphocyte-mediated immunopathology. We report here that MSRV particles induce T-lymphocyte response with a bias in the Vbeta16 chain usage in surface receptor, whatever the HLA DR of the donor. A recombinant MSRV envelope-but not core-protein reproduced similar nonconventional activation. Molecular analysis of Vbeta CDR3 showed that Vbeta16 expansions are polyclonal. Our results thus provide evidence that MSRV envelope protein can trigger an abnormal immune response with similar characteristics to that of superantigens.

Antigens, Viral↗
PubMed2001

[Hemolytic anemia disclosing Wilson's disease. Report of 2 cases].

INTRODUCTION: The liver and central nervous system are the usual targets of Wilson's disease, an inherited disorder of copper metabolism. Severe hemolytic anemia is an unusual complication of Wilson's disease. EXEGESIS: We report two cases of Wilson's disease revealed by acute intravascular hemolytic anemia associated with liver failure. Blood smear analysis showed stippled red cells in one case; hemolytic anemia improved within a few weeks in both patients but progressive liver failure required transplantation in the other. Hemolysis probably results from the toxic effect of free serum copper on erythrocyte membrane. CONCLUSION: Diagnosis of Wilson's disease must be considered in case of acute hemolytic anemia associated with liver failure in young adults.

Adolescent↗
PubMed2001

The role of rheology in hemapheresis.

Rheological therapy attempts to favorably influence the blood flow mechanics for the treatment of diseases, mainly of the microcirculation but also of the macrocirculation. Hemapheresis, originally used only for the elimination of an excess of cellular or plasmatic components, was shown to also influence the hemorheology favorably. As extracorporeal therapy affects the rheology much more than conventional hemorheotherapy, not only cellular or plasmatic hyperviscosity syndromes but also many more diseases associated with organ perfusion problems due to diseases of the micro- and macrocirculation, especially in the elderly, were and are increasingly considered to be indicated. Technical progress led away from plasma exchange as an unspecific and unselective procedure to plasma differential separation using precipitation. adsorption, and filtration. With our recent development, we demonstrated that rheohemapheresis is the most advanced technical procedure. The mechanism of action can well be related to a synergetic consideration of rheology. However. one has to keep in mind that the elimination of blood components such as lipids, immunoglobulins, and endothelial factors may well contribute to the explanation and understanding of the positive clinical effects observed. These speculative aspects need further investigation.

Adult↗
PubMed2001

Bone marrow involvement in lymphomas with hemophagocytic syndrome at presentation: a clinicopathologic study of 11 patients in a Western institution.

Hemophagocytic syndrome (HPS) is a clinicopathologic syndrome that can reveal a non-Hodgkin's lymphoma. The pathologic features of lymphoma associated with HPS remain ill defined. We studied 11 lymphomas associated with HPS on initial bone marrow biopsies, consecutively diagnosed during a 6-year period in a Western institution. There were seven diffuse large B-cell lymphomas (DLBCLs), three T-cell lymphomas (one peripheral T-cell lymphoma unspecified, two hepatosplenic gammadelta T-cell lymphomas [HS gammadeltaTLs]), and one aggressive NK-cell lymphoma/leukemia (NKL). These lymphomas shared common clinicopathologic features with a systemic presentation, a poor outcome (nine patients died within 2 years), and a mild interstitial lymphoid infiltrate of the bone marrow at presentation in nine patients. This equivocal lymphoma infiltrate was blending with normal hematopoietic cells, and CD20 and CD3 immunolabelings were essential for its detection. A high number of reactive T (CD3+) cells, most often with a predominant cytotoxic (CD8+ TiA1+) phenotype, was present in all DLBCLs. By in situ hybridization, Epstein-Barr virus was detected in neoplastic cells of three cases (one DLBCL, one HS gammadeltaTL, and one NKL), which also showed serum viral DNA. Polymerase chain reaction studies disclosed HHV6 DNA sequences in tumor tissues of two DLBCLs, whereas HHV8 DNA was not detected. Because tumor mass indicative of lymphoma was not striking in most patients, bone marrow biopsy appears to be of great value for the diagnosis of an HPS-associated lymphoma, which may be, in Western patients, of B- as well as T- or NK-cell type. Immunostaining for CD3 and CD20 is essential to identify the common subtle lymphoma involvement. Together with a better understanding of the pathogenic processes, an early diagnosis may improve the prognosis of HPS-associated lymphoma.

Adolescent↗
PubMed2001

Familial lupus erythematosus. Clinical and immunologic features of 125 multiplex families.

Evidence for a genetic susceptibility to systemic lupus erythematosus (SLE) in humans is based on the high concordance rate observed in identical twins and on the relatively high incidence of familial cases. Although recent genetic studies have lead to significant advances in the identification of new susceptibility genes in SLE, no large clinico-pathologic study of familial SLE has been reported to date. In the present study, we describe the main clinical and immunologic features of 125 lupus multiplex families including at least 2 cases of SLE and/or discoid lupus erythematosus (DLE), recruited through a French national survey starting in July 1997. Medical records of all affected members were reviewed by the same investigator, all available family members were interviewed using the same standardized procedure, and blood was drawn for autoantibodies typing. Clinical and immunologic features of 90 probands from multiplex SLE families were compared with those of 100 sporadic SLE patients sharing the same French Caucasian origin. The 125 lupus multiplex families included 282 affected members (2.3 patients per family); of the 125 families, 96 were of French Caucasian origin. One hundred multiplex families included 2 affected relatives, while 25 included 3 or more affected individuals. The relationship between affected members was sibs (45%), parent-offspring (31%), and second-degree (24%). An autosomal dominant mode of inheritance was strongly suggested in 1 extended pedigree with 6 clinically affected members, and a recessive pattern was suspected in 5 other families. No obvious mode of inheritance could be suspected in most of the remainder. Among French Caucasians, sex ratio, mean age at onset, and clinical and biologic SLE-related manifestations were not significantly different in multiplex compared with sporadic SLE cases. The analysis of these 125 multiplex families suggests a genetic heterogeneity that should be considered for ongoing genomic screening.

Age of Onset↗
PubMed2001

Anaesthetic management of a child with type VIIc Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome type VIIc is characterized by altered tensile strength of connective tissue. Several severe complications exist but skin fragility is the origin of perioperative morbidity during routine procedures. We describe the difficulties encountered during the anaesthetic management of a child suffering from the disease, and suggest special care advices to avoid any skin injury.

Anesthesia, Inhalation↗
PubMed2000

Ancistroealaines A and B, two new bioactive naphthylisoquinolines, and related naphthoic acids from Ancistrocladus ealaensis.

Two new 5,8'-coupled naphthylisoquinoline alkaloids, ancistroealaines A (1) and B (2), eleutherolic acid (3), and two naphthoic acids, ancistronaphthoic acid A (4) and B (5), have been isolated from Ancistrocladus ealaensis. Their structures were determined by spectroscopic, chemical, and chiroptical methods. Ancistroealaine A (1) exhibited activity against Leishmania donovani and Trypanosoma cruzi in vitro.

Animals↗
PubMed2000

Anthraquinones and betaenone derivatives from the sponge-associated fungus Microsphaeropsis species: novel inhibitors of protein kinases.

An undescribed fungus of the genus Microsphaeropsis, isolated from the Mediterranean sponge Aplysina aerophoba, produces two new betaenone derivatives (1, 2) and three new 1,3,6, 8-tetrahydroxyanthraquinone congeners (5-7). The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data and by CD spectroscopy. This is the first report wherein the (1)H and (13)C NMR data of the betaenone congeners are fully and unambiguously assigned on the basis of two-dimensional NMR spectroscopy. Furthermore, we describe the first elucidation of the absolute configuration of 1-(2'-anthraquinonyl)ethanols such as 5 and 6, by quantum chemical calculation of their circular dichroism (CD) and comparison with experimentally measured spectra. Moreover, it was shown that compounds 1, 5, 6, and 7 are inhibitors of PKC-epsilon, CDK4, and EGF receptor tyrosine kinases.

Animals↗
PubMed2000

Polychromatic phototest as a prognostic tool for polymorphic light eruption.

BACKGROUND: Diagnosis of polymorphic light eruption (PLE) is based on the patient's history, the morphology of the lesions and the results of phototesting. Skin lesions of PLE can be provoked by repetitive UVB or UVA irradiation. However, about 20% of the patients with PLE have negative phototests. As 24% of the patients with PLE go into remission, it was of interest to search for a link between the results of the phototests and the evolution of the photodermatosis. METHODS: Forty patients with PLE were recruited and repetitive phototests were performed. To ensure a good reproducibility of the phototests, one to three phototests were performed on each patient at different stages of the disease including the period when the PLE had gone into remission. RESULTS: Except for one patient, there was a good reproducibility of the repetitive polychromatic phototests: in each patient, the tests remained positive or negative throughout the disease. After long-term follow-up, two different subgroups were identified: 30 patients with active PLE and 10 patients in remission. There were no clinical differences between these two groups apart from the age of onset and the clinical lesions of the PLE. PLE began at an earlier age in the patients in remission and presented mainly with a plaque-type eruption. In total, 52.5% of the patients had at least one positive polychromatic phototest. Phototests were positive only in patients with active disease. All the patients in remission had negative phototests. CONCLUSIONS: Repetitive phototests could be a prognostic marker for PLE. Two subtypes of PLE were identified on the basis of phototest results: the benign form of PLE with negative phototests, which tends to go into remission, and the more severe and more chronic PLE, with positive phototests.

Adult↗
PubMed2000

Photoscratch testing in systemic drug-induced photosensitivity.

Because of numerous false-negative results, photopatch testing is seldom relevant in systemic drug-induced photosensitivity. These false-negative photopatch test results can be attributed to the inability of the drug to penetrate into the epidermis. In order to enhance the penetration of the tested drug into the epidermis, some authors proposed to breach the cutaneous barrier. We performed a prospective study comparing photopatch and photoscratch testing. Fifteen patients presenting with a systemic drug-induced photosensitivity, proved by a favourable outcome after discontinuing the drug, were tested. For each drug, photopatch and photoscratch tests were performed. Two-thirds of the patients had negative photopatch and photoscratch tests with the suspected drugs. Photopatch and photoscratch tests were positive and relevant, respectively, in 3 and 4 patients. Photoscratch tests induced more false-positive results due to irritation confirmed on control subjects. Our study proves that photoscratch tests do not change the sensitivity of phototesting.

Adult↗
PubMed1999

Poly(ADP-ribose) polymerase alleles in French Caucasians are associated neither with lupus nor with primary antiphospholipid syndrome. GRAID Research Group. Group for Research on Auto-Immune Disorders.

OBJECTIVE: To investigate the putative involvement of poly(ADP-ribose) polymerase (PARP) alleles in systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome (APS). METHODS: This study of French Caucasians included 171 unrelated patients with SLE, 88 unrelated patients with primary APS, and 193 ethnically matched healthy controls. The SLE group comprised 89 patients with sporadic SLE and 82 patients with familial SLE. Patients' and controls' DNA were genotyped for the various alleles of a polymorphic CA dinucleotide repeat located within the promoter region of PARP. RESULTS: No statistically significant difference was observed for the distribution of PARP alleles between the healthy control group and each patient group or the pooled SLE patient group. CONCLUSION: The study findings strongly suggest that these alleles do not influence susceptibility to SLE or primary APS in French Caucasians.

Alleles↗