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Biomedical subjects

A Moreau

Publications and source records attributed to A Moreau.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver tissue.

BACKGROUND/AIMS: The objective of the present study was to analyze the expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver slices, which preserve the normal microenvironment of liver cells. METHODS: Rat liver slices were maintained in culture for 15 min to 24 h and examined for ICAM-1 expression by immunohistochemistry and Western blotting in basal conditions and after stimulation with 1000 IU/ml interferon-gamma (IFNgamma), 1000 IU/ml tumor necrosis factor-alpha (TNF alpha) and 50 microg/ml endotoxin. Immunohistochemical results were evaluated using a semiquantitative scoring system. RESULTS: In uncultured slices, ICAM-1 was not detected on hepatocytes. In unstimulated liver slices maintained in organotypic culture, ICAM-1 was induced at the surface of scattered hepatocytes (score at 15 min, 0.33+/-0.47 and at 24 h, 1.17+/-0.69). After 4 h of stimulation, a significant increase in ICAM-1 expression by hepatocytes and adjacent sinusoidal cells, but not by intra-hepatic biliary epithelial cells, was observed for IFNgamma (score: 2.35+/-0.47) and endotoxin (score: 2.67+/-0.47), but not with TNF alpha (score: 0.66+/-0.47). After 24 h of stimulation, a further increase in the extent of ICAM-1 expression by hepatocytes was observed for IFNgamma (score: 3.67+/-0.47) and endotoxin (score: 4.0+/-0.0), and a significant overexpression of ICAM-1 by hepatocytes was detectable after treatment with TNF alpha (score: 3.67+/-0.47). CONCLUSIONS: In rat liver organotypic cultures, TNF alpha, IFNgamma and endotoxin induce the expression of ICAM-1 in hepatocytes and adjacent sinusoidal endothelial cells, but not in portal tracts.

Animals↗
PubMed1998

Fas-mediated apoptosis of hepatic cells.

While the fas/fas ligand system has been extensively investigated in immuno-competent cells, the place of this system in the physiology and pathophysiology of liver cells remains to be clarified. Although we know that fas is present at the surface of hepatocytes--the main hepatic cells--the role of this membranous protein in physiological conditions is not yet elucidated. However it is the localization of fas on the plasma membrane of hepatocytes which explains why these cells are mainly destroyed by apoptosis--in a picture resembling human fulminant hepatitis--when mice are administered with anti-fas antibodies or fas ligand. It is also established that fas is surexpressed in some human chronic liver diseases, such as those induced by hepatitis B or C virus, a situation which could explain the pathogenesis of some liver lesions occurring during these diseases, such as the apoptosis of hepatocytes in piecemeal necrosis. Finally the fact that caspases, a group of cysteine proteases activated in fas-induced apoptosis, opens the way to inhibition of these enzymes by synthetic peptides and to prevent and treat hepatocyte apoptosis. Demonstration of this possibility has been recently reported in animals presenting fulminant hepatitis induced by anti-fas antibodies.

Animals↗
PubMed1998

Peripheral blood stem cell transplantation as front-line therapy in patients aged 61 to 65 years: a pilot study.

The aim of the present trial was to investigate the feasibility of high-dose therapy followed by autologous peripheral blood stem cell transplantation (PBSCT) as a component of front-line treatment in patients with disseminated intermediate- and high-grade non-Hodgkin's lymphoma (NHL) aged 61-65 years. From October 1993 to June 1996, 14 consecutive patients entered this single-center prospective pilot trial. Patients were five males and nine females, median age 63 (range 61-65). The first-line treatment consisted of three courses of CHOP therapy. Patients achieving either a partial response (PR) or a complete response (CR) after initial therapy were eligible for PBSCT, while those with refractory or progressive disease were not autografted but included in the feasibility study in an intent-to-treat analysis. Of the 14 patients, 11 achieved either a CR (one) or a PR (10) after three courses of CHOP while the three patients with no response were not autografted and subsequently died of progressive disease. PBSC collection was feasible in responding patients after G-CSF priming (10 microg/kg/day for 6 days). Conditioning therapy was the BEAM protocol. All patients engrafted after PBSCT. The median time to granulocyte (>0.5 x 10(9)/l) and platelet recovery (>25 x 10(9)/l) was 12 (range 9-18) and 13 days (range 7-22), respectively. No toxic deaths VOD or IP were observed. Four of the 11 responding patients relapsed 2, 7, 9 and 12 months after PBSCT, respectively, and all died from progressive disease. Overall, 7/14 patients are alive and free from disease, 16-43 months after initial diagnosis (median 28). The actuarial overall survival is 45.7 %, and the actuarial event-free survival is 50% at 3.5 years. This study shows the feasibility of high-dose therapy and PBSCT in patients with intermediate- or high-grade disseminated NHL aged 61-65 years. Such patients should not be excluded from trials evaluating the role of ASCT as part of initial treatment for disseminated and histologically aggressive NHL.

Aged↗
PubMed1998

Long-term shake suspension and membrane vesicles of medullary thick ascending limb.

Cultured medullary thick ascending limb (MTAL) cells may lack some of the main carriers of fresh MTAL cells, such as apical Na+-K+(NH4+)-2Cl- cotransporter (BSC-1) and Na+/H+ exchanger (NHE-3). We have developed a technique to maintain rat MTALs several hours in suspension and in a good state of viability. Medullary thick ascending limbs were suspended in a 1:1 mixture of Ham's nutrient mixture F-12 and Dulbecco's modified Eagle's essential medium (HDMEM) supplemented with 25 mM HCO3- and gassed with 95% O2/5% CO2; the resulting mixture was placed in a rotary shaking water bath at 37 degrees C for 16 hours. As seen by electron microscopy, MTALs from the HDMEM-suspension retained a virtually normal tubular organization. Na+-K+(NH4+)-2Cl- cotransport activity and NHE consistent with both apical NHE-3 and basolateral NHE-1 activities were underscored both in intact cells by intracellular pH measurements and in a membrane fraction enriched in apical and basolateral membranes by 22Na+ uptake experiments. These results demonstrate that freshly harvested MTALs can be maintained in a well differentiated state for at least 16 hours; this preparation should make long-term in vitro studies of MTAL transport regulations possible.

Animals↗
PubMed1998

Primary central nervous system lymphomas in 72 immunocompetent patients: pathologic findings and clinical correlations. Groupe Ouest Est d'étude des Leucénies et Autres Maladies du Sang (GOELAMS)

We reviewed 72 primary central nervous system lymphomas occurring in immunocompetent patients. The cases were reviewed for clinical data, histology, immunophenotype, bcl-2 and p53 expression, and Epstein-Barr virus association. Follow-up was available for 40 patients included in the Groupe Ouest Est d'étude des Leucénies et Autres Maladies du Sang (GOELAMS) lymphomes cérébraux primitifs (LCP 88) trial. Each diagnosis, requiring a consensus among at least 3 pathologists, was performed according to the recent Revised European-American Lymphoma classification and equivalents in the updated Kiel classification. Tumors were predominantly classified as diffuse large B-cell lymphomas. There were 3 T-cell lymphomas and 1 Hodgkin lymphoma. The proteins bcl-2 and p53 were expressed in 35% and 16% of the tested cases, respectively. Epstein-Barr virus was not found by in situ hybridization except in the case classfied as a cerebral localization of Hodgkin disease. No significant association was found between subtypes, bcl-2 or p53 expression, and patient survival. From the standpoint of their biologic characteristics, primary central nervous system lymphomas are very similar to systemic diffuse large B-cell lymphomas. In contrast to AIDS-related primary central nervous system lymphomas, primary central nervous system lymphomas are rarely associated with Epstein-Barr virus and in immunocompetent patients they express bcl-2 at a relatively low rate.

Adult↗
PubMed1998

The alpha chain of the nascent polypeptide-associated complex functions as a transcriptional coactivator.

We report the characterization of clone 1.9.2, a gene expressed in mineralizing osteoblasts. Remarkably, clone 1.9.2 is the murine homolog of the alpha chain of the nascent polypeptide-associated complex (alpha-NAC). Based on sequence similarities between alpha-NAC/1.9.2 and transcriptional regulatory proteins and the fact that the heterodimerization partner of alpha-NAC was identified as the transcription factor BTF3b (B. Wiedmann, H. Sakai, T. A. Davis, and M. Wiedmann, Nature 370:434-440, 1994), we investigated a putative role for alpha-NAC/ 1.9.2 in transcriptional control. The alpha-NAC/1.9.2 protein potentiated by 10-fold the activity of the chimeric activator GAL4/VP-16 in vivo. The potentiation was shown to be mediated at the level of gene transcription, because alpha-NAC/1.9.2 increased GAL4/VP-16-mediated mRNA synthesis without affecting the half-life of the GAL4/VP-16 fusion protein. Moreover, the interaction of alpha-NAC/1.9.2 with a transcriptionally defective mutant of GAL4/VP-16 was severely compromised. Specific protein-protein interactions between alpha-NAC/1.9.2 and GAL4/VP-16 were demonstrated by gel retardation, affinity chromatography, and protein blotting assays, while interactions with TATA box-binding protein (TBP) were detected by immunoprecipitation, affinity chromatography, and protein blotting assays. Based on these interactions that define the coactivator class of proteins, we conclude that the alapha-NAC/1.9.2 gene product functions as a transcriptional coactivator.

Animals↗
PubMed1998

Bone-specific expression of the alpha chain of the nascent polypeptide-associated complex, a coactivator potentiating c-Jun-mediated transcription.

The alpha chain of the nascent polypeptide-associated complex (alpha-NAC) coactivator was shown to potentiate the activity of the homodimeric c-Jun activator, while transcription mediated by the c-Fos/c-Jun heterodimer was unaffected. The use of deletion mutants in pull-down assays revealed that alpha-NAC interacted with amino acids 1 to 89 of the c-Jun protein and that the coactivator could interact with both the unphosphorylated and the serine 73-phosphorylated form of c-Jun. N-terminal-deleted c-Jun protein failed to interact with alpha-NAC in mammalian two-hybrid assays, while mutant c-Jun proteins lacking the leucine zipper or the basic domain retained interaction with alpha-NAC in vivo. Kinetics studies with purified c-Jun homodimer and recombinant alpha-NAC proteins allowed determination of the mechanism of coactivation by alpha-NAC: the coactivator stabilized the AP-1 complex formed by the c-Jun homodimer on its DNA recognition sequence through an eightfold reduction in the dissociation constant (kd) of the complex. This effect of alpha-NAC was specific, because alpha-NAC could not stabilize the interactions of JunB or Sp1 with their cognate binding sites. Interestingly, the expression of alpha-NAC was first detected at 14.5 to 15 days postconception, concomitantly with the onset of ossification during embryogenesis. The alpha-NAC protein was specifically expressed in differentiated osteoblasts at the centers of ossification. Thus, the alpha-NAC gene product exhibits the properties of a developmentally regulated, bone-specific transcriptional coactivator.

Animals↗
PubMed1998

Systemic vasculitis in a patient with small-cell neuroendocrine bronchial cancer.

A 75-yr-old male hospitalized for vascular purpura with joint pain had a medical history of polymyalgia rheumatica. A generalized oedematous syndrome occurred and the patient also presented with haemoptysis and complained of transient paraesthesia of the hands and feet. Renal biopsy showed lesions of focal segmental proliferative glomerulonephritis associated with a few cellular crescents. Lung biopsy showed small-cell neuroendocrine carcinoma. After the first course of chemotherapy signs of vasculitis disappeared. Small-cell neuroendocrine carcinomas, which represent 25% of all lung cancers, have numerous paraneoplastic (especially neurological) extrapulmonary manifestations. Disseminated vasculitis has never been described with this type of cancer, whereas nonsmall-cell carcinomas are associated essentially with cutaneous vasculitis or purpura rheumatica. In the case reported here, anticancer chemotherapy allowed vasculitic manifestations to be treated.

Aged↗
PubMed1998

Early intensive therapy with autologous stem cell transplantation in high-risk Hodgkin's disease: long-term follow-up in 35 cases.

Thirty-five adult patients with high-risk HD (HD) defined by (1) Ann Arbor stage IV or bulky nodal disease (tumor/thorax ratio > 0.45) and (2) no or partial response (PR) (< 75%) to the initial 3 courses of ABVD, received an early intensive therapy with autologous stem cell transplantation (ASCT). Thirty patients were considered as partial responders and 5 as refractory to initial chemotherapy. Conditioning regimen consisted of chemotherapy alone (CBV in 11 patients before 1993, BEAM in 13 patients since 1993) followed by adjuvant radiotherapy: 40 Gy) on the initial sites of bulky disease, or 12 Gy total body irradiation plus 120 mg/kg cyclophosphamide in 11 patients with disseminated extra-nodal disease. All 30 patients in PR at the time of ASCT experienced prolonged complete remission (CR). One patient died in CR from an acute myocardial infarction 48 months after ASCT. Four out of the 5 patients with refractory disease at the time of ASCT experienced rapid progression of HD leading to death in 3 cases. After 6 years of CR post-ASCT, the last refractory patient died of myelodysplastic syndrome diagnosed 2 years after intensive therapy. With a median follow-up for surviving patients of 51 months (range: 11-111), the cumulative probability of 8-year overall survival is 75.6% for the entire group of patients, 94.1% for the chemosensitive ones, and 0% for the primary refractory (P < .0001). The cumulative probability of 8-year event-free survival is 79.9% for the entire group of patients, 94.1% for the chemosensitive ones, and 0% for the primary refractory (P < .0001). We conclude that early intensive therapy with ASCT is feasible in patients with high-risk HD and induces a high cure rate in chemosensitive patients. In primary refractory patients, new therapeutic approaches are warranted.

Adolescent↗
PubMed1997

Effects of simvastatin, pentoxifylline and spironolactone on hepatic fibrosis and portal hypertension in rats with bile duct ligation.

AIMS/METHODS: Our aim was to study the antifibrotic and hemodynamic effects of simvastatin (SMV), pentoxifylline (PTX) and spironolactone (SPN), three drugs which may have antifibrotic and/or portal hypotensive properties, in a model of hepatic fibrosis and portal hypertension induced in rats by bile duct ligation. A blind study was performed in five groups of 53 Sprague-Dawley rats: sham, placebo (PL), SMV (2.5 mg x kg(-1) x J(-1)), PTX (50 mg x kg(-1) x J(-1)) and SPN (100 mg x kg(-1) x J(-1)). Drugs were administered by daily gavage over a 4-week period as soon as bile duct ligation was performed. At day 28, the following parameters were evaluated: area of hepatic fibrosis by image analysis after staining collagen with picrosirius and plasma concentrations of hyaluronate, splanchnic and systemic hemodynamics (radiolabeled microspheres). RESULTS: Portal venous pressure (PL: 15.5+/-1.5, SMV: 15.8+/-2.5, PTX: 15.9+/-1.8, SPN: 13.5+/-2.1 mmHg, p<0.05) and porto-systemic shunts (PL: 30+/-31, SMV: 18+/-27, PTX: 25+/-24, SPN: 5+/-4%, p<0.05) were significantly reduced in the SPN group; other hemodynamic parameters were not significantly altered. There was a significant correlation between portosystemic shunts and portal pressure (r(s)=0.47, p<0.01). The area of fibrosis was not significantly different among the four groups of bile duct ligated rats (PL: 8.7+/-3.9, SMV: 7.1+/-3.6, PTX: 7.8+/-2.7, SPN: 6.6+/-3.3%) but was higher than in sham rats (1.5+/-0.5%, p<0.001). Hyaluronate was significantly higher in bile duct ligated rats (from 374+/-162 to 420+/-131 microg/l, among the four groups) than in sham rats (52+/-16 microg/l, p<0.0001). CONCLUSIONS: In this model, none of the drugs prevented hepatic fibrosis. On the other hand, spironolactone decreased portal pressure and prevented porto-systemic shunts. Therefore, this drug may have beneficial effects in patients with early portal hypertension.

Animals↗
PubMed1997

Recurrence of immunoglobulin A nephropathy with immunoglobulin A antineutrophil cytoplasmic antibodies following renal transplantation.

We previously reported the presence of immunoglobulin A (IgA) antineutrophil cytoplasmic antibodies (ANCAs) in patients presenting IgA nephropathy (IgAN), particularly when associated with Henoch-Schonlein purpura. Most of the patients exhibited IgA ANCAs directed at an unknown 50-kd neutrophil protein but no IgG ANCAs. A subgroup of patients presented IgG as well as IgA ANCAs, suggesting an overlap syndrome between Henoch-Schonlein purpura and microscopic polyangiitis. We aimed at confirming the correlation of IgA ANCA titer with disease activity in a patient presenting IgAN relapse following kidney transplantation. The ANCAs were searched for by isotype- and antigen-specific enzyme-linked immunosorbent assay. Specificity was confirmed by antigen-specific enzyme-linked immunosorbent assay and Western blot analysis. At the onset of the disease in 1989, the patient presented with ANCAs of IgA and IgG class with specificity for myeloperoxidase and no rheumatoid factor. End-stage renal failure developed 1 year afterward. In 1991, he received a cadaveric renal allograft, and 9 months later developed acute nephrotic syndrome with rapidly progressive renal failure and recurrence of IgAN on the kidney transplant. An increase in IgA but not IgG ANCAs was found on clinical relapse after kidney transplantation. We conclude that rare patients may present an overlap syndrome between IgG ANCA-positive systemic vasculitis and IgAN, characterized by the presence of IgG and IgA anti-myeloperoxidase antibodies.

Aged↗
PubMed1997

[Acute respiratory distress due to fat embolism].

BACKGROUND: Acute respiratory distress occurring in a child without any past medical history can have different origins. Pulmonary edema can be lesional or hemodynamic in origin. Bronchoalveolar lavage often allows indication of the type of lesional oedema. CASE REPORT: A 13-year old child was hospitalized for acute respiratory distress 24 hours after knee surgery complicated by a fracture of the tibial metaphysis. There were no clinical manifestations of airway obstruction. Chest X-ray showed pulmonary parenchymous pathology. Pulmonary edema secondary to congestive heart failure was eliminated by doppler echocardiogram. The cause of lesional pulmonary edema was found with bronchoalveolar lavage that showed fat drops in the cytoplasm of many alveolar macrophages. CONCLUSION: Fat embolism syndrome may be confirmed by examination of bronchoalveolar lavage fluid.

Acute Disease↗
PubMed1997

Comparative genomic hybridization detects genomic abnormalities in 80% of follicular lymphomas.

Comparative genomic hybridization (CGH) was used to analyse 34 follicular lymphoma (FL) samples. 27 samples showed DNA sequence copy number changes of at least one genomic region (26 samples with at least one gain and nine with at least one loss). Some chromosomes or chromosomal regions were preferentially involved. The most frequently gained regions were chromosome 18q (29% of samples), chromosome X (21%), chromosome 7 (18%), chromosomes 2, 6p and 8q (12%). Two regions were preferentially lost: 6q (12%) and 17p (9%). All these gained and lost regions have been previously reported in cytogenetic studies, confirming the accuracy of CGH in detecting genetic abnormalities in FL. 21% of samples displayed normal profiles, probably reflecting the absence of unbalanced abnormality, which is also in agreement with the cytogenetic data. In conclusion, we showed that CGH is an accurate, reliable and rapid method and we propose the inclusion of CGH in the evaluation of FL at diagnosis.

Chromosome Aberrations↗
PubMed1997

Diterpenoids from germander, an herbal medicine, induce apoptosis in isolated rat hepatocytes.

BACKGROUND & AIMS: Germander was withdrawn from the market after its use for weight control caused an epidemic of hepatitis. Its toxicity was shown to be caused by diterpenoids and their cytochrome P4503A-mediated metabolic activation into electrophilic metabolites that deplete cellular thiols. The aim of the present study was to determine the mechanisms of cell death. METHODS: Isolated rat hepatocytes were incubated for 2 hours with germander diterpenoids (100 micrograms/mL). RESULTS: Diterpenoids decreased cell glutathione, increased cytosolic [Ca2+], activated Ca(2+)-dependent tissue transglutaminase forming a cross-linked protein scaffold, and caused internucleosomal DNA fragmentation and the ultrastructural features of apoptosis. Cell death was prevented by decreasing metabolic activation (with troleandomycin), preventing depletion of glutathione (with cystine), blocking activation of Ca(2+)-modulated enzymes (with calmidazolium), or inhibiting internucleosomal DNA fragmentation (with aurintricarboxylic acid). Apoptosis was increased and diterpenoids caused overexpression of p53 and interleukin 1 beta-converting enzyme in rats treated with dexamethasone (cytochrome P4503A inducer). Apoptosis was also increased by a diet deficient in sulfur amino acids. CONCLUSIONS: The germander furano diterpenoids cause apoptosis within 2 hours in isolated rat hepatocytes. Electrophilic metabolites may stimulate apoptosis by decreasing thiols, increasing [Ca2+], and activating Ca(2+)-dependent transglutaminase and endonucleases.

Amino Acids, Sulfur↗
PubMed1997

An improved digitonin-collagenase perfusion technique for the isolation of periportal and perivenous hepatocytes from a single rat liver: physiological implications for lobular heterogeneity.

Morphological and functional heterogeneity of hepatocytes according to their position in the liver lobule has been known for many years. The digitonin-collagenase perfusion technique is widely used to study hepatocyte heterogeneity and has yielded reliable data. However, with this procedure, periportal (PP) or perivenous (PV) hepatocytes are isolated from different livers, allowing only comparison between cell populations issued from two separate animals. To overcome this drawback, we have modified this technique by perfusing the two main rat liver lobes of a single animal in succession. The procedure involved alternate clamping of the median and the left lateral lobes, restricting digitonin infusion to one lobe via the portal vein, and to the other via the caudal vena cava. Lobe exclusion during digitonin perfusion, and zonal restriction of digitonin-induced damage, were monitored using macroscopic and histological controls. We compared our results with previous data on PP and PV hepatocytes issued from two different livers using the conventional digitonin-collagenase perfusion technique. First, we found that the cellular sensitivity to angiotensin II, a calcium-mobilizing agonist, was 60% to 80% higher in PV than in PP hepatocytes, whereas, previously, no difference had been recorded. Second, we found that albumin messenger RNAs (mRNAs) were 35% more abundant in PP than in PV hepatocytes, whereas, previously, larger differences had been reported. Our results show that PP and PV hepatocytes may be isolated from a single liver using an improved digitonin-collagenase perfusion technique. Furthermore, we suggest that zonal differences can be artificially masked or amplified when comparing PP and PV cell populations from two different livers, indicating that it is preferable to use a single liver for accurate zonal comparisons between hepatocytes.

Albumins↗