Search PubMed⌕ Search

Biomedical subjects

A Moreau

Publications and source records attributed to A Moreau.

At least 55 records · Page 3Linked to original sources
PubMed1999

Detection of translocation t(11;14)(q13;q32) in mantle cell lymphoma by fluorescence in situ hybridization.

To assess an unequivocal diagnosis of mantle cell lymphoma (MCL), we have developed a fluorescence in situ hybridization (FISH) assay, enabling the demonstration of t(11;14)(q13;q32) directly on pathological samples. We have first selected CCND1 and IGH probes encompassing the breakpoint regions on both chromosomes. Then, we have defined experimental conditions enabling us to obtain bright clear-cut signals in all of the samples, independently of the initial fixation conditions. We have analyzed single-cell suspensions from 26 formalin-fixed, paraffin-embedded MCL samples with this set of probes. In all cases, we have found a fusion signal (ie, a t(11;14)(q13;q32) translocation) in 14% to 99% of cells (median, 87%). So far, IGH-CCND1 fusions have been detected in all of the 51 MCL patients that we have analyzed by FISH (either on paraffin-embedded tumor samples or on peripheral blood samples). Regarding the low sensitivity of other techniques used to diagnose t(11;14)(q13;q32) (ie, 70% to 75% for cytogenetics and 50% to 60% for polymerase chain reaction), our FISH assay is by far the most sensitive technique. Moreover, because of the quality of the fluorescent signals and the rapidity of the experiment, this technique is widely applicable, even in routine cytogenetics or pathology laboratories. As MCL patients are usually refractory to standard therapy, an unambiguous diagnosis is needed to propose adapted therapeutic strategies, and this highly sensitive assay may be of great value for accurate diagnosis in difficult cases.

Adult↗
PubMed1999

An alcoholic binge causes massive degradation of hepatic mitochondrial DNA in mice.

BACKGROUND & AIMS: Ethanol causes oxidative stress in the hepatic mitochondria of experimental animals and mitochondrial DNA deletions in alcoholics. We postulated that ethanol intoxication may cause mitochondrial DNA strand breaks. METHODS: Effects of an intragastric dose of ethanol (5 g/kg) on hepatic mitochondrial DNA levels, structure, and synthesis were determined by slot blot hybridization, Southern blot hybridization, and in vivo [3H]thymidine incorporation, respectively. RESULTS: Two hours after ethanol administration, ethane exhalation (an index of lipid peroxidation) increased by 133%, although hepatic lipids were unchanged. Mitochondrial DNA was depleted by 51%. Its supercoiled form disappeared, whereas linearized forms increased. Long polymerase chain reaction evidenced lesions blocking polymerase progress on the mitochondrial genome. Mitochondrial transcripts decreased. Subsequently, [3H]thymidine incorporation into mitochondrial DNA increased, and mitochondrial DNA levels were restored. In contrast, nuclear DNA was not fragmented and its [3H]thymidine incorporation was unchanged. Liver ultrastructure only showed inconstant mitochondrial lesions. Ethanol-induced mitochondrial DNA depletion was prevented by 4-methylpyrazole, an inhibitor of ethanol metabolism, and attenuated by melatonin, an antioxidant. CONCLUSIONS: After an alcoholic binge, ethanol metabolism causes oxidative stress and hepatic mitochondrial DNA degradation in mice. DNA strand breaks may be involved in the development of mitochondrial DNA deletions in alcoholics.

Alcohol Drinking↗
PubMed1999

Catalytic activity of antibodies against factor VIII in patients with hemophilia A.

Hemophilia A is an X chromosome-linked recessive disorder resulting in defective or deficient factor VIII (FVIII) molecules, which, in its severe form, is a life-threatening and crippling hemorrhagic disease. Infusion of homologous FVIII to patients with severe hemophilia A results, in 25% of patients, in the emergence of alloantibodies against FVIII (inhibitors)( ref. 1) that inhibit FVIII procoagulant activity by steric hindrance of the interaction of FVIII either with stabilizing molecules, with molecules essential for its activity or with activating molecules. Here, we report on the proteolysis of FVIII by alloantibodies of two patients with severe hemophilia A, demonstrating a previously unknown mechanism by which FVIII inhibitors may prevent the pro-coagulant function of FVIII. The kinetic parameters of FVIII hydrolysis indicate a functional role for the catalytic immune response in the inactivation of FVIII in vivo. The characterization of alloantibodies against FVIII as site-specific proteases may provide new approaches to the treatment of FVIII inhibitors.

Antibodies, Catalytic↗
PubMed1999

Epstein-Barr virus-associated B cell lymphoproliferative disease after non-myeloablative allogeneic stem cell transplantation.

There is a growing interest in the evaluation of non-myeloablative conditioning therapy for allogeneic stem cell transplantation. Such regimens are expected to produce less toxicity while allowing both engraftment and a graft-versus-disease effect from the large number of donor-derived immunocompetent T lymphocytes given with the stem cells. Heavy immunosuppression used in recipients may have unexpected consequences. We describe the occurrence of a fatal Epstein-Barr virus-associated B cell lymphoproliferative disease (BLPD) early after such a non-myeloablated allogeneic peripheral blood stem cell transplant in a heavily pretreated patient.

Adult↗
PubMed1999

Interleukin 1 and interleukin 1beta converting enzyme (caspase 1) expression in the human colonic epithelial barrier. Caspase 1 downregulation in colon cancer.

BACKGROUND: Interleukin (IL) 1beta converting enzyme (now known as caspase 1) is able to process pro-IL-1beta into its active form and is involved in proapoptotic signalling. AIMS: To characterise IL-1 and caspase 1 expression in human colonic epithelial cells. METHODS: Intracellular IL-1 content (IL-1alpha and IL-1beta) was measured by ELISA in freshly isolated human normal colonocytes. Caspase 1 expression was determined both at the mRNA level using in situ hybridisation and reverse transcription polymerase chain reaction, and at the protein level by immunoblotting experiments using antibodies specific for the proform of caspase 1 and for its cleavage forms. RESULTS: Low amounts of IL-1beta were found in nearly all preparations (92%), and IL-1alpha was detected in only 45% of human colonocyte preparations. The normal colonic epithelium strongly expressed caspase 1, both at the mRNA level and at the protein level in its latent form. In contrast, caspase 1 was not expressed in colon cancer (primary colonic adenocarcinomas and cancer cell lines). CONCLUSIONS: The demonstration that the human colonic epithelial barrier is able to express caspase 1 and its substrate IL-1beta reinforces the concept that, under certain conditions, the epithelium could trigger an inflammatory reaction. In addition, the finding that caspase 1 was downregulated in colonic adenocarcinomas supports the concept that disrupted apoptosis pathways may be involved in tumour formation and/or may confer resistance to treatment.

Adult↗
PubMed1999

Hindlimb patterning and mandible development require the Ptx1 gene.

The restricted expression of the Ptx1 (Pitx1) gene in the posterior half of the lateral plate mesoderm has suggested that it may play a role in specification of posterior structures, in particular, specification of hindlimb identity. Ptx1 is also expressed in the most anterior ectoderm, the stomodeum, and in the first branchial arch. Ptx1 expression overlaps with that of Ptx2 in stomodeum and in posterior left lateral plate mesoderm. We now show that targeted inactivation of the mouse Ptx1 gene severely impairs hindlimb development: the ilium and knee cartilage are absent and the long bones are underdeveloped. Greater reduction of the right femur size in Ptx1 null mice suggests partial compensation by Ptx2 on the left side. The similarly sized tibia and fibula of mutant hindlimbs may be taken to resemble forelimb bones: however, the mutant limb buds appear to have retained their molecular identity as assessed by forelimb expression of Tbx5 and by hindlimb expression of Tbx4, even though Tbx4 expression is decreased in Ptx1 null mice. The hindlimb defects appear to be, at least partly, due to abnormal chondrogenesis. Since the most affected structures derive from the dorsal side of hindlimb buds, the data suggest that Ptx1 is responsible for patterning of these dorsal structures and that as such it may control development of hindlimb-specific features. Ptx1 inactivation also leads to loss of bones derived from the proximal part of the mandibular mesenchyme. The dual role of Ptx1 revealed by the gene knockout may reflect features of the mammalian jaw and hindlimbs that were acquired at a similar time during tetrapod evolution.

Animals↗
PubMed1999

[Physiopathology of tumor-induced osteolysis].

Osteolysis, the most common expression of bone tumor, can cause pain, pathological fracture, epidural spinal cord compression and hypercalcemia. Multinucleated osteoclast-like cells, the main agents in bone resorption, are numerous in benign giant cell tumor of bone and can be recruited and activated by various carcinoma cell lines in vitro in animal models. Polykarion macrophages are also able to resorb bone matrix in a favourable tumoral environment. Direct bone resorption by tumor cells has recently been described in vitro and in vivo in animals. The presence of diffusible substances such as hormones, cytokines and growth factors creates a favourable microenvironment for stimulation of osteoclast-like cells and polykarion macrophages functional ability to resorb bone matrix. These mediators act within a complex but still unelucidated network involving high cell production (tumor cells, normal and reactional stroma as well as hematopoietic cells) and many targets (tumor production (tumor cells, normal and reactional stroma as well as hematopoietic cells) and many targets (tumor cells, monocyte/macrophage lineage cells, and osteoclast-like cells). The presence in the same environment of all these stimulating factors for tumor cell growth and resorbing ability could explain the vicious circle of tumoral and osteolytic progression. A better understanding of the complex mechanism of tumor induced osteolysis is essential for improving the conventional surgical approach to this pathology.

Animals↗
PubMed1999

Multiple rheumatoid bursitis with migrating chylous cysts. Report of a case in a European woman and review of the literature.

We report a case of recurrent multiple bursitis (19 episodes at nine sites) requiring seven surgical procedures in a European women with a 38-year history of severe, nodular, destructive seropositive rheumatoid arthritis unresponsive to second-line drugs. The episodes of bursitis were not correlated with activity of the joint disease. Some cysts migrated over a considerable distance. At least two cysts contained chylous fluid. The histologic study of one cyst demonstrated a cholesterol crystal granuloma. Potential relationships linking cholesterol crystals, chylous cysts, and migrating multiple bursitis are discussed. The relevant literature is reviewed.

Aged↗
PubMed1998

Long-term bone response to particulate injectable ceramic.

Biphasic calcium phosphate particles (BCP), alone or combined with a cellulosic ether vehicle in an injectable composite material (COMP), were implanted in femurs of rabbits. The long-term follow-up (up to 78 weeks) indicated: (1) BCP and COMP induced a foreign-body inflammatory reaction but without fibrous encapsulation. Phagocytosis was mediated by mononucleated macrophages (MC) and giant multinucleated cells (GMNC). Phagocytosis was stronger with COMP and required the recruitment of GMNC while it primarily involved MC in the case of BCP. (2) There appeared to be no significant difference between the bone ingrowth in the defects packed with BCP (dBCP) and in those filled with COMP (dCOMP). Bone reconstruction mostly was achieved after 4 weeks in dBCP but took more time to reach the center of dCOMP. High bone remodeling was observed at the last evaluation times, especially in the case of COMP. (3) Degradation of the materials occurred mainly during the first 4 weeks and was more severe for COMP, which probably was related to the smaller granulometry of its mineral phase. Cell-mediated degradation went on for the 78 weeks and followed two processes: phagocytosis and/or extracellular dissolution of the calcium phosphate particles.

Animals↗
PubMed1998

A formiminotransferase cyclodeaminase isoform is localized to the Golgi complex and can mediate interaction of trans-Golgi network-derived vesicles with microtubules.

A protein of 60 kDa (p60) has been identified using a quantitative in vitro vesicle-microtubule binding assay. Purified p60 induces co-sedimentation with microtubules of trans-Golgi network-derived vesicles isolated from polarized, perforated Madin-Darby canine kidney cells. Sequencing of the cDNA coding for this protein revealed that it is the chicken homologue of formiminotransferase cyclodeaminase (FTCD), a liver-specific enzyme involved in the histidine degradation pathway. Purified p60 from chicken liver has formiminotransferase activity, confirming that it is FTCD or an isoform of this enzyme. Isoforms of FTCD were identified in chicken hepatoma and HeLa cells, and immunolocalize to the region of the Golgi complex and vesicular structures in its vicinity. Furthermore, 58K, a previously identified microtubule-binding Golgi protein from rat liver (Bloom, G. S., and Brashear, T. A. (1989) J. Biol. Chem. 264, 16083-16092), is identical to FTCD. Both proteins co-purify with microtubules and co-localize with membranes of the Golgi complex. The capacity of FTCD to bind both to microtubules and Golgi-derived membranes may suggest that this protein, or one of its isoforms, might have in addition to its enzymatic activity, a second physiological function in mediating interaction of Golgi-derived membranes with microtubules.

Amino Acid Sequence↗
PubMed1998

Long-term survival of hamster-to-rat cardiac xenografts in the absence of a Th2 shift.

BACKGROUND: In hamster-to-rat cardiac xenografts, long-term survival (LTS) is obtained in 60% of recipients if vascular rejection is overcome by cobra venom factor and cyclosporine (CsA). It has been suggested that this accommodation state could be due to the Th2 response. METHODS: We examined the infiltrate by using immunostaining and the accumulation of cytokine mRNA (interferon-gamma [IFN-gamma], interleukin [IL]-4, IL-10, IL-13, and transforming growth factor-betal [TGF-beta1]) by using competitive reverse transcriptase polymerase chain reaction, in hamster hearts grafted into LEW.1A rat. RESULTS: Hearts from untreated and treated (cobra venom factor and CsA) but rejecting recipients presented a rapid and severe vascular rejection. In contrast, hearts from long-surviving treated animals had subnormal cardiac muscle with a mild infiltrate, principally macrophages, which peaked on day 15. T lymphocytes were also maximal on day 15 (12% of the infiltrate). Rejected grafts from untreated recipients showed accumulation of IFN-gamma mRNA but low levels of IL-10, TGF-beta, and IL-13. In hearts rejected by treated recipients, IFN-gamma mRNA did not increase and TGF-beta mRNA was higher. In LTS, IL-10, TGF-beta, and IL-13 transcripts were up-regulated (P<0.001), while IFN-gamma mRNA decreased (P<0.001). In both groups, IL-4 expression remained at a nonsignificant level. CONCLUSIONS: The profile of cytokine mRNAs in LTS could result in part from CsA, known to up-regulate TGF-beta and to down-regulate IFN-gamma. Moreover, CsA does not inhibit IL-10 production by monocyte/macrophages, the major infiltrating cells (60%). Lastly, LTS is induced in the absence of IL-4, which suggests that the high IL-4 production could simply be correlated with LTS without being a condition for it.

Animals↗
PubMed1998

Evidence for a role of CLIP-170 in the establishment of metaphase chromosome alignment.

CLIPs (cytoplasmic linker proteins) are a class of proteins believed to mediate the initial, static interaction of organelles with microtubules. CLIP-170, the CLIP best characterized to date, is required for in vitro binding of endocytic transport vesicles to microtubules. We report here that CLIP-170 transiently associates with prometaphase chromosome kinetochores and codistributes with dynein and dynactin at kinetochores, but not polar regions, during mitosis. Like dynein and dynactin, a fraction of the total CLIP-170 pool can be detected on kinetochores of unattached chromosomes but not on those that have become aligned at the metaphase plate. The COOH-terminal domain of CLIP-170, when transiently overexpressed, localizes to kinetochores and causes endogenous full-length CLIP-170 to be lost from the kinetochores, resulting in a delay in prometaphase. Overexpression of the dynactin subunit, dynamitin, strongly reduces the amount of CLIP-170 at kinetochores suggesting that CLIP-170 targeting may involve the dynein/dynactin complex. Thus, CLIP-170 may be a linker for cargo in mitosis as well as interphase. However, dynein and dynactin staining at kinetochores are unaffected by this treatment and further overexpression studies indicate that neither CLIP-170 nor dynein and dynactin are required for the formation of kinetochore fibers. Nevertheless, these results strongly suggest that CLIP-170 contributes in some way to kinetochore function in vivo.

Animals↗
PubMed1998

Dynein and dynactin are localized to astral microtubules and at cortical sites in mitotic epithelial cells.

The mitotic spindle is often positioned in a characteristic location during development, for example to enable the proper segregation of developmental determinants [1,2]. When epithelial cells divide, the mitotic spindle is often positioned parallel to the plane of the epithelium, so that both daughter cells contribute to the epithelium [3]. The mechanisms by which mitotic spindles are positioned have not been characterized in great detail, but evidence is accumulating that in some systems the dynein-dynactin microtubule motor complex plays a role [4-6]. Dynein has yet not been localized to cortical sites where it could bind to microtubules and exert a force that might orient the mitotic spindle, however [7,8]. Here, we report that in mitotic polarized epithelial cells, the dynein-dynactin complex accumulates, from prometaphase onwards, along astral microtubules and at cortical spots, into which many of the astral microtubules dock. The spots are assembled at the lateral plasma membrane, in the region below the tight junctions. Their formation is inhibited by cytochalasin D, and under these conditions the spindles do not orient properly. This novel localization of the dynein-dynactin complex is consistent with a role for the complex in the positioning of the mitotic spindle. We also show that, during prophase, the motor complex colocalizes with the nuclear envelope, consistent with it having a role in separating the centrosomes that are associated with the nuclear envelope.

Animals↗
PubMed1998

Long-term results of total abdominopelvic irradiation in non-Hodgkin's lymphomas after failure of chemotherapy.

PURPOSE: To evaluate the therapeutic efficacy of moderate-dose total abdominopelvic irradiation (TAI) in a retrospective series of pretreated non-Hodgkin's lymphomas (NHL). METHODS AND MATERIALS: From 1977 to 1994, 45 patients received TAI after failure of chemotherapy (CT). According to the Working Formulation, 10 patients were diagnosed with class A (group I), 19 with class B, C, or D (follicular) (group II), and 16 with class E or more severe (group III) NHL. Irradiation consisted of two daily fractions of 0.80 Gy each for a total dose of 20 Gy. RESULTS: Mean follow-up after TAI was 102 months (range 8-156). For the entire group, the complete response (CR) rate was 66%, the partial response (PR) rate 29%, 10-year overall survival (OS) 35%, 10-year disease-free survival (DFS) 29%, and median survival 32 months. When results between subgroups were compared, CR was 70% in group I, 84% in group II, and 44% in group III; and survival was statistically higher in group II than in groups I and III: 10-year OS 52% vs. 10% (p < 0.01) and 31% (p < 0.05), respectively, 10-year DFS 37% vs. 10% (p < 0.03) and 19% (p < 0.05), respectively. Grade III or IV complications were gastrointestinal in 27% of patients and hematologic in 25%. CONCLUSION: Large-field irradiation in moderate doses could provide an alternative to bone marrow transplantation in refractory NHL, especially in cases showing a follicular growth pattern.

Abdomen↗
PubMed1998

Identification of B10, an alkaline phosphodiesterase of the apical plasma membrane of hepatocytes and biliary cells, in rat serum: increased levels following bile duct ligation and during the development of cholangiocarcinoma.

Alkaline phosphodiesterase (APDE) is associated with the cellular plasma membrane of many organs. Several isoforms are also detected in normal human serum and their respective amounts vary in liver diseases but their significance is unknown. The aims of this study were: 1) to identify a serum form of B10, an APDE exclusively localized at the apical pole of the plasma membrane of rat hepatocytes and biliary cells; 2) to gain insight into its origin; and 3) to investigate its behavior, in two liver diseases in which an abnormal membrane expression of B10 has been reported, namely cholestasis and cholangiocarcinoma. A soluble form of B10 was immunoprecipitated from normal rat serum, which amounted to 13% of total serum APDE activity. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the size of the serum enzyme was 125 kd, which is slightly lower than that found in the plasma membrane (130 kd). In bile, a 120-kd and a 130-kd form was found. A sixfold and fivefold increase of B10 APDE activity was observed in the serum of bile duct-ligated rats and in the Long-Evans Cinnamon (LEC) rats which spontaneously develop cholangiocarcinoma. The molecular size of the form present in serum was unchanged. A threefold increase was also observed in LEC rats which had not yet developed a cholangiocarcinoma. In conclusion, we identified a soluble form of B10 in normal rat serum. The increase in serum B10 in the experimental and pathological conditions investigated does not seem to result from passage of the biliary form to the serum but seems to be caused by increased cleavage of the membrane form. Its rise early during the onset of cholangiocarcinoma suggests that B10 in the serum might be a marker of carcinogenesis and/or be involved in the development of cholangiocarcinoma.

Animals↗
PubMed1998

Approach to automation in immunohistochemistry.

The introduction of immunochemical techniques into the routine pathology laboratory has significantly expanded the capabilities of the pathologist in diagnostic procedures. Immunostaining represents a powerful diagnostic tool in the identification and localization of cellular antigens, in paraffin sections, frozen tissues and cell preparations. The labeled-streptavidin-biotin method provides excellent sensitivity and performance. This multistep procedure includes: incubation of the slide with primary antibody, reaction with the biotinylated secondary antibody, binding with an enzyme conjugated streptavidin and revelation with chromogen substrate. Evaluation of the finished product is directly dependent on the quality of the technique. The main critical steps of this manual method are reagents application, incubation times and rinsing. These steps could be accessible to automation. Automation in immunohistochemistry could guarantee a continuous quality of labelling in improving standardisation, optimization and traceability of operations. The required qualifications are analytical flexibility, low cost, walkaway operation, user-friendly interface and biosafety.

Automation↗
PubMed1998

Comparative evaluation of automated systems in immunohistochemistry.

From October 1995 to March 1997, we evaluated five instruments for immunohistochemistry automation: The Techmate 500 (Dako), the Ventana 320/ES (Ventana), the Optimax Plus (Biogenex, Menarini), the Cadenza (Shandon), and the Immunostainer (Coulter-Immunotech). The aim of the evaluation was to compare the different instruments to the manual method in our laboratory which performs about 17 500 immunohistochemistries per year. PRINCIPLE: Three instruments use flat immunohistolabelling, the others use capillarity immunohistolabelling. ANALYTICAL FLEXIBILITY: we compared the number of protocols per run, the multitask capability, and the ability to adapt manual protocols to the different instruments. To compare the management of the workcell, we used the level of selfchecking, reagent and slides preparation time, and waste management. We measured the duration of the different steps of the process, the throughput in slides/h, and the operator working time per slide. Compared to the manual method, the total cost for reagents and consumables was found to be multiplied by 3 for the Ventana which is a closed system, by 2 for the Techmate, by 1.5 for the Optimax and Cadenza, and identical for the Immunostainer. CONCLUSION: Automation of immunohistochemistry is now possible; the Optimax is still in development, small laboratories will appreciate the Cadenza, laboratories requiring a high flexibility with many protocols will use the Immunostainer open system, laboratories with few technicians will prefer the Ventana closed instrument, now available as the Nexes modular system.

Automation↗