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L Xerri

Publications and source records attributed to L Xerri.

At least 73 records · Page 4Linked to original sources
PubMed1996

Expression of FGF1 and FGFR1 in human melanoma tissues.

Fibroblast growth factor 2 (FGF2) has been implicated in the pathogenesis of malignant melanoma (MM), but the role of other FGFs and their receptors (FGFRs) is not elucidated. To determine whether FGF1 and FGFR1 may be involved in MM growth in vivo, we have studied the expression of the FGF1 and FGFR1 genes in 77 fresh MM biopsy samples, using RT-PCR analysis. Samples of benign nevi, normal skin and carcinoma cell lines were included as controls. Using RT-PCR analysis, expression of FGF1 and FGFR1 was observed in 69/77 and 68/77 cases, respectively. Immunohistochemical detection of the FGFR1 protein was positive in reactive stromal cells and at a much lower level in neoplastic cells. In situ hybridization experiments demonstrated FGFR1 mRNA mainly located in the stromal component. Southern blot analysis of genomic DNA prepared from MM tumors did not show any structural alteration of the FGFR1 gene. There was no correlation between FGF1/FGFR1 expression and the usual clinicopathological parameters of MM. We conclude that FGF1 and FGFR1 are frequently co-expressed in MM, a situation that may contribute to aberrant autocrine and paracrine pathways. Due to the absence of correlation with clinico-pathological parameters, this expression cannot be used as a marker of prognosis in the management of MM patients.

Actins↗
PubMed1996

Insulin-induced lipoatrophy in type I diabetes. A possible tumor necrosis factor-alpha-mediated dedifferentiation of adipocytes.

OBJECTIVE: To test the hypothesis that tumor necrosis factor (TNF)-alpha may mediate the loss and the dedifferentiation of subcutaneous fat tissue in the insulin-induced lipoatrophies of a diabetic patient who presented extensive lesions. RESEARCH DESIGN AND METHODS: An in vitro exploration of cytokine production by peripheral blood mononuclear cells (PBMC) from the reported case was performed and compared with the same explorations of PBMC from three nondiabetic subjects and three diabetic patients without lipoatrophic lesions. A proliferation test and an evaluation of TNF-alpha and interleukin (IL)-6 production from PBMC in presence of insulin were studied. RESULTS: The production of TNF-alpha and IL-6 by the macrophages of the patient in presence of insulin were dramatically increased in comparison with control subjects. This process needed cooperation with other lymphoid cells and was abrogated by dexamethasone. CONCLUSIONS: In our reported case, a local hyperproduction of TNF-alpha from macrophages that was induced by the injected insulin could explain the dedifferentiation of the adipocytes of the subcutaneous tissue and the reversion that was induced by the local injection of dexamethasone.

Adipocytes↗
PubMed1995

[Lymphoproliferative syndrome induced by Epstein-Barr virus after kidney transplantation: value of genotypic analysis].

Forty-six days after renal transplantation for inborn tubulointerstitial nephropathy, an 18-year-old man was rehospitalized for renal failure with creatinine at 200 mumol/l. There was no sign of infection and ciclosporin level was within therapeutic range. Transplant biopsy showed minor interstitial infiltration with mononucleated cells. Methylprednisolone by 10 mg/kg/d bolus did not improve renal function and OKT3 5 mg/d was substituted for ciclosporin but had to be stopped on day 8 because of a severe infectious syndrome. The patient developed fever (39 degrees C), erythemato-pultaceous pharyngitis followed by major multiple lymph node and spleen enlargement. The diagnosis of primary Epstein-Barr infection was confirmed serologically. Histology of a submaxillary lymph node reported monomorphic immunoblastic lymphoproliferation. Immunologic phenotyping showed CD19, CD20 and CD22 surface antigens characteristic of B cells and in situ Epstein-Barr hybridization was positive in 100% of the cells. Southern Blot showed an oligoclonal pattern. Ciclosporin and azathioprin were stopped and the patient was treated with corticosteroids (15 mg/d) and aciclovir given orally (3.2 g/d) for 3 months. Outcome at six months was favorable with normalization of the renal function and complete regression of the infectious syndrome. This case demonstrated the importance of molecular biology techniques for virologic and genotypic assessment of lymphomatous proliferation allowing positive aetiologic diagnosis.

Acyclovir↗
PubMed1995

PCR-mismatch analysis of p53 gene mutation in Hodgkin's disease.

Expression of the p53 protein can be detected by immunohistochemistry in Reed-Sternberg (RS) cells, the presumed neoplastic component of Hodgkin's disease (HD) lesions. At present, there is no clear molecular evidence that p53 positive immunostaining in HD correlates with the presence of mutations or other structural alterations of the p53 gene. To address this question, 49 cases of HD have been investigated for p53 expression by immunohistochemistry, using the DO1 monoclonal antibody on paraffin sections. Thirty-seven out of 49 cases (75 per cent) exhibited positive immunostaining restricted to RS cells and variants. Among these 37 positive cases, ten cases were selected on the basis of a rich content of RS cells showing virtually 100 per cent DO1 positivity. A PCR-mismatch strategy was chosen for the detection of p53 mutations. The threshold level of sensitivity was assessed on positive cell-line controls. A proportion of 10-15 per cent p53 mutated cells mixed in a normal population could be identified. Total genomic DNA was extracted from the ten selected HD cases and PCR amplification of exons 5-8 of the p53 gene was performed. Heteroduplex mismatch analysis revealed no structural alterations of the p53 gene in any case. In view of these findings, it appears unlikely that the sensitivity of the method by itself can fully explain the negative results, although this possibility cannot be completely ruled out. Thus, it is conceivable that p53 positive immunostaining in HD may not necessarily imply genomic alterations in the classic 'hot spot' regions and may be related to another mechanism of p53 protein stabilization.

Gene Expression↗
PubMed1995

Search for rearrangements and/or allelic loss of the fas/APO-1 gene in 101 human lymphomas.

The authors analyzed the possible occurrence of rearrangements and/or allelic loss of the fas/APO-1 gene in a representative series of human lymphomas, including 101 cases of Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHL). The rationale for this study was double. Chromosome 10 alterations, frequently observed in lymphoma subtypes, encompass the chromosomal localization of fas/APO-1. In addition, Ipr mouse mutants, which present with a generalized lymphoproliferative disease, were shown to exhibit alterations of fas/APO-1 structure and expression. In this retrospective study, the authors performed gene dosage of fas/APO-1 by Southern blots. No fas/APO-1 alterations were observed in the 31 HD cases. Among 70 T-cell and B-cell NHL, allelic loss of fas/APO-1 was observed in three cases. Two cases with different clinical, phenotypic, and histologic presentations showed a rearrangement of fas/APO-1. A third case showed amplification. Thus fas/APO-1 alterations do occur in human lymphomas, although at a relatively low frequency.

Alleles↗
PubMed1995

Frequent expression of FAS/APO-1 in Hodgkin's disease and anaplastic large cell lymphomas.

FAS/APO-1 (CD95) is a membrane glycoprotein belonging to the tumour necrosis factor/nerve growth factor receptor family, and which can trigger apoptosis in some lymphoid cell lines. Immunohistochemistry combined with Northern blotting allowed determination of the pattern of FAS/APO-1 expression in a series of Ki-1 [CD30] positive lymphoid malignancies, including 27 Hodgkin's disease and eight anaplastic large cell lymphomas. CD30 negative tumours used as controls included 27 B-cell non-Hodgkin's lymphomas. 14 T-cell non-Hodgkin's lymphomas, four reactive lymphadenitis, and non-lymphoid tissues. Immunohistochemistry, performed on frozen sections, revealed a strong FAS/APO-1 expression in 25 out of 27 (92%) Hodgkin's disease cases, predominantly in Reed Sternberg cells; 50 to 100% of the neoplastic cells in eight out of (100%) anaplastic large cell lymphoma cases were positive. In contrast, positive FAS/APO-1 immunostaining was observed only in 22 out of 41 (53%) CD30 negative non-Hodgkin's lymphomas. Northern blot analysis detected variable amounts of the FAS/APO-1 transcript in the immunohistochemistry-positive samples. These results suggest possible hyper-expression of FAS/APO-1 (CD95) in Hodgkin's disease and anaplastic large cell lymphomas.

Gene Expression Regulation, Neoplastic↗
PubMed1995

Polymerase chain reaction detection of circulating melanocytes as a prognostic marker in patients with melanoma.

BACKGROUND AND DESIGN: Polymerase chain reaction (PCR) detection of circulating tumor cells from malignant melanoma (MM) was recently described, but the prognostic value of this method in the treatment of patients with MM remained unclear. In the present prospective study, blood samples (n = 193) were collected from 93 patients with MM: 10 stage I patients after primary tumor resection, 18 patients with regional lymph node metastases before node resection, 33 disease-free but high-risk patients (previously treated for node metastases), and 32 patients with distant metastases. Circulating melanocytes were detected using a reverse transcriptase PCR method that analyzes tyrosinase gene expression. All patients were kept under regular surveillance. RESULTS: The PCR assay was always negative in normal individuals and in subjects with non-MM metastatic cancer, while it was positive in 16 of 32 patients with disseminated MM. Five of eight patients who were PCR-positive before node dissection vs one of 10 who were PCR-negative relapsed within 6 months after surgery. In high-risk but apparently disease-free patients, the risk of relapse within the next 6 months was 3.8 times higher after a positive test result. In patients with distant metastases, a positive PCR predicted rapid disease progression. CONCLUSIONS: These data suggest that PCR detection of circulating melanocytes can be considered as a marker for rapid postoperative relapse after node dissection in patients with MM with regional node metastases, for short-term relapse in high-risk disease-free patients, and for rapid and severe progression in patients with distant metastases. This test may have a crucial interest in the treatment of patients with MM.

Base Sequence↗
PubMed1994

Expression of the p53 gene in Hodgkin's disease: dissociation between immunohistochemistry and clinicopathological data.

Expression of the p53 protein has been detected recently by immunohistochemistry in Hodgkin's disease (HD), but the relationship between p53 expression and the prognosis and clinicopathological heterogeneity of HD is still unclear. To address these questions we investigated 49 cases of HD for p53 expression by immunohistochemistry using the DO1 monoclonal antibody (MAb) on paraffin sections. Thirty-five cases were simultaneously tested with the 1801 MAb on frozen sections. Thirty-seven of 49 cases (75%) were DO1 positive while 14 of 35 (40%) were PAb 1801 positive. Both MAbs gave a nuclear staining restricted to Reed Sternberg cells (RSCs) and variants and distributed among the three HD subtypes analyzed (ie, nodular lymphocyte predominant, nodular sclerosing, and mixed cellularity). The percentage of positive neoplastic cells in each case was heterogeneous, ranging from almost 100% to less than 5%. In 39 patients for whom clinical data were available statistical analysis did not show any significant correlation between p53-positive immunostaining and clinical staging, B symptoms, probability of relapse, or disease-free survival. We conclude that p53 expression is a common event in HD regardless of histological subtyping, but does not bear any pejorative significance.

Antibodies, Monoclonal↗
PubMed1994

NM23 expression in metastasis of malignant melanoma is a predictive prognostic parameter correlated with survival.

The management of patients presenting with metastatic malignant melanoma (MM) is hampered by the substantial variability in survival of these patients and the lack of prognostic markers. In the search for a reliable predictive parameter, we have investigated the expression of the nm23 gene, considered to be a major regulator of the metastatic process. We have analysed by Northern blot the nm23 mRNA level in tumour tissue obtained from metastases of 20 stage II and ten stage III patients with MM. Normal human tissues and benign naevi were simultaneously examined. The level of nm23 expression was highly heterogeneous in MM metastases, with a mean value which was higher than the mean level in normal tissues and naevi. Correlative study was focused on the overall survival following resection of the metastasis in which nm23 Northern blot analysis was performed. Patients displaying higher nm23 expression in metastatic tissue (above the mean level) tended to have a longer survival than others (P = 0.08), and this difference was significant for patients presenting with isolated regional lymph node involvement (P = 0.035). The time from biopsy of the primary MM to the appearance of the first lymph node metastasis also showed a positive correlation with the nm23 mRNA level in this metastasis. The present study is not only in accordance with previous reports showing that the nm23 gene may be implicated in MM progression, but also suggests the reliable value of nm23 expression as a prognostic marker for patients presenting with metastatic MM.

Female↗
PubMed1994

Heterogeneity of rearranged T-cell receptor V-alpha and V-beta transcripts in tumor-infiltrating lymphocytes from Hodgkin's disease and non-Hodgkin's lymphoma.

Hodgkin's disease is histologically characterized by the presence of Reed-Sternberg cells (RSC) and reactive cells, including numerous T lymphocytes. Some forms of B cell-non-Hodgkin's lymphoma also contain a rich T-cell population. Previous studies have suggested that the T-cell receptor repertoire of tumor-infiltrating T lymphocytes (TITL) that act specifically against tumor-related antigens, should be restricted. The authors in this study used the polymerase chain reaction to explore the possible existence of such an immunologic response of TITL against RSC or neoplastic B cells. They studied variable (v) region genes of T-cell receptor alpha and beta chains expressed by infiltrating lymphocytes in biopsy specimens from seven patients with Hodgkin's disease and three with B cell-non-Hodgkin's lymphoma. These latter samples were selected based on a rich T-cell content. Primers specific for 18 different V-alpha and 21 V-beta families were used. In every case, TITL showed an unrestricted pattern of expression similar to the repertoire observed in peripheral blood lymphocytes. Although such experiments are limited, the apparent lack of selection of a single or a limited number of T-cell subsets in the affected tissues did not support the existence of an in vivo immunologic interaction between TITL and antigens related to RSC or neoplastic B cells.

Blotting, Southern↗
PubMed1994

In vitro activity of the tribactam GV104326 against gram-positive, gram-negative, and anaerobic bacteria.

GV104326 is the first member of a new class of antibiotics (tribactams) selected for development. It combines a particularly broad spectrum (including gram-negative and gram-positive aerobes and anaerobes) with high potency, resistance to beta-lactamases, and complete stability to dehydropeptidases. Comparative MICs were determined for GV104326 against 415 recent clinical isolates (including beta-lactamase producers), using representative antibacterial agents (imipenem, amoxicillin-clavulanic acid, cefpirome, ciprofloxacin, gentamicin, and erythromycin). GV104326 was particularly active against gram-positive bacteria; in general, its in vitro activity was equivalent to that of imipenem, equivalent to or better than that of amoxicillin-clavulanic acid, and superior to that of cefpirome, ciprofloxacin, and erythromycin. Against gram-negative bacteria, GV104326 possessed activity similar to that of imipenem and cefpirome against enterobacteria and Haemophilus spp. but its activity was superior to that of amoxicillin-clavulanic acid. GV104326 showed excellent antianaerobe activity. GV104326 was stable to all clinically relevant beta-lactamases and was rapidly lethal to susceptible bacteria. In Escherichia coli, GV104326 bound predominantly to PBPs 1a and 2 and at low concentrations osmotically stable round forms were observed. GV104326 showed an affinity for PBPs 2 and 4 of Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed1993

Unrestricted T-cell receptor V-region gene repertoire in tumor-infiltrating lymphocytes from human breast carcinomas.

BACKGROUND: Several lines of evidence indicate that a more favorable prognosis is correlated with the degree of lymphocyte infiltration within breast carcinomas. The characterization of these T-cell infiltrates appears necessary to explore the possible existence of an in situ immunologic response of the host against neoplastic cells. Previous studies have indeed suggested that the T-cell receptor (TCR) repertoire of tumor-infiltrating T-lymphocytes (TIL) should be restricted if they act specifically against tumor-related antigens. METHODS: To address this question, the expression of variable (V) region genes of the TCR-alpha and beta chains in intratumoral lymphocytes from five breast carcinoma biopsy specimens and one normal mammary gland specimen was analyzed using the polymerase chain reaction (PCR). The neoplastic samples included one medullary carcinoma and four ductal infiltrating carcinomas selected on the basis of a rich lymphoid stromal component. Primers specific for 18 different V alpha and 21 V beta families were used for PCR. RESULTS: In every case, TIL showed an unrestricted pattern of TCR V-region gene expression, similar to the repertoire observed in peripheral blood lymphocytes and in the normal breast tissue. CONCLUSIONS: According to these nonquantitative PCR experiments, the apparent lack of selection of a limited number of T-cell specificities in the affected tissues does not favor the existence of an in vivo lymphoid recruitment based on TCR recognition of neoplastic antigenic determinants. Further studies, however, leading to an accurate quantification of immunologically relevant T-cell clones and including larger series of cases still are necessary before it will be possible to draw a final conclusion.

Blotting, Southern↗
PubMed1993

Tyrosinase gene expression in human tissues.

The occasional occurrence of primary extra-cutaneous malignant melanomas (MM) has led to the hypothesis that melanocytes derived from the neural crest may be arrested in their migration and may undergo an in situ malignant transformation. However, aggregates of nevus cells have only rarely been identified by histological examination in a few organs other than skin and eye. Tyrosinase is a melanin biosynthetic enzyme that is considered one of the most specific markers of melanocytic differentiation. We have attempted to detect cells committed to the melanocytic lineage, in human tissues, by means of tyrosinase gene expression. Total RNA was extracted from normal and neoplastic tissues and analyzed using a highly sensitive reverse transcription PCR assay with primers specific for the tyrosinase gene. Peripheral blood mononuclear cells (PBMC) from healthy subjects were used as negative controls. Tyrosinase transcripts were identified in a wide range of normal organs such as skin, lymph nodes, antrum, colon, kidney, lung, testis, ovary, breast, and peripheral nerve. Tyrosinase RNA was also detected in neoplastic samples including benign cutaneous nevi, lymph nodes involved by MM, breast carcinoma, liposarcoma, malignant lymphoma, and schwannoma. PBMC from patients with metastatic MM were also positive, while no positivity was detected in blood specimens from patients with other cancers. Therefore, it appears likely that cells expressing the tyrosinase gene are present in a wide range of human tissues. Although these cells still have to be accurately identified, one could propose that they might correspond to either fully differentiated melanocytes, melanocytic precursors, or Schwann cells bearing potentialities of melanocytic differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

In situ expression of the IL-1-alpha and TNF-alpha genes by Reed-Sternberg cells in Hodgkin's disease.

The histopathologic pattern of tissues involved by Hodgkin's disease (HD) suggests excessive activation of environmental cells by cytokines released by Hodgkin-Reed-Sternberg (HRS) cells, which are considered as the neoplastic component of HD lesions. This hypothesis has been supported by many studies performed in vitro using HD cell lines. In this study, we have tried to demonstrate the cytokine-producing cells in an environment as close as possible to the in vivo conditions, using in situ hybridization onto frozen sections of HD samples. [35S]-labelled single-stranded RNA probes were prepared by transcribing human cDNA fragments of the TNF-alpha and IL-1 alpha genes subcloned into appropriate vectors. A total of 19 specimens of HD lesions, including 7 cases of nodular sclerosing (NS) type and 12 cases of mixed cellularity (MC), were tested with both types of probes. Clinical stages included stage I (6 cases), stage II (4 cases), stage III (6 cases) and stage IV (3 cases). TNF-alpha and/or IL-1 alpha expression was observed in 12 among 19 HD cases. However, neither the histological type nor the clinical status of the patients was correlated with the profile of cytokine secretion. Most of the cytokine-producing cells could be identified as HRS cells due to their morphological appearance. In 3 cases, simultaneous analysis by immunohistochemistry and in situ hybridization showed that IL-1 alpha/TNF-alpha mRNA-producing cells simultaneously expressed the CD30 antigen, thereby confirming the HRS nature of these cells.

Antigens, CD↗
PubMed1992

Detection of gastrin mRNA by in situ hybridization using radioactive- and digoxigenin-labelled probes: a comparative study.

The hormone gastrin is mainly produced by the G cells of the antral mucosa and plays a major role in the regulation of digestive mucosal growth. Since it permits identification of cell types containing mRNA, in situ hybridization (ISH) appears to be an interesting method for studying gastrin-producing tissues. In this study, in situ detection of gastrin mRNA has been carried out on frozen sections of four human normal antral mucosa samples and of six colonic carcinomas removed from patients with high levels of plasma gastrin, using a gastrin oligonucleotidic DNA probe. We have compared the results provided respectively by the [35s] labelling and the digoxigenin labelling of the synthetic probe. Positive cells were found in each normal sample analysed with radioactive- as well as digoxigenin-labelled antisense probes. The total number of cells expressing gastrin mRNA appeared slightly higher with the [35s]-labelled probe, while the digoxigenin-labelled probe gave a better definition of positive signals. In contrast, neither radioactive nor cold probes gave positive signals in the six colonic carcinoma samples, although gastrin expression had been demonstrated in these tumours using a reverse transcriptase-PCR method. These results show that, although ISH does not seem sensitive enough to allow the detection of very low levels of gastrin expression, it would appear to be a reliable method for visualizing gastrin mRNA in human antral mucosa.

Base Sequence↗
PubMed1991

[Bacterial infections. Progress and new prospects in chemo-antibiotic therapy].

During the last 10 years, a very large number of molecules with antibacterial activity has been developed by pharmaceutic industry. The principal objectives of pharmacological research are to obtain ever wider spectra of activity and increased antibacterial action in order to combat "emerging" agents and those resistant to traditional treatment, as well as longer acting drugs so as to improve patient compliance. These objectives might be attained by the molecules now in the phase of clinical trial, especially by the new injectable or oral cephalosporins and new fluoroquinolones.

4-Quinolones↗