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Biomedical subjects

P Brousset

Publications and source records attributed to P Brousset.

At least 55 records · Page 3Linked to original sources
PubMed1998

Kaposi's sarcoma-associated herpesvirus (KSHV) in bone marrow biopsies of patients with Waldenstrom's macroglobulinaemia.

Kaposi's sarcoma-associated herpesvirus (KSHV) is suspected to play a role in the aetiology of multiple myeloma. Because of similarities in the pathophysiology of multiple myeloma and Waldenstrom's macroglobulinaemia (WM), we investigated DNA samples from 20 bone marrow biopsies with WM for the detection of KSHV by PCR (KS330/ORF26). We performed two rounds of amplification and found that only 1/20 of the DNA samples obtained from biopsies had a detectable KSHV sequence. The positive patient was also infected by the human immunodeficiency virus (HIV). Our data provide evidence that KSHV cannot be implicated in the pathogenesis of WM.

Bone Marrow Diseases↗
PubMed1998

Telomerase activity might persist in the human thymus throughout life.

Telomerase activity has been demonstrated at low levels in peripheral blood lymphocytes but at high levels in germinal centre B cells and thymocyte subpopulations. This study shows that telomerase is activated in the normal human thymus at different times of life. Telomerase activity was detected in thymic protein extracts from two newborn babies and from a 12 year old boy, as well as in extracts from two of six adult patients. The two positive cases were patients aged 54 and 66 years. These results suggest strongly that the thymus can remain functional despite involution in elderly patients.

Adult↗
PubMed1998

Telomerase activity in Hodgkin's disease.

Telomerase activity has been demonstrated in various types of cancers including lymphoid neoplasms. The tumour specificity of telomerase activity has been a subject of debate since the description of detectable enzymatic activity in non neoplastic tissues. We and others have demonstrated that such activity was present in non Hodgkin's lymphomas as well as in reactive hyperplastic lymph nodes and tonsils. However, we at the same time were surprised by the absence of telomerase activity in most cases of Hodgkin's disease. We have extended our previous study by adding additional cases and confirm that in the majority of cases, Hodgkin and Reed-Sternberg cells lack telomerase activity (only 2 cases positive out of 20). These results may indicate that the tumour cells of Hodgkin's disease evolve different pathways for maintaining the length of their telomeres during the process of becoming immortal.

Hodgkin Disease↗
PubMed1997

Association of the Epstein-Barr virus with Hodgkin's disease in Southern Israel.

Epstein-Barr virus (EBV) has been frequently documented in the putative neoplastic Hodgkin-Reed-Sternberg (HRS) cells, in lymph nodes from patients with Hodgkin's disease (HD). This association varies in different geographic areas and between industrialized and developing countries, as does the epidemiological pattern of the disease. In the present study of 106 cases of HD from the Soroka Medical Center in Beer-Sheva, which serves as the only hospital for most of the southern part of Israel, we found an association with EBV expression in only 30% of the patients; 45% of mixed cellularity (MC) cases compared with 21% of nodular sclerosis (NS) cases were positive for EBV. The number of patients in the 0-14-year-old age group was limited; however, 8 of these II children were EBV positive. This low association rate of HD with the presence of EBV sequences is probably related to the small number of children in our series. A low proportion of EBV-associated disease in older adults may be contributory. Other factors may be involved.

Adolescent↗
PubMed1997

A new subtype of large B-cell lymphoma expressing the ALK kinase and lacking the 2; 5 translocation.

Seven cases of large B-cell lymphoma which define a previously unrecognized subgroup are reported. Morphologically they are comprised of monomorphic large immunoblast-like cells, containing large central nucleoli, which tend to invade lymphatic sinuses. Superficially they resemble anaplastic large cell lymphoma (ALCL) but they lack CD30. These lymphomas express epithelial membrane antigen (as do ALCL), but also contain intracytoplasmic IgA of a single light chain type (five cases) and an endoplasmic reticulum-associated marker detected by antibody VS38. They lack lineage-associated leukocyte antigens with the exception of CD4 (5 of 5 cases) and CD57 (5 of 7 cases). They are labeled by antibodies detecting both the intracytoplasmic and extracellular regions of the ALK receptor kinase, suggesting that they express the full-length form of this molecule. This was confirmed by Western blotting (in the one case tested) which showed a band of 200 kD in tumor cell lysates, and by polymerase chain reaction (PCR) amplification of mRNA encoding intracellular and extracellular ALK sequences (in the two cases tested). There was no evidence by cytogenetics (one case analyzed) or reverse transcriptase-PCR (three cases tested) of the 2; 5 translocation or the resultant NPM-ALK gene, as is commonly found in ALCL. All but one of the patients were male and all but one were adults, and in all but the latter case the disease followed an aggressive course.

Adolescent↗
PubMed1997

Epstein-Barr virus-associated Hodgkin's disease: epidemiologic characteristics in international data.

Hodgkin's disease (HD) has long been suspected to have an infectious precursor, and indirect evidence has implicated Epstein-Barr virus (EBV), a ubiquitous herpesvirus, as a causal agent. Recent molecular studies using EBER in situ hybridization or latency membrane protein-I (LMP-I) immunohistochemistry have identified EBV latent infection in up to 50% of HD tumors. However, the epidemiologic features of these cases have not been examined in detail. To explore the epidemiology of EBV-positive HD so as to understand the role of EBV in HD etiology more clearly, this project accumulated patient data from 14 studies that had applied these EBV assays to HD tumors. With information on age at diagnosis, sex, ethnicity, histologic subtype, country of residence, clinical stage and EBV tumor status from 1,546 HD patients, we examined risk for EBV-positive disease using logistic regression. Forty percent of subjects had EBV-positive tumors, and EBV prevalence varied significantly across groups defined by the study variables. Odds ratios (OR) for EBV-associated HD were significantly elevated for Hispanics vs. whites (OR = 4.1), mixed cellularity vs. nodular sclerosis histologic subtypes (OR = 7.3, 13.4, 4.9 for ages 0-14, 15-49, 50+ years), children from economically less-developed vs. more-developed regions and young adult males vs. females (OR = 2.5). These findings suggest that age, sex, ethnicity and the physiologic effects of poverty may represent biologic modifiers of the EBV association and confirm that this association is strongly but variably linked to histologic subtype. The data augment biologic evidence that EBV is actively involved in HD pathogenesis in some cases but describe epidemiologic complexity in this process.

Adolescent↗
PubMed1997

Telomerase activity in reactive and neoplastic lymphoid tissues: infrequent detection of activity in Hodgkin's disease.

We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues involved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (HD) (n = 14). Clearly evident telomerase activity was found in all lymphoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL. These results were expected because of the proliferative and immortal nature of the cell lines and most malignant cells. However, positive results were obtained with the TRAP assay in all hyperplastic lymph nodes and tonsils, which raises the issue of derepression of telomerase activity during an immune response. Telomerase activity alone therefore does not distinguish malignant lymphoid proliferations from reactive states. Telomerase activity was detected in only 1 of 14 cases (7%) of lymphoid tissues involved by HD. Eight of the 13 negative cases were considered to be interpretable because of the lack (3 of 13 cases) or low level (5 of 13 cases) of telomerase inhibition. The five remaining cases could not be evaluated because of their telomerase inhibitor content. The findings imply either transient or very low levels of telomerase activity in HD or that HD for the greater part is a telomerase-independent neoplasm. Microdissection studies are needed to identify subsets of cells carrying telomerase activity in both reactive and neoplastic lymphoid tissues.

Chromosomes, Human↗
PubMed1997

Cysteine protease CPP32, but not Ich1-L, is expressed in germinal center B cells and their neoplastic counterparts.

Ich-1/Nedd2 and CPP32/YAMA are cysteine proteases related to interleukin 1-beta-converting enzyme (ICE), which act as apoptosis effectors. Both molecules are expressed in T- and B-cell lines. The authors investigated their in vivo cellular distribution in normal and neoplastic human lymphoid tissues. Sixty-eight representative non-Hodgkin's lymphomas (NHL) and Hodgkin's disease (HD) samples, normal lymphoid organs, and nonlymphoid tumors were analyzed by immunohistochemistry (IHC). CPP32 expression in benign tissues was restricted to germinal center B cells, plasma cells, and a few interfollicular immunoblasts. All follicular NHLs and most diffuse large cell NHLs were CPP32 positive. Among T-cell NHLs, CPP32 expression was mainly observed in anaplastic large cell NHLs, whereas the other subtypes were less frequently positive. In contrast, lymphoid organs displayed only weak Ich1-L expression, located in sinusal histiocytes and thymic epithelial cells. Lymphomas were Ich1-L negative, except for T-cell-rich B-cell NHLs, and about half of the HD samples, in which Reed-Sternberg cells (RSC) were usually Ich1-L positive/CPP32 negative. Extralymphoid Ich1-L reactivity was found in particular organs like the kidney and various tumors. Western blot analysis confirmed the specificity of immunostaining. Neither CPP32 nor Ich1-L expression were correlated with intratumoral DNA fragmentation, as determined by the TUNEL assay. Altogether, these results indicate that CPP32 is preferentially expressed in germinal centers and thus could be involved in B-cell maturation. The differential expression of CPP32 and Ich1-L suggests that cysteine proteases differ in substrate specificities and carry out functions unrelated to apoptosis.

Apoptosis↗
PubMed1997

AIDS-related primary brain lymphomas: histopathologic and immunohistochemical study of 51 cases. The French Study Group for HIV-Associated Tumors.

Fifty-one cases of acquired immunodeficiency syndrome (AIDS)-related primary brain lymphomas (AR-PBL) were investigated for clinical characteristics; human immunodeficiency virus (HIV)-associated disorders; histopathologic features; immunophenotype; Epstein-Barr virus (EBV) infection; and, when frozen tissue was available, oncogene rearrangements. AR-PBL occurred late in the course of AIDS and were usually associated with other systemic or cerebral disorders and with a low level of CD4 lymphocytes. All cases were high grade lymphomas according to the Working Formulation or updated Kiel classification, and often displayed a multifocal pattern. Thirty cases were classified as immunoblastic with plasmacytic differentiation, 18 cases were large cell lymphomas with an immunoblastic component or centroblastic polymorphic lymphomas, and 2 were small noncleaved non-Burkitt lymphomas (Working Formulation). This latter category is classified as Burkitt's-like lymphoma in the REAL nomenclature. One case could not be classified because of necrosis. AR-PBL showed a high level expression of activation and adhesion molecules. The presence of EBV was detected in most cases, and, when PCR was used, this was a constant finding. bcl-2 oncoprotein and latent membrane protein-1 (LMP-1) were strongly expressed. None of the tested cases expressed p53, or were rearranged for bcl-2 or c-myc oncogenes. This study confirms the immunophenotypic specificity of AR-PBL, which may reflect the special immune status of the brain.

Adult↗