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P A Bryon

Publications and source records attributed to P A Bryon.

At least 19 recordsLinked to original sources
PubMed1999

Enhanced expression of p16ink4a is associated with a poor prognosis in childhood acute lymphoblastic leukemia.

The tumor suppressor gene p16ink4a is homozygously deleted in numerous T as well as in some B lineage acute lymphoblastic leukemia (ALL). We therefore analyzed the clinical and biological implications of this feature by studying p16ink4a expression in 58 cases of childhood ALL. mRNA and protein were significantly correlated and both appeared more highly expressed in B than in T lineage ALLs: 13 out of the 15 T cell ALLs did not show any p16ink4a expression. The main result of this study is the strong prognostic value of p16ink4a expression. When stratifying the patients in three groups according to p16ink4a expression, we observed in univariate analysis: (1) the shortest disease-free survival for patients presenting a high p16ink4a level; (2) contrasting with the good prognosis in the group of patients expressing p16ink4a at low level; (3) while cases without any expression of the inhibitor were associated with a medium course of the disease (P=0.0165). This prognostic value was confirmed by the multivariate analysis showing therapeutic regimen and p16ink4a protein expression as the only variables retained in the model. A specific metabolic profile related to cellular survival and proliferation was observed in each of the three p16ink4a expression groups. Among the cell cycle-related proteins we analyzed, only p21waf1 bcl-2 and CDK4 were significantly and positively correlated to p16ink4a. Furthermore, CDK6 was also strongly expressed in the group of cases with high p16ink4a level. An enhancement of p16ink4a, p21waf1 and bcl-2 was previously described in prolonged cellular survival, while aging cells showed a decrease in CDK4 expression. The concomitant high expression of the oncogenic protein CDK4 (and of CDK6), we observed, may amplify the leukemic advantage of prolonged lifespan blast cells by favoring cell progression through G1 phase. These data suggest that at least two mechanisms may be associated in the oncogenesis of very aggressive ALLs, ie deregulation of cell multiplication and prolonged blast lifespan.

Adolescent↗
PubMed1998

Glucocorticoids induce G1 as well as S-phase lengthening in normal human stimulated lymphocytes: differential effects on cell cycle regulatory proteins.

In order to analyze dexamethasone effects on peripheral blood lymphocyte proliferation, we defined various experimental conditions: dexamethasone introduced (i) at the time of phytohemagglutinin stimulation, (ii) 48 h after the beginning of phytohemagglutinin stimulation, and (iii) on unstimulated lymphocytes. In stimulated lymphocytes, we observed an early G1 accumulation (P < 0.005), a delayed increase in the duration of S-phase (P < 0.03), and a consequent increase in cell-cycle duration. The expression of several cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors (CKIs) was modified. Cyclin D3, CDK4, and CDK6 involved in G1-phase control were significantly decreased under dexamethasone treatment whatever the level of stimulation of lymphocytes (stimulated or unstimulated PBL). Cyclin E and CDK2, acting in G1/ S-phase transition and S-phase regulation, decreased in stimulated lymphocytes before any modification of S-phase (P < 0.002). The expression of CKIs, mainly of p27Kip1, appeared to vary with the degree of cell stimulation: a decrease was observed on treated unstimulated lymphocytes, while p27Kip1 increased in dexamethasone-treated cells during stimulation. Our results indicate sequential modifications of the cell-cycle regulation by dexamethasone starting with an action on G1 followed by S-phase control modifications. The protein analysis pinpoints the major complexes concerned: CDK4 and CDK6/cyclin D are mainly involved in G1-phase modifications, while CDK2 and its partner, cyclin E, might be specifically involved in the lengthening of S-phase. The variations observed for p27Kip1 might amplify the functional effects of dexamethasone on kinasic complexes.

Apoptosis↗
PubMed1998

Measurement accuracy in confocal microscopy.

Confocal laser scanning microscopy provides optical serial sections through thick biological samples, making it possible to perform both three-dimensional visualization and three-dimensional quantitative analysis. On human lymphocytes, we measured geometrical features, cell contents in DNA and in cyclin A and CDK1 proteins, localization and colocalization of these two proteins. Cells were acquired at a vertical sampling step of 0.5 micron, which gives sufficient information about cell labelling. For the purpose of obtaining fast and reliable data at a reduced time cost, we examined various possibilities to simplify acquisition. For example, it might be possible to increase the vertical sampling step to 2.0 microns while preserving an acceptable accuracy of measurements. Further limiting the acquisition to the central sections appeared to give only rough estimations about the whole cells. Finally, we compared confocal microscopy to conventional two-dimensional epifluorescence microscopy. Confocal microscopy appeared slightly less accurate as regards content estimation, but was an invaluable tool when investigating three-dimensional structures and, more especially, localization of proteins.

Cells, Cultured↗
PubMed1998

Burkitt-like lymphomas in AIDS patients: characterization within a series of 103 human immunodeficiency virus-associated non-Hodgkin's lymphomas. Burkitt's Lymphoma Study Group.

PURPOSE: Burkitt-like lymphoma (BLL) is a tumor with morphologic features intermediate between Burkitt's lymphoma (BL) and large-cell lymphoma, but its relationship with these lymphomas is currently unclear. We have therefore analyzed its characteristics within a large series of human immunodeficiency virus (HIV)-associated lymphomas. MATERIALS AND METHODS: Clinical, histologic, immunophenotypic, and molecular analyses were performed on 103 patients with AIDS lymphomas. RESULTS: Nineteen cases (18.4%) were identified as BLL. They were monoclonal B-cell proliferations, as evaluated by immunoglobulin (Ig) gene rearrangement analyses, and had rearrangement of the c-myc oncogene in 68% of cases but not the bcl-2 gene, in contrast to a previous study on non-HIV-associated BLL. This molecular pattern was therefore identical to that of typical BL, suggesting that they represented tumors of similar origin. However, some features could clearly differentiate BLL from BL and were similar to those seen in the diffuse large-cell immunoblastic lymphomas (DLC-IBL) group. These included a greater frequency of Epstein-Barr Virus (EBV) infection (79% v 48%, P = .04), an upregulation of CD39 (50% v 0%, P = .0007) and CD70 (75% v 15%, P = .003) activation antigens and of the CD11a/LFA-1 adhesion molecule (83% v30%, P = .05), and, finally, a lower CD4 count (mean, 119/microL v 270/microL, P = .04). CONCLUSION: BLL is a frequent entity among AIDS lymphomas and should be considered as a morphologic variant of BL in the context of severe immunodepression that occurs in HIV-infected patients.

Adult↗
PubMed1997

Cytohistological and immunological classification of canine malignant lymphomas: comparison with human non-Hodgkin's lymphomas.

Non-Hodgkin's lymphomas (NHLs) in man are on the increase. They are also common in dogs, which, as close companions of man, may constitute a useful experimental model. However, comparisons cannot be made without a reliable morphological and immunological classification of canine NHL. Canine NHLs (n = 134) were classified on the basis of fine-needle lymph-node aspirates according to the Kiel classification, and 92 were re-classified according to the Working Formulation and the updated Kiel classification, in a histological and immunological study. The immunophenotype was determined (1) in 92 cases by the use of the pan-T anti-CD3 polyclonal antibody and the pan-B anti-mb1 monoclonal antibody on paraffin wax-embedded tissue sections, and (2) in 47 cases by the use of a panel of polyclonal and monoclonal antibodies on fresh preparations and frozen tissue. Cytological analysis showed a predominance of high-grade lymphomas (73.9%) over low-grade lymphomas (26.1%); it also demonstrated forms not reported in other species (small-cell variants, lymphomas with macronucleolated medium-sized cells [MMCs], and polymorphic lymphomas with a centroblastic component). Histological examination revealed the rarity of follicular lymphomas (2.2% of cases), an appearance suggestive of T-cell neoplasia (8.7% of cases), and evidence that some MMC lymphomas originated in the marginal perifollicular zones. Some (26%) of the lymphomas were of the T-cell phenotype: the majority of these consisted of small-cell, low-grade lymphomas and mycosis fungoides, the rest being either high-grade pleomorphic lymphomas (mixed or large-cell) or, rarely, high-grade, small noncleaved-cell, plasmacytoid lymphomas. No lymphoma expressed a double (T and B) phenotype. This study revealed similarities with, but also notable differences from, human NHL. In particular, the MMC lymphomas may constitute an interesting equivalent of human marginal zone B-cell lymphomas.

Animals↗
PubMed1997

Growth fractions in canine non-Hodgkin's lymphomas as determined in situ by the expression of the Ki-67 antigen.

The proportion of proliferating cells in non-Hodgkin's lymphomas (NHLs) as determined in situ by the expression of the Ki-67 antigen, has prognostic value in human oncology, and is strongly related to the different grades of malignancy. The evaluation of the Ki-67 index in canine NHLs may be useful in assessing the individual variability of the growth fraction in the different sub-types of lymphoma, and also the validity of the classification in terms of grade of malignancy. The growth fraction was evaluated in 92 canine NHLs, previously classified according to the Kiel classification (as adapted to the canine species), by determining the expression of the Ki-67 antigen with the MIB1 antibody on (1) paraffin-wax tissue sections in all 92 cases, and (2) fine-needle aspirates or tumour imprints in 30 cases. The labelling appeared satisfactory in 88% of the cases, with good concordance between the histological and cytological data. A highly significant correlation (P < 0.001) was established between the proportion of Ki-67+ cells and the classification into low-grade (Ki-67 index < 21%) and high-grade malignancy (Ki-67 index > 21% and usually > 29%). In the low-grade lymphoma group, a macronucleolated medium-sized-cell lymphoma not found in man had the lowest proliferation index. In the high-grade malignancy group, the number of Ki-67+ cells seemed to be proportional to cell size, whatever the phenotype, with the rare exceptions of some unclassifiable small-cell Burkitt-type or plasmacytoid lymphomas, which were highly proliferating. The classification of lymphomas into low-grade and high-grade appears to correlate well with their proliferative index. The existence of individual variations, within given categories of canine NHL, suggests that, as in human medicine, prognosis may be assisted by determining the growth fraction at initial diagnosis, and by fine-needle aspiration at relapses.

Animals↗
PubMed1997

Incidence, predictive factors, and outcome of lymphoma transformation in follicular lymphoma patients.

PURPOSE: To assess the incidence of lymphoma transformation in the natural history of follicular lymphoma (FL) patients and the factors that are predictive of this event. PATIENTS AND METHODS: Two hundred twenty patients with FL treated in our institution between 1975 and 1990, with a median follow-up duration of 9 years, were included in this retrospective analysis. RESULTS: Transformation was proven by histology in 34 patients or by cytology in 13 patients and was considered as highly probable on clinical arguments in five patients for an overall incidence of 24%. The probability of transformation was 22% at 5 years and 31% at 10 years and tended to plateau after 6 years. Predictive factors for transformation were nonachievement of complete remission (CR) after initial therapy (P < 10(-4), low serum albumin level (< 35 g/L) (P = .001), and beta 2-microglobulin level greater than 3 mg/L (P = .02) at diagnosis. In a multiparametric analysis, only beta 2-microglobulin level retained prognostic significance for freedom-from-transformation (FFT) survival (P = .04). Transformation accounted for 44% of deaths and was associated with a poor outcome, with a median survival time of 7 months. CONCLUSION: Transformation is an early event in the course of the disease and is mainly observed in patients with known adverse prognostic factors or those who do not achieve CR after initial treatment. These findings may be useful to select follicular lymphoma patients for intensive therapeutic approaches.

Adult↗
PubMed1996

Evaluation of five green fluorescence-emitting streptavidin-conjugated fluorochromes for use in immunofluorescence microscopy.

Fluorescein isothiocyanate (FITC) is largely used in immunofluorescence methods. We propose to analyse the quality of some recent fluorochromes using image analysis. Fluorochromes tested include FITC and dichlorotriazinylaminofluorescein (DTAF), dipyrrometheneboron difluoride (BODIPY), Rhodol Green and cyanine 2. RAMOS cells were immunolabelled against the proliferating cell nuclear antigen (PCNA) revealed by the biotin-streptavidin technique. Slides were mounted in anhydrous glycerol or in buffered glycerol (pH 7.0 or pH 8.5). No antifading medium was added. Cell fluorescence emission intensity and bleaching characteristics were measured. Rhodol Green exhibited the highest fluorescence intensity and the best photobleaching resistance. Although BODIPY also resisted well during the photobleaching assay, its fluorescence intensity was weak. FITC, DTAF and cyanine 2 showed intermediate fluorescence intensity and a fast decay of fluorescence. Among the green emitting fluorochromes tested, Rhodol Green appeared to be the best.

Bacterial Proteins↗
PubMed1996

Splenic lymphoma with villous lymphocytes: clinical presentation, biology and prognostic factors in a series of 100 patients. Groupe Francais d'Hématologie Cellulaire (GFHC).

The diagnosis of splenic lymphoma with villous lymphocytes (SLVL) was assessed by a panel of cytologists in a series of 100 patients. Clinical and biological characteristics were analysed in relation to prognosis. SLVL is a chronic B-cell lymphoproliferative disorder characterized by splenomegaly and the presence, in peripheral blood, of lymphocytes with "villous' projections. The cytological diagnosis can be difficult in patients without an absolute lymphocytosis which was observed in 24% of cases. B-cells expressed CD19+, CD20+, CD22+, CD24+ and DBA44+, whereas the expression of CD5, CD10 and CD25 was usually negative. SLVL is a disease of the elderly with a relatively benign clinical course. In the present series the 5-year overall survival was 78%. Deaths in 15 patients were related to disease progression or treatment (nine cases). Patients with a leucocyte count > 30 x 10(9)/1 or lymphocyte count < 4 x 10(9)/1 or initially treated with chemotherapy had significantly (P < 0.001) lower overall survival than other patients. From these findings, treatment abstention should be considered in patients with favourable prognostic factors; on the other hand, the efficacy of conventional chemotherapy remains to be evaluated in patients with unfavourable prognostic factors.

Adult↗
PubMed1996

Differential expression of cell proliferation regulatory proteins in B- and T-lineage acute lymphoblastic leukaemias.

In order to better understand the molecular background of differences between the clinical picture of T- and B-lineage ALLs, we studied the expression of several proteins involved in the regulation of cell proliferation in bone marrow blast cells from 30 cases of previously untreated acute lymphoblastic leukaemia (ALL); 14 cases were T- and 16 B-cell lineage ALLs. We studied several cyclin-dependent kinases (cdk1, cdk2, cdk4, cdk6) and cyclins (cyclin A, cyclin B1, cyclin D3 and cyclin E). We also studied proliferating cell nuclear antigen (PCNA) and Bcl-2 expression, the latter protein known to be involved in the prolonged survival of B-lineage ALL blasts. Proteins obtained from cell lysates were resolved on polyacrylamide gel followed by immunodetection and densitometry of specific bands. Expression of cdk1 and PCNA, markers of proliferative activity, was significantly higher in T- than in B-lineage ALL. Cdk6, which was highly correlated to PCNA, was also higher in T-cell ALL. In contrast, B-lineage ALL displayed a higher expression of anti-apoptotic protein Bcl-2. We hypothesize that those particularities may reflect differential roles of cell multiplication and apoptosis in the neoplastic proliferation of B- and T-lineage ALL.

Adult↗
PubMed1996

POEMS syndrome, arterial thrombosis and thrombocythaemia.

The case of a 22-year-old man with polyneuropathy, endocrinopathy, skin change and monoclonal gammopathy of IgG-lambda type is described. There was no solitary plasmocytoma, osteosclerotic myeloma or Castleman's disease. However, significant thrombocytosis occurred and the patient developed arterial thrombosis, these were attributed to essential thrombocythaemia in the absence of other aetiological factors.

Adult↗
PubMed1995

Methods for cell proliferation analysis by fluorescent image cytometry.

Methods were developed for multimodal microscopic image analysis in order to identify and analyze one cell type under various microscopic conditions. Our purpose was to quantify both total DNA content using propidium iodide (PI) stain and S-phase fraction using the bromodeoxyuridine (BrdUrd) incorporation technique in cell population subsets. The model chosen was plasma cells in bone marrow triply labelled with fluorescein isothiocyanate (FITC) for intracytoplasmic immunoglobulins, with amino-methylcoumarin-acetate (AMCA) for BrdUrd, and with PI for DNA. Image analysis included three phases. First, plasma cells were recognized on FITC images, and the centroid positions were stored. Second, plasma cell nuclei were geodesically reconstructed from these stored positions using PI images in which DNA content was measured, and the nuclear mask outlines were stored. Third, BrdUrd incorporation level of plasma cells was measured on AMCA images inside PI nuclei masks and stored. Image DNA vs. BrdUrd scatterplots were obtained for cells selected according to the expression of intracytoplasmic immunoglobulin. Thus, both ploidy and proliferation could be independently evaluated on a subset of the cellular population.

Animals↗
PubMed1995

Cdk1 is a marker of proliferation in human lymphoid cells.

To better understand the relationship between the proliferation of human lymphoid cells and the expression of cdk1, a catalytic subunit of the histone H1 kinase (H1K), we examined its mRNA and protein content in 3 B-cell lines: Ramos, Reh-6 and IARC 963. Cells were elutriated according to their position in the cell cycle. Cell fractions were analyzed for cdk1 mRNA and protein cellular content by Northern blot and immunoblot, respectively, as well as for H1K activity. Both mRNA and protein amounts and H1K activity varied according to cell cycle phase, the lowest values being observed in G1-enriched fractions. For comparison, elutriated fractions were also tested for the expression of cdk2 and cdk4 proteins. Both showed some variations among fractions, but they were less clear than those of cdk1. We also tested 29 samples of lymphoid neoplastic and non-neoplastic tissues for proliferative activity (percentage of S and G2/M cells estimated by flow cytometry) and expression of cdk1, cdk2 and cdk4 proteins. We found a significant correlation between the percentage of cells in S or S + G2/M phases and cdk1 protein content but not cdk2 or cdk4 content. We conclude that cdk1 expression in human lymphoid cells varies during the cell cycle at both mRNA and protein levels.

Biomarkers↗
PubMed1995

Plasma cell proliferation in monoclonal gammopathy: relations with other biologic variables--diagnostic and prognostic significance.

PURPOSE: We investigated the place of direct plasma cell proliferation analysis beside other biologic data in monoclonal gammopathy, particularly the serum level of C-reactive protein (C-RP) PATIENTS: Eighty patients were studied at the time of their diagnosis. Patients with a serum creatinine level greater than 200 mumol/L were excluded. METHODS: Plasma cell proliferation analysis was performed after bromodeoxyuridine incorporation and double immunoenzymatic labeling on cytological smears, making determination of the plasma cell labeling index (LI) possible. The other biologic variables studied were related to tumor burden (plasmacytosis, hemoglobin, serum levels of monoclonal immunoglobulin, albumin) or to kidney function (creatinine). beta 2-microglobulin (beta 2-M), C-RP, lactic dehydrogenase (LDH), and calcemia were also assessed. RESULTS: No correlation was found between LI and serum C-RP. LDH was the sole variable significantly correlated to C-RP (P < 0.01). Besides the biologic parameters used for the staging according to the Durie and Salmon classification, beta 2-M, albumin and LI were significantly different between stages (P < 0.0002, < 0.0004, < 0.00001). LDH and C-RP showed no significant difference. Results were similar when patients with and without bone lesions were analyzed separately. Multivariate analysis ranked these variables as follows with respect to prognostic value: beta 2-M, LI, and age. CONCLUSION: Among the variables analyzed, LI is the sole true reflector of cell proliferation. We confirm its diagnostic and prognostic value.

Adult↗
PubMed1995

An original perifollicular zone cell in the canine reactive lymph node: a morphological, phenotypical and aetiological study.

In this study of 109 canine reactive lymph nodes, the perifollicular zone (PZ) cell was characterized by cytological, histological, immunocytochemical and electron microscopical techniques. The PZ cell was always found in association with plasma cell hyperplasia. Its main cytological characteristics were medium size, fine chromatin and a large central prominent nucleolus with a small amount of pale cytoplasm. It was located in a clearly recognizable PZ surrounding the follicles; this zone was particularly well developed at the capsular pole of the lymph node. Electron microscopical findings indicated a poorly differentiated cell. Immunolabelling indicated a CD3-, cIg-, Ki-67- immunophenotype, suggesting a resting B cell. These results suggest that the PZ cell belongs either to a post-follicular stage between large immunoblasts and plasma cells or, as is more likely, to a pre-follicular lymphoid subpopulation occurring early in the B-cell differentiation scheme, as with most human marginal zone (MZ) cells. Its high frequency of occurrence in reactive lymph nodes in mammary tumour lymphadenopathies, systemic lupus erythematosus and leishmaniasis, suggests that the PZ cell has a special role in the canine immune response, or perhaps in the arrested maturation of the normal developmental process.

Animals↗
PubMed1995

Detection of EBV mRNA in nodular sclerosis type of Hodgkin's disease using in situ hybridization with EBER 1 and EBER 2 probes with regard to the immunophenotype of Reed-Sternberg cells.

Hodgkin's disease (HD) is a heterogenous disorder in terms of morphology, immunophenotype, genotype and association with viruses. Seroepidemiologic, immunohistochemical and molecular studies suggest that Epstein-Barr Virus (EBV) plays an important role in the pathogenesis of HD. We used in situ hybridization (ISH) with digoxigenin-labeled EBER 1 and EBER2 probes to examine a series of 28 lymph node specimens from untreated patients from Poland with the nodular sclerosis NS 1 and NS 2 subtypes of HD to detect EBV mRNA in Reed-Sternberg cells (RSC), or in small non-neoplastic lymphocytes called "bystander cell" (ByC). EBV mRNA was detected in 12 of 28 cases (32.1%). Furthermore, the expression of Latent Membrane Protein (LMP) of EBV strongly correlated with expression of EBER 1 and EBER 2 in RSC but not in "bystander cells", which were LMP negative. The correlation between EBV status and immunophenotype of RSC are discussed.

Herpesvirus 4, Human↗