Biomedical subjects

G Roos

Publications and source records attributed to G Roos.

At least 55 records · Page 3Linked to original sources

PubMed1999

Establishment and characterization of a mouse strain (TLL) that spontaneously develops T-cell lymphomas/leukemia.

In this study, a mouse strain (TLL) that spontaneously develops T-cell lymphomas/leukemia with an early onset and high incidence was established and characterized. All tumors analyzed were found to express the alpha,beta T-cell receptor, and the majority of them had a mature, CD3+CD4+CD8- immunophenotype. In a few cases, tumors with a more immature CD3+CD4+CD8+ phenotype were isolated. Expanded phenotyping using a broad panel of lymphocyte differentiation markers confirmed the mature T-cell phenotype of the tumors. Histologic and cell cycle analysis of the tumors revealed an aggressive lymphoblastic malignancy with a very high proliferation rate and widespread engagement of bone marrow and lymphoid as well as nonlymphoid organs. Thus, the TLL mouse strain represents a unique model for the analysis of the oncogenesis and progression of mature T-cell tumors and for the development of therapeutic measures to combat such tumors.

Animals↗

PubMed1999

Follow-up guidelines for nonmetastatic renal cell carcinoma based on the occurrence of metastases after radical nephrectomy.

OBJECTIVE: To define guidelines for the follow-up management of nonmetastatic renal cell carcinoma (RCC), by assessing tumour recurrences and the clinical course in patients who had undergone radical nephrectomy. PATIENTS AND METHODS: The records of 187 patients with pT1-3, N0-X, M0 RCC who underwent radical nephrectomy between 1982 and 1997 were reviewed prospectively. Clinicopathological variables were compared with the time of first recurrence, site of metastasis and reason for diagnosis. RESULTS: Metastases were diagnosed in 98 sites in 56 of the 187 patients (30%). The risk for developing metastases increased with stage; 80% of the patients had their metastases diagnosed within 3 years (median 14.5 months) after nephrectomy. The time to first diagnosis was longer for patients with pT1 tumours and for those with skeletal metastases. The cause-specific 5-year survival rate for pT1 tumours was 95%, for pT2 87% and for pT3 tumours 37%. All patients with diploid pT1-2 RCC survived, having a survival advantage over those with aneuploid pT1-2 tumours (P=0.018). Also, pT1-2 tumours of < 5 cm were associated with better survival rates. Among 74 patients with pT3 tumours, 45 got metastases; DNA ploidy in these tumours did not influence survival. Of 30 patients with lung metastases, 28 were diagnosed during follow-up, while 25 of 26 other metastatic sites were diagnosed because of symptoms. CONCLUSIONS: The risk for tumour progression depends mainly on stage; these results indicate no need for follow-up in patients with diploid pT1-2 tumours or with aneuploid pT1 tumours of < 5 cm. For patients with aneuploid pT1-2 tumours of > 5 cm and pT3 tumours, follow-up is indicated.

Adult↗

PubMed1999

Neuroendocrine differentiation in renal cell carcinoma--evaluation of chromogranin A and neuron-specific enolase.

Chromogranin A and neuron-specific enolase (NSE) as neuroendocrine markers were evaluated in 200 patients with renal cell carcinoma, and 15 patients with benign renal cysts. Immunoassays of serum levels and immunohistochemical staining of tumour tissue were performed. Serum chromogranin A was elevated in 28 (14%) patients with renal cell carcinoma, but the levels did not differ from those for patients with benign cysts. Serum NSE was elevated in 54 (27%) patients, significantly higher compared with controls (p = 0.0002). Serum chromogranin A level was positively correlated to serum creatinine and age, but not to tumour stage or grade. Serum NSE level was positively correlated to tumour stage and grade, but not to serum creatinine or age. Immunohistochemical staining for chromogranin A was positive in 1 of 24 (4%), and for NSE in all 18 (100%) tumours analysed. In a multivariate analysis, tumour stage, grade, and serum NSE, but not chromogranin A, were significant predictors of prognosis.

Adult↗

PubMed1999

V(H) gene family utilization in different B-cell lymphoma subgroups.

V(H) gene family specific polymerase chain reaction (PCR) amplification was performed in 87 B-cell lymphoma samples from 4 different subgroups. No apparent restriction in the VH gene usage was found in follicular lymphomas, lymphoplasmacytoid lymphomas or large B-cell lymphomas, whereas a biased VH1 utilization was shown in patients with chronic lymphocytic leukemia. Eleven of 18 chronic lymphocytic leukemia cases utilized the VH1 gene family, and nucleotide sequencing of the VH1 gene rearrangements revealed that a majority utilized the DP10 (51p1) germline gene, which has been reported to be strongly associated with autoimmune disease. No VH5 or VH6 rearrangements were amplified in the chronic lymphocytic leukemia subgroup, 2 gene families which previously have been found to be over-represented in these patients. In a high proportion (40%) of large B-cell lymphomas, VH gene family-specific PCR failed to amplify any rearrangement. Using primers hybridizing to the framework regions 2 and 3 and Southern blot analysis of the immunoglobulin heavy chain locus, clonal rearrangements were displayed in two-thirds of these PCR negative cases. However, the rearrangement status could not be elucidated in 5 of 35 patients with large B-cell lymphoma.

DNA Primers↗

PubMed1999

Clonal evolution as judged by immunoglobulin heavy chain gene rearrangements in relapsing precursor-B acute lymphoblastic leukemia.

Oligoclonality and ongoing clonal evolution are common features in patients with precursor-B (pre-B) acute lymphoblastic leukemia (ALL), as judged by immunoglobulin heavy chain (IgH) gene rearrangement analysis. These features are considered to be results of secondary rearrangements after malignant transformation or emergence of new tumor clones. In the present study we analyzed the IgH gene rearrangement status in 18 cases with relapsing pre-B ALL using variable heavy chain (V(H)) gene family specific polymerase chain reaction (PCR) amplification and single stranded conformation polymorphism (SSCP) analysis. Clonal IgH rearrangements were displayed in all leukemias but one, and altered rearrangement patterns occurred in five cases (29%), which were selected for detailed nucleotide sequence analysis. In one case, multiple subclones at diagnosis were suggested to be derived from a progenitor clone through joining of different V(H) germline gene segments to a pre-existing D-J(H) complex (V(H) to D-J(H) joining). Evidence for V(H) gene replacement with identical N-sequences at the V(H)-D junction and a common D-J(H) region was observed in one case. Diversification at the V(H)-D junction consisting of heterogeneous N-sequences were observed in one case. This molecular modification of the V(H)-D region could fit a hypothesized "open-and-shut" mechanism. Nevertheless, despite these ongoing events at least one IgH rearrangement remained unchanged throughout the disease in most patients, indicating that the immunoglobulin heavy chain locus can be a suitable marker for detection of minimal residual disease (MRD).

Base Sequence↗

PubMed1999

Clonal rearrangements in childhood and adult precursor B acute lymphoblastic leukemia: a comparative polymerase chain reaction study using multiple sets of primers.

Ig heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements were investigated by polymerase chain reaction (PCR) amplification of diagnostic tumour samples from 91 patients (57 children and 34 adults, with cut-off at age 16) with precursor B acute lymphoblastic leukemia (ALL). Using primers directed to the framework regions (FR) 1, 2 and 3 of the IgH gene, clonal IgH rearrangements were observed in 82, 58 and 58%, respectively, whereas clonality was presented in 45 and 27% using primers hybridising to the TCR delta and gamma genes. A combination of all five primer sets used resulted in 96% positive cases (children 100%, adults 88%). The frequency of clonal IgH rearrangements correlated to patient age with a significantly lower fraction of positive cases in the adult group. The concomitant usage of more than one V(H) family gene was similar for childhood and adult ALL, and an over-representation of V(H)6 rearrangements was found in childhood ALL. Twenty-five out of 91 cases (27%) displayed an oligoclonal pattern for either IgH or TCR gene rearrangements (children 37%, adults 12%). A comparative analysis of samples from different compartments was performed in 23 patients, and differences between two or three compartments were observed in seven cases. Unexpectedly large, clonally appearing PCR products of 540-715 bp were found in three leukemias and sequence analysis verified their clonal nature. In summary, using multiple sets of primers clonal rearrangements of IgH and TCR genes can be detected in a very high frequency, including previously neglected large size PCR products. A common heterogeneity was demonstrated in different compartments reflecting ongoing clonal evolution, which can make detection of minimal residual disease (MRD) in ALL troublesome. Therefore, we suggest that a minimum of three targets should be used to minimise false-negative results.

Adolescent↗

PubMed1999

Prognostic significance of the Heidelberg classification of renal cell carcinoma.

OBJECTIVE: The specific genetic alterations characterising renal cell carcinoma (RCC) have lead to the recognition of distinctive types of tumours. In a large material of patients, the prognostic and clinical information of these different tumour types were evaluated. METHODS: Tumours from 186 patients were evaluated retrospectively according to the guidelines given by the Heidelberg Classification Conference. All patients were primarily nephrectomised and TNM staged, and the follow-up times for alive patients varied between 44 and 174 months. RESULTS: The material consisted of 145 conventional (non-papillary), 25 papillary, 12 chromophobe and 4 unclassified RCCs. There was no difference in tumour size between the different RCC types. Among patients with conventional RCC, 37% had distant metastases at the time of diagnosis, significantly more frequently than 16% in patients with papillary and 8% in chromophobe RCC (p = 0.044 and 0.048, respectively). Conventional RCC more frequently had vein invasion compared with papillary RCC (p = 0.009). Patients with chromophobe and papillary RCC survived significantly longer than patients with conventional RCC (p = 0.017 and 0.031, respectively). CONCLUSIONS: A significant difference in clinical behaviour between the different RCC types was found. Patients with conventional RCC had a higher incidence of metastases, vein invasion and had adverse survival compared with papillary and chromophobe RCCs. Thus, the RCC types recognised by specific genetic alterations seem to represent different malignant phenotypes.

Adult↗

PubMed1999

Immunohistochemical analysis of the proliferation associated nuclear antigen CENP-F in non-Hodgkin's lymphoma.

CENP-F is a newly characterized cell cycle-associated nuclear antigen that is expressed in low amounts in G0/G1 cells and that accumulates in the nuclear matrix during S phase with a maximal expression in G2/M cells. CENP-F can be analyzed by flow cytometry and used as a proliferation marker. In the present study, therefore, we characterized the expression of CENP-F in non-Hodgkin's lymphoma by immunohistochemical techniques to detect potential dysregulation of the protein or to establish CENP-F as a reliable proliferation marker. A polyclonal rabbit antibody reacting with CENP-F was prepared and used for immunohistochemical analyses after antigen retrieval. The rabbit antibody produced immunofluorescence patterns, flow cytometric profiles, and Western blot reactivity identical to those of the human autoantibody used in earlier studies. The percentage of CENP-F-positive and Ki-67-positive cells, as well as the labeling index, S-phase time, and potential doubling time, derived from in vivo iododeoxyuridine incorporation, were evaluated in 41 non-Hodgkin's lymphomas. Aggressive lymphomas showed higher CENP-F values than did indolent cases (10.1 vs. 3.4%). The percentage of CENP-F-positive cells correlated significantly to the S-phase fraction (r(s) = 0.68), the Ki-67 index (r(s) = 0.56) and the labeling index of iododeoxyuridine (r(s) = 0.47), as well as to S-phase time and potential doubling time (r(s) = 0.34 and -0.40). A lower fraction of CENP-F-positive cells was found, compared with the Ki-67 index (4.9 vs. 9.4%), supporting previous observations that CENP-F was expressed in a fraction of actively growing cells. These correlative data indicate that CENP-F expression defines a specific subpopulation of growing cells and that no clear evidence for dysregulation was found. Accordingly, CENP-F seems to be a useful proliferation marker for formalin-fixed and paraffin-embedded material.

Animals↗

PubMed1998

Telomerase activity in relation to p53 status and clinico-pathological parameters in breast cancer.

Cell cycle deregulation can occur at different levels in cancer. In human breast cancer it includes overexpression of cyclins D1 and E, down-regulation of cyclin-dependent kinase inhibitors and inactivation of the retinoblastoma and p53 tumor suppressor proteins. Telomerase activity is strongly associated with an immortal phenotype and expression of telomerase is linked to the cell cycle. We have recently demonstrated a connection between specific cell cycle defects within the pRB pathway and levels of telomerase activity in breast cancer. In the present study, 106 tumors were investigated for p53 gene and protein status. By single strand conformation polymorphism (SSCP) analysis, 15% showed mutations within exons 5-8 and by immunohistochemistry (IHC), 29% were p53 positive. Tumors with a telomerase activity above median (i.e., telomerase(high)) were significantly associated with p53 protein accumulation (p = 0.004), but not with p53 gene mutations. The strongest telomerase expression was found in tumors with p53 protein accumulation. Morphologic grade, estrogen and progesterone receptor expression differed significantly between the telomerase(high) and telomerase(low) groups (p < 0.0001, p = 0.016 and p = 0.046, respectively), but no difference was observed for stage or nodal status. Telomerase(high) tumors were significantly associated with a poor prognosis for node-negative (N0) patients (p = 0.008), but not for node-positive (N+) patients, whereas the opposite was demonstrated for tumors with p53 accumulation. The survival data indicated that telomerase expression has biological importance particularly for N0 tumors, suggesting that telomerase(low) tumors constitute a group of "pre-immortalized" tumors with a good prognosis.

Breast Neoplasms↗

PubMed1998

Telomere analysis by fluorescence in situ hybridization and flow cytometry.

Determination of telomere length is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Fluorescence in situ hybridization (FISH) of telomere repeats has been used to calculate telomere length, a method called quantitative (Q)-FISH. We here present a quantitative flow cytometric approach, Q-FISHFCM, for evaluation of telomere length distribution in individual cells based on in situ hybridization using a fluorescein-labeled peptide nucleic acid (PNA) (CCCTAA)3probe and DNA staining with propidium iodide. A simple and rapid protocol with results within 30 h was developed giving high reproducibility. One important feature of the protocol was the use of an internal cell line control, giving an automatic compensation for potential differences in the hybridization steps. This protocol was tested successfully on cell lines and clinical samples from bone marrow, blood, lymph nodes and tonsils. A significant correlation was found between Southern blotting and Q-FISHFCMtelomere length values ( P = 0.002). The mean sub-telomeric DNA length of the tested cell lines and clinical samples was estimated to be 3.2 kbp. With the Q-FISHFCMmethod the fluorescence signal could be determined in different cell cycle phases, indicating that in human cells the vast majority of telomeric DNA is replicated early in S phase.

Base Sequence↗

PubMed1998

Expression of cyclin E and the cyclin-dependent kinase inhibitor p27 in malignant lymphomas-prognostic implications.

Cyclin E and the cyclin-dependent kinase inhibitor p27 are two important regulators of the G1-S transition modulating the activity of cyclin-dependent kinases. Aberrations in the cell cycle control are often observed in tumors and might even be mandatory in tumor development. To investigate the importance of cell-cycle defects in malignant lymphomas we have characterized the expression of cyclin E and p27 in 105 newly diagnosed lymphomas using immunohistochemistry. A significant, inverse correlation between p27 and cyclin E expression was observed (rs = -.24, P = .02) and both proteins correlated with the S-phase fraction (rs = -.35, P < .001 and rs = . 45, P < .001, respectively). The inverse relationship between p27 expression and proliferation was abrogated in some lymphomas, suggesting that p27 downregulation can represent a genuine aberration. Survival analysis was performed in 105 patients with a median observation time of 86 months. Low p27 and high cyclin E expression were significantly associated with a poor prognosis (P = . 0001 and .03, respectively). In a multivariate Cox analysis, p27 expression, stage, serum lactate dehydrogenase level, grade, and age were independent prognostic factors, in contrast to S-phase fraction and cyclin E expression. This is the first report showing that p27 expression in malignant lymphomas has independent prognostic significance, which necessitates future studies regarding its more precise biological role in lymphoid tumorogenesis.

Biomarkers, Tumor↗

PubMed1998

Telomerase activity in Hodgkin's disease.

Telomere maintenance executed by the action of telomerase seems to be a prerequisite for immortalization. Telomerase is found in most cell lines and malignant tumors. A telomerase-independent mechanism for telomere maintenance in Hodgkin's disease has been proposed in the absence of detectable telomerase activity. In this study, telomerase activity was detected in 31 of 77 Hodgkin's disease samples and a strong correlation between eosinophilia and absence of detectable telomerase activity was found. Purified eosinophils and specifically eosinophil-derived neurotoxin and eosinophilic cationic protein, both ribonucleases, were found to degrade telomerase. Purified neutrophils also exhibited weak telomerase degradative activity. Reanalysis of previously telomerase-negative Hodgkin's disease samples with eosinophilia using ribonuclease inhibitors resulted in the detection of telomerase activity. Ribonuclease-containing cells in vivo thus have a considerable impact on the detectability of telomerase. In Hodgkin's disease samples without eosinophilia, 24 of 27 exhibited telomerase activity at decreased levels compared with non-Hodgkin's lymphomas and at increased levels compared with reactive nodes indicative of a telomerase positive tumor component in Hodgkin's disease. Telomerase positivity of the Hodgkin's and Reed-Sternberg cells in vivo was also supported by high levels of telomerase expression in Hodgkin's disease cell lines. Based on our data, Hodgkin's lymphomas are potential targets for antitelomerase therapy.

Eosinophils↗

PubMed1998

Combination of LC-MS and LC-NMR as a Tool for the Structure Determination of Natural Products

Application of both LC-MS and LC-NMR to a partially purified extract of Vernonia fastigiataled to the direct identification of antibacterial sesquiterpene lactones 1-9 without isolation of individual compounds. The rapid structural analysis of both major and minor components of this class of compounds demonstrated the power of structure-guided screening as a complementary method to assay-guided screening.

Journal Article↗

PubMed1998

[Single ventricle (cor trilocular biatriatum). A case report].

Univentricular hearts represent rare complex cardial malformations. We report a case of a 34-year old male with single ventricle, two atria, tricuspid atresia, large atrial septal defect, complete transposition and pulmonary valvar stenosis. There were no signs of chronic pulmonary hypertension. Intensive clinical analysis of the cardiac malformation was first performed at the age of five years. Conclusion was that the patient would have no benefit from operation. The patient had nearly normal live conditions with a profession, family and some sportive activities like squash. He died of sudden cardiac death. The malformation was examined by sequential segmental analysis and in comparison with the embryonic development. Special features are emphasized. Clinical picture, prognosis and therapy are reported from literature. During the last years development of cardiac surgery achieved good results. Special morphologic constellations, as in our case, may be the reason that conservative therapy can be sufficient for prolonged survival with good quality of life.

Adult↗

PubMed1998

Alterations of the immunoglobulin heavy chain locus in progressive B-cell lymphomas.

Twenty-two patients with relapsed or progressive B-cell lymphomas (BCL) were analysed for alterations in the rearrangement status in the immunoglobulin heavy (IgH) chain gene in samples obtained on different occasions during the course of the disease. The analysis was performed using Southern blot hybridization of the IgH gene and polymerase chain reaction (PCR) amplification of the VH gene families combined with single-strand conformation polymorphism (SSCP) analysis. Using Southern blot analysis, we found that all 22 lymphomas displayed clonal IgH rearrangements, and changes during tumour progression occurred in 8 cases. These alterations were mainly observed in cases with follicular or transformed lymphomas. More than one malignant (sub)clone, indicated by more than two rearranged bands, was detected in one case at diagnosis and in three cases at relapse. Outgrowth of subclones with divergent rearrangement patterns in different compartments was also observed in 2 out of 8 cases. PCR-SSCP analysis indicated that all 15 cases studied displayed clonal rearrangements and in 6 cases altered rearrangement patterns were detected in later samples. Southern blotting and PCR-SCCP analysis gave equivalent results. No association was found between time to relapse or survival time and alterations in rearrangement pattern. The present study illustrates that the neoplastic cell clones in BCL often display alterations in their IgH locus, but the significance of this feature remains to be clarified.

Blotting, Southern↗

PubMed1998

Expression of activation markers CD23 and CD69 in B-cell non-Hodgkin's lymphoma.

The activation associated proteins CD23 and CD69 are expressed on cells of different lineages upon mitogenic stimulation. CD23 is a well characterized multifunctional protein in lymphocyte development recognized as a diagnostic marker for chronic lymphocytic leukaemia. CD69 is one of the earliest markers expressed after activation of T cells, but its function is unclear. The aim of this study was to investigate the expression of these antigens in B-cell non-Hodgkin's lymphomas (NHL) in relation to clinical behaviour. Ninety samples from 84 patients with NHL of B cell type were studied for the expression of CD23 and CD69 in CD20+ B cells by flow cytometric dual parameter analysis. In individual lymphomas the CD23 and CD69 antigens showed an "on or off" pattern with most or very few cells positive for each antigen. The CD23 antigen was expressed in 23 of 53 (43%) indolent lymphomas and in 2 of 37 (5%) aggressive cases. Most indolent lymphomas (81%) and about half the aggressive cases (53%) expressed the CD69 antigen. Thus, both markers were associated with indolent type. CD23 expression correlated with chronic lymphocytic leukaemia subtype and CD69 expression with male gender, advanced stage, newly diagnosed lymphoma and shorter survival.

Adult↗

PubMed1998

Low rate of somatic hypermutations characterize progressive B-cell lymphomas.

Immunoglobulin heavy (IgH) chain gene rearrangements were characterized in 40 samples from 15 patients with B-cell lymphomas at different time points during tumour progression. Using polymerase chain reaction (PCR) amplification and single strand conformation polymorphism (SSCP) analysis of variable heavy (VH) chain gene segments, we found that 6 cases displayed alterations in their IgH chain rearrangements at relapse. These alterations were mainly observed in follicular or transformed lymphomas, but no association to clinical features was found. Nucleotide sequence analysis revealed a low frequency of mutations in 3 cases, whereas 1 case displayed an extensive mutation rate in a compartment with transformed morphology at relapse. The mutations observed most probably resulted from somatic hypermutations. Further, the mutations were scattered randomly over the VH gene segment and no significant bias favouring amino acid substitutions was observed in 3 cases, suggesting that the tumour cells had not been subjected to antigen-driven selection. In 1 case, however, the mutation pattern indicated that the tumour cells had been affected by an antigen selection process. In the 2 remaining cases, the original V(H)DJ(H) rearrangement could no longer be detected by VH gene family specific PCR at relapse, but using primers specific for the framework region 2 or 3 altered rearrangements were demonstrated, implying that mutations had been introduced in framework region 1. However, the majority of the tumour cell clones analysed were relatively stable during tumour progression, which make them eligible for analysis of minimal residual disease using the VH gene regions as molecular markers.

Adult↗

PubMed1998

Flow cytometric DNA index and karyotype in childhood lymphoblastic leukemia.

Flow cytometric DNA-index (DI(FCM)) and karyotype were analysed in 82 consecutive children with acute lymphoblastic leukemia (ALL) during a 10 year period. A statistically significant correlation existed between modal chromosome number and DI(FCM) (p = 0.009). DI(FCM) could reliably identify leukemias with >51 chromosomes, whereas only three out of 12 cases with modal chromosome numbers between 47-51 were classified as aneuploid by DI(FCM). In the pseudodiploid group only one out of 20 leukemias had a DI(FCM) > 1.0. Five leukemias with a diploid karyotype showed an aneuploid DI(FCM) and in three patients the flow cytometric measurement revealed biclonality undetected by karyotyping. During treatment aneuploid clones could be detected by DI(FCM) in a substantial number of cases where the cytogenetic analysis was normal, and the opposite was also demonstrated in one case. DI(FCM) gave prognostic information, showing that cases with a DI > 1.12 (corresponding to 51 chromosomes) had a superior outcome with treatment protocols today in use.

Adolescent↗