Biomedical subjects

G Roos

Publications and source records attributed to G Roos.

At least 91 records · Page 5Linked to original sources

PubMed1996

Heterogeneity in renal cell carcinoma and its impact no prognosis--a flow cytometric study.

In the process of tumour progression genetic instability is the basis for the evolution of tumour cell clones with various genotypic and phenotypic characteristics causing heterogeneity. Renal cell carcinoma has a long prediagnostic growth period, which increases the probability of clonal evolution. We have studied 200 consecutive renal cell carcinomas, addressing the interrelationship between intratumour heterogeneity and clinicopathological factors. DNA ploidy patterns were analysed in multiple samples from each tumour using flow cytometry and compared with clinical stage, tumour invasion, metastatic rate and survival. Eighty-five of 192 evaluable tumours (44%) were homogeneous concerning DNA ploidy (62% diploid, 38% aneuploid). Among 107 heterogeneous tumours a majority (79%) contained aneuploid as well as diploid cell clones. Homogeneously diploid tumours had a lower incidence of local tumour spread compared with tumours with aneuploid cell clones (P < or = 0.001), but the frequency of distant metastasis at time of diagnosis was similar. The presence of aneuploidy in at least one sample from a tumour was a significant adverse prognostic factor (P < 0.001), whereas the degree of heterogeneity had no influence on survival. The frequent heterogeneity demonstrated indicates that multiple samples must be investigated to evaluate properly the malignant character of renal cell carcinoma.

Adult↗

PubMed1996

Pectin-supplemented enteral diet reduces the severity of methotrexate induced enterocolitis in rats.

BACKGROUND: Administration of methotrexate (MTX) to rats fed an elemental diet results in a high mortality from severe enterocolitis. Previous studies have shown that pectin is an important precursor of substrates for intestinal structure and function and may facilitate intestinal recovery after enterocolitis. The aim of this study is to evaluate the effect of pectin on MTX-induced enterocolitis in rats. METHODS: Rats received intragastric infusion of either 1% pectin-supplemented or pectin-free elemental diet from the beginning of the study via a gastrostomy. On the 4th day animals received either MTX, 20 mg/kg intraperitoneally, or saline injection and were killed on the 7th day for sampling. RESULTS: Pectin supplementation significantly decreased body weight loss, organ water content, and intestinal myeloperoxidase levels and increased mucosal protein, DNA, and RNA content in enterocolitis rats. The intestinal permeability was increased by administration of MTX, and pectin supplementation significantly reversed the increased permeability in the distal small bowel and colon. Pectin supplementation also lowered the magnitude of bacterial translocation, decreased plasma endotoxin levels, and restored bowel microecology. CONCLUSIONS: Pectin significantly decreased MTX-induced intestinal injury and improved bowel integrity.

Animals↗

PubMed1996

Predictive value of DNA ploidy in bladder cancer treated with preoperative radiation therapy and cystectomy.

The predictive value of flow cytometric DNA analysis of cells from bladder washings was evaluated in 43 patients with muscle-invasive or recurrent superficial bladder cancer treated with preoperative radiotherapy and cystectomy. There was no correlation between ploidy status of the primary tumour and survival, neither was there any correlation between ploidy and the occurrence of residual tumour in the cystectomy specimens. Patients without residual tumours in the cystectomy specimen had significantly longer survival time than those with residual tumours. Concomitant carcinoma in situ was correlated with better survival, which is surprising, considering the malignant potential of this lesion. In this study DNA ploidy did not predict tumour response to radiotherapy nor was it of any prognostic significance.

Carcinoma in Situ↗

PubMed1996

Proliferating cell nuclear antigen expression in renal cell carcinoma. Prognostic implications.

The proliferating cell nuclear antigen (PCNA) is a nuclear protein associated with cells in active cell cycle. The expression of PCNA was evaluated immunohistochemically in 3-6 samples from 68 renal cell carcinomas. A total of 279 tumour samples were analysed using the monoclonal antibody PC-10, and the percentage of positively stained cell nuclei (PCNA-index) was determined. The tumour PCNA-index varied between 0.9-17.5%, with a mean value of 4.9%, significantly different from normal kidney cortex samples (p < 0.001). A significant difference in PCNA-index was found between the different tumour grades, whereas no significant difference was found between clinical stages. Concerning DNA ploidy, aneuploid tumours had a significantly higher PCNA-index compared with diploid tumours (p = 0.002). There was a significant survival advantage for patients with low tumour PCNA-indices (< 3.5%) compared with those with high indices (> 3.5%, p = 0.019), a difference also found for patients with non-metastatic disease (p = 0.012). Our data shows that PCNA expression can be analysed and that it may constitute an additional prognostic parameter for patients with renal cell carcinoma.

Adult↗

PubMed1995

p53 expression and cell proliferation in squamous cell carcinomas of the head and neck.

BACKGROUND: In squamous cell carcinoma of the head and neck (SCCHN), overexpression of the p53 protein has been found in 34-80% of the tumors studied. No data are available regarding p53 expression versus tumor cell proliferation and prognosis for this tumor type. METHODS: p53 protein levels were studied by immunohistochemical staining of 33 primary SCCHN using 3 antibodies (DO7, PAb 1801, and CM1) that react with different epitopes of the p53 protein. The cellular expression of p53 was compared with in vivo incorporation of the thymidine analog iododeoxyuridine (IdUrd) and expression of proliferating cell nuclear antigen (PCNA). RESULTS: Twenty-one tumors (64%) had a positive nuclear staining for p53 with the monoclonal antibody DO7, which reacts with a denaturation-resistant epitope in wild-type and mutant p53. PAb 1801 and CM1 reacted with 19 and 20 tumors, respectively, all of which were DO7-positive. No correlation was found between incorporation of IdUrd and p53 expression or between PCNA and p53 expression. The data indicate that intracellular accumulation of the p53 protein was related to tumor stage and localization of the tumor. No indication of a clinical or prognostic significance of p53 expression in SCCHN was found. CONCLUSIONS: No association between p53 deregulation and tumor cell proliferation was found.

Carcinoma, Squamous Cell↗

PubMed1995

Tumour S-phase activity, nucleotide profile and RNA levels after hepatic artery occlusion and reperfusion in an experimental model of secondary liver carcinoma.

Rats with carcinoma of the colon implanted into the liver were subjected to hepatic arterial occlusion for 30-120 min. Regrowth of the tumour after reperfusion was evaluated by immunohistological determination of S-phase activity after injection of bromodeoxyuridine. Levels of RNA and nucleotides, and energy charge, were also examined. DNA synthesis was observed in the entire tumour except in necrotic areas of controls and after 30-min ischaemia with 2-h reflow. Almost all tumoral DNA synthesis was abolished by 2 h of ischaemia, except in a few cells in the tumour periphery, which after reperfusion for 22 and 40 h grew into a band-like concentric layer. Levels of energy charge, adenosine, uridine and guanosine 5'-triphosphates, and RNA were unchanged in liver tissue after hepatic arterial occlusion but decreased in the tumour. In conclusion 30 min of ischaemia did not damage the tumour cells substantially. Ischaemia for 2 h seemed able to kill the tumour cells except those in the periphery in areas nourished by the portal vein where tumour regrowth was seen. The liver tissue was not damaged.

Animals↗

PubMed1995

Immunohistochemical detection of oncoprotein 18 (Op18) in malignant lymphomas.

Expression of oncoprotein 18 (Op18), an intracellular phosphoprotein up-regulated in many malignant cell types, was evaluated in a series of normal lymphoid tissue and malignant lymphomas. In normal tonsils and reactive lymph nodes, the majority of Op18-positive cells were present in the germinal centres, whereas cells in the mantle zone were essentially negative and the interfollicular areas showed occasional positive cells. Double staining for PCNA and Op18 revealed that Op18 expression only to some extent was correlated with cell proliferation, as determined by PCNA expression. Non-Hodgkin's lymphomas exhibited a variable Op18 expression, and in Hodgkin's disease, Reed-Sternberg and Hodgkin cells frequently expressed Op18 with a strong staining intensity. Using Op18-PCNA double staining in malignant lymphomas, Op18 expression could also be partially dissociated from cell proliferation. By using confocal microscopy, the intracellular localization of Op18 was studied, demonstrating diffuse reactivity in the cytoplasm in interphase cells and during mitosis, whereas nuclei and condensed chromosomes were negative. In conclusion, Op18 was expressed at variable levels in most, perhaps all, proliferating lymphocytes in benign lymphoid tissue as well as in malignant lymphomas. However, the Op18 protein was also detected in a significant fraction of apparently non-cycling normal and neoplastic lymphocytes.

Antibodies, Monoclonal↗

PubMed1995

Radiosensitizing effect of estramustine in malignant glioma in vitro and in vivo.

Estramustine-phosphate (EMP), a combination of nornitrogen mustard and 17 beta-estradiol, has been demonstrated to exert specific antiproliferative effects on human glioma cells in vitro. The cytotoxic effect is, at least partially, mediated by inhibiting microtubule function. In this study the combined effect of EMP and radiation was evaluated in the human glioma cell-lines, 251-MG and 105-MG, in vitro, and in the rat glioma BT4C in vitro and in vivo. In all cell-lines an additive effect of EMP and radiation was obtained in vitro. Assuming equal effect of EMP is obtained in subsequent radiation fractions, the cell kill will be increased from 2-3 to 5-10 logs if delivering 30 fractions of 2 Gy combined with EMP. In the BT4C rat model the combined effect was found to be synergistic. Flow cytometry demonstrated an arrest in G2/M phase in all cell-lines after EMP treatment. This block in G2/M phase in addition to the previously demonstrated induction of free oxygen radicals, and the increase of blood flow with an assumed subsequent increase of oxygenation, might provide an explanation for the observed radiosensitizing effect of estramustine.

Animals↗

PubMed1995

Peripheral blood lymphocyte subsets in polymyalgia rheumatica.

Peripheral blood lymphocytes from 23 patients with polymyalgia rheumatica (PMR) were characterized using monoclonal antibodies and flow cytometry in a two-year prospective study. There were no significant differences in absolute numbers or relative percentages of lymphocytes or CD3+, CD4+, CD8+ T cells or the CD4+ T cell functional subsets, virgin (CD4+CD45RA+) and memory (CD4+CD29+) T cells, in patients before or during corticosteroid treatment compared to controls. Previous reports on decreased levels of CD8+ T cells as a characteristic of PMR/giant cell arteritis was not confirmed. The absolute number and relative percentage of lymphocytes with natural killer cell activity, CD16+ CD56+ cells, were significantly lower in patients with active untreated PMR as well as during corticosteroid treatment compared to controls, but at the two-year follow-up the difference was less marked.

Aged↗

PubMed1995

[Neurocysticercosis].

A 54-year-old female patient with a 10-year history of ventriculoperitoneal shunt resulting from communicating hydrocephalus of undetermined aetiology is reported. Transient gait disturbances and cerebral infarction at the age of 46 did not lead to further insights into the nature of the disease. After many years with only occasional disturbances, a distinct organic brain syndrome developed. Thorough examination led to a tentative diagnosis of neurocysticercosis; this was based on the history, liquor diagnosis and cerebral microcalcifications in CT. Despite the initiation of specific therapy, the patient died of the sequelae of the disease. At autopsy, characteristic cicatricial residues of mainly basal leptomeningitis were found with collapsed parasitic cysts. Additional intracerebral mesenchymal-glial reactions were less conspicuous. Residual ependymitis had caused aqueductal stenosis. Death was due to cachexia, bronchopneumonia and a lung abscess. The clinical course and morphology of neurocysticercosis are discussed. The disease has become rare in our country, but is globally the most important parasitic disease of the central nervous system.

Brain↗

PubMed1995

Vein invasion in renal cell carcinoma: impact on metastatic behavior and survival.

PURPOSE: The development of a thrombus extending into the veins is well recognized in renal cell carcinoma. We investigated the hypothesis that vein invasion alone has no adverse impact on survival but is a highly negative factor in other tumors. MATERIALS AND METHODS: In 200 consecutive patients invasion of the renal vein and vena cava was evaluated and compared with the clinical course. RESULTS: A total of 26 patients had vena caval and 47 had renal vein invasion. Patients with venous invasion had a significantly shorter survival but no survival difference was demonstrated based on the level of involvement. CONCLUSIONS: Our study indicates that vein invasion itself seems to be an important prognostic factor in renal cell carcinoma.

Adult↗

PubMed1995

p53 mutations, protein expression and cell proliferation in squamous cell carcinomas of the head and neck.

Thirty-three patients with squamous cell carcinoma of the head and neck region were studied concerning p53 protein expression and mutations in exons 4-9 of the p53 gene using immunohistochemistry, polymerase chain reaction (PCR)-single strand conformation polymorphism analysis and DNA sequencing. Immunoreactivity was found in 64% and p53 gene mutations in 39% of the tumours. Thirty-three per cent of the immunopositive and 50% of the immunonegative tumours were mutated within exons 5-8. In one immunopositive tumour three variants of deletions were observed. Sequencing of the p53 mutated, immunonegative tumours revealed four cases with deletions, one case with a transversion resulting in a stop codon and one case with a splice site mutation which could result in omission of the following exon at splicing. All mutations in the immunonegative tumours resulted in a truncated p53 protein. No association between p53 gene status and expression of proliferating cell nuclear antigen (PCNA) or cell proliferation as judged by in vivo incorporation of the thymidine analogue iododeoxyuridine (IdUrd) was found.

Base Sequence↗

PubMed1995

DNA content in colorectal carcinoma: a flow cytometric study of the epithelial fraction.

The aim of this study was to estimate the proliferative activity of the epithelial fraction in human colorectal carcinomas. Cell suspensions from 27 human colorectal carcinomas were simultaneously selected for epithelial cells and analyzed for DNA content. The staining procedure we employed, after dispersing the tumour sample into a single-cell suspension, included propidium iodide and a monoclonal antibody to the intermediate filament cytokeratin specific for secretory epithelia of normal human tissue and cells of epithelial origin in adenocarcinomas. This technique made it possible to distinguish the epithelial cell population from non-epithelial cells in the tumour. Flow cytometry was used for DNA analysis and the results obtained after epithelial selection were compared with conventional DNA analysis of crude tumour tissue. No difference in S-phase values of diploid and aneuploid cytokeratin positive cells were seen, whereas analysis of crude tumour cell suspensions showed lower S-phase values in diploid tumours compared to aneuploid ones. When cytokeratin-positive cells in the tumour were selected, we found presence of diploid tumour cells in almost all aneuploid tumours.

Aged↗

PubMed1994

Cell-cycle-regulated phosphorylation of oncoprotein 18 on Ser16, Ser25 and Ser38.

Oncoprotein 18 (Op18) has been independently identified due to its increased phosphorylation in response to external signals and its up-regulated expression in acute leukemia. We have identified two serine residues of Op18 that are phosphorylated after triggering by the T cell antigen receptor. One of these residues, Ser25, was shown to be a likely substrate for the mitogen-activated protein (MAP) kinase, while the other residue, Ser16, was shown to be phosphorylated in response to increased intracellular calcium. Our previous site-mapping studies of Op18 also revealed that basal phosphorylation of Op18 is mainly located on Ser38, which was found to be the primary in vitro phosphorylation site of p13suc1-precipitated cdc2 kinase activities. These findings raised the possibility that Op18 may be a substrate for both receptor-regulated calcium-induced protein kinases and the MAP kinase family, as well as being a substrate for the cell-cycle-regulated cdc2 kinase family. In the present report we have performed site-mapping studies of cell-cycle-regulated fluctuations of Op18 phosphorylation. The results reveal that S-phase progression of a synchronised leukemic T cell line is associated with increased phosphorylation of both the Ser25 and Ser38 residues. Moreover, during mitosis, a burst of phosphorylation was observed and at this stage of the cell cycle a major fraction of Op18 was phosphorylated at multiple sites. Phosphorylation of Op18 during mitosis was located primarily on Ser38 and to lesser extent on Ser25, Ser16 and at an unidentified C-terminal residue. In vitro phosphorylation experiments, employing two distinct members of the cdc2 kinase family, were consistent with involvement of both p34-cdc2 and p33-cdk2 in cell-cycle-regulated phosphorylation of Ser25 and Ser38 of Op18. Most importantly, the ratio of Ser25/Ser38 phosphorylation observed in vitro, using either p34-cdc2 or p33-cdk2, was found to be the same as the ratio observed in intact cells during all phases of the cell cycle. These findings suggest that Op18 may be a physiological substrate for several members of the cdc2 kinase family during both the S-phase and the mitotic phase of the cell cycle.

Amino Acid Sequence↗

PubMed1994

Telomere shortening in renal cell carcinoma.

The ends of human chromosomes consist of a specialized structure, the telomere, composed of repeats of TTAGGG making up a total of 5-15 kilobase pairs, depending on age and proliferative activity of the tissue. The major function of telomeres is to provide stability to chromosomes and protect underlying unique coding sequences from degradation. There is a loss of telomeric sequences following every cell division estimated to be between 50 and 65 basepairs/cell division in human fibroblasts and embryonic kidney cells in vitro. This loss is due to the fact that DNA replication is incomplete for one strand at each telomere end. In lower eukaryotes there is a compensation mechanism provided by the enzyme telomerase, which is inactive in human somatic cells. Telomerase activation has also been detected in vitro immortalized human cells. In this study we analyzed renal cell carcinoma for the occurrence of telomere shortening using the probe (TTAGGG)4. Southern blots of HinfI-digested DNA revealed a shortening of mean telomere restriction fragment (TRF) length of 0.4 to 2.5 kilobase pairs in 2 or 3 intratumoral samples in all 10 tumors analyzed. No obvious intratumoral heterogeneity was found in mean TRF length values. However, heterogeneity was shown by the occurrence of at least two separate peak TRF values in 7 of 10 tumors, indicating the presence of different tumor cell clones. A conflicting observation was made when we evaluated the intensity of the hybridization signals, where three of the tumors showed an increase in hybridization signals despite concomitant TRF reduction. We found no correlation between tumor size and calculated tumor cell divisions undergone. In two tumors, the calculated cell division cycles were unrealistically low compared to the tumor size. These data suggest that telomerase activation might occur in human renal cell carcinoma.

Base Sequence↗

PubMed1994

[Unilateral testicular tumor in adrenogenital syndrome].

In male patients with congenital adrenogenital syndrome (AGS), in addition to the well known adrenal changes, tumor-like testicular proliferations may be observed. They have been known from literature since decades, but have become rare due to modern therapy. Especially in the mild and inapparent cases of AGS, the "tumors" cause clinical and morphological problems. The case of a 34 year old male AGS patient is presented, who underwent resection of a large adrenal cortical adenoma at age 28. Six years later, orchiectomy followed because of a testicular tumor. In frozen sections, the "Leydig cell-like" tumor caused diagnostic difficulties. After usual embedding and examination, the diagnosis of testicular "tumor" in AGS was confirmed. By review of the literature, pathomorphogenesis and morphology of these testicular tumors as well as possible histogenesis of their cells are discussed. Because of the close similarity to Leydig cell tumors, this most important differential diagnosis is especially considered. As a rule, testicular tumors in AGS are no indication for orchiectomy.

Adrenal Hyperplasia, Congenital↗

PubMed1994

Cell kinetics of renal cell carcinoma studied with in vivo iododeoxyuridine incorporation and flow cytometry.

In 29 patients with renal cell carcinoma tumor cell kinetics were studied by in vivo labeling with 100 mg. iododeoxyuridine given 3 to 7 hours before nephrectomy. Two to 6 samples were analyzed from each tumor after fixation in ethanol. Iododeoxyuridine was analyzed by specific antibodies using flow cytometric analysis of labeled cells and parameters, such as labeling index and potential tumor doubling time, could be determined. Samples from 28 tumors were evaluable. Mean labeling index of the tumors was 2.7%, which was significantly different from the 0.35% index in kidney cortex tissue. There was no statistical difference in labeling index among the clinical stages. The mean potential tumor doubling time in the tumor cells was 20.3 days, which was significantly different compared with 137.7 days in kidney cortex tissue. There was a frequent intra-tumoral heterogeneity of potential tumor doubling times. Diploid and aneuploid samples had significantly different potential tumor doubling (mean 37.4 and 12.5 days, respectively). Potential tumor doubling had a significant impact on the survival time (p = 0.004), which also was noted in the patients with aneuploid tumors (p = 0.003). Our study shows that in vivo incorporation of iododeoxyuridine successfully can be analyzed in renal cell carcinoma. Potential tumor doubling time gives valuable prognostic information on the clinical behavior of the patients.

Adult↗

PubMed1994

Multiclonality and altered RFLP patterns for immunoglobulin heavy-chain and T-cell receptor genes in relapsing lymphomas.

BACKGROUND: Alteration of morphological appearance as well as of clinical behaviour is common in relapsing non-Hodgkin's lymphomas. The aim of this study was to investigate the stability of the genes encoding the immunoglobulin heavy-chain and the T-cell receptor during the course of the disease in relapsing non-Hodgkin's lymphomas. MATERIAL AND METHODS: Nineteen patients with relapsed or progressive non-Hodgkin's lymphomas were analysed with respect to alterations of the restriction fragment length polymorphism (RFLP) pattern for Ig heavy chain (IgH) using probes for the C mu and J regions and for T-cell receptor (T-beta, T-gamma chain) genes. DNA was extracted from tumour material taken at different occasions during the course of the disease. RESULTS: All 19 cases showed clonal rearrangements of the IgH locus, and 2 cases showed simultaneous rearrangement of the genes coding for the T-cell receptors. Three or more rearranged bands, indicating more than one malignant clone, were detected in 1 case at the time of the diagnosis and in 5/19 (26%) cases in DNA from samples taken at relapse, all 6 cases showing discordant or transformed morphology. Altogether, in 11 out of 19 cases (58%), changes of the IgH rearrangement pattern could be visualized by RFLP. In all these cases except one, the new RFLP pattern included at least one rearranged band from the pattern of the first taken sample. In one case a clonal T-gamma receptor gene rearrangement was detected in a diagnostic sample but not in a sample taken at relapse. In 4 out of 6 cases with transformed lymphomas, clonal changes were observed at time of transformation. Evolution of clones with different RFLP patterns in different compartments were observed in 1 out of 6 studied cases. CONCLUSIONS: The present study illustrates that non-Hodgkin's lymphomas are unstable in their IgH genome. The observations of clonal evolution, multiclonality, and different clones in different compartments offer an explanation to the troublesome situation when treating relapsed lymphomas.

Cloning, Molecular↗