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Biomedical subjects

B Tribukait

Publications and source records attributed to B Tribukait.

At least 37 records · Page 2Linked to original sources
PubMed1999

Assessment of cell proliferation by Ki-67 staining and flow cytometry in fine needle aspirates (FNAs) of reactive lymphadenitis and non-Hodgkin's lymphomas.

This study was undertaken to assess cell proliferation in FNAs from a series of 57 non-Hodgkin's lymphomas (NHL) and 11 cases of reactive lymphadenitis using Ki-67 staining and flow cytometry (FCM). The results were compared and correlated to the cytomorphological subgrouping according to Kiel classification. The mean percentages of Ki-67 positivity were 16.6% and 61.1% for low and high grade lymphomas, respectively (P < 0.001). The mean S-phase fraction (SPF) determined by FCM was 4.61% for low grade and 12.9% for high grade lymphomas (P < 0.001). The figures for Ki-67 positivity and S-phase fraction in reactive lymphadenitis were 16.8% and 40%, respectively. We observed a strong correlation in low grade lymphomas between Ki-67 and SPF. A good correlation was also found in reactive lymphadenitis. In high grade lymphomas, however, with highly scattered Ki-67 and S-phase values, this correlation was lost. In some cases this discrepancy can be explained by a rich admixture of non-neoplastic, non-proliferating cells in aspirates from diploid tumours. In addition, the existence of a minor aneuploid tumour cell population of high proliferation such as that in Ki-1 lymphomas will not be accurately analysed by FCM but is easily assessed by Ki-67 staining. However, the main reason seems to be a high variability between the fraction of cells in S-phase and the total number of cells in G1, S and G2 in individual tumours.

Adult↗
PubMed1998

Comparison of routine flow cytometric DNA analysis of fresh tissues in two laboratories: effects of differences in preparation methods and background models of cell cycle calculation.

Routine flow cytometric DNA analysis was compared in two laboratories by using matched fresh-frozen breast cancer and soft tissue sarcoma biopsy specimens. Laboratory I applied the Vindelöv preparation method and an exponential background subtraction algorithm in the cell cycle calculation. Laboratory II used the Formalin-protease preparation technique and the sliced-nuclei background model. The results of the ploidy analysis showed good agreement between the two laboratories; however, the results of the cell cycle analysis showed considerable systematic differences between labs. Laboratory I obtained significantly lower values of S-phase fraction and higher values of G2-phase fraction than laboratory II. To explain these discrepancies, the effects of differences in the preparation methods and background subtraction algorithms were studied. The Vindelöv preparation method yielded higher debris and aggregation levels than the Formalin-protease technique and tended to give higher %S and %G2 values. When the two background models were used in the same histograms, the exponential background model tended to give %S values distinctly lower than and %G2 values almost identical to those obtained with the sliced-nuclei algorithm. The sum of these effects accounts for the observed inter-laboratory discrepancies. Different from the sliced-nuclei fit, the exponential background fit often did not accommodate to the original data in the <2c histogram region and resulted in a considerable inter-operator variability of %S calculation in histograms with <5% S. When aggregate correction was added to the sliced-nuclei algorithm, the differences between %S values in histograms from the two laboratories almost disappeared.

Algorithms↗
PubMed1998

Chromosome 16q24 deletion and decreased E-cadherin expression: possible association with metastatic potential in prostate cancer.

BACKGROUND: Deletion of chromosome 16q is a frequent aberration in prostatic carcinoma, indicating the existence of candidate tumor suppressor genes involved in the pathogenesis of prostate cancer. METHODS: Chromosome 16 numerical aberration and loss of 16q were studied by fluorescence in situ hybridization in 31 primary and 22 metastatic tumors from 53 patients. The results were compared with E-cadherin expression, tumor grade and stage, and DNA ploidy. RESULTS: Numerical chromosome 16 aberrations, 16q deletion, and loss of E-cadherin expression were found in 29%, 35%, and 29% of the primary tumors, respectively, and in 73%, 73%, and 73% of the metastases, respectively. High tumor grade and DNA aneuploidy were also found to have significant correlation with metastases. CONCLUSIONS: Deletion of chromosome 16q24 and/or loss of the E-cadherin function appears in a high frequency in metastases of prostate cancer. The strong correlations suggest that they may be important risk factors, contributing to the metastatic potential of the tumor.

Adenocarcinoma↗
PubMed1998

Sialyl-Tn antigen as a marker of colon cancer risk in ulcerative colitis: relation to dysplasia and DNA aneuploidy.

BACKGROUND & AIMS: Expression of the mucin-associated carbohydrate antigen sialyl-Tn (STn) and DNA aneuploidy has each been shown to correlate with malignant transformation in patients with sporadic colon cancer and in those with ulcerative colitis (UC). This study aimed to determine how STn expression topographically and temporally relates to aneuploidy and neoplasia in patients with long-standing UC. METHODS: Twenty-six patients enrolled in a cancer surveillance program were studied, and 1691 mucosal specimens from repeated colonoscopies and colectomies were assessed in a standardized, prospective fashion for the presence of dysplasia, aneuploidy, and STn antigen. RESULTS: STn was expressed in 47% of specimens from 6 patients who underwent colectomy for dysplasia and 7% of specimens from 6 well-matched patients who underwent surgery for medical intractability. Seven other patients who never developed dysplasia or aneuploidy expressed STn in 6% of biopsy specimens. STn expression was independent of aneuploidy in colons both with and without dysplasia. Of 5 patients with aneuploidy but without dysplasia, 4 expressed STn earlier than aneuploidy. CONCLUSIONS: In UC, STn antigen and DNA aneuploidy are independent markers of neoplastic transformation. Determination of STn expression may complement dysplasia and aneuploidy for identification of risk for colonic neoplasia in UC.

Adolescent↗
PubMed1998

Primary nonurachal adenocarcinoma in the bilharzial urinary bladder: deoxyribonucleic acid flow cytometric and morphologic characterization in 93 cases.

OBJECTIVES: To characterize adenocarcinomas of the urinary bladder by their DNA profiles and their proliferative properties. METHODS: Primary nonurachal adenocarcinomas, found in 93 patients with bilharzial bladder carcinomas, were studied using DNA flow cytometry. Tumor ploidy and S-phase fraction were related to tumor grade, stage, cell type, and lymph node status. RESULTS: Aneuploidy with high S-phase fractions, found in 90% of the tumors, demonstrates the high malignancy potential of these tumors, the majority of which were found to be muscle-infiltrative. There were no relationships between ploidy or S-phase fraction and tumor grade and stage. Lymph node metastases, present in 24% of the 93 patients, were found exclusively in nontetraploid aneuploid tumors with high S-phase fractions exceeding 100%. Paraffin-embedded tissues compared with fresh material gave the same information on ploidy, whereas bladder washing did not provide adequate information. CONCLUSIONS: The high aggressiveness of adenocarcinomas in the biharzial bladder is confirmed and can be explained by their proneness to develop gross chromosomal aberrations combined with high cell proliferation.

Adenocarcinoma↗
PubMed1997

Neoplastic transformation of the pelvic pouch mucosa in patients with ulcerative colitis.

BACKGROUND & AIMS: Some patients with ulcerative colitis (UC) receiving an ileal pelvic pouch with ileoanal anastomosis (IPAA) develop persistent severe villous atrophy in the pouch mucosa. To investigate if mucosal atrophy indicates a risk for subsequent neoplastic transformation of the ileal pouch mucosa, a follow-up study was undertaken. METHODS: Seven patients with UC and an IPAA in whom persistent severe atrophy (type C) developed and 14 control patients with no or only slight atrophy (type A) were prospectively surveyed by flexible videoendoscopy with multiple biopsies for assessment of possible neoplastic changes. RESULTS: The median time of the pouch in function was 9 years for both groups. Dysplasia was found in 5 of 7 patients in the type C group (71%) compared with none in the type A group (P < 0.001). Four patients had low-grade dysplasia, and 1 patient had sequential multifocal development into high-grade dysplasia. Multifocal DNA aneuploidy was found in 2 patients, 1 with low-grade and 1 with high-grade dysplasia. CONCLUSIONS: Patients with UC and a long-standing IPAA who develop persistent severe mucosal atrophy are at risk also of neoplastic transformation of the pouch mucosa.

Adolescent↗
PubMed1997

Phase II studies on prostate cancer.

OBJECTIVES: To evaluate different study designs and the general utility of phase II trials on prostate cancer. METHODS: Extensive literature studies and correspondance within the working group during 1 year were summarized in a preliminary manuscript. The manuscript was finalized at a 1 day meeting and is presented here as a consensus document. RESULTS: The main objectives of phase II studies are to assess whether a treatment is sufficiently active to justify comparative phase III studies, and to obtain further information on adverse reactions. Bidimensionally measurable lesions are traditionally studied, allowing objective criteria for response and progression to be applied. However, as skeletal metastases do not fulfill the criteria for such lesions, the majority of patients with metastatic prostate cancer are not eligible for traditionally-designed phase II trials. Therefore, ancillary response parameters, especially serum prostate-specific antigen (PSA), have been proposed for use. For the evaluation of adverse reactions, the criteria of the World Health Organization were proposed for use. A review of various statistical designs was presented, with a focus on their advantages and disadvantages in phase II trials. CONCLUSIONS: The role of PSA in phase II trials has not yet been firmly established. Further study of its correlation with other endpoints is needed. In future phase II trials, a shift to softer endpoints than traditionally used may enhance the process of evaluation of new antitumor drugs. Phase II studies may even be replaced by early phase III studies, especially in situations where new drugs do not have very heavy adverse effects.

Clinical Trials, Phase II as Topic↗
PubMed1996

A comparison of proliferation markers and their prognostic value for women with endometrial carcinoma. Ki-67, proliferating cell nuclear antigen, and flow cytometric S-phase fraction.

BACKGROUND: The understanding of proliferation is a central issue in oncology. Several methods exist for the assessment of the growth fraction and cell-cycle time, but comparative studies that give the clinician advice about the most reliable use of new markers are few. The aim of the current study was to perform methodologic, descriptive, comparative, and prognostic studies of Ki-67, proliferating cell nuclear antigen (PCNA), and flow cytometric S-phase fraction (SPF) in endometrial carcinoma. METHODS: The expression of Ki 67 (n = 175) and PCNA (n = 146) were studied immunohistochemically; and the SPF (n = 297) by flow cytometry. The median follow-up time was 78 months. RESULTS: Neither Ki-67 nor PCNA had any correlation to either the stage or the histopathologic subtype of the tumors, but they were covariant with the histopathologic grade (P < 0.05). There was an interrelationship between Ki-67 and PCNA (P < 0.001), and both were associated with the size of the SPF (P < 0.0001 and P < 0.05, respectively). Mean SPF was high in advanced stages and strongly associated with histopathologic subtype (P < 0.0001) and ploidy (P < 0.0001). Tumors with strong Ki-67 expression were more often aneuploid (P < 0.01). In initial analyses, Ki-67 and SPF were predictors of poor survival (P < 0.05 and P < 0.001, respectively), whereas PCNA was not. When SPF was added to a comprehensive multivariate model, Ki-67 provided no further prognostic information, whereas SPF remained a powerful predictor of survival. CONCLUSIONS: Ki-67 and, to a lesser extent, PCNA, give approximate estimates of the growth fraction, whereas SPF only reflects the proportion of cells in S-phase. However, SPF is by far the strongest predictor of survival.

Adult↗
PubMed1996

S-phase fraction of 155 soft tissue sarcomas: correlation with clinical outcome.

BACKGROUND: Traditionally, grade is considered the most important prognostic factor for soft tissue sarcomas (STS). However, because of the alleged difficulties in reproducibility of grading, new, objectively determined prognostic factors would be of value. The aim of our study was to establish if S-phase fraction (SPF) measured with flow cytometry was of prognostic significance for STS. METHODS: In this study, we included all 193 adult STS patients with superficial trunk or limb tumors who were treated by the Helsinki University Central Hospital (HUCH) STS group between January 1987 and May 1993. One hundred and seventy-two formalin fixed paraffin embedded tumor samples were available. SPF measurement was successful in 155 cases. RESULTS: Eighty-six cases were diploid. Ploidy was found to have no effect on overall survival. The median SPF was 6.8% (diploid tumors, 4% and nondiploid tumors, 12.9%). A high SPF predicted a shorter survival in patients with diploid tumors (P=0.003). The prognostic value was even stronger when we studied disease specific survival and excluded from analysis samples that contained less than 50% tumor cells (P=0.011). However, no prognostic value could be detected in nondiploid tumors or in the material as a whole. CONCLUSIONS: Our results suggest that high SPF is an adverse prognostic factor for survival of patients with diploid STS. However, further studies are needed to confirm these results.

Adolescent↗
PubMed1996

Prognostic significance of proliferative and apoptotic fractions in low grade follicle center cell-derived non-Hodgkin's lymphomas.

BACKGROUND: The biologic parameters, DNA ploidy and proliferative activity, have been suggested as prognostic factors in non-Hodgkin's lymphoma (NHL). However, reports on the prognostic importance of these factors in follicle center cell-derived (FCC) centroblastic/centrocytic (CB/CC) NHL patients with long follow-up are scarce. METHODS: Apoptotic fractions were quantified in 60 patients with CB/CC NHL by in situ labeling of DNA strand breaks in nuclei [TdT-mediated dUTP/dATP in situ 3'OH--end labeling (TUNEL)]. The findings were related to S-phase and MIB-1 counts, DNA ploidy, and clinical outcome. RESULTS: In CB/CC NHL, the percentages of proliferating and apoptotic cells were lower than in reactive germinal centers (GC; P < 0.05; mean, 0.188 vs 3.263% and 19.05 vs. 69.4% for TUNEL and MIB-1 positive cells in CB/CC and GC, respectively). Significantly higher percentages of MIB-1 and TUNEL positive cells were observed in patients with complete remission when compared with the partial remission / no response group (P < 0.01). The size of proliferative and apoptotic fractions did not correlate with the overall survival of the patients. However, follicular and diffuse growth pattern, elevated serum lactic dehydrogenase, advanced stage, and age indicated a lower probability of 5- and 10-year survival. CONCLUSIONS: The investigation of proliferative and apoptotic fractions in FCC lymphomas may help to define groups of patients to who would benefit from aggressive, high dose therapy protocols and patients to whom less aggressive strategies can be applied safely.

Adult↗
PubMed1996

Existence of phosphorylated and dephosphorylated forms of cytosolic thymidine kinase (TK1).

In this study we examine whether different TK1 variants of pI 6.9 and 8.3 found by isoelectric focusing gel electrophoresis (IFE) reflect just a phenotype difference due to phosphorylation modifications or have a real phenotypic background. The phosphorylation degree of purified TK1 variants was analyzed by determining the changes in the pI values after treatment with alkaline phosphatase, using IFE. The genetic origin of the two TK1 variants was studied by determining their mol wt. by means of SDS-gelelectrophoresis. Furthermore, the subcellular distribution of the two TK1 variants was also studied. Alkaline phosphatase treatment changed the pI value of purified TK1 from 6.9 to 8.3. No change in the pI value was found when purified TK1 corresponding to pI 8.3 was treated in the same way. Similar results were obtained when treated a cytosolic fraction with alkaline phosphatase. Antibody raised against the C-terminal part of human TK1 only recognized the dephosphorylated TK1 variant corresponding to pI 8.3. There was no difference in the molecular weight between the two TK1 variants. Thus, we concluded that the TK1 variants corresponding to pI 6.9 and 8.3 are of the same genetic origin, but consist of phosphorylated and dephosphorylated forms.

Animals↗
PubMed1996

Mutant p53 protein as a predictor of survival in endometrial carcinoma.

The expression of mutated p53 protein was studied in paraffin-embedded, formalin-fixed tumour specimens from 183 women with endometrial carcinoma. Fifty-five per cent of the specimens were negative, whereas the staining intensity was weak, moderate or strong in 15, 2 and 28% of cases, respectively. Strong p53 expression (> 75% of the cells stained) was more common in uterine papillary serous cancers and clear cell cancers than in other tumour subtypes (P < 0.001), as well as in poorly differentiated tumours (P < 0.01) and in tumours with nuclear grade 3 (P < 0.0001). Strong p53 expression was also more frequently found in aneuploid tumours (P < 0.0001) and in tumours with a high S-phase fraction (P < 0.001). Strong p53 expression was highly predictive of poor survival in the univariate analysis (P = 0.006) and in the Cox multivariate analysis which included age, stage and grade. However, it lost most of its impact when the strongly prognostic nuclear grade and ploidy were added to the multivariate models.

Adult↗
PubMed1996

Carcinoma of the endometrium: do the nuclear grade and DNA ploidy provide more prognostic information than do the FIGO and WHO classifications?

The aim of this study was to compare the World Health Organization (WHO), the International Federation of Gynecology (FIGO), and nuclear grading systems and to evaluate their reproducibility, as well as their prognostic impact, in relation to clinical variables and DNA ploidy. The study comprised 266 women with endometrial carcinoma in clinical stages I-IV. Low-risk patients, i.e., patients with grade 1-2 tumors in clinical stage I, were generally not included. In univariate Cox analyses, WHO, FIGO, and especially nuclear grading (p < 0.001), as well as age, stage, and ploidy, were prognostic regarding survival. In the multivariate Cox analyses, WHO and FIGO grades yielded little further independent information beyond nuclear grade. When DNA ploidy was added to the analyses, nuclear grade lost most of its impact because aneuploidy was a powerful factor (p < 0.001) that covaried with nuclear grade. The WHO, FIGO, and nuclear grading systems were found to be subjective, with correlation coefficients of approximately 0.60 between different pathologists. Age, stage, and aneuploidy were the most important predictors of outcome in the multivariate analyses. Nuclear grade was a strong prognostic factor in the univariate analyses and a more important indicator than the commonly used histopathological grading systems.

Adult↗
PubMed1996

Characterization of a peptide antibody against a C-terminal part of human and mouse cytosolic thymidine kinase, which is a marker for cell proliferation.

An affinity-purified anti-TK1 antibody (pAb1) raised against a synthetic peptide (amino acids K211PGEAVAARKLFAPQ225) corresponding to part of the C-terminus of human cytosolic thymidine kinase (TK1) was produced and characterized by enzyme-linked immunosorbent assay, Western immunoblotting and immunoprecipitation as well as by immunostaining of intact cells. pAb1 recognized a single 25 kDa TK1 polypeptide in extracts of human and rodent cells. The protein was localized to the cytoplasm, as studied by immunohistochemistry and there was no staining in G1/G0 cells or mutant cells lacking TK1 activity, while it was high in S-phase and G2 cells. When series of peptides were tested for antibody binding in which alanine was replacing each of the other amino acids one by one, lysines 211 and 220, proline 212 and glutamic acid 214 were found to be important for antibody reactivity. These results indicate that amino acids 211-214, which may form a turn region, constitute a major recognition site for pAb1, and this structure may also be involved in the cell cycle-dependent modification of TK1, pAb1 is a very useful tool for studies of the cell cycle regulation of TK1, and it may be used to identify and quantify rapidly proliferating cells such as tumor cells.

Amino Acid Sequence↗
PubMed1995

Fluorescence image cytometry for measurement of nuclear DNA content in surgical pathology.

A study was made on various methodological aspects of fluorescence image cytometry (FICM) for measurement of nuclear DNA content by using CCD cameras attached to an epifluorescence microscope. Cell nuclei of paraffin-embedded specimens from mouse tissues and human prostate carcinomas were isolated and stained with 4'-6-diamidino-2-phenylindole (DAPI). We found that fluorescence fading, lamp stability, and the homogeneity of the illumination can easily be controlled. A camera with a signal-to-noise ratio of 53 dB gave a slightly more precise measurement than did a 46-dB camera. The linearity of the analysis results was very good. The coefficient of variation of mouse kidney standard cells in the DNA histograms was about 5% and 7.4% in histograms of prostate carcinoma biopsies. Stained cell nuclei can be stored for long periods at -20 degrees C without impairment of quality. Comparative measurements of ploidy by FICM and flow cytometry confirmed the accuracy of the FICM analyses. Thus, FICM appears to be an easy method for quantifying the DNA content of visually inspected cell nuclei in surgical pathology.

Animals↗