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E Thorud

Publications and source records attributed to E Thorud.

At least 37 records · Page 2Linked to original sources
PubMed1986

DNA flow cytometry of cells obtained from old paraffin-embedded specimens. A comparison with results of scanning absorption cytometry (a methodological study).

Suspensions of single cell nuclei were obtained from 31 different samples of 7-9 years old paraffin-embedded bladder cancer biopsies. The DNA content of the ethidium-bromide-stained nuclei was analyzed by flow cytometry (FCM). The tumour stemline ploidy, as determined by FCM, was compared with that obtained by Feulgen scanning absorption cytometry (SACM) in imprints obtained from the same biopsy before it was fixed. Fifteen tumours that were diploid by FCM were also diploid by SACM. All of the 16 tumours with non-diploid DNA-stemlines by FCM were non-diploid by SACM, though minor differences between the ploidy values were occasionally seen when the results of the two methods were compared. The background activity due to cell debris was considerable and resulted in a mean variation coefficient (CV) of 5.1% for human spleen cells fixed and embedded before preparation for FCM in the same way as the tumour samples. In the tumour samples there was a large and unpredictable variation of the ratio between the DNA values of chicken erythrocytes (internal standard) and diploid cells. In some specimens this ratio would have resulted in incorrect evaluation of the FCM DNA histogram. The following method for evaluation of FCM histograms is therefore proposed: Single peak histograms obtained from paraffin embedded tissue should always be interpreted as representative for a diploid cell population. In FCM histograms from paraffin-embedded tissue with more than one peak, the first peak should be considered as representing diploid cells.

Animals↗
PubMed1986

DNA flow cytometry in human bladder carcinoma.

The cell kinetic fractions (G0/G1; S; G2 + M) were evaluated by DNA flow cytometry (DNA FCM) in 102 biopsies from bladder carcinoma, previously untreated by cytotoxic therapy, and in 25 biopsies taken at least 3 months after prior treatment (chemotherapy, radiotherapy, surgery). Non-diploid DNA-stemlines were most often found in tumours of a high T category and of a high histopathological grade. Also the number of tumours with a fraction of cells in S-phase above 10% correlated with the clinical stage and histological grade. When the cytotoxic treatment preceded the actual biopsy by 3 months or more the distribution of stemline ploidies in the recurrent or residual tumours were similar to that seen in previously untreated patients. Furthermore, 4 of 5 individual muscle infiltrating bladder tumours treated with surgery, radiotherapy or systemic chemotherapy had the same stemline ploidy before and after treatment. The analysis of ploidy and cell kinetic parameters obtained from DNA FCM offers a possibility to evaluate the prognosis and the therapy effects in human bladder carcinoma.

Aged↗
PubMed1986

Evidence of mouse epidermal subpopulations with different cell cycle times.

In order to obtain information on the distribution of total cell cycle times in hairless mouse epidermis, basal cells were isolated and prepared for DNA flow cytometry at intervals after a pulse labeling with 50 microCi of thymidine. The DNA distributions were recorded, and cells were sorted from windows in the S, G2, and G1 phases of the cell cycle, collected on glass slides, and subjected to autoradiography. The proportions of labeled cells were scored in each fraction, and the percentage of labeled mitoses was determined in histologic sections from the same animals. Grain count distributions were recorded at selected time points over labeled cells in sorted fractions and over labeled mitoses. The movement of the labeled S-phase cohort was thus followed through all cell cycle phases. Peaks in labeled cells were observed at about 36 h in S phase, G2 phase, and mitosis, and high levels of labeled G2 cells and mitoses were seen at about 80 h. These results indicate the existence of one rapidly cycling subpopulation of keratinocytes with a cell cycle time slightly less than 30 h, in addition to keratinocytes with considerably longer cell cycle times. The first peak of labeled G2 cells reached only about 30%. This is consistent with earlier findings of about 30% G2 cells with a rapid traverse, and 70% with a considerably delayed traverse through G2 phase. The proportion of labeled G1 cells reached a value corresponding to twice the initial labeling index at 8 h after pulse labeling. This is consistent with previously obtained phase durations, indicating an unperturbed cell cycle traverse of labeled cells from S phase through G2 and mitosis.

Animals↗
PubMed1985

Preservation of cytometric DNA distribution and epithelial marker expression after tumor progression of human large bowel carcinomas.

Tumor specimens were obtained from seven patients with large bowel carcinomas at operation of the primary neoplasm and by resection of local recurrences or metastases 2 1/2 to 36 months later. All specimens were evaluated with regard to nuclear DNA distribution as measured by flow cytometry and expression of carcinoembryonic antigen (CEA), secretory component, epithelial IgA, and HLA-DR antigens, as determined by immunofluorescence staining of tissue sections. Both the DNA distributions and the immunohistochemical staining patterns were similar in the primary and secondary tumors. These findings are in keeping with a monoclonal or oligoclonal tumor progression in advanced large bowel carcinoma.

Adult↗
PubMed1985

DNA flow cytometry in human testicular cancer.

DNA flow cytometry revealed aneuploid tumour stemlines in 19 of 20 primary testicular cancers without significant difference of the ploidy values between seminomas and non-seminomas. In 7 of 8 analyzable histograms the S-phase activity was 22-51%. A metastatic mature teratoma had 6% cells in S-phase. These results support the clinical observation that testicular cancer is usually a rapidly growing human tumour. The high percentage of aneuploidy in testicular cancer may be of clinical value in the diagnosis of this malignancy.

DNA, Neoplasm↗
PubMed1985

Bleomycin and radiation therapy in squamous cell carcinoma of the upper aero-digestive tract: a phase III clinical trial.

A group of 222 consecutive patients admitted with squamous cell carcinoma of the upper aero-digestive tract were studied in a prospectively randomized and stratified clinical trial. One-half of the patients received bleomycin injected intramuscularly 1 hour before the radiation treatment daily for 5 days a week; the other half received radiation therapy without the added chemotherapy. The total dose of radiation in both groups was about the same, and was given with curative intent even to the patients with advanced tumors who constituted the majority in both groups. Interstitial radiation as boost therapy or surgery was added in patients with residual tumor if the lesions were considered operable and the patient's condition would allow surgery. The addition of bleomycin did not increase the combined local and regional tumor control rates nor did it improve the survival, but did significantly increase the morbidity and the complication rate.

Adult↗
PubMed1985

Estimation of circadian variations in cell cycle phase durations in murine epidermal basal cells.

Circadian variations in the proliferative activity of squamous epithelia are well known. However, circadian variations in the duration of the various cell cycle phases (S, G2 and mitosis) have been disputed. The percent labelled mitoses method, which is traditionally used to obtain duration of cell cycle phases, is poorly suited for identification of circadian variations. Therefore methods combining changes in compartment size (cell cycle phase) and cellular flux through the compartments have been used. Three different methods using such data are presented. These incorporate various simplifying assumptions that cause methodological errors. Limits for use of the different methods are indicated. The use of all three methods gives comparable and pronounced circadian variations in the duration of S and G2 phase. These results are also compatible with circadian variations in the mitotic duration, but they may also represent artefacts due to sensitivity to model errors.

Animals↗
PubMed1984

Circadian variation in the susceptibility of mouse epidermis to tumour induction by methylnitrosourea.

To study possible circadian differences in the sensitivity of hairless mouse epidermis to a small dose of a short-acting alkylating carcinogen, groups of animals were painted once with 0.2 mg methylnitrosourea (MNU) at 08.00, 12.00, 20.00 and 24.00 h. Other animals were painted three times at weekly intervals at 08.00 and at 20.00 h, respectively. Significantly higher tumour yields were found in animals painted at 20.00 h (when the cell cycle progression and DNA synthesis rate are lowest, and when relatively large numbers of late G1 cells may accumulate) than at any other time point investigated. Hence a circadian variation in sensitivity to MNU in mouse epidermis is confirmed. This may be due to the variations in flux of cells through the S phase. The formation of DNA/carcinogen adducts may be facilitated at times of low flux with many cells in late G1, and fixation of these errors in DNA may take place by the subsequent increased flux through S, before repair is possible.

Animals↗
PubMed1984

Subpopulations of slowly cycling cells in S and G2 phase in mouse epidermis.

Evidence has been presented supporting the existence of heterogeneity in cell-cycle progression in mouse epidermis, The present study was undertaken to characterize this heterogeneity in more detail. Hairless mice were continuously labelled with tritiated thymidine every 4 hr for 4 days. Basal cell suspensions were prepared from slices of mouse skin at intervals during the experiment and subjected to DNA flow cytometry. Cell-cycle analysis was combined with sorting of cells from windows in G1, S and G2 phase, and the proportion of labelled cells within each window was determined in autoradiographs. Reanalysis and resorting to control the purity of of sorted fractions were performed. Computer simulations of the data were made using a mathematical model assuming different S and G2 phase characteristics. A good fit to the data was only obtained when heterogeneity in mouse epidermal cell-cycle progression was assumed, indicating the existence of slowly traversing, distinct subpopulations of cells in G2 and S phase. These cells are assumed to contribute to about 40% of all cells in S phase and to about 70% of all in G2 phase. The estimated residence times in the resting states were 38 and 32 hr in S and G2 phase, respectively. Two-parameter sorting based on DNA and light scatter indicated that slowly cycling cells were larger than the average. There is no evidence of significant subpopulations of permanently non-proliferating keratinocytes in any of the cell-cycle phases.

Animals↗
PubMed1984

Different epidermal cell kinetic effects of hydroxyurea when injected at two different times of the day.

Circadian rhythms in epidermal basal cell-cycle progression in hairless mouse skin have been repeatedly demonstrated. A dose of 10 mg/animal hydroxyurea (HU), given to inhibit DNA synthesis was injected intraperitoneally to two groups of hairless mice. One group was injected at 10.00 hours MET, when the cell-cycle progression and cell division rate are relatively high, and another group was injected at 20.00 hours, when the same variables are at minimum values. Various cell kinetic methods--[3H]TdR autoradiography, DNA flow cytometry and the stathmokinetic method (Colcemid)--were used to study HU-induced alterations in cell kinetics. Hydroxyurea (HU) immediately reduced the labelling index (LI) to less than 10% of controls when injected at both times of the day, and higher then normal values were observed 8 hr later. A subsequent decrease towards normal values was steeper in the 20.00 hours injected group. The proportion of cells with S-phase DNA content was transiently reduced in both series, but the reduction was less pronounced and control values were reached earlier in the series injected at 10.00 hours. The observed alterations in LI and fraction of cells in S phase were followed by comparable alterations in the fraction of cells in G2 and in the mitotic rate. Hence the changes in G2 and mitotic rate are easily explained as consequences of the previous perturbations in the S phase. The time-dependent differences in the cell kinetic perturbations caused by HU in the S phase may be explained by a circadian-phase-dependent action of HU on the influx and efflux of cells to and from the S phase, respectively. At 10.00 hours the efflux of cells from S is most heavily inhibited; at 20.00 hours the influx is predominantly blocked. Hence, when physiological flux is high HU mainly blocks the efflux from S, but when flux normally is low, HU mainly blocks the entrance to S. Within 20 hours after the HU injection, the cell kinetic variables had approached the unperturbed circadian pattern.

Animals↗
PubMed1984

DNA flow cytometry in primary breast carcinoma.

DNA Flow cytometric values were recorded in 66 primary breast carcinomas. Twenty-six tumors were found to be diploid whereas 40 were non-diploid. About 10% of the cells belonged to the S-phase fraction. Non-diploid tumors had significantly larger S-cell fractions (greater than 10%) than diploid ones. High tumor ploidy correlated positively with high clinical stage (stage I versus stage greater than or equal to II) and with high histological grade but was unrelated to estrogen-receptor content and menopausal status.

Breast Neoplasms↗
PubMed1983

Is heterogeneous expression of HLA-dr antigens and CEA along with DNA-profile variations evidence of phenotypic instability and clonal proliferation in human large bowel carcinomas?

Epithelial expression of HLA-DR determinants and CEA was studied by immunofluorescence in tissue sections from 33 large bowel carcinomas of different histological grade and clinico-pathological stage; flow cytometric DNA measurements were performed in 31 of the tumours. Well-differentiated carcinomas showed a strikingly patchy staining, particularly for HLA-DR and all except one had a near-diploid DNA content. The latter feature might reflect cancer development at an early stage where no distinctly aneuploid DNA clone had as yet become a predominant subline. With decreasing degree of differentiation, the epithelial antigen expression became more homogeneous for individual tumours and the proportion of distinctly aneuploid DNA profiles increased. In the poorly differentiated group of carcinomas, epithelial staining was quite uniform, both for HLA-DR determinants and for CEA, and those tumours studied for DNA content were of the aneuploid variety. These observations are in agreement with the clonal proliferation theory of tumour development proposed by Nowell in 1976.

Adult↗
PubMed1983

Inhibition of methylcholanthrene-induced skin carcinogenesis in hairless mice by the membrane-labilizing agent DMSO.

The effects of dimethyl sulphoxide (DMSO) are in some respects similar to those of retinoids. DMSO has the ability to penetrate cellular membranes and to enhance the penetration of other molecules. It may be reasonable to assume that DMSO treatment results in differentiation of cells, possibly through membrane-mediated events. This may be of importance for the study of the carcinogenic process. The release of a certain amount of lysosomal enzymes to the extracellular space is a normal function of the cell (Hickman & Neufeld, 1972), and a certain release of the cytoplasmic and lysosomal enzymes to the extracellular space is not necessarily deleterious for the cells (Volden, Haugen & Skrede, 1980). The purpose of the present investigation was to study the possible effects of DMSO on methylcholanthrene-induced skin carcinogenesis. Since the uptake of lysosomal enzymes by cultured cells appears to involve a membrane receptor process, the effects of the carcinogen and the solvents on the rate of secretion of lysosomal enzymes and lactate dehydrogenase from HeLa cells were investigated.

Animals↗
PubMed1983

DNA cytometry of primary breast cancer. Comparison of microspectrophotometry and flow cytometry, and different preparation methods for flow cytometric measurements.

In 18 biopsy specimens from human breast carcinoma a comparison was made between DNA measurements obtained by microspectrophotometry (MSP) of Feulgen-stained nuclei in imprints and flow cytometry (FCM) of nuclei stained with ethidium bromide. For each specimen FCM was performed both with ethanol-fixed cells and unfixed cells. In addition, single cell suspensions were made from other 11 fresh mammary cancer biopsies. Parts of these suspensions were analysed both by MSP (Feulgen-stained smears) and FCM (ethanol-fixed, mitramycin-stained cells). The MSP histograms show selected tumour cells and tumour-like cells. This explains the higher proportion of cells with DNA content above the 2 c level. A good agreement was found between the results obtained by MSP and FCM with regard to the ploidy of the DNA stemline(s). FCM of fixed cells (multiple-step procedure) yielded a slightly lower proportion of diploid cells than FCM of the unfixed cells (one-step procedure), probably owing to loss of small cells during the different preparation steps. It is concluded that the results from DNA-histograms obtained from MSP and FCM can be compared as to DNA-stemline ploidy of the cell population but not as to the proportion of cells with non-diploid DNA-content.

Aneuploidy↗
PubMed1982

Epidermal proliferation characteristics are similar in the pilary canal of mouse hair follicles and in interfollicular epidermis.

Proliferation characteristics of basal cells in the pilary canal of resting hair follicles were investigated and compared with corresponding parameters in interfollicular epidermis of hairless mice. The mitotic rates had similar 24-h means at both locations. Distinct circadian rhythms which showed phasing and amplitudes similar to that in interfollicular epidermis, were demonstrated by the 3H-TdR labelling index, the mitotic rate and the mitotic index. Influx of cells to and efflux of cells from the S phase were measured in the early morning and in the evening by a 3H-TdR double labelling method. The influx values were similar at both times of both locations. The efflux values recorded in the morning were more than twice the values seen in the evening in both the pilary canal and in interfollicular epidermis. The epidermal motitic rate in the pilary canal was depressed by epidermal extracts, and increased after adhesive tape stripping in the same way as in interfollicular epidermis. The results indicate no heterogeneity in cell proliferation characteristics between the two locations, and suggest that similar mechanisms are responsible for maintainance of growth equilibrium at both sites.

Animals↗
PubMed1982

Large-bowel carcinomas with different ploidy, related to secretory component, IgA, and CEA in epithelium and plasma.

Immunofluorescence staining for carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA was evaluated semiquantitatively in 85 large-bowel carcinomas in relation to degree of tumour differentiation, Dukes' stage, and plasma CEA level. The tumours were divided into a near-diploid (ND, 28) and an aneuploid group (AN, 57) by means of flow-cytometric DNA measurements. Expression of SC and IgA in neoplastic epithelium was positively related to differentiation in both groups. The AN tumours scored significantly higher for CEA than the ND ones, but the staining was apparently unrelated to differentiation or Dukes' stage. CEA expression in the transitional mucosa adjacent to ND tumours was negatively correlated with tumour differentiation, whereas epithelial IgA and SC in this zone showed a substantially higher positive correlation with tumour differentiation, and a somewhat stronger negative correlation with Dukes' stage in the ND than in the AN group. Plasma CEA levels were significantly related to Dukes' stage, only in patients with AN tumours, and only in this group were positively correlated with estimates of total tumour CEA for Dukes' stages A and B. For Dukes' stages C and D (disseminated tumours), moreover, the plasma CEA levels were found to be significantly higher in the AN group. These findings indicate that the DNA profile of large-bowel carcinomas is related both to the way neoplastic cells influence the activity of the transitional mucosa and their capacity for expression and release of epithelial products. AN tumours thus seem to be more active as "secretors" of CEA than ND ones.

Adenocarcinoma↗
PubMed1982

Adrenalin has differential effects on epidermal cell cycle progression in mice.

The cell kinetic response after intraperitoneal injection of the 10 micrograms adrenalin was investigated in hairless mouse epidermis. Changes in the proportion of cells in S and G2 phase were studied by means of flow cytometry of isolated basal cells. Changes in the proportion of cells in prophase and metaphase, changes in the mitotic rate (Colcemid method) and in cell cycle progression of 3H-TdR labeled cells were studied in histologic sections. The results showed that adrenalin has a differential effect on cell proliferation in mouse epidermis. The cell progression rate from S phase through G2 phase to metaphase is increased in one cohort of cells shortly after adrenalin injection. Simultaneously another cohort of cells is reversibly delayed or blocked in prophase. In agreement with most previous studies a significantly reduced cell division rate was seen 2-3 hr after adrenalin injection. At this time the proportions of cells in prophase and G2 phase were normalized, whereas a significant increase in the proportion of cells in S phase had cycle progression out of S phase might be responsible for the reduced mitotic rate seen after adrenalin administration.

Animals↗