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PubMed1975

Cell proliferation and cell differentiation in tissue cultures of adult muco-cilliary epithelia.

Explants and monolayers from a variety of muco-ciliary epithelia were cultivated in vitro and the kinetics of their proliferation and differentiation described. New epithelial lining and epithelial-like monolayer sheets of cells formed in which the migration cells were all originally undifferentiated cycling stem cells. The divided and differentiated in ML growth into cell types characteristic of the tissue source: however, the control mechanisms which regulate cell division and cell differentiation in the tissues were lost outside the tissue framework. Cell division and cyto-differentiation in ML growths both in ciliated and in mucus-producing cells, were not always mutually exclusive.

Animals↗
PubMed1976

Chromatin structure and function in proliferating cells.

The conclusions that we would like to draw from this review are the following: (a) Chromatin structure and function are exceedingly sensitive to changes in the proliferative state of a cell. Differences can be detected between cells in mitosis, G1 and S, and even between G0 and G1 cells. (b)These differences are very unlikely to be artifactual, since similar changes can also be demonstrated in intact nuclei. (c) Some of these differences can be abolished by extraction of chromatins with low concentrations of salt. (d) Differences between chromatins of normal and neoplastic cells can also be detected, but they are largely related to differences in the extent of cell proliferation. (e) A number of laboratories have been very busy in trying to elucidate chromatin structure with different technologies. Sometimes a change in a macromolecule cause by a physiological stimulus can tell us as much about its structure as a thousand instruments. The changes occuring in chromatin of proliferating cells could perhaps be profitably used to know more about chromatin structure.

Animals↗
PubMed1992

Proliferating cell nuclear antigen (PCNA/cyclin) in plant proliferating cells: immunohistochemical and quantitative analysis using autoantibody and murine monoclonal antibodies to PCNA.

Proliferating-cell nuclear antigen (PCNA), also known as cyclin, is synthesized in proliferative cells and recently was identified as DNA polymerase-delta auxiliary protein. In this paper, the association of PCNA to the proliferative cells of plants was analysed using both autoantibodies to PCNA obtained from a patient with systemic lupus erythematosus (SLE) and murine monoclonal antibodies. By immunohistochemical analysis, nuclei of cells around the growing point in soybean root tips reacted strongly with autoantibodies to PCNA in the serum from a patient with SLE. The plant PCNA in root tip cells was purified by ammonium sulfate fractionation, DEAE chromatography, and affinity chromatography. The partially purified plant PCNA was tested by immunoblotting and a 34 kD polypeptide reacted with both the human anti-PCNA autoantibody and a mouse monoclonal antibody against human PCNA (TOB 7). In addition, the purified plant PCNA reacted with both antibodies in enzyme-linked immunosorbent assay (ELISA). The binding of anti-PCNA serum to the animal PCNA was blocked by the plant PCNA in this ELISA. The association of PCNA with growing cells in plants was further confirmed by quantitative sandwich type ELISA using two murine monoclonal antibodies to PCNA, TOB7 and TO17. Those results suggested that PCNA in both plant and animal cells had the same immunological and biochemical characteristics and the plant PCNA might play an important role in cell growth, existing as it does in proliferating plant cells. The concentration of PCNA in soybean germ extract before germination was less than 5 ng ml-1 (protein concentration, 6.8 mg ml-1), but that of the root tip stem including the growing point increased to 887 ng ml-1 (protein concentration 3.8 mg ml-1) in the second day after germination.

Animals↗
PubMed1979

Cell proliferation and cortical cell production in relation to wool growth.

The relationship of wool growth to cell proliferation in the follicle bulb and to the subsequent migration and growth of the fibre cortical cells was investigated in 10 Peppin Merino sheep. These sheep had been maintained on a low, medium or high level of nutrient intake to ensure a wide range in wool growth. The number and mitotic activity of the germinal cells in the follicle bulb were determined after administration of colchicine. Cortical cell size was measured following isolation of the fibre cells by acid-treatment of wool. The average fibre production of the follicle varied from 4.1 x 10(4) to 13.2 x 10(4) micron3/day in these sheep. There were also substantial differences between sheep in the mitotic activity of the germinal cells in the bulb, the rate of cell proliferation being highly correlated with the average daily fibre production of the follicle (r = + 0.88, n = 10). However, the size of the germinal cell population differed from sheep to sheep and was not closely related to the level of fibre production (r = + 0.48, n = 10). The average turnover time of these cells was inversely related to fibre production and varied from 41.6 to 19.4 h (r = -0.82, n = 10). Multiple regression analysis of the data showed that the average daily fibre production of the follicle was largely determined by the number of germinal cells present in the bulb and their rate of proliferation (R = +0.95, n = 10). Variations in cell turnover time and in cortical cell size were not significant in influencing the rate of fibre production. In these sheep, the average cortical cell varied in size from 658 to 1279 micron 3 and the positive correlation (r = + 0.83, n = 10) found between cell size and fibre production is considered to merely reflect an allometric relationship. The proportion of germinal cells contributing to the fibre cortex was found to be small and variable, ranging from 9.4 to 17.8%. Furthermore, this proportion was not related to the nutritional level of these sheep, and it is thought that the variability in the distribution of cells to the fibre may be attributed to genetic differences between sheep.

Animals↗
PubMed1992

The expression of proliferating cell nuclear antigen in paraffin sections of peripheral, node-negative non-small cell lung cancer.

Cell proliferation of 40 peripheral, node-negative non-small cell lung cancers (NSCLC) treated with surgery alone was investigated by immunohistochemical analysis with the monoclonal antibody (MoAb) PC10, which recognizes a proliferating cell nuclear antigen (PCNA) in formalin-fixed and paraffin-embedded material. Results were correlated with DNA ploidy and S-phase fraction (SPF) analyzed by DNA flow cytometric study. Mitotic count (MC) was analyzed by light microscopic study and histopathologic features. PCNA immunoreactivity was seen in all samples and confined to the nuclei of cancer, but not to the surrounding, tumor-negative cells; its frequency ranged from 0-70% (median, 15%), and tumors expressed either a low (0-25%, n = 25) or intermediate (26-75%, n = 15) proliferative activity. There was no relationship between PCNA immunoreactivity and tumor stage or among size, histologic type, and mitotic count (MC). Tumors with intratumoral blood vessel invasion (BVI) showed a significantly higher (P less than 0.005) PCNA immunoreactivity than BVI-negative tumors. PCNA scores were significantly higher (P less than 0.005) in DNA aneuploid (n = 22) than in DNA diploid (n = 18) tumors and correlated significantly with the SPF of DNA aneuploid tumors (r = 0.825, P less than 0.0001), but not with diploid tumors (r = 0.002, P = 0.9). Intermediate proliferating tumors had a significantly higher (P less than 0.01) MC than their counterparts. In univariate analysis, significant predictors of survival were tumor classification (T1 versus T2), tumor size (less than or equal to 2.6 cm versus more than 2.6 cm), BVI (BVI-negative versus BVI-positive), MC (less than or equal to 8 versus more than 8), and PCNA immunoreactivity (low versus intermediate). DNA ploidy and SPF did not influence survival significantly. Only PCNA immunoreactivity retained its independent level of significance (P = 0.02) by multivariate analysis. It was concluded that PCNA immunostaining is a simple and clinically useful method for estimating cell proliferation in formalin-fixed, paraffin-embedded tissue of resected peripheral, node-negative NSCLC.

Adult↗
PubMed1992

Reversible G1 arrest induced by dimethyl sulfoxide in human lymphoid cell lines: kinetics of the arrest and expression of the cell cycle marker proliferating cell nuclear antigen in Raji cells.

In order to elucidate further the mechanism of reversible cell cycle arrest induced by treatment of Raji cells with 1.5% dimethyl sulfoxide (DMSO), we have performed a detailed analysis of the kinetics of arrest and of reentry into the cell cycle after removal of DMSO and have correlated cell cycle progression with expression of proliferating cell nuclear antigen (PCNA). No significant effect of DMSO on cell cycle patterns, assessed by flow cytometric analysis of bromodeoxyuridine-prelabeled cells, was seen for the first 19 h of treatment. A clear reduction of entry into S phase was detected by about 25 h of treatment; essentially all cells were arrested with a G1 content of DNA after 96 h of treatment. When DMSO-arrested cells were released from the block, entry into S phase began at 12 h after release and continued in a fairly asynchronous manner for a further 12-14 h. In arrested cells, the content of PCNA was reduced to about 25% of the amount present in logarithmically growing G1 phase cells. Six h after release from DMSO, PCNA RNA transcripts were first detected by Northern blotting. The increase of PCNA protein, detected by Western blotting, was seen by 9 h after release. The kinetics of entry into the cell cycle and restoration of PCNA protein are similar to that seen in serum stimulation of quiescent cells. These results suggest that DMSO reversibly arrests proliferation of Raji cells at G0 or at an early point in G1 phase and that progression through late G1 phase and entry into S phase are correlated with synthesis of the PCNA gene product.

Antigens, Neoplasm↗
PubMed1977

Autoradiographic demonstration of proliferating cells in cerebrospinal fluid.

The proliferative activity of cells, isolated from 82 human CSF specimens, was examined by 3H-thymidine autoradiography. High labelling indices (LI) were found in acute viral meningitis (up to 8 per cent) and radiculitis (up to 6 per cent). CSF cell proliferation was also shown in the subacute stages of viral diseases and in other inflammatory processes (LI ranging from 0.5 per cent to 3 per cent). Most of the cells labelled from these CSF specimens were large lymphocytes, "lymphoid cells" and plasmacytes. Their presence in CSF is presumed to indicate an immune reaction. By the demonstration of a proliferative activity of these cells, aseptic inflammatory processes can be differentiated from "unspecific" pleocytosis. Because of a correlation between the LI of CSF cells and the stages of some inflammations, this method is suggested for an assessment of pregression or remission of chronic processes, e.g. "chronic meningitis" and multiple sclerosis. It can also be used in experimental research: the same type of mononuclear cells was labelled after having been cultured for 23 hours prior to the incubation with 3H-thymidine. Proliferating tumor cells as well as proliferating non-neoplastic mononuclear cells were demonstrated in CSF from various neoplastic diseases. In the clinical diagnosis of these processes, the method is of limited value. It proved very useful, however, for an assessment of the therapeutic effects of intrathecal cytostatic therapy. CSF specimens from non-inflammatory and non-neoplastic diseases regularly contained very few proliferating cells (LI: less than 0.1).

Autoradiography↗
PubMed1992

Proliferating cell nuclear antigen (PCNA) in common epidermal lesions. An immunohistochemical study of proliferating cell populations.

A commercially available antibody to proliferating cell nuclear antigen was used to characterize and compare proliferating cell populations in paraffin sections of benign, premalignant, and malignant lesions of human epidermis using routine immunohistochemical techniques. Three patterns emerged. An ordered pattern was found in prurigo nodularis and keratoacanthoma, wherein moderately and strongly positive nuclei were distributed in a continuous, basal-suprabasal layer of relatively uniform thickness. There was graded loss and ultimate extinction of PCNA staining in progressively more superficial epidermal cells. A basal dysplastic pattern was found in actinic keratosis and squamous cell carcinoma. Nuclei of essentially all dysplastic cells of both categories expressed PCNA, with a preponderance of strongly positive nuclei. These were localized to basal-suprabasal zones that were often expanded. Loss of PCNA reactivity toward the surface was often abrupt. Bowen's disease exhibited a diffuse dysplastic pattern, wherein large numbers of moderately and strongly positive nuclei, in random array, were present in essentially full thickness distribution. In many fields, however, a layer of cytologically bland basal cells, with faint or no nuclear staining, was interposed between dysplastic epithelium and dermis. This study has demonstrated that proliferating cell populations in epidermal lesions can be assessed with simple, inexpensive methods. There were consistent differences between the proliferating cell populations of the various entities studied, differences that can be reasonably correlated with other known clinical, microscopic, and biologic features of the lesions. This technique should provide an interesting new avenue for study of diverse cutaneous diseases.

Antigens, Neoplasm↗
PubMed1992

Malignant change in trichilemmal cysts: a study of cell proliferation and DNA content.

We have examined proliferative activity in a series of pilar and trichilemmal cysts using an antibody to proliferating cell nuclear antigen. In benign lesions proliferative activity was confined to the basal layers of the squamous epithelium. Lesions showing malignant change showed increased proliferative activity and were not confined to the basal layer. These findings were correlated with studies on DNA content using flow cytometry.

Adolescent↗
PubMed1992

[Immunohistological study on the expression of proliferating cell nuclear antigen (PCNA/cyclin) in human colorectal lesions].

The purpose of this study was to clarify the significance of immunohistological staining for PCNA/cyclin in human colorectal lesions. Our results: The PCNA-positive cells existed at the bottom of colonic tubuli in the normal and hyperplastic conditions. In the neoplastic lesions, however, the positive cells were existed at the relatively surface of the mucosa (chi 2: P less than 0.01) and distributed irregularly from the bottom to the top of carcinoma tissue. These results suggested that immunohistological staining for PCNA would specifically detect the cell proliferation and be beneficial for practical use and clinical application of the diagnosis of the colorectal lesions.

Adenocarcinoma↗
PubMed1975

Kinetic analysis of cell size and DNA content distributions during tumor cell proliferation: Ehrlich ascites tumor study.

In order to study the growth dynamics of proliferating and non-proliferating cells utilizing discrete-time state equations, the cell cycle was divided into a finite number of age compartments. In analysing tumor growth, the kinetic parameters associated with a retardation in the growth rate of tumors were characterized by computer simulation in which the simulated results of the growth curve, the growth fraction, and the mean generation time were adjusted to fit the experimental data. The cell age distibution during the period of growth was obtained and by a linear transformation of the state transition matrices, was employed to specify the cell size and DNA content distributions. In an application of the model, the time-course behavior of cell cycle parameters of Ehrlich ascites tumor is illustrated, and the parameters important for the transition of cells in the proliferating compartment to the non-proliferating compartment are discussed, particularly in relation to the G1-G0 and G2-G0 transitions of non-cycling cells as revealed by the variation of cell size distribution.

Animals↗
PubMed1992

Measurement of proliferating cell nuclear antigen (PCNA) and its clinical application in oral cancers.

The PCNA score was measured in oral squamous cell carcinoma (SCC), and its relationship to other cell proliferation markers, Ki-67 score, S-phase fraction (SPF), and AgNORs counts was investigated. The PCNA score ranged from 0.4% to 43.5% with an average value of 22.8%, the Ki-67 score ranged from 4.9% to 40% with an average of 24.1%, and the SPF ranged from 0.4% to 32.5% with an average of 12.4%, while AgNORs counts ranged from 2.53/nucleus to 7.03/nucleus with an average of 4.74/nucleus. These four parameters were closely interrelated. There was a significant difference in PCNA score between malignant and nonmalignant lesions, suggesting a difference in growth activity. The mean PCNA score decreased significantly from 20.0% to 8.0% after cancer chemotherapy. The response of cancer cells to anticancer agents may be estimated by consecutive measurement of PCNA, since the PCNA score dropped after treatment in cases showing a favorable prognosis.

Antigens↗
PubMed1978

[Curve of labeled mitoses with different states of cell proliferation kinetics. V. Effect of the circadian rhythm of cell proliferation on the shape of the labeled mitosis curve].

The influence of the diurnal rhythm in cell proliferation processes on the behavior of labeled mitoses curve (LMC) is under investigation. The mathematical model predicts that LMC observed following 3H-thymidine administration to experimental animals at different day-times can differ greatly even when temporal parameters of the mitotic cycle remain unchanged. The analysis of the experimental data on the hamster's cheek pouch epithelium suggests that diurnal differences in LMCs cannot be explained in certain cases by the influences of transient processes in cell kinetics only, and therefore the existence of a slight trend in prolongation of periods of the mitotic cycle cannot be completely excluded.

Animals↗
PubMed1976

Electron microscopic autoradiographic studies of gliogenesis in rat optic nerve. I. Cell proliferation.

Electron microscopy and 3H-thymidine autoradiographic techniques were used to study the fine structure of proliferating cells in developing rat optic nerve. Before the closure of the optic canal almost all of the cells incorporating radioactive thymidine are ventricular cells, but after closure (16 days of gestation) the vast majority are differentiating astroblasts or oligodendroblasts. Labeled astroblasts show a range in their degree of differentiation; some cells lack 90 A cytoplasmic filaments while others have glial filaments and abundant cytoplasmic organelles. In contrast to astroblasts, all of the labeled oligodendroblasts are in the early stages of differentiation. The proliferation of oligodendroblasts starts at five days postnatal, approximately a day or two before the onset of myelination.During myelinogenesis a few of the labeled oligodendroblasts show presumptive connections to myelin sheaths. Microglial cells do not appear to play a major role in gliogenesis since they form less than 2% of all the labeled cells. The results of this study indicate that astroblasts and oligodendroblasts, rather than undifferentiated glioblasts, are the major source of macroglia. The finding that proliferating glia are in the processof differentiation agrees with recent studies which show that differentiated cells can divide.

Age Factors↗