Early Stages Of Transformation Research Articles

Nucleolar organizer regions in lining epithelium adjacent to squamous cell carcinoma of human oral mucosa

The value of silver staining of nucleolar organizer regions (AgNOR) counts as a diagnostic aid has been reported for several neoplastic entities. Previous studies have proved the value of the morphometric evaluation of AgNOR in the detection of incipient cellular alterations. A morphometric analysis of AgNORs was performed in oral mucosa epithelium adjacent to squamous cell carcinoma compared with normal mucosa epithelium and the carcinomatous parenchyma. Highly statistically significant differences in all 5 AgNOR-related parameters assessed were found between normal mucosa and mucosa adjacent to cancer. Conversely, the corresponding nuclear parameters failed to exhibit significant differences. The parameter AgNOR contour index plotted for individual cases affords a cutoff value that could prove useful in identifying epithelia at early stages of transformation. AgNOR evidenced significant variations in epithelium adjacent to oral squamous cell carcinoma, which did not exhibit morphologic signs of atypia. Based on this study, AgNOR would be a quantitative, discriminative aid, easy to monitor in a pathology laboratory, in detecting incipient cellular alterations. These findings contribute to the issue of early diagnosis and to the knowledge of tumoral growth.

THE OVEREXPRESSION OF THE SIALYL-LEWIS(X) MOIETY IS AN INDEPENDENT AND A MORE CONSISTENT MARKER OF COLON CARCINOGENESIS THAN THE OVEREXPRESSION OF C-MYC AND KI-RAS ONCOGENES

The expression of the carbohydrate antigen sialyl-Le(x) and of the oncogenes c-myc and Ki-ras increases after malignant transformation of the colorectum. Since the overexpression of these two oncogenes may affect O- or N-linked carbohydrate chain synthesis, we investigated if this is the case for sialyl-Le(x). In parallel sections from 11 adenomas and 9 colorectal carcinomas Ki-ras and c-myc mRNAs were detected by in situ hybridization and sialyl-Le(x) by immunohistochemistry. The moderate to high overexpression of sialyl-Le(x) found in 64% of adenomas and in 89% of carcinomas is a sharply delineated process, closely related to the local stage of tissue transformation. By contrast, the moderate to high overexpression of c-myc mRNA detected in 27% of adenomas and in 78% of carcinomas affects the whole adenomatous or carcinomatous tissue in a homogeneous manner. The Ki-ras mRNA was moderately and homogeneously overexpressed in 18% of adenomas and in 11% of carcinomas, but its expression level did not differ in adenoma and carcinoma of the same specimen. The independence of the three alterations was confirmed in HT-29 cells and its subclones 16.2 and 15.2, in which the relative amounts of total sialyl-Le(x) epitope were 100%: 67%: 38% while the amounts of c-myc mRNA or Ki-ras mRNA determined by Northern blotting did not vary. These data indicate that in human colon the expression of sialyl-Le(x) is independent from c-myc or Ki-ras oncogenes. It occurs more frequently in the early stage of transformation and is more consistently associated with the malignant process than the overexpression of either oncogene.

Immunosurveillance by T-lymphocytes in pretumoral stages of chemically induced pancreatic carcinogenesis

Cellular immune-response during pancreatic carcinogenesis induced by N-nitroso-bis(2-hydroxy-propyl)amine in Syrian Golden hamsters was studied using a mouse antiserum to hamster T-lymphocytes in indirect immunofluorescence. The chronology of lesions in this model is, acinar cell atypia, cystadenoma, ductal hyperplasia and adenocar-cinoma. Lymphocyte infiltration began before microscopic lesions. Starting as an interstitial and interlobular migration, this earliest population was composed of various kind of mononuclear cells including T-cells. As pancreatic lesions proceeded, an abundant lymphocyte supply through newly formed capillaries (angiogenesis), gave rise to inter- and intralobular nodules composed almost exclusively of T-cells. Migrating from nodules, T-cells invaded and readily destroyed the exocrine tissue. Formation of hyperplastic ducts and of adenocarcinoma was accompanied by considerable accretion of the basal membrane (fibrosis). T-cells were located outside and around this basal membrane so that they never invaded the ductal epithelium. Our results suggest there is an effective immunosurveillance in the early stages of transformation that becomes ineffective at later stages as a consequence of T-cells' inability to pass through the basal membrane barrier surrounding the ductal epithelium in preneoplasic lesions (ductal hyperplasia) and in adenocarcinoma. Extending our observations to human pancreatic cancer could provide a new insight in cellular immunosurveillance and, as a consequence might, help cellular immunotherapeutic approaches for this almost fatal disease.

Reduced cell-cell communication between mitotic and nonmitotic coupled cells

The effects of mitosis on gap junctional intercellular communication (GJIC) were quantified in a clonal cell line of spontaneously immortalized rat granulosa cells (SIGC) using a fluorescence recovery after photobleaching assay. Reduction of GJIC was associated with the process of mitosis and was first apparent at the onset of prophase. Resumption of GJIC between newly divided cells and surrounding cells occurred slowly, requiring several hours following cytokinesis before reestablishment of maximal rates. Mitotic rates of GJIC in SIGC were comparable to values obtained in interphase cells partially uncoupled by 0.5 m M octanol. Limited studies of other cell lines generalized the mitotic-associated reduction of GJIC observed in SIGC. The data suggest that mitosis is one process which alters GJIC. This could be of significance when there is a change in the rate of proliferation, such as in the acquisition of immortalization, an early stage of transformation.

From Centrally Planned to Market Economy: The Road from CPE to PCPE

This paper deals with the early stages of transformation of centrally-planned economies (CPEs) into market economies during which expectations play a key role. It focuses on the transitional phase during which the economy is not any more a CPE but has not yet become a market economy. During this phase the economy is referred to as a "previously centrally-planned econony" (PCPE). A simple model is developed to analyze the consequences of expected price liberalization. The CPEs undergoing transformation lack depth and breadth of financial markets. The analysis illustrates the benefits from an early development of such markets. It demonstrates the cost of a fine-tuning strategy and the benefits from a quick implementation of price reform. The paper also examines means to reduce "liquidity overhang," and shows that they involve taxation of one form or another. The consequences of privatization are analyzed and the benefits from an early development of an effective tax system highlighted.

Extended life span of human endometrial stromal cells transfected with cloned origin-defective, temperature-sensitive simian virus 40

Human endometrial stromal cells transfected with an origin-defective, temperature-sensitive simian virus 40 recombinant plasmid are dependent on T-antigen function for proliferation and at the permissive temperature have an extended life span in culture. Southern blot analysis indicates that the transfected gene is present in low copy number, possibly at a single integration site. Normal stromal cells are capable of 10 to 20 population doublings in culture. Transfected cultures have been carried at the permissive temperature to 80 population doublings before crisis. In the multistep model of malignant transformation of human cells, these cells represent one of the earliest stages: extended but finite life span. We have used these cells to investigate alterations in signal transduction that may be responsible for this early stage of transformation caused by the large T antigen. Temperature shift experiments indicate that the expression of ornithine decarboxylase (ODC) but not of c-fos is altered by the large T antigen. Induction of c-fos by serum or 12-O-tetradecanoylphorbol-13-acetate is independent of temperature. However, in the transfected cells, the induction of ODC by asparagine or serum is greatly enhanced at the permissive temperature. This result indicates that the large T antigen acts downstream of c-fos but upstream of ODC expression in the signal-transducing cascade.

Melanosis and associated tumors in transgenic mice.

Melanosis was found to various extents in a wide array of tissues of all 23 autopsied mice whose transgene consisted of the tyrosinase promoter fused to the simian virus 40 early-region oncogenic sequences. Pigmentation in a given animal was attributable to any or all of the following; an increase in numbers of some normally pigmented cells of neural crest origin (a result compatible with early stages of transformation); elicitation of melanin synthesis in some cells that normally have little melanin, or none at all (the latter possibly signaling metaplasia); unusual intercellular transfer of pigment granules from melanocytes into certain normally unpigmented epithelia and endothelia; and profusion of melanin-phagocytizing cells. Neoplasms, occasionally also containing melanin, arose in association with some of these melanotic tissues and included three choroid plexus tumors, three endocardial tumors, two peripheral nerve sheath tumors (schwannomas), two cochlear tumors, two pineal gland tumors, one salivary gland tumor, and one nasal mucosa tumor. These apparently originated independently of the ocular and cutaneous melanomas found in the same animals. The events involved in melanosis may thus contribute to neoplastic conversion.

The 21-kDa protein is a transformation-sensitive metalloproteinase inhibitor of chicken fibroblasts.

We report the electrophoretic purification and characterization of the 21-kDa protein, an extracellular matrix component synthesized during the early stages of transformation of chicken embryo fibroblasts infected with Rous sarcoma virus (Blenis, J., and Hawkes, S. P. (1983) Proc. Natl. Acad. Sci. U. S. A. 80, 770-774; Blenis, J., and Hawkes, S. P. (1984) J. Biol. Chem. 259, 11563-11570). The NH2-terminal amino acid sequence of the protein is greater than 60% identical to a consensus sequence of mammalian tissue inhibitor of metalloproteinases (TIMP). It shares several biochemical properties with other metalloproteinase inhibitors, including evidence of intrachain disulfide bonds and resistance to cleavage by trypsin. An electrophoretic assay employing a metal ion-dependent gelatinase from conditioned cell culture medium demonstrates inhibitor activity for purified 21-kDa protein. The 21-kDa protein is the major inhibitor in the extracellular matrix and appears unique in solubility properties among inhibitors with a TIMP-like sequence. Statistical analysis of amino acid composition data for these inhibitors defines two distinct groups (TIMP and TIMP-2) and supports a close relationship for the 21-kDa protein with the TIMP group. However, the apparent size and lack of glycosylation align it more closely with the TIMP-2 group of proteins. Therefore, it is possible that the 21-kDa protein is a variant of TIMP or, alternatively, represents a third protein within the metalloproteinase inhibitor family. This report provides the first evidence that avian metalloproteinase inhibitors are similar in sequence to their mammalian counterparts.

From Centrally-Planned to Market Economies: The Road from Cpe to Pcpe

This paper deals with the early stages of transformation of centrally-planned economies (CPEs) into market economies during which expectations play a key role. It focuses on the transitional phase during which the economy is not any more a CPE but has not yet become a market economy. During this phase the economy is referred to as a previously centrally-planned econony (PCPE). A simple model is developed to analyze the consequences of expected price liberalization. The CPEs undergoing transformation lack depth and breadth of financial markets. The analysis illustrates the benefits from an early development of such markets. It demonstrates the cost of a fine-tuning strategy and the benefits from a quick implementation of price reform. The paper also examines means to reduce liquidity overhang, and shows that they involve taxation of one form or another. The consequences of privatization are analyzed and the benefits from an early development of an effective tax system highlighted.

From Centrally-Planned to Market Economies: The Road from CPE to PCPE

This paper deals with the early stages of transformation of centrally-planned economies (CPEs) into market economies during which expectations play a key role. It focuses on the transitional phase during which the economy is not any more a CPE but has not yet become a market economy. During this phase the economy is referred to as a “previously centrally-planned economy” (PCPE). A simple model is developed to analyze the consequences of expected price liberalization. The CPEs undergoing transformation lack depth and breadth of financial markets. The analysis illustrates the benefits from an early development of such markets. It demonstrates the cost of a fine-tuning strategy and the benefits from a quick implementation of price reform. The paper also examines means to reduce “liquidity overhang,” and shows that they involve taxation of one form or another. The consequences of privatization are analyzed and the benefits from an early development of an effective tax system highlighted.

Chemical and viral transformation of cultured skin fibroblasts from patients with familial polyposis coli

Treatment of skin fibroblasts from an FPC patient with 4NQO or MNNG followed by sequential passaging caused morphological changes of the cells, which showed characteristics of transformed cells such as a high frequency of colony formation in agarose, increased growth ability, and chromosomal abnormalities. This and other fibroblast lines from 5 of 12 FPC patients had an increased susceptibility to 4NQO cytotoxicity, which was caused by enhanced 4NQO-reductase activity rather than by reduced DNA repair. However, the susceptibility to cytotoxicity of MNNG and repair of MNNG-damaged DNA were normal in FPC cells. The tumor promoters TPA and DHTB enhanced the frequency of chemical transformation of the FPC fibroblasts, and protease inhibitors suppressed the promoter-enhanced transformation. The skin fibroblasts from many FPC patients exhibited increased susceptibility to transformation by murine sarcoma viruses. Analysis of the viral DNA and RNA after infection revealed that the increased susceptibility is determined at an early stage of transformation. Two out of 5 MNNG-transformed clones of FPC fibroblasts, isolated from agarose, had increased expression of c-Ki- ras or c-Ha- ras, and 4 of 4 MSV-transformed clones showed high expression of viral Ki- ras. These clones grew further after isolation from agarose, but were mortal and did not form tumors in nude mice. The present results suggest that additional changes in morphologically transformed FPC fibroblasts are required for malignant transformation.

“Hit and run” transformation of mouse c127 cells by Bovine Papillomavirus type 4: The viral DNA is required for the initiation but not for maintenance of the transformed phenotype

Morphological transformation of C127 mouse fibroblasts by bovine papillomavirus type 4 (BPV-4) DNA depends on additional factors, including cell density, the presence of TPA, the concentration of fetal calf serum, and the physical state of the input DNA. Low cell density or the presence of TPA allows the achievement of full transformation, suggesting that disturbance of cell-to-cell contact may be necessary for the expression of the malignant phenotype. TPA also induces a burst of viral DNA synthesis and transcription. The frequency of focus formation is fivefold higher in the presence of high serum than in low serum, indicating that growth factors are required during the early stages of transformation. Although the same number of foci is obtained with either circular or linear DNA, the cells transfected with linear DNA are at a more advanced stage of transformation, being capable of anchorage-independent growth and tumorigenic in nude mice; only 5 out of 21 of these cell lines contain viral DNA in integrated and rearranged forms. In contrast cells transfected with circular DNA are anchorage-dependent but tumorigenic in mice, and do not contain any viral DNA. The linear DNA has an interrupted E1 ORF and fully transformed cells are obtained also with a subgenomic viral DNA fragment containing part of the Ll ORF, the complete E6, E7, and E8 ORFs, and the truncated E1 ORF under the control of the BPV-4 regulatory region; viral DNA is not maintained in any of these cell lines. In total, only 15% of the transformed cell lines contains viral DNA. These results are discussed in the light of the “hit and run” model of cell transformation.

2Crおよび9Cr鋼のγ→α変態と炭化物析出

The γ→α transformation and the carbide precipitation in 2Cr and 9Cr steels were investigated by using optical and electron microscopy. In the 2Cr steel, the proeutectoid ferrite was observed at early stages of transformation, while the lamellar structure with α and cementite was observed at later stages around the nose temperature. In the 9Cr steel, the eutectoid structure composed of α and M23C6 were observed from early stages of transformation. Above the nose temperature, α and M23C6 appeared as a lamellar structure. Below the nose temperature, carbides were aligned in ferrite. Factors affecting the rate of the γ→α transformation and the morphology of carbide precipitation are discussed in this paper.

Crystallization of icosahedral phase from glassy Pd-U-Si alloys.

The glassy-to-icosahedral phase transformation in Pd-U-Si alloys is studied by using x-ray and transmission electron diffraction. It is found that the transformation is polymorphous and it proceeds via a nucleation and growth process. The nucleation is homogeneous, and a large number of nuclei (\ensuremath{\simeq}${10}^{18}$ ${\mathrm{cm}}^{\ensuremath{-}3}$) are found in the early stage of transformation which can be explained by the existence of short-range icosahedral order in the corresponding glassy phase. It appears that the icosahedral particles grow by atomic attachment at the particle interphase boundary. Some particles are in pentagonal or hexagonal shape, which reflects the internal symmetry of icosahedral phase. Coarsening is believed to occur during the growth process. A picture of the transformation is presented and comparisons are made with other results on glassy-to-icosahedral phase transformations.

An increase in plasminogen activator mRNA occurs at an early stage in ethylnitrosourea-induced transformation of rat brain cells.

Brain tumor cells cultured after transplacental induction by the nitrosamide, N-ethyl-N-nitrosourea had a higher level of plasminogen activator activity than control cells from adult rat brain. Cultures (BE10) derived 2 days after exposure to the carcinogen showed a rise in this proteolytic activity at the 17th passage but were not able to form colonies in agar or tumours in syngeneic rats until passages 44/45. Cultures (BE11) derived 2 days after exposure to buffer did not show a rise in this enzyme activity nor were they able to grow in agar or animals at comparable passages. Zymography and inhibition studies showed that the enzyme produced by the tumour cells was related to human tissue-type plasminogen activator rather than to urokinase. Northern blot analysis showed a higher level of tissue plasminogen activator related mRNA in tumour cells than control cells. There was an increase in mRNA level during passaging of the carcinogen-exposed culture, BE10, which correlated with the increased enzyme activity. There was no rise in the barely detectable mRNA levels of the comparable buffer-exposed culture, BE11. The results suggest that alteration in the transcriptional control of this proteolytic enzyme occurs at an early stage in the transformation process.

Organic petrology of Hat Creek coal deposit No. 1, British Columbia

The upper Eocene Hat Creek coal deposits of British Columbia, Canada, are one of the thickest lignite to subbituminous coal deposits of the world, and comprise 350–550 m of coal. Samples of sedimentary organic material were taken from a 560-m interval of interbedded shale, siltstone and carbonate that was penetrated by corehole 75–106 in the centre of the coal basin, and the reflectances of huminite (eu-ulminite) from coal and kerogen from the organic material were determined and petrographical analyses were made. The coal deposit contains many leaf- and resinite-rich horizons, and the reflectance of huminite in these horizons in lower than in corresponding horizons containing less liptinite. When compared with huminite in adjacent coal beds, the reflectance of huminite in shale is lower, that in siltstone is similar, and huminite associated with carbonate rocks has slightly higher reflectance values. The petrological variation in the coal is mainly within the huminite group of macerals. The coal at the top of the deposits is lignite (% R o = 0.38) and becomes subbituminous C (% R o = 0.50) at the base. The inertinite content is very low, indicating a low level of peat fire or oxidation. The early stages of transformation of gelinite to macrinite are described. The paleoenvironment appeared to be lacustrine, as determined by organic petrological analysis of coals and interbedded sediments. Four major zones, each containing many subzones, were found. Paleoenvironments were similar for the A and C zones and also for the B and D zones.

Effect of mercurials on lymphocyte functions in vitro

The effect of in vitro treatment with mercurials on several functions of mouse lymphocytes was studied. When lymphocytes were cultured in the presence of mercurials, DNA synthesis induced by mitogen (concanavalin A, phytohemagglutinin-P, lipopolysaccharide) and polyclonal B cell activation induced by lipopolysaccharide were strongly inhibited by methylmercuric chloride at the concentration of 10 −6 M, but mercuric chloride inhibited these functions by 50% at 10 −5 M. Furthermore, 10 −7 M methylmercuric chloride and 10 −6 M mercuric chloride inhibited mixed lymphocyte reaction by 80%. Thus, the inhibitory effect of methylmercuric chloride was 10 times stronger than that of mercuric chloride when the mercurials were present in the culture throughout the incubation. On the other hand, DNA synthesis once induced by mitogens was not significantly affected when 10 −6 M methylmercury was added during the last 3 h of the incubation. Pretreatment with 10 −6 M methylmercury for 1 h, however, showed 50% inhibition of thymidine incorporation into DNA and also reduced the rate of metabolism of phosphatidyl inositol by 50%. These results indicate that methylmercury may act on mouse lymphocytes at an early stage of transformation induced by the mitogens, while inorganic mercury failed to cause the pronounced difference in its potency of inhibition on the functions of lymphocytes by the different treatments of the cells under the various conditions used.

Neoplastic transformation of human diploid fibroblasts (KMST-6) by treatment with 60Co gamma rays.

Normal fibroblasts (KMS-6) derived from a human embryo were transformed in culture into neoplastic cells (KMST-6) by repeated treatment with 60Co gamma ray irradiation. Repeated treatment was necessary to obtain transformation. Control normal cells exhibited normal karyotype (46, XX) and stopped dividing due to cellular ageing at the 40th passage. The transformed cells are presently growing indefinitely (140th passage) and exhibit prominent karyologic aberrations, both numerical and structural. These 2 characteristics, indefinite growth and abnormal karyotype, are thought to be the most important parameters for neoplastic transformation of human fibroblasts. Other indispensable parameters are the presence of active mitotic figures on confluent cell sheets and colony-type morphology. Transformed cells grow into colonies with relatively smooth edges, while normal fibroblasts form colonies with jagged edges, due to the protrusion of growing fibroblasts. Other parameters, such as elevated plating efficiency, enhanced colony formation in soft agar, low serum requirement for growth, high saturation density, and acquisition of transplantability, are not reliable in the early stages of transformation. These parameters probably appear at rather later stages of transformation following several cell divisions. Among other characteristics, the transformed KMST-6 cells exhibit a B-type isozyme pattern of glucose-6-phosphate dehydrogenase, lactate-dehydrogenase isozyme pattern of human origin, no evidence of viral infection and no production of C-type virus particles.

The Strengthening Mechanism in Consolidated Rapidly Solidified Alloys

ABSTRACTAttempts have been made to study mechanisms of strengthening in the Ni68W22C8B2 and the Ni45CO20 Cr10MO4Fe5B16 alloy systems during their amorphous crysialline transitions. In the Ni68W22C8B2 system where amorphous particulates of varying sizes have been cons Ti a ed at high pressure and low temperature (3.6 MPa, and 673°K respectively), the initial stage of crystallization is marked by transformation of the localized regions of the specimen. These crystallized regions contain microcracks and voids. Microhardness measurements from the consolidated specimens indicate an increasing trend in the microhardness with decreasing particulate sizes. Premature failures of the consolidated specimen during tensile stress measurements have been attributed to the presence of microcracks and voids in these specimens. In the Ni45Co20Crl0Mo4Fe5B16 alloy system isothermal annealing of an initially amorphous alloy has been allowed to produce grains of varying sizes. The tensile stress measurements from these thermally annealed ribbons indicate two distinctly different functional relationships between the strength, σ, and the grain size parameter, λ. In the early stage of transformation where grain reach a maximum growth of up to 400 Å, the functional form of the strength, σ, with the grain parameter, λ, is σ = σ + K Log λ, where σO and K are constants. During latter stages of transformation, where grains larger than 400 Å have been formed, the strength, σ, varies with the inverse square root of the grain sizes. This latter relationship is analogous with the well known Hall-Petch relationships, which describes the strength, σ, as a function of the grain sizes in conventionally processed alloys.

Isochromosome 17q in Ph-negative chronic myelocytic leukemia

No Ph chromosome was found in three clinically suspected chronic myelocytic leukemia (CML) patients, although one had metaphases with trisomy 13. An isochromosome of the long arm of chromosome 17 [i(17q)] was found in these patients when two of them were in acute blastic crisis (ABC) and the other in an early stage of transformation. Although an i(17q) is frequently seen in ABC of Ph-positive CML, it is rarely reported in Ph-negative CML. The finding of an i(17q) chromosome in Ph-negative CML appears to indicate, as in Ph-positive CML, that the disease is transforming into ABC. A series of cytogenetic studies in this group of patients may possibly aid in predicting the patients' pending ABC and may also lead to understanding the pathogenesis of ABC.