Differential enamel and osteogenic gene expression profiles in odontogenic tumors.

Odontogenic tumors occur within the jaw bones and may be derived from odontogenic epithelium or ectomesenchyme or contain active components of both tissue types. We investigated the gene expression profile of enamel matrix proteins (EMPs), genes related to osteogenesis, and the mineralization process in odontogenic tumor cell populations focusing on an ameloblastoma (AB-1), a keratocystic odontogenic tumor (KCOT-1), and a calcifying epithelial odontogenic tumor (CEOT-1). All cell populations were shown to be epithelial in origin by CK14 expression. All tested EMPs were expressed by all odontogenic tumor cell types, with higher transcript levels seen in the AB-1 population especially for AMEL, AMBN, and ODAM. CEOT-1 cell populations showed a greater content of ALP-positive cells as well as higher ALP mRNA levels. Using qRT-PCR, we found a higher expression of 8 genes in the CEOT-1 compared to the AB-1 and KCOT-1. In this study we demonstrated the establishment of AB-1, KCOT-1 and CEOT-1 cell populations. The unique gene expression profiles of AB-1, KCOT-1, and CEOT-1 cells and their interactions with the surrounding microenvironment may support their unique tumor development, progression, and survival.

Colorectal cancer and hypercholesterolemia: review of current research.

AIM: In spite of ample research about a high level of cholesterol in the blood of patients with colorectal cancer (CRC), the relationship between factors causing hypercholesterolemia and factors leading to CRC development is not fully investigated. The purpose of this article is to provide a review of the current research about the risk factors leading to the development of hypercholesterolemia and CRC, and to show the relationship between these factors, hypercholesterolemia and CRC with the implication for CRC preventive and treatment practices. METHODS: A systematic search of MEDLINE and PUBMED databases between 1990 and 2005 was conducted to locate the studies that investigated the risk factors causing CRC and hypercholesterolemia. From among 255 studies found, 66 were selected that matched the following criteria for selection: (1) reported original research; (2) discussed at least one of the listed eight factors; (3) discussed hypercholesterolemia; and/or (4) discussed colon or rectum cancer. RESULTS: The studies were grouped according to four areas of research: (1) studies that explored the relationship between different factors and CRC incidences; (2) studies that investigated the relationship between different factors and CRC incidences and the role of mutations in causing CRC; (3) studies that looked at the factors causing hypercholesterolemia; and (4) studies that explored the relationship among the factors, hypercholesterolemia, and CRC development. A discussion of the studies is presented and the details related to the studies major aspects are summarized in 4 tables. CONCLUSION: The review has revealed a relationship between factors that can lead to the development of CRC and those that lead to hypercholesterolemia. Although the role of many individual risk factors is still controversial the analysis of their significance in combination might be important for diagnostic and development of the models for prediction of cancer occurrence.

[Chronically HIV-1 infected human monocyte culture U937 as a model for assessing the efficacy of anti-HIV agents]. / Khronicheski infitsirovannaia VICH-1 kul'tura monotsitov cheloveka U937 kak model' dlia otsenki éffektivnosti anti-VICh-preparatov.

Cell culture U937 chronically infected with HIV-1 is suggested as a model for adequate evaluation of antiviral activity of HIV inhibitors. Azidothimidine (AZT) notable decreased HIV-1 reproduction in chronically infected U937 cells to passages 15-18. Glycirrhizic acid (GA) effectively inhibited the virus production during the first four passages, while in subsequent passages (up to passage 20) decreased the virus production by only 60% in comparison with the control. If a combination of AZT and GA (1:1000) was used, p24 was not detected in the culture fluid by passage 20. Culturing of U937 cells with AZT led to a 10-fold decrease in the amount of DNA 2-LTR in comparison with the total content of proviral DNA, the content of HIV-1 DNA 1-LTR remaining virtually unchanged. Culturing of U937 with a combination of AZT and GA resulted in a notable decrease in the content of proviral DNA 2-LTR after passage 3, while after passage 9 this form of HIV-1 DNA was not detected at all.

[Detection of unintegrated forms of proviral DNA in HIV infections]. / Opredelenie kol'tsevykh form provirusnoi DNK pri VICh-infektsii.

The content of 1-LTR and 2-LTR circular forms of HIV-1 proviral DNA was determined by nested PCR. Outer and inner primers for the first and second stages of PCR were selected in the env and gag regions that allowed the authors to simultaneously test 1- and 2 LTR of DNA HIV-1 forms in the analyzed samples. The accumulation of circular species of HIV-1 DNA was shown to occur during HIV infection as well for acutely infected cell lines as chronically infected mononuclear cells. The cell cultures providing productive infection was characterized by higher levels of 2-LTR circular HIV-1 DNA. Analysing the clinical samples demonstrated greater differences in the accumulation of the circular forms of proviral DNA. It was detected in 16 tested clinical samples both of 1-LTR and 2-LTR circular DNA in 6 samples and 1-LTR in 11 samples of 2-LTR of HIV-1 DNA is a minor fraction in most clinical samples, but in some samples the relative content of 1-LTR/2-LTR DNA was shown to be 1:1.

[Cloning proviral DNA sequences of the human T-cell leukemia virus (HTLV-1) from the genome of cultured MT-4 cells]. / Klornirovanie provirusnykh DNK-posledovatel'nostei virusa T-kletochnogo leikoza cheloveka tipa 1 (HTLV-1) iz genoma kul'tury kletok MT-4.

MT-4 cell line is a continuous strain of human T lymphocytes expressing defective noninfective subviral HTLV-1 particles. A fragment of sequence encoding the p24 protein and gene for envelope protein (env) have been obtained from genomic DNA of this culture by polymerase chain reaction. Both HTLV-1 fragments were cloned in bacterial vectors, and the nucleotide sequence of these regions was determined. The cloned DNA fragment encoding the p24 has only four point nucleotide exchanges. Analysis of the env gene structure revealed that the sequence had several amino acid exchanges and two deletions (13 bp and 70 bp).

[Study of anti-HIV activity of azidothymidine and fluorothymidine 5'-phosphonates]. / Izuchenie anti-HIV-aktivnosti 5'-fosfonatov azidotimidina i ftortimidina.

It was established that 5'-phosphonates of 3'-azido-2',3'-dideoxythymidine (AZT) inhibit HIV reproduction in the MT-4 cell line as well as AZT. However, the viability of HIV-infected MT-4 cells after treatment with phosphonates was considerable higher that after AZT treatment. Inhibitory activities of 5'-phosphonates of 3'-fluoro-2',3'-dideoxythymidine (FLT) on HIV-infected MT-4 cells were rather low. The mechanism of action of these derivatives and prospects for their application for suppressing HIV infection are discussed.

[The characteristics of the long-term continuous cultivation of a cell line chronically infected with the human immunodeficiency virus type-1]. / Osobennosti dlitel'nogo nepreryvnogo kul'tivirovaniia linii kletok, khronicheski infitsirovannoi virusom immunodefitsita cheloveka 1 tipa.

A chronically HIV-1-infected culture of continuous human monocytes producing infectious virus during long-term continuous cultivation (over 200 passages) without the addition of noninfected cells was generated. HIV-1 produced by this culture had typical morphology and complete set of virus-specific proteins. This cell line is proposed for use as an additional model for the evaluation of antiviral effects of various drugs.

[Comparison of the radiosensitivity of chromosomes during the S and G2 periods in regenerating rat liver cells]. / Sravnenie radiochuvstvitel'nosti khromosom v periodakh S i G2 v kletkakh regeneriruiushchei pecheni krys

Radiosensitivity of chromosomes at S and G2 periods was studied by means of autoradiography technique in cells or regenerating liver of rats treated with X-rays at the doses of 150 and 300 r. The experiments were made so that the interval between irradiation and mitosis in S and G2 cells was equal. The results have shown that under the experimental conditions there are significant differences in the yield of chromosome aberrations between the labelled and intact cells. This withnesses for the existence of differences in radiosensitivity of chromosomes at different periods of mitotic cycle.