Control of sub-terahertz gyrotron frequency by modulation-anode voltage: Comparison of theoretical and experimental results.

This paper presents a comparison of simple self-consistent theory data and experimental results aimed to study the influence of the anode voltage on the frequency of the subterahertz gyrotron with the goal of frequency stabilization. Numerical simulations of the electron beam formation and beam-wave interaction in a 0.26 THz gyrotron are performed.

SMALL INTESTINAL TUMORS.

Unlabelled: Small intestine is the longest part of the gastrointestinal tract. It represents 75% of its length and 90% of the mucosal surface. Benign tumors are observed at 3-6% and the malignant--1-3% of all cancers of all GI malignancies.

Cat scratch disease.

Approximately 24,000 people are infected with cat scratch disease (CSD) every year. CSD is caused by the bacteria Bartonella henselae, a gram-negative bacteria most often transmitted to humans through a bite or scratch from an infected cat or kitten. Although CSD is often a benign and self-limiting condition, it can affect any major organ system in the body, manifesting in different ways and sometimes leading to lifelong sequelae.

Pain affecting procedures in non-resectable pancreatic carcinoma.

Unlabelled: Pancreatic cancer is third most common cancer of the gastrointestinal tract in Bulgaria, accouting for 11, 6% in 2008. The leading symptom in patients with pancreatic cancer is the pain. The pain can be related with neoplasms and their metastasis.

Effects of exogenous stress protein 70 on the functional properties of human promonocytes through binding to cell surface and internalization.

The presence of antibodies against the major stress protein, Hsp70, in patients with autoimmune diseases led us to hypothesize that Hsp70 may occur extracellularly, and could exert chaperoning and regulatory effects on various cells. We examined the action of pure Hsp/Hsc70 on the main physiological functions of human promonocytic U-937 cells. The protein was isolated from calf muscle and was shown to be a mixture of inducible Hsp70 (60%) and constitutive Hsc70 (40%) isoforms.

Accumulation of major stress protein 70kDa protects myeloid and lymphoid cells from death by apoptosis.

The major heat shock protein, hsp70, is known to contribute to the mechanisms of cell protection against a variety of stress and cytotoxic factors, providing an increase of cell survival. Whether hsp70 could be implicated in the rescue of cells from stress-induced death proceeding on apoptotic pathway is not well established. Here we report that susceptibility of myeloid and lymphoid cell lines to apoptosis induced by heat shock or ethanol coincides with hsp70 content and can be modulated by changes in expression of this protein.

[The structure of Alu-like DNA nucleotide sequences in cyclostomes and fishes].

By methods of DOT hybridization and polymerase chain reaction (PCR) structures similar to Alu repeats were shown in the genome of fish and lamprey. The fact of the presence of such sections in representatives of many orders of fishes, and also our experimental data allow to suppose that Alu-like structures, similar to 3' region of Alu repeats on mammals, have been already formed in these. The evolutionary significance of described structures has been supposed.

[The physical mapping of human chromosomes. II. The production of unique chromosome-specific DNA fragments using the polymerase chain reaction with oligonucleotide primers to conservative regions of Alu repeats].

Unique DNA fragments localised between Alu-repeats have been produced by PCR. The reaction was carried out with oligonucleotide primers to conservative regions of Alu-repeats. The DNA fragments from different pulls, individual clones, chromosome-specific clonotecs derived from phage lambda, cosmids and individual human chromosomes served as matrixes.

[The physical mapping of human chromosomes. The use of the polymerase chain reaction on unique DNA sequences with a known location on chromosome 3].

16 pairs of oligonucleotide primers, complementary to unique DNA sequences of human chromosome 3, were synthesized. For 10 of these, fragments of expected length were generated in polymerase chain reaction (PCR). These fragments may be used as markers for detailed physical mapping of this chromosome.

[Extracellular DNA in the blood of pregnant women].

The level of extracellular DNA increases in the blood of women during pregnancy. By means of PCR, the full-size Alu repeats were observed among extracellular blood DNA repeats of pregnant women. Furthermore, with Tc65 type primer the PCR method allowed to observe in the blood DNA fragments flanked by inverted Alu repeats (inter Alu repeats).

A new and rapid method for visualising DNA replication in spread DNA by immunofluorescence detection of incorporated 5-iododeoxyuridine.

We have developed a new and rapid immunofluorescent method for visualisation of replicated regions on fixed DNA fibers. Using this method we have found in 5-fluorodeoxyuridine (FrdU)-blocked human cells distinct replication units covering about 60 kb of DNA and corresponding in size to single replicons or chromatin loops. Our results also suggest that nonadjacent replicons within a replicon cluster may be activated after FrdU arrest and that the method may be adapted for localization on fibers of specific DNA sequences.

Differential binding of human nuclear proteins to Alu subfamilies.

Several diagnostic differences that distinguish human Alu subfamilies are clustered just downstream from the B box of the RNA polymerase III promoter; we tentatively refer to this diagnostic region as the DB box. Assuming that this region might determine the relative transcriptional activity of Alu subfamilies, we examined the interaction of nuclear proteins with DB box sequences representing different Alu subfamilies. Gel mobility shift assays suggest the existence of two factors which discriminate among the DB boxes of different Alu subfamilies: 1) An abundant, ca.

Binding specificity of human nuclear protein interacting with the Alu-family DNA repeats.

We have demonstrated earlier that human cells contain nuclear protein interacting with conserved GC-rich sequence motifs of human Alu-family DNA repeats. One of these sequences is located in the region between elements A and B of bipartite RNA polymerase III promoter of Alu (AB-region). In this study we have used a DNase I footprinting assay with an Alu restriction subfragment covering AB-region, as well as a gel mobility shift assay with appropriate synthetic oligonucleotides to analyse in more detail the interaction of the protein with AB-region.

Rat DNA sequence associated with a complex form of DNA polymerase alpha in nonregenerating liver interacts with a ubiquitous transcription/replication factor Oct-1.

A ubiquitous mammalian transcription factor, Oct-1 (also known as OTF-1, NF-A1, OBP100, or NFIII), stimulates the initiation of replication of adenovirus DNA, and may also be involved in the activation of some chromosomal replication origins. If this is true, binding sites for Oct-1 should be present within regions responsible for the initiation of DNA replication. In this study such a binding site has been identified within a 340bp fragment that was originally isolated from a minor fraction of DNA associated with a complexed form of DNA polymerase alpha from nonregenerating rat liver, and which shows autonomous replication sequence activity in a transient transfection assay.

[Several copies of angiogenin gene are present in the mammalian genome].

Human cDNAs coding for angiogenin were isolated from Li7 hepatoma. Analysis of the nucleotide sequences of isolated cDNA clones and its comparison with recently published sequences of cDNA and human angiogenin gene permitted to suggest that an intron is present in the 5' region of the gene, dividing the coding and 5' untranslating regions. The size of the intron exceeds 1700 b.

Human nuclear protein interacting with a conservative sequence motif of Alu-family DNA repeats.

Human retrotransposons, Alu-family DNA repeats (AFRs), have variable nucleotide sequence but conservative short elements, which may have important functions, are also present. In our previous reports we have described human nuclear DNA-binding protein interacting with AFRs and evidence was presented that the protein recognizes sequence motif 5'-GGAGGC-3' which is conserved in the spacer of RNA polymerase III promoter of AFRs and in the SV40 T-antigen-dependent replication origin of AFRs. In this study it was found that double-stranded synthetic oligonucleotides containing indicated conservative sequences of AFRs actually have high-affinity binding site for HeLa nuclear protein.

[Cloning of human erythropoietin gene].

The 17-mer oligonucleotide probe homologous to the fragment of the gene for human erythrocyte differentiation factor erythropoietin was used to screen the human genomic library for this gene. Restriction analysis and partial sequencing of one of the identified clones have confirmed that the clone does contain the human erythropoietin gene. We are planning to use the cloned human erythropoietin gene for developing a stably transfected mammalian cell line that should secrete erythropoietin.

[Content of carcinogenic nitroso compounds in food products].

The data are provided on the content of carcinogenous N-nitroso compounds in foods manufactured in a region with a high gastric carcinoma incidence. It was found that foods under analysis have a high content of carcinogenous nitroso compounds. The foods were also found to contain N-nitrosopiperidine, a carcinogen inducing tumors of the gastrointestinal tract.

[Several enzymic properties of the DNA-polymerase alpha complexes with antibodies].

A highly specific rabbit antiserum against DNA polymerase alpha from regenerating rat liver (antigen AG 1) and an antiserum against the preparation of the enzyme proteolytic fragments possessing catalytic activity (antigen AG 2) were obtained. The enzyme neutralization test revealed that antibodies against AG 2 inhibit the DNA polymerase activity in a much stronger degree, than those against AG 1. Data from a kinetic analysis of the enzyme complexed with the antibodies against AG 1 suggest that the catalytic and binding sites for dNTP and free Mg2+ are altered.

[Cellular DNA repair, proliferative activity and biochemical characteristics in the human premature aging syndrome (progeria)].

Fibroblasts of a patient with the Hutchinson-Gilford progeria show a decreased proliferative activity in culture and run through no more than 19 subcultivations. Progeria cells rejoin gamma-induced single strand DNA breaks to the same extent and with the same rate as do normal cells. Spontaneous and induced by X-ray chromosome aberration frequency in progeria cells does not differ from that in normal cells.