921. Resolvability and convexity properties in the Sierpiński product of graphsMichael A. Henning, Sandi Klavžar, Ismael G. Yero, 2024, original scientific article Abstract: Let $G$ and $H$ be graphs and let $f \colon V(G)\rightarrow V(H)$ be a function. The Sierpiński product of $G$ and $H$ with respect to $f$, denoted by $G \otimes _f H$, is defined as the graph on the vertex set $V(G)\times V(H)$, consisting of $|V(G)|$ copies of $H$; for every edge $gg'$ of $G$ there is an edge between copies $gH$ and $g'H$ of $H$ associated with the vertices $g$ and $g'$ of $G$, respectively, of the form $(g,f(g'))(g',f(g))$. The Sierpiński metric dimension and the upper Sierpiński metric dimension of two graphs are determined. Closed formulas are determined for Sierpiński products of trees, and for Sierpiński products of two cycles where the second factor is a triangle. We also prove that the layers with respect to the second factor in a Sierpiński product graph are convex.
Keywords: Sierpiński product of graphs, metric dimension, trees, convex subgraph
Published in DiRROS: 16.02.2024; Views: 261; Downloads: 114
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922. Tumor vaccinesMojca Frank Bertoncelj, Alojz Ihan, 2006, review article Abstract: Tumor vaccines have several potential advantages over standard anticancer regirrcents. They represent highly specific anticancer therapy. Inducing tumor-specific memory T-lymphocytes, they have potential for long-lived antitumor effects. However, clinical trials, in which cancer patients were vaccinated with tccmor aaccines, have been so far mainly disappointing. There are many reasons for the inefficiency of tumor vaccines. Most cancer antigens are normal self-molecules to which imrrtune tolerance exists. That is why the population of tumor-specific lymphocytes is represented by a small number of low-affinity T-lymphocytes that induce weak antitumor immune response. Simultaneously, tumors evolve many mechanisms to actively evade immune system,what makes them poorly immunogenic or even tolerogenic. Novel irrtmunotherapeutic strategies are directed toward breaking immune tolerance to tumor antigens, enhancing immunogenicity of tumor vaccines and overcoming mechanisms of tumor escape. There are several approaches, unfortunately, all of them still far away from an ideal tumor vaccine that would reject a tumor. Difficulties in the activation of antitumor immune response by tumor vaccines have led to the development of alternative immunotherapeutic strategies that directly focus on effector mechanisms of immune system (adoptive tumor-specific T-lymphocyte transfer and tumor specific monoclonal antibodies).
Published in DiRROS: 15.02.2024; Views: 214; Downloads: 57
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923. Electrochemotherapy of tumoursGregor Serša, Maja Čemažar, Damijan Miklavčič, Zvonimir Rudolf, 2006, review article Abstract: Electroehemotherapy consists of chemotherapy followed by local application of electrie pulses to the tumour to increase drug delivery into cells. Drug uptake can be inereased by electroporation for only those drugs whose transport through the plasma membrane is impeded. Among many drugs that have been tested so far, only bleomycin and cisplatin found their way from preclinical testing to clinical trials. In vitro studies demonstrated several fold inerease of their cytotoxicity after electroporation of cells. In vivo, electroporation of tumours after local or systemic administration of either ofthe drugs, i.e. electrochemotherapy, proved to be an effective antitumour treatment. In preclinical studies on several tumour models, electrochemotherapy either with bleomycin or cisplatin was elaborated and parameters for effective local tumour control were determined. In veterinary medicine, electrochemotherapy also proved to be effective in the treatment of primary tumours in cats, dogs and horses. In human clinical studies, electrochemotherapy was performed on the patients with progressive disease andaccessible tumour nodules of different malignancies. All clinical studies demonstrated that electrochemotherapy is an effective treatment for local tumour control in cancer patients.
Published in DiRROS: 15.02.2024; Views: 233; Downloads: 67
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925. The role of p38 MAP kinase in cancer cell apoptosisMetka Lenassi, Ana Plemenitaš, 2006, review article Abstract: Background. Cellular behaviour in response to many extracellular stimuli is mediated through MAP kinase signalling pathways. p38 MAP kinase that is represented in mammals by four isoforms (p38alfa, p38beta, p38gama and p38delta) is one of the four main subgroups of MAP kinases. Recent studies show that p38 activation is necessary for cancer cell death initiated by variety of anti-cancer agents. This finding connected cancer therapies previously considered to be mechanistically unrelated and raised the possibility of developing anti-cancer agents that lack the side effects causedby events upstream of p38 MAPK Many of the details of p38 induced apoptosis still need to be elucidated. Since most of the past studies rely only on the cell culture models, all the results have to be verified using in vivo models. Also very little is known about the role of p38 mediated apoptosis on non-neoplastic cells in response to anti-cancer agents. Conclusion. Although p38 activation of cancer cell apoptosis is a very complexprocess, recent studies indicate a good starting point for new strategies that would increase the efficiency and decrease the toxicity of proven therapies.
Published in DiRROS: 15.02.2024; Views: 201; Downloads: 44
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926. Ameloblastic fibromaMarko Božič, Nataša Ihan Hren, 2006, review article Abstract: Background. Ameloblastic fibroma (AF) is a rare odontogenic tumour. It consists of odontogenic ectomesenchyme resembling the dental papilla and epithelium resembling dental lamina and enamel organ without dental hard tissues. Case report. A case report of a large ameloblastic fibroma involving the body of mandible from the lower Icff second incisor (32) to the lower leftsecond molar (37) is presented. To our knowledge this is the only case of ameloblastic fibroma reported from Slovenia. Conclusions. An aggressive surgical treatment is suggested because of the possibility of recurrence and the possibility of malignant transformation of an AF to an ameloblastic fibrosarcoma.
Published in DiRROS: 15.02.2024; Views: 203; Downloads: 47
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927. Partial domination in supercubic graphsCsilla Bujtás, Michael A. Henning, Sandi Klavžar, 2024, original scientific article Abstract: For some $\alpha$ with $0 < \alpha \le 1$, a subset $X$ of vertices in a graph $G$ of order $n$ is an $\alpha$-partial dominating set of $G$ if the set $X$ dominates at least $\alpha \times n$ vertices in $G$. The $\alpha$-partial domination number ${\rm pd}_{\alpha}(G)$ of $G$ is the minimum cardinality of an $\alpha$-partial dominating set of $G$. In this paper partial domination of graphs with minimum degree at least $3$ is studied. It is proved that if $G$ is a graph of order $n$ and with $\delta(G)\ge 3$, then ${\rm pd}_{\frac{7}{8}}(G) \le \frac{1}{3}n$. If in addition $n\ge 60$, then ${\rm pd}_{\frac{9}{10}}(G) \le \frac{1}{3}n$, and if $G$ is a connected cubic graph of order $n\ge 28$, then ${\rm pd}_{\frac{13}{14}}(G) \le \frac{1}{3}n$. Along the way it is shown that there are exactly four connected cubic graphs of order $14$ with domination number $5$.
Keywords: domination, partial domination, cubic graphs, supercubic graphs
Published in DiRROS: 15.02.2024; Views: 267; Downloads: 104
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930. Cysteine cathepsins, stefins and extracellular matrix degradation during invasion of transformed human breast cell linesIrena Zajc, Aleš Bervar, Tamara Lah Turnšek, 2006, original scientific article Abstract: Background. Human breast cellular model, comprising four cell lines originating from spontaneously immortalized human breast epithelial MCF10A cell line, its c-Ha-ras transfectant, MCF10AT, and two tumourigenic derivatives, cultured from two sequential mouse xenographs, MCF10AT-Ca1a and MCF10AT-Ca1d, were used to compare the relative protein concentration of cathepsins and stefins in single cells. Methods. The relative protein concentration of cathepsins and stefins in single cells was analysed by confocal microscopy, and compared to their protein expression in cell homogenates. Results. The most invasive, MCF10AT cell line contained several fold higher protein concentration of cathepsin B and increased levels of stefins, but similar levels of cathepsin L, compared with the parental MCF10A cells. This was associated with five fold higher endocytosis of Matrigel-DQ-collagen IV (DQC) and a simultaneous increase in signal overlap between DQC and cathepsin L as well as DQC and stefin B, but a decrease in that of DQC and cathepsin B overlap in the MCF10AT cells. Simultaneously, increased signal overlaps between both cathepsins and between cathepsins-stefins pairs, were observed in this cell line. Conclusions. These results suggest that the increased collagen endocytosis and degradation in theinvasive phenotype significantly affect also the subcellular localization of cysteine cathepsins and stefins. Based on these and the reports of other authors, we hypothesize that the intracellular degradation may also be assoeiated with cathepsin L, whereas cathepsin B in the ras transformed breastcells is involved in both, the intracellular and pericellular degradation of extracellular matrix during cell migration and invasion.
Keywords: breast neoplasms, tumor cells cultured, neoplasms invasiveness, cathepsins, extracellular matrix
Published in DiRROS: 15.02.2024; Views: 236; Downloads: 56
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