St. Cercet. Virusol. 34 (2) 2004

Contents

• 5 - Constantin Levaditi - 130 years from his birth - C. Cernescu [more...]

  Abstract. By his books and papers Levaditi (1874-1953) is considered between the founders of Virology, Immunology and, Chemotherapy. His main achievements were the discovery of viral ethiology of poliomyelitis, the studies of neurotrope ectodermoses (herpes, zona-zoster, lymphogranulomatose inguinale) and, the introduction of bismuth therapy in syphilis.

  Keywords: Constantin Levaditi, papers, viral ethiology.

• 7 - Herpes viruses in post-transplant diseases - Irina Alexiu [more...]

  Abstract. Organ transplantation have become a standard therapy for a certain number of diseases. Post-transplant infections and graft rejection are the major risks conected to this intervention. Infectious process features for transplant recipients are given by the post-transplant timing of these issues and by many other factors described as risk factors  for different ethiologic agents. Herpesviruses are main pathogens in post-transplant pathology, by their latency and way of action on biological modified organism during immunosupression. Here it is presented risk factors, clinical aspects and diagnostic features for herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalic virus (CMV), Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV6).

  Keywords: post-transplant infections, risk factors, diagnostic, HSV, VZV, CMV, EBV, HHV6.
• 21 - p53 family and its role in human cancers - Coralia Bleotu [more...]

  Abstract. The p53 tumor suppressor is a significant barrier in development of human cancer. In normal conditions, very low levels of p53 are maintained through the action of MDM2, and additional proteins of similar nature, which promote the ubiquitinilation and degradation of p53 in non-stressed cells. In response to various types of stress, relatively high concentrations of p53 are accumulating and p53 activation by fosforilation/ acetilation may culminate in dramatic cell changes including growth arrest, senescence and apoptosis. Degradation or inactivation of p53 by viral oncoproteins, together with p53 mutations are common events in human carcinogenesis. There is a lot of therapeutic strategy that target p53. Activation of p53 pathway that is implicated in apoptosis is crucial for anticancer therapy.
  Now, the p53 families comprise three members: p53, p63, p73 and their isoforms. The new family members have an additional conserved domain (a SAM domain) at their C-termini, which may be involved in developmental processes. The current information suggests that members of the p53-family factors have overlapping as well as distinct biological functions.

  Keywords: p53, p63, p73, growth arrest, apoptosis, senescence, therapy.
• 35 - Effect of methotrexat therapy on the immunological parameters in rheumatoid arthritis - Marinela Bostan¹, Stefania Marineata², Lorelai Irina Brasoveanu¹ [more...]

  ¹â€œStefan S. Nicolau” Institute of Virology, Center of Immunology, Bucharest, Romania
  ²Medical Center Vademecum, Bucharest, Romania

  Abstract. Rheumatoid arthritis (RA) is a autoimmune disease whose pathology involves some important humoral and cellular components. The aim of this study was to evaluate the ability of therapy with methotrexate along or in combination with prednisone to control the expression of immunological markers in peripheral blood or synovial fluid cells from RA patients. Therefore, in order to analyse of phenotypic marker distribution in RA cells we used direct immunofluorescence method.
  Flow cytometric analyses showed that levels of lymphocyte populations and subpopulations (CD4+, CD8+, CD19+, CD56+CD16+) and expression of activation markers (CD25+, HLA-DR) were affected in tested RA patients as compared with normal subjects. Our results were correlated with significant decreased of some clinical parameters.
  Associated therapy prednisone - methotrexate was well tolerated and provided clinical and immunological benefits. In conclusion, the present study offer a correct image of activated immunological status and might direct and control the response in therapy.

  Keywords: rheumatoid arthritis, flow cytometry, lymphocyte, therapy.
• 45 - Fractal analysis characterization of biological structures - Loretta Ichim [more...]

  Abstract. Fractal analysis has proven to be a useful tool in quantifying the structure of biological process and objects. We feel that one of the great challenges facing biologists lies in translating these 'self-evident' concepts into comprehensive models of the patterns and processes observed in nature. This paper presents a few examples of biological structures and systems modelled by modern techniques of fractal analysis.

  Keywords: fractals, self-similarity, fractal dimension, morphometry, complexity.
• 53 - Cellular and molecular factors regulating the cell cycle - Daniela Nicoleta Petrusca¹ and Lotus Mester² [more...]

  ¹â€œStefan S. Nicolau” Institute of Virusology, Center of Immunology, Bucharest, Romania
  ²Bucharest University, Faculty of Biology, Bucharest, Romania

  Abstract. The cell cycle is a tightly-regulated events order in which progression are involved multiple checkpoints that assess extracellular growth signals, cell size and DNA integrity. All positive and negative signals with intracellular or extracellular origin are integrated by a protein engine consisting of holoenzymes with kinaze activity, which trigger crucial transitions during the cell cycle. In this review the mechanisms by which the mammalian cell cycle integrates and responds the different nature signals throught its specific molecules are discussed.

  Keywords: Cell cycle, cyclines, cyclin dependent kinases (CDKs), cyclin dependent kinases inhibitors (CKIs), retinoblastoma (RB), p53.
• 63 - Hypotheses on antiviral and antitumoral activity of hypericin and related naphtodianthrones - C.N. Zaharia¹, Alexandrina Nuta², St. Prodescu¹ [more...]

  ¹"Stefan S Nicolau" Institute of Virology, Bucharest, Romania
  ²Research and Development National Institute for Chemistry and Petrochemistry, Bucharest, Romania

  Abstract. The work presents some aspects on Hypericin and related naphthodianthrones antiviral and antitumoral activity, and hypotheses some mechanisms of action on viruses (e.g. influenza A, citomegalic, HSV 1 and 2, HIV etc.) and different tumors affecting nose, brain, esophagus, pancreas, stomach, lung, bladder, etc.

  Keywords: Hypericin, naphthodianthrone, antiviral activity, apoptosis, photosensitizes, photodynamic therapy.