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St. Cercet. Virusol. 35 (1) 2005

Contents

• 3 - Impact of maternal and obstetric variables on umbilical cord blood used for transplantation - Mihaela Chivu¹, Coralia Bleotu¹, Camelia Sultana¹, Simona Cornianu-Drăgan², M.C. Russu², S. Nastasia², D. Hudiţă¹, C. Cernescu¹[more...]

  ¹â€žÅžtefan S. Nicolau” Institute of Virology, Bucharest, Romania
  ²â€žDr. I. Cantacuzino” Clinical Hospital, Bucharest, Romania

  Abstract. In this study, we reviewed the reasons for umbilical cord blood (UCB) donors’ rejection and discarding collected units. Therefore, we analyzed the obstetric factors affecting total nucleated cells (TNC) content of cord blood units, in order to establish the criteria for UCB donor selection in our geographic area. UCB was collected from 45 normal uncomplicated pregnancies in the Department of Obstetrics from „Dr. I. Cantacuzino” Hospital, Bucharest. In every case, following data were recorded: gestation length, gestation number, type of delivery (cesarean, vaginal, spontaneous), and the newborn characteristics: weight and sex. For each sample, TNC content, percentage and number of CD34+ cells, and viability were analyzed. The results showed that TNC content increases with cord blood volume, gestational length and newborn weight. The mean blood volume was 42.37 ± 13.5 ml and the mean TNC per unit was 55.49 ± 19.4 x 107. Stepwise regression analysis revealed a positive and significant correlation (r = 0.89) between the two variable. TCN increase also, with gestational length and body weight, meanwhile the CD34+ cell content do not go through important changes. The mean CD34 percentage obtained was 0.37 ± 0.06, and the total number of CD34+ cells was 4.827 ± 0.8204 x 104 / ml UCB. Multivariate analysis of data set up various equations which consider whole these parameters and which could be valuable in predicting the TNC content of a UCB collected unit. It can be established if the unit is useful or not, preventing the storage of inadequate samples. Concluding, the maternal and obstetric factors have a significant impact on UCB cell quantity and quality. The main criteria for UCB collection and storage resulted to be: a gestational age higher than 36-40 weeks and newborn weight > 3200g; gestation number ≤ 2 and placental weight > 700g can be added to standard criteria in order to improve the bank efficiency. Our results become helpful also, in evaluating stored UCB units in order to establish if those are adequate or not for clinical transplant utilization.

  Keywords: umbilical cord blood, donor selection, obstetric factors.

• 11 - Natural evolution of avian influenza virus H5N1 - Simona Cornianu-Drăgan [more...]

  “Ştefan S. Nicolau” Institute of Virology, Bucharest, Romania
  Abstract. Avian inflenza virus H5N1 is a highly pathogenic strain which has caused a lot of severe problems regarding medical and economical issues. Influenza H5N1 is considered a threat for public health for many reasons: the expansion of the host range of the virus including migratory birds and other domestic and wild species, spread of the highly pathogenic strains, the occurrence of transmission to humans, the threat of a new influenza pandemic. First, the outbreaks of H5N1 avian influenza, occured in poultry from certain regions in Asia. The first human cases of infection with H5N1 were documented in 1997. Between 2003 and 2004 several outbreaks of avian influenza H5N1 were reported in China and other countries from Eastern Asia. The virus was transmitted to humans and caused severe illness, the disease being fatal in a great number of cases. This situation led to the development of certain strategies for epidemiological control. Today, the efforts are made towards the elimination of virus reservoir, the surveillance of virus isolates, the development of efficient programs in order to eliminate human transmission and the production of effective vaccines against currently circulating avian influenza strains.

  Keywords: avian influenza virus H5N1, pandemic, surveillance, prevention.
• 19 - Rapid diagnostic in influenza virus infection - Simona Ruţă [more...]

  „Ştefan S. Nicolau” Institute of Virology, Bucharest, Romania
  Abstract. Usually, clinicians diagnose the flu on the basis of whether it is epidemic in the community and whether the person's complaints fit the current pattern of symptoms. The use of the laboratory tests to identify the virus is important during an epidemic. Health officials do laboratory tests to determine which type of flu virus is responsible for the epidemic. At present there is considerable interest in the development of a rapid and reliable method for the identification of viral respiratory pathogens. Regarding influenza viruses, the segmented nature of their genomes makes reassortment among viruses an important mechanism for generating genetic diversity. The DNA array technology has been reported to have been used for the typing and subtyping of influenza viruses. DNA array technology offers the possibility of rapid detection of reassortant viruses and of simultaneous infection of humans with both a „human” virus and an „avian”  virus, which could result in a true influenza pandemic. This technology found immediate applications in an influenza pandemic action plan.

  Keywords: influenza, rapid tests, RT-PCR, DNA microarray.
• 29 - Human risk of new avian influenza viruses - C. Cernescu [more...]

  „Ştefan S. Nicolau” Institute of Virology, Bucharest, Romania
  Abstract. A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks în poultry în China and seven other east Asian countries between late 2003 and early 2004. The same virus was isolated în 2005 în Novosibirsk Russian province and în Khazahstan and also în India and Myanmar. At present, these viruses are poorly transmitted from poultry to humans, and there is no conclusive evidence of human-to-human transmission. However, continued, extensive exposure of the human population to H5N1 viruses increases the likelihood that the viruses will acquire the necessary characteristics for efficient human-to-human transmission through genetic mutation or reassortment with a prevailing human influenza A virus. Furthermore, contemporary human H3N2 influenza viruses are now endemic în pigs în southern China and can reassort with avian H5N1 viruses în this 'intermediate host'. Therefore, it is imperative that outbreaks of H5N1 disease în poultry în Asia are rapidly and sustainably controlled.

  Keywords: avian influenza, pandemia, reasortants, pathogenicity, surveillance.

• 41 - Variables for mathematical modelling of a flu pandemic - C. Cernescu [more...]

  „Ştefan S. Nicolau” Institute of Virology, Bucharest, Romania
  Abstract. Building a mathematical model of the spread of influenza is difficult because of differences in virus transmission and virulence, lack of understanding of the primary factors affecting the spread of influenza, and shortage of population-based data. The model presented here for the spread of the disease through the population take into account Romanian demographic data. Some of the most important virus variables described are based on illness and death rates reported in earlier influenza pandemics and epidemics. The complete list of all the variables discussed is as follow:
  – population data: age pyramid, density, household size, schools size, distance travelled to school/work place, migration;
  – infection parameters: seasonality, incubation interval, viral shedding, attack rate, heterogeneity in infectiousness (contact rate).

  Keywords: influenza pandemic, mathematical model, demographic factors, infection parameters.

• 49 - Diagnostic implications of screening tests in hepatitis C virus infection - Camelia Sultana, Simona Ruţă, Loredana Manolescu, C. Cernescu [more...]

  UMF „C. Davila”, „Ştefan S. Nicolau” Institute of Virology, Bucharest, Romania
  Abstract. Screening blood donations for anti-HCV antibodies serum presence generally prevents the transmission of hepatitis C virus by transfusion. The aim of the present study was to evaluate the efficiency of the enzyme immunoassay (EIA) screening în identifying potentially infectious patients. 52 patients who tested positive în EIA anti HCV (Dia Pro Diagnostics Bioprobes) were further assessed by HCV Western Blot (Wellcozyme, Murex) to confirm the results and by RT-PCR (AMPLICOR HCV MONITOR ROCHE, vs 2.0) to asses the presence of HCV RNA în plasma. Results were correlated with the serum reactivity în the EIA screening test and the alanine aminotransferase (ALT) rate (calculated by dividing the ALT value of the samples by the upper normal limit). 41 patients had strong positive results în the EIA assay (serum reactivity >3) and high ALT rates (2 times higher than the upper normal limit - UNL). 97.6% of these samples were WB positive, only one had an indeterminate result with a band for the core antigen. 92.7% of the samples were RT- PCR positive, including the one with an indeterminate profile în the Western Blot assay. 6 patients had low reactivity în EIA and normal ALT values, HCV infection was confirmed by Western Blot în 50% of the cases, but all samples tested negative for HCV RNA. 5 patients had serum reactivity în EIA less than 3 and high ALT values. Western Blot results were positive în only 20% of theese cases, while HCV-RNA was detected în 40% of the cases. Our study suggests a strong relation between a high serum reactivity determined în the EIA screening test, and the presence of active infection (detectable HCV-RNA by RT PCR). An indeterminate WB profile does not exclude the presence of viremia, especially în patients with high levels of serum transaminases.

  Keywords: HCV, enzyme immunoassay, imunoblotting assay, RT PCR, optical density (OD), cut off (CO), sensitivity, specificity.

• 57 - Hypericin effec on lipid membranes - Beatrice Macri¹, D. Popescu^1,2, Maria-Luiza Flonta¹, Gh. Stoian¹, C.N. Zaharia³ [more...]

  ¹Bucharest University, Faculty of Biology, Bucharest, Romania                                                                   
  ²â€žCaiub Iacob” Institute of Applied Mathematics, Bucharest, Romania                                                                  
  ³â€žÅžtefan S. Nicolau” Institute of Virology, Bucharest, Romania

  Abstract. Hypericin is one of the active compounds from Hypericum perforatum, very efficient in photodynamic therapy and possessing an antiviral potential. The goal of our study was to elucidate the transmembranary mechanism of this compound. Using fluorescence spectroscopy and fluorescence microscopy techniques, hypericin was characterized in different solvents, and its mechanism of interaction with artificial and natural lipidic membranes was described. From the spectral point of view, hypericin was described to change its monomeric form into a dimeric one, depending on the polarity of the used solvent. Biologically speaking, only the existence of the monomeric form was proved to exist into the biological media, this type of structure being essential for its antiviral action.

  Keywords: hypericin, monomeric form, dimeric form, fluorescence spectra, transmembranary mechanism.

• 65 - Molecular diagnostic in common and opportunistic infections of central nervous system in adolescents infected with human immunodeficiency virus type 1 - GraÅ£iela Ţârdei [more...]

  "Victor BabeÅŸ" Infectious Diseases Hospital, Bucharest, Romania

  Abstract. Molecular detection and identification of viral pathogens by PCR or oligonucleotide microarray hybridization become increasingly applicable to cerebrospinal fluid (CSF) samples. Improvements în nucleic acid chemistry are helping these technologies become more suitable for use în a wide range of clinical condiţions, allowing lower concentrations of viral sequences to be detected. HIV infecţion is associated with various central and peripheral nervous system disorders. Multiple levels of the nervous system may be affected simultaneously by many pathogens, further complicating their diagnosis. No laboratory or neuroimaging study results are specific for HIV dementia, which is a diagnosis of exclusion. Likewise, cerebrospinal fluid abnormalities are also common în patients with HIV infecţion and no neurologic symptoms. The prevalence of neurologic disorders probably will increase as more effective treatments of HIV and opportunistic infecţions extend the lives of patients with AIDS. Recognition and early diagnosis of these disorders is crucial because the institution of therapy may dramatically change patients' quality of life and survival time. Each of the nucleic acid-based strategies discussed below offers different advantages when validating CNS disease targets.

  Keywords: Molecular detection, viral genome, cerebrospinal fluid (CSF).