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M Santak

Publications and source records attributed to M Santak.

4 recordsLinked to original sources

Detection of hepatitis C virus RNA in alpha interferon derived from in vitro culture of leukocytes of human origin.

In order to assure the virological safety of blood products, in addition to serological testing of individual donations and virus inactivation steps undertaken during manufacture, routine PCR testing for HCV RNA of starting materials (plasma, cells), intermediates or final product is necessary. The aim of this study was to determine the rate of HCV RNA positive batches of human native leukocyte interferon during large-scale production. Our findings indicate the presence of HCV RNA in 6.1% batches despite acidification of intermediates in order to inactivate Sendai virus.

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Incidence of hepatitis C virus RNA in anti-HCV negative plasma pools in Croatia.

The risks of transmitting viral infection by blood and products derived from plasma have long been known and still remain an area of concern. Blood banks and transfusion centres are faced with the imminent introduction of nucleic acid amplification testing (NAT) of plasma pools as used by the plasma industry. In this paper, we show a part of our results of a validation study of an in-house method for routine polymerase chain reaction (PCR) screening for hepatitis C virus (HCV) RNA in plasma pools and the results of testing 2,718 anti-HCV negative plasma pools for the presence of HCV RNA. The European Committee for Proprietary Medical Products (CPMP) recommended that from 1 July 1999, only batches derived from plasma pools tested and found non-reactive for HCV RNA, using validated test methods of suitable sensitivity and specificity, should be batch released by authorities. The quality and efficiency of NAT detection of HCV RNA is among others influenced by the efficacy of RNA isolation, the primer selection and the use of control samples. Using modern molecular biology techniques (sensitive and specific in-house amplification methods for detection of HCV RNA and automated sequencing), we analysed samples of plasma pools from different Croatian transfusion centres. By detection of HCV RNA in an NIBSC working reagent (genotype 3) and a Pelispy HCV RNA run control (genotype 1) we determined a high reproducibility and sensitivity (below 100 International Units (IU)/ml) for our in-house method. By direct sequencing PCR cDNAs we proved the specificity of the test system and the possibility of determining the HCV genotype when the method was used for PCR screening of HCV RNA in single donations. Of 2,718 anti-HCV negative plasma pools we have found that 2.1$ were HCV RNA positive. Results of our investigation confirm the necessity of testing HCV RNA in plasma pools to further increase the safety of human plasma-derived drugs.

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Comparative study of the effects of peptidoglycan monomer and structurally related adamantyltripeptides on humoral immune response to ovalbumin in the mouse.

Peptidoglycan monomer, GlcNAc-MurNAc-L-Ala-D-isoGln-mesoDAP(omega NH2)-D-Ala-D-Ala (PGM) originating from Brevibacterium divaricatum and synthetic adamantyltripeptides, diastereoisomers of D,L-(adamant-2-yl)-Gly-L-Ala-D-isoGln (AdTP1 and AdTP2) exhibit immunomodulating activity. An experimental model in the mouse has been established with suboptimal amounts of ovalbumin (OVA) as the immunogen, and parallel testing of adjuvant activity of these three immunomodulators was carried out in Balb/c, C57B16 or CBA mice. Tested compounds (100 or 200 micrograms/mouse) mixed with OVA in saline (50 micrograms/mouse) were administered s.c. Anti-OVA was assayed by ELISA in the sera of mice taken 7 days after the boosters (given on days 14 and 28). The treatment with PGM and one of the diastereoisomers, AdTP2, resulted in significantly higher increase in anti-OVA IgG levels (stimulation index up to 46) with respect to controls and groups treated with AdTP1. The effect of AdTP2 treatment was comparable to that of PGM in most experiments after the first booster, but after the second booster PGM exhibited markedly better effect. PGM and AdTP2 also induced markedly higher levels of IgG1 and IgG2 anti-OVA subclasses than detected in controls and AdTP1 treated mice, indicating that these two immunomodulators might upregulate both Th1-like and Th2-like immune responses.

Acetylmuramyl-Alanyl-Isoglutamine↗

Introduction of the gene amplification technique to decrease the risk of hepatitis C virus transmission by plasma products.

The viral safety of plasma-derived products with respect to hepatitis C virus (HCV) is assured by selection of donors, screening of individual donations for antibodies to HCV and the incorporation of effective viral inactivation-removal steps into manufacturing processes. As antibody screening of single donations is not sufficient to completely eliminate HCV RNA positive plasmas from plasma pools, testing for HCV RNA by gene amplification techniques may be necessary to identify positive donations. Using modern molecular biology techniques, we developed a specific, sensitive and reproducible method for routine PCR screening for HCV RNA in plasma pools.

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