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J Kratochvil

Publications and source records attributed to J Kratochvil.

17 recordsLinked to original sources
PubMed1998

Antibodies against the GB virus C envelope 2 protein before liver transplantation protect against GB virus C de novo infection.

GB virus C (GBV-C) is a newly discovered RNA virus related to the Flaviviridae family. Although GBV-C is not yet associated with any cause of liver disease, a humoral immune response against the GBV-C envelope 2 (E2) protein has been observed. Therefore, we studied the prevalence and clinical relevance of GBV-C RNA and anti-E2 antibodies in patients undergoing orthotopic liver transplantation (OLT). In addition, we tested whether the prevalence of anti-E2 antibodies may protect against GBV-C infection. Of the 182 liver recipients included in this study, 117 of these were evaluated for GBV-C recurrence or de novo infection. GBV-C RNA was detected in sera or plasma using single-tube, reverse-transcriptase polymerase chain reaction, and anti-E2 antibody was detected by enzyme immunoassay (EIA). Cumulative patient and graft survival was tested by using Kaplan-Meier analysis. The independence of prognostic values was assessed by using Cox regression analysis. Before OLT, GBV-C RNA and anti-E2 were detected in 4.0% to 28.6% and 10.0% to 68.8%, respectively, of patients suffering from different forms of chronic liver diseases. GBV-C reinfection after OLT was determined in 85.7%. Of the patients without evidence of exposure to GBV-C before OLT, 30 of 65 (46.2%) became GBV-C RNA positive after OLT. None of the 38 patients who were anti-E2 antibody positive before OLT became GBV-C RNA positive after OLT. Neither patient nor graft survival was significantly affected by the presence of either GBV-C RNA or anti-E2 antibody before OLT. Our data indicate that 1) GBV-C RNA positive patients have a high risk of reinfection after OLT, and 2) the presence of anti-E2 antibodies before OLT is associated with an absence of GBV-C infection after OLT, which may indicate a protective role of anti-E2 antibodies.

Adult↗
PubMed1998

Detection of GB virus C by the RT-PCR LCx system.

The recent publication of representative genomic sequences of GBV-C has permitted the selection of PCR primers for detection of GBV-C in clinical samples by PCR techniques. Traditional amplification methodologies which couple reverse transcription polymerase chain reaction (RT-PCR) and Southern blot detection are slow, cumbersome, and can be technique dependent. This has hampered studies to determine the clinical significance of GBV-C. We report the selection of highly conserved PCR primers and a probe useful for semi-automated RT-PCR using the Abbott LCx system. This adaptation of the LCx system expands its capabilities to include the detection of RNA by RT-PCR, in addition to DNA detection by ligase chain reaction (LCR).

Automation↗
PubMed1990

The adenovirus EII early promoter has multiple EIA-sensitive elements, two of which function cooperatively in basal and virus-induced transcription.

The mechanism by which the adenovirus-encoded nuclear oncogene EIA activates transcription of several viral and host promoters is an important issue in the regulation of eucaryotic gene expression and virus-host cell interactions. Identification of cis-acting elements of the promoters and the cognate host transcription factors that are targets for EIA action is crucial for our understanding of the EIA-mediated control of coordinately regulated genes. The adenovirus EII early promoter has a complex architecture and contains two overlapping promoters with start sites at +1 (major promoter) and -26 (minor promoter). The major promoter responds strongly to virus-encoded trans activators EIA and EIV and contains four elements: a TAGA motif analogous to the TATA box, two EIIF sites present in an inverted orientation, and an ATF/CREB site. To determine precisely the roles played by these cis-acting elements in both basal and virus-induced transcription when the promoter is situated in its natural context, we investigated the phenotype of a series of linker scan promoter substitution mutants inserted into the viral chromosome. Promoter constructs harboring linker scan mutations in each element were rebuilt into a novel EIA- adenovirus vector, and transcriptional activity was monitored in virus-infected cells. In the absence of virus-encoded trans activators, basal activity in vivo was dependent on all four cis-acting elements. Surprisingly, a promoter mutant with only one of the two EIIF sites intact could not promote transcription in vivo, suggesting that the two EIIF sites function cooperatively even in basal transcription. Promoters harboring mutations in either of these two EIIF sites also failed to bind to an infection-specific form of EIIF in gel shift assays and competed only very weakly for EIIF binding with the wild-type promoter fragment. The dramatic cooperativity shown by the two inverted EIIF sites of the EII promoter both in vivo and in vitro could reflect simultaneous contact of both sites by the transcription factor EIIF. Furthermore, promoter mutants with mutations in the TAGA motif, the two EIIF sites, and the single ATF site all failed to respond to virus-encoded trans activators. Whereas recent results demonstrate that EIIF activity can be modulated independently by EIV, leading to transactivation of this promoter, our results and those published previously strongly indicate that the three different transcription factors that bind to TAGA, EIIF, and ATF motifs of the EII early promoter are all targets for EIA regulation in vivo. Thus, strong transactivation of the EII early promoter through these multiple EIA-sensitive elements and independently by the recently discovered EIV pathway suggests that the EII early promoter is stringently regulated in virus-infected cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenovirus Early Proteins↗
PubMed1984

Theiler's virus antigen detected in mouse spinal cord 2 1/2 years after infection.

Spinal cord sections from mice injected with Theiler's murine encephalomyelitis virus (TMEV) and surviving for 1 year and longer after infection were stained for virus antigen by two immunohistochemical techniques. Virus antigen was detected from 1 to 2 1/2 years after infection, a time when no virus was recovered at an assay sensitivity of 50 plaque-forming units per gram of tissue. The implication this has regarding the detection of a virus in MS is discussed.

Animals↗
PubMed1978

[The proportion of potassium and calcium in the vitreous body in relation to the time of death].

The method of atomic absorption spectrophotometry was employed to estimate the proportion of potassium and calcium in vitreous humour in 47 deceased persons. The amount of both was found to increase in linear proportion to the time elapsed from death. The correlation can be expressed in the form of equations. The simultaneous estimation of the proportion of potassium and calcium in vitreous humour enables a more precise ascertainment of the time of death than the estimation of merely one of the two elements. In persons who died of brain injuries, strangulation or who had suffered from conditions associated with metabolic breakdown, the time of death should not be determined according to the amount of calcium in vitreous humour; in such cases only the proportion of potassium should be exploited.

Adult↗