The dominance of a mutant isolated from a persistent infection (VW-Pi) over wild-type vesicular s... more The dominance of a mutant isolated from a persistent infection (VW-Pi) over wild-type vesicular stomatitis virus (w-t-VSV) in mixed infections was described previously (
This report demonstrates the presence of the neutral glycosphingolipid, globoside, on the villous... more This report demonstrates the presence of the neutral glycosphingolipid, globoside, on the villous trophoblast layer of human placenta. Immunoreactivity for globoside which is the receptor used by human parvovirus B19 was strongest in villous trophoblast cells of first trimester placentae, with diminished reactivity in second trimester placentae, and a near lack of staining for the antigen in those of third trimester. This relative reduction in globoside-specific immunoreactivity in placentae of increasing gestational ages was confirmed using thin-layer chromatographic analyses of extracted neutral glycolipids from the syncytiotrophoblast layer and cytotrophoblast cells of first and third trimester placental villi. The presence of globoside on the protective trophoblast layer of the villi provides a potential pathway whereby B19 may be transmitted from an infected mother to the fetus. The virus once across the placental barrier, may gain access to its erythroid precursor target cells within fetal villus capillaries. The observed change found in globoside immunoreactivity correlates well with the observation that fetal outcome is worse when maternal infection occurs during first or second trimester as compared to an infection occurring near term. The reason for this observed difference in fetal outcome may be due not only to the presence of more target cells potentially to infect during the first and second trimesters, but also to the greater number of viral receptors present on the villous trophoblast layer.
Clinical and diagnostic laboratory immunology, Mar 1, 2001
Human parvovirus B19 can cause congenital infection with variable morbidity and mortality in the ... more Human parvovirus B19 can cause congenital infection with variable morbidity and mortality in the fetus and neonate. Although much information exists on the B19-specific antibody response in pregnant women, little information is available describing the cell-mediated immune (CMI) response at the maternal-fetal interface. The focus of this study was to characterize the CMI response within placentas from women who seroconverted to B19 during their pregnancies and compare it to controls. Immunohistochemical techniques were used to identify the various immune cells and the inflammatory cytokine present within placental tissue sections. Group 1 consisted of placentas from 25 women whose pregnancies were complicated by B19 infection; 6 women with good outcome (near-term or term delivery), and 19 with poor outcome (spontaneous abortion, nonimmune hydrops fetalis, or fetal death). Group 2 consisted of placentas from 20 women whose pregnancies were complicated with nonimmune hydrops fetalis of known, noninfectious etiology. Group 3 consisted of placentas from eight women whose pregnancies ended in either term delivery or elective abortion. The results of the study revealed a statistically significant increase in the number of CD3-positive T cells present within placentas from group 1 compared to group 2 or 3 (13.3 versus 2 and 1, respectively) (P < 0.001). In addition, the inflammatory cytokine interleukin 2 was detected in every placenta within group 1 but was absent from all placentas evaluated from groups 2 and 3. Together, these findings demonstrate evidence for an inflammation-mediated cellular immune response within placentas from women whose pregnancies are complicated with B19 infection.
Bacterial bloodstream infections (BSI) and ensuing sepsis are important causes of morbidity and m... more Bacterial bloodstream infections (BSI) and ensuing sepsis are important causes of morbidity and mortality. Early diagnosis and rapid treatment with appropriate antibiotics are vital for improving outcome. Nucleic acid amplification of bacteria directly from whole blood has the potential of providing a faster means of diagnosing BSI than automated blood culture. However, effective DNA extraction of commonly low levels of bacterial target from whole blood is critical for this approach to be successful. This study compared the Molzyme MolYsis ™ Complete5 DNA extraction method to a previously described organic bead-based method for use with whole blood. A well-characterized S. aureus-induced pneumonia model of sepsis in canines was used to provide clinically relevant whole blood samples. DNA extracts were assessed for purity and concentration and analyzed for bacterial rRNA gene targets using PCR and sequence-based identification. Both extraction methods yielded relatively pure DNA with median A260/280 absorbance ratios of 1.71 (MolYsis ™) and 1.97 (bead-based). The organic bead-based extraction method yielded significantly higher average DNA concentrations (P <0.05) at each time point throughout the experiment, closely correlating with changes observed in white blood cell (WBC) concentrations during this same time period, while DNA concentrations of the MolYsis ™ extracts closely mirrored quantitative blood culture results. Overall, S. aureus DNA was detected from whole blood samples in 70.7% (58/82) of MolYsis ™ DNA extracts, and in 59.8% (49/82) of organic bead-based extracts, with peak detection rates seen at 48 h for both MolYsis ™ (87.0%) and organic bead-based (82.6%) methods. In summary, the MolYsis ™ Complete5 DNA extraction kit proved to be the more effective method for isolating bacterial DNA directly from extracts made from whole blood.
Human parvovirus B19 is the cause of a common childhood disease that usually has a mild and self-... more Human parvovirus B19 is the cause of a common childhood disease that usually has a mild and self-limited course. Complete viral replication and subsequent cell lysis are limited to early erythroid precursor cells expressing the globoside receptor. Individuals with shortened red blood cell half-lives and immunocompromised or immunosuppressed patients, as well as pregnant women and developing fetuses, are at risk for severe anemia and/or persistent infection from human parvovirus B19. Selection of the diagnostic test(s) to use to detect parvovirus B19 is patient dependent. Serological testing is most appropriate in immunocompetent individuals, including children and pregnant women, who have symptoms consistent with parvovirus B19 infection or a history of recent exposure. Conversely, a molecular amplification assay should be chosen to detect parvovirus B19 DNA in individuals lacking an adequate antibody-mediated immune response. In summary, it is critical that clinicians are educated about the most appropriate diagnostic test to detect parvovirus B19 infection in their patients because selecting an inappropriate or inaccurate test for parvovirus B19 can lead to misinformation and/or misdiagnosis.
The dominance of a mutant isolated from a persistent infection (VW-Pi) over wild-type vesicular s... more The dominance of a mutant isolated from a persistent infection (VW-Pi) over wild-type vesicular stomatitis virus (w-t-VSV) in mixed infections was described previously (
This report demonstrates the presence of the neutral glycosphingolipid, globoside, on the villous... more This report demonstrates the presence of the neutral glycosphingolipid, globoside, on the villous trophoblast layer of human placenta. Immunoreactivity for globoside which is the receptor used by human parvovirus B19 was strongest in villous trophoblast cells of first trimester placentae, with diminished reactivity in second trimester placentae, and a near lack of staining for the antigen in those of third trimester. This relative reduction in globoside-specific immunoreactivity in placentae of increasing gestational ages was confirmed using thin-layer chromatographic analyses of extracted neutral glycolipids from the syncytiotrophoblast layer and cytotrophoblast cells of first and third trimester placental villi. The presence of globoside on the protective trophoblast layer of the villi provides a potential pathway whereby B19 may be transmitted from an infected mother to the fetus. The virus once across the placental barrier, may gain access to its erythroid precursor target cells within fetal villus capillaries. The observed change found in globoside immunoreactivity correlates well with the observation that fetal outcome is worse when maternal infection occurs during first or second trimester as compared to an infection occurring near term. The reason for this observed difference in fetal outcome may be due not only to the presence of more target cells potentially to infect during the first and second trimesters, but also to the greater number of viral receptors present on the villous trophoblast layer.
Clinical and diagnostic laboratory immunology, Mar 1, 2001
Human parvovirus B19 can cause congenital infection with variable morbidity and mortality in the ... more Human parvovirus B19 can cause congenital infection with variable morbidity and mortality in the fetus and neonate. Although much information exists on the B19-specific antibody response in pregnant women, little information is available describing the cell-mediated immune (CMI) response at the maternal-fetal interface. The focus of this study was to characterize the CMI response within placentas from women who seroconverted to B19 during their pregnancies and compare it to controls. Immunohistochemical techniques were used to identify the various immune cells and the inflammatory cytokine present within placental tissue sections. Group 1 consisted of placentas from 25 women whose pregnancies were complicated by B19 infection; 6 women with good outcome (near-term or term delivery), and 19 with poor outcome (spontaneous abortion, nonimmune hydrops fetalis, or fetal death). Group 2 consisted of placentas from 20 women whose pregnancies were complicated with nonimmune hydrops fetalis of known, noninfectious etiology. Group 3 consisted of placentas from eight women whose pregnancies ended in either term delivery or elective abortion. The results of the study revealed a statistically significant increase in the number of CD3-positive T cells present within placentas from group 1 compared to group 2 or 3 (13.3 versus 2 and 1, respectively) (P < 0.001). In addition, the inflammatory cytokine interleukin 2 was detected in every placenta within group 1 but was absent from all placentas evaluated from groups 2 and 3. Together, these findings demonstrate evidence for an inflammation-mediated cellular immune response within placentas from women whose pregnancies are complicated with B19 infection.
Bacterial bloodstream infections (BSI) and ensuing sepsis are important causes of morbidity and m... more Bacterial bloodstream infections (BSI) and ensuing sepsis are important causes of morbidity and mortality. Early diagnosis and rapid treatment with appropriate antibiotics are vital for improving outcome. Nucleic acid amplification of bacteria directly from whole blood has the potential of providing a faster means of diagnosing BSI than automated blood culture. However, effective DNA extraction of commonly low levels of bacterial target from whole blood is critical for this approach to be successful. This study compared the Molzyme MolYsis ™ Complete5 DNA extraction method to a previously described organic bead-based method for use with whole blood. A well-characterized S. aureus-induced pneumonia model of sepsis in canines was used to provide clinically relevant whole blood samples. DNA extracts were assessed for purity and concentration and analyzed for bacterial rRNA gene targets using PCR and sequence-based identification. Both extraction methods yielded relatively pure DNA with median A260/280 absorbance ratios of 1.71 (MolYsis ™) and 1.97 (bead-based). The organic bead-based extraction method yielded significantly higher average DNA concentrations (P <0.05) at each time point throughout the experiment, closely correlating with changes observed in white blood cell (WBC) concentrations during this same time period, while DNA concentrations of the MolYsis ™ extracts closely mirrored quantitative blood culture results. Overall, S. aureus DNA was detected from whole blood samples in 70.7% (58/82) of MolYsis ™ DNA extracts, and in 59.8% (49/82) of organic bead-based extracts, with peak detection rates seen at 48 h for both MolYsis ™ (87.0%) and organic bead-based (82.6%) methods. In summary, the MolYsis ™ Complete5 DNA extraction kit proved to be the more effective method for isolating bacterial DNA directly from extracts made from whole blood.
Human parvovirus B19 is the cause of a common childhood disease that usually has a mild and self-... more Human parvovirus B19 is the cause of a common childhood disease that usually has a mild and self-limited course. Complete viral replication and subsequent cell lysis are limited to early erythroid precursor cells expressing the globoside receptor. Individuals with shortened red blood cell half-lives and immunocompromised or immunosuppressed patients, as well as pregnant women and developing fetuses, are at risk for severe anemia and/or persistent infection from human parvovirus B19. Selection of the diagnostic test(s) to use to detect parvovirus B19 is patient dependent. Serological testing is most appropriate in immunocompetent individuals, including children and pregnant women, who have symptoms consistent with parvovirus B19 infection or a history of recent exposure. Conversely, a molecular amplification assay should be chosen to detect parvovirus B19 DNA in individuals lacking an adequate antibody-mediated immune response. In summary, it is critical that clinicians are educated about the most appropriate diagnostic test to detect parvovirus B19 infection in their patients because selecting an inappropriate or inaccurate test for parvovirus B19 can lead to misinformation and/or misdiagnosis.
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