Biomedical subjects

R Pyles

Publications and source records attributed to R Pyles.

4 recordsLinked to original sources

PubMed2006

Multilaboratory comparison of hepatitis C virus viral load assays.

We report a multilaboratory evaluation of hepatitis C virus (HCV) viral load assays to determine their linear range, reproducibility, subtype detection, and agreement. A panel of HCV RNA samples ranging in nominal concentration from 1.0 to 7.0 log10 IU/ml was constructed by diluting a clinical specimen (genotype 1b). Replicates of the panel were tested in multiple laboratories using the Abbott TaqMan analyte-specific reagent (Abbott reverse transcription-PCR [RT-PCR]), Roche TaqMan RUO (Roche RT-PCR), Roche Amplicor Monitor HCV 2.0 (Roche Monitor), and Bayer VERSANT HCV RNA 3.0 (Bayer bDNA) assays. Bayer bDNA-negative specimens were tested reflexively using the Bayer VERSANT HCV RNA qualitative assay (Bayer TMA). Abbott RT-PCR and Roche RT-PCR detected all 28 replicates with a concentration of 1.0 log10 IU/ml and were linear to 7.0 log10 IU/ml. Roche Monitor and Bayer bDNA detected 27 out of 28 and 13 out of 28 replicates, respectively, of 3.0 log10 IU/ml. Bayer TMA detected all seven replicates with 1.0 log10 IU/ml. Bayer bDNA was the most reproducible of the four assays. The mean viral load values for panel members in the linear ranges of the assays were within 0.5 log10 for the different tests. Eighty-nine clinical specimens of various genotypes (1 through 4) were tested in the Bayer bDNA, Abbott RT-PCR, and Roche RT-PCR assays. For Abbott RT-PCR, mean viral load values were 0.61 to 0.96 log10 greater than the values for Bayer bDNA assay for samples with genotype 1, 2, or 3 samples and 0.08 log10 greater for genotype 4 specimens. The Roche RT-PCR assay gave mean viral load values that were 0.28 to 0.82 log10 greater than those obtained with the Bayer bDNA assay for genotype 1, 2, and 3 samples. However, for genotype 4 samples the mean viral load value obtained with the Roche RT-PCR assay was, on average, 0.15 log10 lower than that of the Bayer bDNA. Based on these data, we conclude that the sensitivity and linear range of the Abbott and Roche RT-PCR assays enable them to be used for HCV diagnostics and therapeutic monitoring. However, the differences in the viral load values obtained with the different assays underscore the importance of using one assay when monitoring response to therapy.

Genotype↗

PubMed2006

Toll-like receptors, innate immunity and HSV pathogenesis.

In the last decade, substantial progress has been made in understanding the molecular mechanisms involved in initial host responses to viral infections, and how viral recognition leads to the innate responses that ultimately shape the adaptive immune response. Viruses, including herpes simplex virus (HSV) types 1 and 2, trigger toll-like receptors (TLRs) that elicit cytokine and chemokine production. In turn, this can create local resistance and modulate T- and B-cell-mediated immunity. TLR activation by HSV-produced molecules (or other synthetic agonists) leads to the remodelling of draining lymph nodes. This enhances the screening of naive T-cells, from which antigen-specific lymphocytes can be selected and expanded. The innate response thereby serves to direct a timely and effective acquired immune response, through the initial TLR recognition of viral pathogen-associated molecular patterns that can limit or possibly exacerbate viral pathogenesis. Recently, these findings have been exploited by strategies that utilize synthetic TLR agonists as prophylactic or therapeutic devices. Such devices prime innate immune responses, enhancing host resistance to viral infections, including experimental HSV infections.

Herpes Simplex↗

PubMed1995

Effect of different regimens of gut decontamination on bacterial translocation and mortality in experimental acute pancreatitis.

OBJECTIVE: To assess the effect of four regimens of antibiotics (compared with a control regimen of distilled water) given orally on gut decontamination, bacterial translocation, and mortality in acute necrotising pancreatitis in mice. DESIGN: Randomised experimental study. SETTING: University hospitals, USA and Italy. MATERIALS: 150 young Swiss Webster mice. INTERVENTION: All mice were fed a diet deficient in choline and supplemented with ethionine. They were then randomised to be given by gavage (36 hours after starting the diet): distilled water (controls, group 1); aztreonam along (group 2); neomycin, erythromycin, metronidazole (group 3); polymyxin B and amikacin (group 4); polymyxin B, amikacin, amphotericin B (group 5). 20 Mice in each group were treated for 10 days, and the remaining 10 in each group were killed after 3 days. MAIN OUTCOME MEASURES: Survival, and qualitative and quantitative cultures of the liver, lungs, pancreas and caecum. RESULTS: The best survival rate during the first 7 days was in group 5, but by day 10 there was no difference among the groups. All the antibiotic regimens reduced the number of bacteria in the caecum and all but aztreonam alone (group 2) reduced the rate of translocation of both Gram negative and Gram positive bacteria to all organs studied. Translocation of yeast occurred in those animals in groups 2, 3, and 4 in which there was overgrowth of fungi in the caecum. CONCLUSION: Gram negative and Gram positive organisms and fungi may have an important role in infective morbidity and mortality in acute pancreatitis, and selective decontamination with polymyxin B, amikacin, amphotericin B reduced the incidence of translocation related infections and early mortality in mice with acute necrotising pancreatitis.

Acute Disease↗

PubMed1983

Narial closure in toads; which muscles?

Narial closure in frogs never involves intrinsic narial muscles; rather it is effected by action of the M. submentalis, a muscle of the lower jaw. None of more than 40 species of frogs examined showed any strained muscles in the snout, anterior to the eyes. Direct stimulation of all the relevant muscles, as well as electromyography with simultaneous measurement of air flow at the nostrils, confirms Gaupp's hypothesis that the muscular displacement of the M. submentalis is transmitted via bones and cartilages of the snout to close the nares.

Animals↗