Use of robotized DNA isolation and real-time PCR to quantify and identify close correlation between levels of Neisseria meningitidis DNA and lipopolysaccharides in plasma and cerebrospinal fluid from patients with systemic meningococcal disease

The present study, using robotized DNA isolation and quantitative PCR based on the Neisseria meningitidis-specific capsular transport A gene, demonstrates the ease, rapidity, specificity, and sensitivity of quantifying neisserial DNA in plasma (n = 65) and cerebrospinal fluid (CSF) (n = 12) from patients with systemic meningococcal disease. We found a close correlation between the levels of neisserial DNA and lipopolysaccharides in plasma (r = 0.905) and in CSF (r = 0.964). The median concentration of neisserial DNA in plasma in 23 patients with persistent shock was 2 x 10(7) copies/ml, versus <10(3) copies/ml in 42 nonshock patients. Furthermore, quantitative PCR made possible estimates of the total number of meningococci in plasma, as opposed to conventional blood cultures, suggesting about 1,000 dead meningococci for every viable bacterium. Finally, with logistic regression analyses, neisserial DNA may predict a patient's disease severity and outcome at hospital admission. The number of meningococci in plasma and CSF appears to be the main determinant of the lipopolysaccharide levels, clinical presentation, and outcome.     

Human dendritic cells following Aspergillus fumigatus infection express the CCR7 receptor and a differential pattern of interleukin-12 (IL-12), IL-23, and IL-27 cytokines, which lead to a Th1 response

Aspergillus fumigatus is the most prevalent airborne fungal pathogen and causes fatal invasive aspergillosis in immunocompromised patients. Given the essential role of dendritic cells (DC) in initiating and regulating immune responses, we investigated the impact of A. fumigatus conidial infection on human DC. A. fumigatus conidia were rapidly internalized and induced the release of tumor necrosis factor alpha within the first 8 h. After A. fumigatus infection, the majority of DC underwent full maturation, although CCR7 expression was observed only in DC that had internalized the conidia. Additionally, the analysis of regulatory cytokines showed that infected DC simultaneously produced interleukin-12p70 (IL-12p70) and significant amounts of IL-10. IL-10 neutralization was not able to further increase IL-12p70 production from infected DC. Whereas the central role of IL-12 in the generation of Th1 cells has long been appreciated, recently two other members of the IL-12 family, IL-23 and IL-27, were reported to play important roles in the regulation of gamma interferon (IFN-gamma) production from na?ve and memory T cells. A. fumigatus-infected DC were also able to express high levels of IL-23p19 and low levels of IL-27p28 at later stages of infection. According to this expression pattern, A. fumigatus-infected DC were able to prime IFN-gamma production of na?ve T cells. Thus, this study on the expression of the new IL-12 family members controlling the Th1 response sheds light on a novel aspect of the contribution of DC to anti-Aspergillus immunity.     

HLA -A, -C, -B, -DRB1, -DQB1 and -DPB1 allele and haplotype frequencies in 4514 healthy Norwegians

We report HLA-A, -C, -B, -DRB1, -DQB1 and -DPB1 allele frequencies and estimated haplotype frequencies from 4514 healthy Norwegians who volunteered to participate in the Norwegian Bone Marrow Donor Registry. HLA genotyping was conducted on a Next Generation Sequencing platform. Data were analyzed using Arlequin and Pypop software. No significant deviations from Hardy-Weinberg Equilibrium were noted at any of the loci studied. We discuss the representability for the Norwegian population and argue that the presented HLA data could serve as a Norwegian reference panel.     

T-cell immune response assessment as a complement to serology and intranasal protection assays in determining the protective immunity induced by acellular pertussis vaccines in mice

The relative value of antibodies and/or T-cell immune responses to Bordetella pertussis antigens in the immunity induced by acellular pertussis (aP) vaccines is still an open issue, probably due to the incomplete knowledge on the mechanisms of protective immunity to pertussis. The relevance of T-cell immune responses in protection from pertussis has been demonstrated in murine and human models of infection; thus, in this study, the ability of different vaccine preparations of three component (pertussis toxin, filamentous hemagglutinin, and pertactin) aP vaccines to induce T-cell responses was investigated in mice. All vaccine preparations examined passed the immunogenicity control test, based on antibody titer assessment, according to European Pharmacopoeia standards, and protected mice from B. pertussis intranasal challenge, but not all preparations were able to prime T cells to pertussis toxin, the specific B. pertussis antigen. In particular, one vaccine preparation was unable to induce proliferation and gamma interferon (IFN-gamma) production while the other two gave borderline results. The evaluation of T-cell responses to pertussis toxin antigen may provide information on the protective immunity induced by aP vaccines in animal models. Considering the critical role of the axis interleukin-12-IFN-gamma for protection from pertussis, our results suggest that testing the induction of a key protective cytokine such as IFN-gamma could be an additional tool for the evaluation of the immune response induced by aP vaccines.     

Surface residues dynamically organize water bridges to enhance electron transfer between proteins

Cellular energy production depends on electron transfer (ET) between proteins. In this theoretical study, we investigate the impact of structural and conformational variations on the electronic coupling between the redox proteins methylamine dehydrogenase and amicyanin from Paracoccus denitrificans. We used molecular dynamics simulations to generate configurations over a duration of 40 ns (sampled at 100-fs intervals) in conjunction with an ET pathway analysis to estimate the ET coupling strength of each configuration. In the wild-type complex, we find that the most frequently occurring molecular configurations afford superior electronic coupling due to the consistent presence of a water molecule hydrogen-bonded between the donor and acceptor sites. We attribute the persistence of this water bridge to a “molecular breakwater” composed of several hydrophobic residues surrounding the acceptor site. The breakwater supports the function of nearby solvent-organizing residues by limiting the exchange of water molecules between the sterically constrained ET region and the more turbulent surrounding bulk. When the breakwater is affected by a mutation, bulk solvent molecules disrupt the water bridge, resulting in reduced electronic coupling that is consistent with recent experimental findings. Our analysis suggests that, in addition to enabling the association and docking of the proteins, surface residues stabilize and control interprotein solvent dynamics in a concerted way.     

Effect of grapefruit juice on cyclosporin A pharmacokinetics in pediatric renal transplant patients

Cyclosporin A (CsA) is an important immunosuppressant that is prone to numerous drug interactions. Grapefruit juice has been investigated, as a possible adjunct to CsA dosing in adult renal transplant recipients, to decrease CsA metabolism and reduce dosages. This study investigated this combination in pediatric renal transplant patients. Six stable pediatric renal transplant patients were entered into an open-label, four-period cross-over study in which patients were given their current CsA dose as either an oral solution (CsA-Sol) or a microemulsion (CsA-ME). In addition, drugs were administered concurrently with water or grapefruit juice. Steady-state pharmacokinetic profiles were taken during each of the four periods. Following the concurrent administration of grapefruit juice, CsA whole-blood 12-h trough levels were significantly increased during CsA-Sol dosing. Furthermore, the CsA elimination rate constant was significantly reduced during the same period. After CsA-ME dosing, no differences in CsA pharmacokinetics were found between concurrent water or grapefruit ingestion. Grapefruit juice co-administration reduced the production of CsA metabolites, AM1 and AM9, during CsA-Sol dosing. No changes in CsA metabolite production were found when patients were given CsA-ME with grapefruit juice as compared with water. Hence, alterations in CsA absorption and elimination occur with concurrent grapefruit juice ingestion when stable pediatric renal transplant patients are taking the oral CsA solution, but not the microemulsion formulation. These changes may be mediated by alterations in intestinal or hepatic metabolism, or drug absorption. The effect of grapefruit juice on CsA absorption is not readily predictable in these patients.     

Knowledge and attitudes of folate, and use of dietary supplements among women of reproductive age in Norway 1998

BACKGROUND: Authorities in many countries, including Norway from March 1998, recommend that women consume supplemental folate before and early in pregnancy to prevent neural tube defects. The aim of this survey was to establish Norwegian baseline data on knowledge, use and attitudes of folate and dietary supplements before implementing national campaigns on folate and pregnancy. METHOD: A telephone survey was carried out in late 1998 among 1,146 Norwegian women of reproductive age. The women were recruited from a nationally representative stratified random sample. RESULTS: Among the women aged 18-45 years, 50.4% had heard about folate, 32.9% knew about its role in pregnancy and 9.5% that it may prevent a malformation. Only 4.0% of the women knew that the critical period for folate supplementation to prevent a neural tube defect is before and early in pregnancy. The strongest determinants of knowledge were closeness to a pregnancy and educational level. Dietary supplements were used daily or almost daily by 53.3% of the women. The most commonly used types were multivitamin supplements and cod liver oil while only 0.9% of the women reported current use of supplemental folate. The women were also asked about use of folate and dietary supplements before or early in their last pregnancy: 44.3% reported that they had used a dietary supplement and 2.4% had used folate. Among the few women who had been pregnant within the last year of the interview, 10.3% reported use of a folate supplement. Overall, 56.0% of the women stated that they would use a folate supplement in a future pregnancy and 66.7% that they wanted more information about folate. CONCLUSIONS: Although about half of Norwegian women had heard about folate in 1998, just below 10% knew that it could prevent a malformation. Use of folate supplements was low in 1998, but more than half of the women stated that they would use folate supplements in a future pregnancy.     

5-HYDROXYTRYPTAMINE-INDUCED CONTRACTION OF THE MARMOSET AORTA IS MEDIATED BY A 5-HT1-LIKE RECEPTOR

1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT₂ antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta.
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A₂ agonist U44069 in order to amplify the responses; or (ii) exposed to N ^ω-nitro- L -arginine (100 μmol/L) plus LY 53857 (0.1 μmol/L; a 5-HT₂ receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated.
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT_1D antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT₃ and 5-HT₄ receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase.
4. The above effects fulfil the criteria for a 5-HT₁-like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT₁-like receptor.