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E Cox

Publications and source records attributed to E Cox.

At least 37 records · Page 2Linked to original sources
PubMed2005

The effect of different isolation procedures on canine leucocyte populations and on lectin-induced lymphocyte proliferation.

Proliferation assays performed on peripheral blood mononuclear cells (PBMC) are commonly used in experimental and clinical immunology. A prerequisite for an in vitro assay is the ability to obtain relatively pure populations of mononuclear cells from whole blood, as contaminating polymorphonuclear cells may affect the proliferation of lymphocytes. Purification of canine leucocytes from whole blood is associated with difficulties in obtaining pure lymphocytes in high yields. The aim of this study was to optimize the lymphocyte purification from canine whole blood in terms of total cell recovery and purity, while not influencing the proliferation capacity of the isolated cells. To acquire optimal isolation of canine lymphocytes several density gradient media of different densities and osmolalities were examined. For optimal phagocyte removal, pre-treatment of whole blood with carbonyl iron/arabic gum and/or adherence to fibrinogen pre-coated polystyrene tissue flasks were examined. Lectin-induced proliferation was used as measurement of cell activity of the obtained cell fractions after the different separation procedures. Canine blood pre-treated with carbonyl iron/arabic gum followed by density gradient centrifugation with medium 'G' (density: 1.079 g/cm(3), osmolality: 256 mOsm) and adherence to pre-coated polystyrene tissue flask obtained the best PBMC cultures with a median lymphocyte purity of 88% and a median yield of recovered lymphocytes of 54%. This culture also resulted in the highest proliferation and subsequently the highest stimulation index upon lectin stimulation.

Animals↗
PubMed2005

Therapeutic benefit of eletriptan compared to sumatriptan for the acute relief of migraine pain--results of a model-based meta-analysis that accounts for encapsulation.

A novel model-based meta-analysis was used to quantify the dose-response relationship of sumatriptan and eletriptan for the proportion of patients that achieve migraine pain relief up to 4 h after treatment. The proportion of patients that became pain free was also evaluated. This analysis includes some unique features, allowing comparison of sumatriptan and eletriptan doses that have not been directly compared in a head to head study and also permitting comparison between the two drugs at multiple time points up to 4 h after treatment. Because the analysis allows comparison of response to blinded sumatriptan with that to marketed sumatriptan and contains timepoints as early as 0.5 h, it is especially suited to detection of possible effects of encapsulation on sumatriptan's therapeutic effectiveness and thus was employed to assess this also. Data from 19 randomized placebo controlled clinical trials were jointly analysed using a random-effects logistic regression model. The results of this analysis show a significant clinical benefit of eletriptan 40 mg compared to sumatriptan 100 mg at any point in time up to 4 h after treatment. The benefit of eletriptan 40 mg is greatest around 1.5-2 h after treatment with an absolute difference at 2 h of 9.1% (7.4-11.5%) more patients achieving pain relief and 7.3% (5.8-8.6%) more patient achieving pain free when compared to sumatriptan 100 mg. An absolute benefit of more than 5% of patients is maintained from 45 min up to 4 h after treatment for pain relief and from 1.5 h up to 4 h for pain free. Eletriptan 20 mg was superior to sumatriptan 50 mg and similar to sumatriptan 100 mg for pain relief while it was similar to sumatriptan 50 mg for pain free. The benefit of eletriptan 20 mg when compared to sumatriptan 50 mg is greatest around 1.5-2 h after treatment with an absolute difference at 2 h of 5.0% (2.9-8.1%) more patients achieving pain relief. An absolute benefit of more than 3% of patients was maintained from 1 h up to 3 h after treatment. No significant difference was found between eletriptan 20 mg and sumatriptan 50 mg for the fraction of patients that became pain free. No significant effect of encapsulation of sumatriptan was found on the time course of response up to 4 h after treatment when compared to commercial sumatriptan.

Capsules↗
PubMed2004

Oral immunization of piglets with recombinant F4 fimbrial adhesin FaeG monomers induces a mucosal and systemic F4-specific immune response.

The importance of adhesins in the pathogenicity of several bacteria resulted in studies on their usefulness in vaccines. In this study, the gene of the F4(K88)-fimbrial adhesin FaeG of the pathogenic enterotoxigenic Escherichia coli (ETEC) strain GIS26 was cloned in the pET30Ek-LIC vector and expressed with an N-terminal His- and S-tag in the cytoplasm of BL21(DE3). Recombinant FaeG (rFaeG) subunits were isolated from insoluble cytoplasmic aggregates and refolded into a native-like F4 receptor (F4R)-binding conformation. Indeed, the presence of conformational epitopes was shown by ELISA and the ability to bind the F4R was observed by inhibiting the adhesion of F4+ ETEC to F4R+ villi with increasing concentrations of native-like refolded rFaeG subunits. The rFaeG subunits appear as monomers, whereas the purified F4 fimbriae are multimers. Oral immunization of newly weaned piglets with native-like rFaeG induced a mucosal and systemic F4-specific immune response, significantly reducing F4+ E. coli excretion from 2 till 5 days following challenge infection. However, improvement of stability and immunogenicity of rFaeG is necessary since a higher F4-specific response was obtained following immunization with purified F4 fimbriae. Furthermore, the N-terminal fusion of a His- and S-tag was not detrimental for binding the F4R, supporting the use of FaeG as mucosal carrier. In conclusion, oral immunization with a recombinant fimbrial adhesin subunit of Escherichia coli induces a mucosal and systemic fimbriae-specific immune response.

Adhesins, Bacterial↗
PubMed2004

Conserved regions in the sequence of the F4 (K88) fimbrial adhesin FaeG suggest a donor strand mechanism in F4 assembly.

Oral immunization of newly weaned piglets with recombinant F4 (K88) fimbrial adhesin FaeG induces a F4-specific immune response, significantly reducing F4+ Escherichia coli excretion following challenge. In order to use FaeG subunits in an oral vaccine against F4+ enterotoxigenic E. coli, it is necessary to determine the conservation of the adhesin subunit. Hereto, the faeG sequence was determined of 21 F4ac+ E. coli field isolates from piglets with diarrhoea and subsequently compared with these of the reference strain GIS26 and previously reported FaeG sequences from F4ab, F4ac and F4ad antigenic variant strains. The FaeG amino acid sequence was 96-100% homologous within each F4 serotype, but only 92 and 88% when the F4ab and F4ad antigenic variants were compared with the F4ac antigenic variant. Furthermore, the conserved regions of the adhesin suggest a donor strand mechanism in F4 fimbriae assembly as reported for type 1 and P pili. In conclusion, the results of the reported experiments support the usefulness FaeG in an oral subunit vaccine against F4+ E. coli infections or as a mucosal carrier since the adhesin is conserved among F4+ E. coli field isolates.

Adhesins, Escherichia coli↗
PubMed2004

Inhibition of adhesion of F18+ Escherichia coli to piglet intestinal villous enterocytes by monoclonal antibody against blood group H-2 antigen.

Enterotoxigenic and verotoxigenic F18+ Escherichia coli colonising the pig small intestine, adhere to receptors on intestinal villous enterocytes by F18 fimbriae. The aim of the present study was to define the F18R nature. The knowledge on the nature of this receptor could be important for the development of receptor-based treatments against F18+ E. coli-induced disease. The adhesion of F18+ E. coli to pig intestinal villous enterocytes was analysed in an in vitro assay. The adhesion of F18+ E. coli but not of F4ac+ E. coli was strongly inhibited by monoclonal antibodies (mAb) with blood group H-2 specificity. Conversely, blood group H-1 specific mAb could not inhibit the adhesion of F18+ E. coli nor F4ac+ E. coli. Moreover, the blood group H-2 trisaccharide strongly inhibited the adhesion of F18+ E. coli, but only partially the adhesion of F4ac+ E. coli. These data demonstrate that the F18 receptor contains the blood group antigen H-2 (alpha-fuc-(1-2)-beta-Gal-(1-4)-GlcNAc) as major carbohydrate.

Animals↗
PubMed2004

Priming of piglets against enterotoxigenic E. coli F4 fimbriae by immunisation with FAEG DNA.

Early vaccination is necessary to protect pigs against postweaning diarrhoea caused by enterotoxigenic Escherichia coli (ETEC). However, at present no commercial vaccine allows successful vaccination. This is partly due to the presence of maternally derived antibodies. Since DNA vaccines are suggested to be superior to protein vaccines in young animals with maternal antibodies, we determined whether the fimbrial adhesin (FaeG) of F4ac(+) ETEC could be used as a plasmid DNA vaccine to prime piglets in a heterologous prime-boost approach. Hereto, pcDNA1/faeG19 was constructed and expression of rFaeG in Cos-7 cells was demonstrated. Thereafter, pigs were immunised (days 0, 21 and 42) intramuscularly by injection or intradermally by gene gun and humoral and cellular immune responses were analysed. Even though responses were low, results demonstrated that intramuscular injection was superior to gene gun delivery for priming the humoral immune response since higher antibody titres were raised, whereas gene gun delivery better induced a cellular response, evaluated by a lymphocyte proliferation assay. Effective priming of the humoral immune response was evidenced by high IgG titres 1 week after a protein boost with purified F4. The low responses to the pcDNA1/faeG19 DNA vaccination suggest that delivery of the DNA and/or the expression of the faeG gene should be improved.

Animals↗
PubMed2004

Gastrointestinal transit time of nondisintegrating radio-opaque pellets in suckling and recently weaned piglets.

The objective was to determine the gastrointestinal (GI) transit times of pellets in piglets at different time points around weaning, as transit times are essential criteria to develop oral drug delivery systems. Nondisintegrating radio-opaque pellets were given orally in order to define the transit times by radiography. The radiographs were analysed with a software programme to calculate the number of pellets present in the different parts of the GI tract. In suckling piglets, the gastric emptying was faster (75% in 1.5 to 3.5 h), and the colonic accumulation (to 73%) was greater than in weaned piglets (3 days, 2 and 3 weeks postweaning, 65% gastric emptying in 18 h, 75% in 17 h, and 75% in 7 h, respectively; maximal colonic accumulations of 48%). Immediately after weaning, the transit was markedly prolonged but shortened with increased postweaning time (3 days, 2 and 3 weeks postweaning, 85% excretion in 175.5, 77, and 50.5 h, respectively). Three weeks postweaning, the transit was no longer affected by weaning as transit times were similar to values reported in growing and adult pigs, and retention appeared to be restricted to the stomach and the colon. These data are of crucial importance in the design of enteric-coated formulations for oral administration of vaccines and therapeutics to young piglets and for human research using the pig model.

Animals↗
PubMed2004

Binding of a monoclonal antibody positively correlates with bioactivity of the F4 fimbrial adhesin FaeG associated with post-weaning diarrhoea in piglets.

Piglets are susceptible to F4 (K88)+ enterotoxigenic Escherichia coli (ETEC)-induced neonatal and post-weaning diarrhoea. The F4 fimbriae are composed of some minor subunits and the major subunit FaeG that also constitutes the adhesin. Parenteral vaccination of sows with an F4-containing vaccine protects the suckling piglets against neonatal F4+ ETEC-induced diarrhoea, but no commercial (mucosal) vaccine exists against F4+ ETEC-induced weaning diarrhoea. To develop a vaccine, a bioactive F4-receptor (F4R) binding FaeG molecule is required that binds to the F4R following oral immunization and induces a FaeG-specific immune response. The present study reports the altered binding of the FaeG-specific monoclonal antibody IMM01 with bioactive versus non-bioactive F4 fimbrial adhesin FaeG. The correlation of altered IMM01 binding with altered FaeG bioactivity permits the use of an IMM01-based ELISA as a fast, specific and sensitive in vitro selection for potent F4 or (recombinant) FaeG antigen formulations, useful in an F4+ ETEC vaccine.

Adhesins, Escherichia coli↗
PubMed2004

1alpha,25-dihydroxyvitamin D3 increases IgA serum antibody responses and IgA antibody-secreting cell numbers in the Peyer's patches of pigs after intramuscular immunization.

Pigs were injected intramuscularly (i.m.) twice with human serum albumin (HSA) with or without 1alpha,25-dihydroxyvitamin D3[1alpha,25(OH)2D3] with a 5-week interval. The supplementation of 1alpha,25(OH)2D3 enhanced the HSA-specific IgA serum antibody response but decreased the IgM, IgG, IgG1 and IgG2 responses. Furthermore, higher numbers of HSA-specific IgA antibody-secreting cells were obtained in systemic lymphoid tissues (local draining lymph node, spleen and bone marrow) as well as in Peyer's patches and lamina propria of the gut (GALT). In addition, the in vivo mRNA expression for Th1 [interferon (IFN)-gamma, interleukin (IL-2)], Th2 (IL-4, IL-6 and IL-10) and Th3 [transforming growth factor (TGF)-beta] cytokines as well as the percentage of different cell subsets (CD2+, CD4+, CD8+, IgM+, MHC II+, CD25+) of monomorphonuclear cells from the local draining lymph node were determined at different time-points after the i.m. immunizations. Cytokine profiles did not resemble a typical Th-cytokine profile using 1alpha,25(OH)2D3: higher levels of IL-10 and significantly lower levels of IL-2 were observed the first day after the primary immunization. However, significantly higher levels of IL-2 and significantly lower levels of IFN-gamma were observed the first day after the second immunization. Furthermore, after the second immunization TGF-beta mRNA expression decreased more quickly in the 1alpha,25(OH)2D3 group. This difference became significant 7 days after the second immunization. One week later a significantly higher percentage of CD25+ cells was observed in this group, indicating more activated T and B cells using the steroid hormone. These results suggest that in pigs the addition of 1alpha,25(OH)2D3 to an intramuscularly injected antigen can enhance the antigen-specific IgA-response and prime GALT tissues, but the relation with cytokines and cell phenotype in the local draining lymph node needs further clarification.

Adjuvants, Immunologic↗
PubMed2004

F4 fimbriae expressed by porcine enterotoxigenic Escherichia coli, an example of an eccentric fimbrial system?

An overwhelming number of infectious diseases in both humans and animals are initiated by bacterial adhesion to carbohydrate structures on a mucosal surface. Most bacterial pathogens mediate this adhesion by fimbriae or pili which contain an adhesive lectin subunit. The importance of fimbriae as virulence factors led to research elucidating the regulation of fimbrial expression and their molecular assembly process. This review provides an overview of the current knowledge of induction, expression and assembly of F4 (K88) fimbriae and discusses its unique as well as its identical characteristics compared to other intensively studied fimbriae or pili expressed by Escherichia coli.

Animals↗
PubMed2003

Enteric-coated pellets of F4 fimbriae for oral vaccination of suckling piglets against enterotoxigenic Escherichia coli infections.

To prevent enterotoxigenic Escherichia coli (ETEC) induced postweaning diarrhoea, the piglet needs an active mucosal immunity at the moment of weaning. In the present study, the feasibility of oral vaccination of suckling piglets against F4+ETEC infection with F4 fimbriae was studied. Furthermore, oral vaccination with enteric-coated pellets of F4 fimbriae was compared to vaccination with F4 fimbriae in solution. Therefore, piglets were orally administered 1mg F4 fimbriae in pellets or in solution during three successive days at the age of 7 and 21 days, whereas control piglets were not vaccinated. Five days postweaning (33 days of age), all animals were orally challenged with F4+ETEC. Despite the induction of an immune response upon oral administration of both F4 fimbriae in pellets as in solution, the colonisation of the small intestine by F4+ETEC upon oral challenge could not be prevented. However, a marginal but significant reduction in F4+ E. coli faecal excretion was found in the piglets vaccinated with F4 fimbriae in pellets, indicating that the use of an enteric-coat which protects the F4 fimbriae against inactivation by milk factors and degradation by enzymes and bile improves vaccination.

Administration, Oral↗
PubMed2003

Open status of pig-breeding farms is associated with slightly higher seroprevalence of F18+ Escherichia coli in northern Belgium.

F18+ enterotoxigenic and verotoxigenic Escherichia coli (E. coli) are widespread and induce post-weaning diarrhoea and oedema disease, respectively. No commercial vaccine exists. Therefore, the F18 herd seroprevalence of 178 randomly selected pig-breeding farms in northern Belgium was evaluated by determining F18-specific IgG antibody titres in pooled sera of sows per breeding farm. This survey reported the first data concerning F18 herd seroprevalence and showed that F18+ E. coli seroprevalence was common in northern Belgium. Significantly more open pig-breeding farms were F18 seropositive (96.4%) compared to closed (88.8%). Furthermore, no clear association was determined between the F18 herd seroprevalence and the number of sows per breeding farm (rsp = 0.19), or with the number of fattening pigs per breeding farm (rsp = 0.17).

Animal Husbandry↗
PubMed2003

Reduced faecal excretion of F4+-E coli by the intramuscular immunisation of suckling piglets by the addition of 1alpha,25-dihydroxyvitamin D3 or CpG-oligodeoxynucleotides.

In this study it was analysed whether intramuscular (IM) immunisation of piglets with F4 during the suckling period could protect against oral challenge with F4(+)-Escherichia coli and whether addition of 1alpha,25(OH)(2)D(3) or CpG-ODN could improve this protection.F4-seronegative F4-receptor positive pigs were divided into four groups of five pigs each. The pigs were intramuscularly injected with F4 fimbriae only or supplemented with 1alpha,25(OH)(2)D(3) (D(3)-group) or CpG-ODN (CpG-group). The control group received PBS in IFA. Seven days after the second immunisation, all pigs were intragastrically inoculated with 1 x 10(10) CFU of F4(+)-E. coli. All F4-injected groups, showed a reduced faecal excretion of F4(+)-E. coli. However, this reduction was only statistically significant in the D(3)-group 2 days post challenge. Pigs in the latter group showed a secondary antibody response upon challenge, indicating that F4-primed memory B-cells were present in the gut-associated lymphoid tissues at that moment.CpG-ODN, on the other hand, did not enhance the F4-specific antibody response. However, CpG-ODN significantly increased the F4-specific as well as mitogen-induced proliferation of peripheral blood monomorphonuclear cells indicating a direct or indirect overall effect on T-lymphocytes. In conclusion, supplementation with 1alpha,25(OH)(2)D(3) or CpG-ODN improved protection against an F4(+)-E. coli infection. This protection was most obvious for 1alpha,25(OH)(2)D(3) and indicates its potential use in veterinary vaccines against enteropathogens.

Adjuvants, Immunologic↗
PubMed2003

Influence of preapheresis clinical factors on the efficiency of CD34+ cell collection by large-volume apheresis.

We evaluated 120 leukapheresis procedures (93 patients), in order to detect clinical factors that influence the efficiency of CD34+ collection using Cobe Spectra trade mark cell separators. Hematocrit was >27% and platelet count >30 000/microl in >95% of patients. Platelet transfusions were given if the postprocedure count was &<20 000/microl. Multiple regression analysis was used to analyze putative factors, and a predictive equation defined by stepwise regression modeling. The mean efficiency was 0.59 (s.d. 0.27). Sex (M>F; P=0.01), the volume processed (inversely; P=0.01) and CD34+ cell count (inversely; P=0.04) were associated with efficiency, whereas hematocrit, platelet or leukocyte count, catheter type and patient weight were not. The effect size for predictive factors was small (R(2)=0.21). Adverse events were limited to hypocalcemia. We conclude that female sex, volume processed and CD34+ cell count adversely influence the efficiency of CD34+ cell leukapheresis. However, the impact of volume and CD34+ cell count is small, and likely to be offset by the influence of these same factors on overall yield. Leukapheresis appears to be safe and efficient for autologous blood and marrow transplantation patients with hematocrit >27% and platelet count >30 000/microl.

Antigens, CD34↗
PubMed2002

Antigen dose modulates the immunoglobulin isotype responses of pigs against intramuscularly administered F4-fimbriae.

Parenteral immunisation normally induces a systemic antibody response characterised by high IgG and low IgA responses. In the present study, the effect of different doses of F4-fimbriae on the isotype-specific antibody response after intramuscular immunisation was studied in pigs. Pigs were injected twice with a 9 weeks interval with either 1, 0.1 or 0.01 mg of F4-ETEC fimbriae. The dose of 1mg F4 induced significantly lower primary F4-specific IgG and IgM responses than the doses of 0.1 and 0.01 mg F4, but primed for an enhanced F4-specific IgM serum antibody response after the booster immunisation. Furthermore, the dose of 0.1mg induced the highest F4-specific IgA serum response which was significantly higher than after injection with 0.01 and 1mg F4. Moreover, both lower doses (0.1 and 0.01 mg) showed a higher number of F4-specific IgA and IgG antibody secreting cells (ASC) in the local draining lymph nodes of the pigs. This study demonstrated that low doses of purified F4-ETEC fimbriae, especially the 0.1mg dose, are optimal for inducing F4-specific IgA responses after IM immunisation.

Animals↗
PubMed2002

Carbon isotopes as a tool to evaluate the origin and fate of vinyl chloride: laboratory experiments and modeling of isotope evolution.

Accumulation of vinyl chloride (VC) is often a main concern at sites contaminated with chlorinated ethenes and ethanes due to its high toxicity. Since there can be several possible sources of VC and ethene at such sites, assessing the origin and fate of VC can be complicated. Aim of this study was to evaluate carbon isotope fractionation associated with various anaerobic processes that lead to the production of VC and ethene in view of using isotopes to evaluate the origin and fate of these compounds in groundwater. Microcosms were constructed using sediments and groundwater from a contaminated site and amended with potential precursors for VC and ethene production. In the microcosms with dichloroethene isomers, sequential reductive dechlorination was observed, and isotopic enrichmentfactors of -19.9 +/- 1.5 per thousand for cis-1,2-dichloroethene, -30.3 +/- 1.9 per thousand for trans-1,2-dichloroethene, and -7.3 +/- 0.4 per thousand for 1,1-dichloroethene were obtained. In microcosms with chlorinated ethanes, 1,2-dichloroethane (1,2-DCA) and 1,1,2-trichloroethane (1,1,2-TCA) were predominantly transformed by dichloroelimination to ethene and VC, respectively, and enrichmentfactors of -32.1 +/- 1.1 per thousand for 1,2OCA and -2.0 +/- 0.2 per thousand for 1,1,2-TCA were observed. Except for 1,1,2-TCA, a strong 13C enrichment in each of the potential precursor of VC was observed, which opens the possibility to trace the origin of VC based on the isotope ratio of potential precursors. Furthermore, it was possible to model the isotope evolution of VC present as substrate or intermediate product as a function of time. The study demonstrates that carbon isotope ratios can potentially be used for qualitative and possibly quantitative evaluation of the origin and fate of VC at sites with complex contaminant mixtures.

Carbon Isotopes↗