Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 159
Filter
1.
Clin Exp Immunol ; 216(2): 159-171, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38330230

ABSTRACT

Natural killer (NK) cells are innate lymphocytes capable to recognize and kill virus-infected and cancer cells. In the past years, the use of allogeneic NK cells as anti-cancer therapy gained interest due to their ability to induce graft-versus-cancer responses without causing graft-versus-host disease and multiple protocols have been developed to produce high numbers of activated NK cells. While the ability of these cells to mediate tumor kill has been extensively studied, less is known about their capacity to influence the activity of other immune cells that may contribute to a concerted anti-tumor response in the tumor microenvironment (TME). In this study, we analyzed how an allogeneic off-the-shelf cord blood stem cell-derived NK-cell product influenced the activation of dendritic cells (DC). Crosstalk between NK cells and healthy donor monocyte-derived DC (MoDC) resulted in the release of IFNγ and TNF, MoDC activation, and the release of the T-cell-recruiting chemokines CXCL9 and CXCL10. Moreover, in the presence of prostaglandin-E2, NK cell/MoDC crosstalk antagonized the detrimental effect of IL-10 on MoDC maturation leading to higher expression of multiple (co-)stimulatory markers. The NK cells also induced activation of conventional DC2 (cDC2) and CD8+ T cells, and the release of TNF, GM-CSF, and CXCL9/10 in peripheral blood mononuclear cells of patients with metastatic colorectal cancer. The activated phenotype of MoDC/cDC2 and the increased release of pro-inflammatory cytokines and T-cell-recruiting chemokines resulting from NK cell/DC crosstalk should contribute to a more inflamed TME and may thus enhance the efficacy of T-cell-based therapies.

2.
J Appl Microbiol ; 130(2): 464-477, 2021 Feb.
Article in English | MEDLINE | ID: mdl-32687650

ABSTRACT

AIMS: To understand the genetics involved in surface attachment and biofilm formation of Listeria monocytogenes. METHODS AND RESULTS: An in vitro screen of a Himar1 transposon library of L. monocytogenes strain 15G01 identified three transposants that produced significantly different biofilm levels when compared to the wild-type strain; two mutants exhibited enhanced biofilm formation and one produced less biofilm biomass than the wild-type. The mutant 15G01 mprF::Himar1, which had a transposon insertion in the mprF gene, was selected for further analysis. The mutant produced a more densely populated biofilm on solid surfaces such as stainless steel and polystyrene, as determined using scanning electron and light microscopy. The 15G01 mprF::Himar1 mutant remained viable in biofilms, but showed an increase in sensitivity to the cationic antimicrobial gallidermin. The mutant also displayed reduced invasiveness in CaCo-2 intestinal cells, suggesting virulence properties are compromised by the inactivation of mprF. CONCLUSIONS: Biofilm formation and gallidermin resistance of L. monocytogenes is influenced by mprF, but this trait is associated with a compromise in invasiveness. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of pathogenic microorganisms in the food processing environment can cause a significant problem, especially when these microorganisms are established as biofilms. This study shows that the inactivation of the mprF gene results in enhanced biofilm formation and abiotic surface attachment of L. monocytogenes.


Subject(s)
Antimicrobial Cationic Peptides/pharmacology , Bacterial Proteins/metabolism , Biofilms/growth & development , Drug Resistance, Bacterial/genetics , Listeria monocytogenes/physiology , Bacterial Proteins/genetics , Caco-2 Cells , Humans , Listeria monocytogenes/drug effects , Listeria monocytogenes/genetics , Listeria monocytogenes/pathogenicity , Mutation , Virulence/genetics
3.
Anaesthesia ; 71(7): 788-97, 2016 07.
Article in English | MEDLINE | ID: mdl-27291598

ABSTRACT

We compared the accuracy and precision of the non-invasive Nexfin(®) device for determining systolic, diastolic, mean arterial pressure and pulse pressure variation, with arterial blood pressure values measured from a radial artery catheter in 19 patients following upper abdominal surgery. Measurements were taken at baseline and following fluid loading. Pooled data results of the arterial blood pressures showed no difference between the two measurement modalities. Bland-Altman analysis of pulse pressure variation showed significant differences between values obtained from the radial artery catheter and Nexfin finger cuff technology (mean (SD) 1.49 (2.09)%, p < 0.001, coefficient of variation 24%, limits of agreement -2.71% to 5.69%). The effect of volume expansion on pulse pressure variation was identical between methods (concordance correlation coefficient 0.848). We consider the Nexfin monitor system to be acceptable for use in patients after major upper abdominal surgery without major cardiovascular compromise or haemodynamic support.


Subject(s)
Abdomen/surgery , Blood Pressure Determination/instrumentation , Blood Pressure Determination/methods , Blood Pressure Monitors , Blood Pressure/physiology , Postoperative Care/methods , Arterial Pressure/physiology , Equipment Design , Female , Humans , Male , Middle Aged , Postoperative Care/instrumentation , Reproducibility of Results
4.
Br J Anaesth ; 116(6): 784-9, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27199311

ABSTRACT

BACKGROUND: Although arterial hypotension occurs frequently with propofol use in humans, its effects on intravascular volume and vascular capacitance are uncertain. We hypothesized that propofol decreases vascular capacitance and therefore decreases stressed volume. METHODS: Cardiac output (CO) was measured using Modelflow(®) in 17 adult subjects after upper abdominal surgery. Mean systemic filling pressure (MSFP) and vascular resistances were calculated using venous return curves constructed by measuring steady-state arterial and venous pressures and CO during inspiratory hold manoeuvres at increasing plateau pressures. Measurements were performed at three incremental levels of targeted blood propofol concentrations. RESULTS: Mean blood propofol concentrations for the three targeted levels were 3.0, 4.5, and 6.5 µg ml(-1). Mean arterial pressure, central venous pressure, MSFP, venous return pressure, Rv, systemic arterial resistance, and resistance of the systemic circulation decreased, stroke volume variation increased, and CO was not significantly different as propofol concentration increased. CONCLUSIONS: An increase in propofol concentration within the therapeutic range causes a decrease in vascular stressed volume without a change in CO. The absence of an effect of propofol on CO can be explained by the balance between the decrease in effective, or stressed, volume (as determined by MSFP), the decrease in resistance for venous return, and slightly improved heart function. CLINICAL TRIAL REGISTRATION: Netherlands Trial Register: NTR2486.


Subject(s)
Anesthetics, Intravenous , Cardiac Output/drug effects , Hemodynamics/drug effects , Propofol , Vascular Resistance/drug effects , Abdomen/surgery , Adult , Aged , Algorithms , Blood Volume/drug effects , Female , Heart Function Tests , Humans , Male , Middle Aged , Stroke Volume , Vascular Capacitance/drug effects , Venous Pressure/drug effects
5.
Semin Cancer Biol ; 33: 74-85, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25882379

ABSTRACT

Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are emerging as key adaptation mechanisms in response to loss of proteostasis, with major cell autonomous and non-autonomous functions impacting cancer progression and therapeutic responses. In recent years, vital physiological roles of the ER in maintenance of proteostasis, Ca(2+) signaling and trafficking through the secretory pathway have emerged. Some of these functions have been shown to be decisive for mobilizing certain signals from injured/dying cancer cells in response to certain anticancer treatments, toward the plasma membrane and ultimately emit them into the extracellular environment, where they may act as danger signals. The spatiotemporally defined emission of these signals, better known as damage-associated molecular patterns (DAMPs), distinguishes this type of cancer cell death from physiological apoptosis, which is tolerogenic in nature, thereby enabling these dying cancer cells to alert the immune system and "re-activate" antitumor immunity. The emission of DAMPs, decisive for immunogenic cell death (ICD) and which include the ER chaperone calreticulin and ATP, is reliant on a danger signaling module induced by certain assorted anticancer treatments through oxidative-ER stress. The main focus of this review is to discuss the emerging role of ER-stress regulated pathways and processes in danger signaling thereby regulating the cancer cell-immune cell interface by the extracellular emission of DAMPs. In particular, we discuss signaling contexts existing upstream and around PERK, a major ER-stress sensor in ICD context, which have not been emphatically discussed in the context of antitumor immunity and ICD up until now. Finally, we briefly discuss the pros and cons of targeting PERK in the context of ICD.


Subject(s)
Cell Membrane/metabolism , Neoplasms/immunology , Unfolded Protein Response , Adenosine Triphosphate/metabolism , Animals , Apoptosis , Calcium/metabolism , Calreticulin/metabolism , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Stress , Humans , Inflammation/metabolism , Molecular Chaperones/metabolism , Neoplasms/metabolism , Neoplasms/pathology , Neoplasms/therapy , Oxidation-Reduction , Oxidative Stress , Reactive Oxygen Species/metabolism , Signal Transduction
6.
Allergy ; 69(8): 1085-91, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24888457

ABSTRACT

BACKGROUND: Airborne pollen is a major symptom trigger in allergic rhinitis patients, but the impact of pollen differs among patients and regions and is influenced by environmental factors. To study these complex relationships, there is a need for data on the severity of symptoms in space and time. 'Citizen science' is increasingly recognized as an effective tool to monitor changes in our environment. The aim of this study was to investigate the feasibility of a citizen science-based survey to monitor spatiotemporal variation in allergic rhinitis symptoms. METHODS: Participants were recruited through the Web site Allergieradar.nl. After registering by completing an extensive questionnaire, they entered (preferably daily) their symptoms of eyes, nose, and lungs on a scale from 1 to 10, as well as their geographic location. RESULTS: The registration questionnaire revealed that the majority of the participants (77%) had physician-diagnosed hay fever and 65% of the participants had been tested positively for their allergy. This study shows that the symptom scores of the participants are related to (i) pollen concentrations in the air, (ii) the self-reported sensitivity profile, and (iii) the sales of prescription antihistamines in The Netherlands. CONCLUSION: Our data indicate that the collection of allergic rhinitis symptom data by 'citizen science' is feasible and has an added value in studies on the impact of pollen.


Subject(s)
Rhinitis, Allergic/epidemiology , Spatio-Temporal Analysis , Symptom Assessment , Adolescent , Adult , Aged , Aged, 80 and over , Child , Drug Prescriptions , Female , Geography, Medical , Histamine Antagonists/therapeutic use , Humans , Male , Middle Aged , Netherlands/epidemiology , Population Surveillance , Registries , Rhinitis, Allergic/diagnosis , Rhinitis, Allergic/drug therapy , Surveys and Questionnaires , Young Adult
7.
Eur Surg Res ; 52(1-2): 50-62, 2014.
Article in English | MEDLINE | ID: mdl-24642533

ABSTRACT

BACKGROUND: Ischemia-reperfusion (I/R) models have shown that C-reactive protein (CRP) and immunoglobulin M (IgM) are involved in complement activation. Binding of CRP and IgM to damaged cell membranes initiates complement activation and aggravates I/R injury in various organs. However, the time course of CRP- and IgM-mediated complement activation and the relation to hepatocellular injury and inflammation in liver I/R are unknown. AIM: To evaluate the time course of IgM- and CRP-related complement activation and the relation to hepatocellular injury and inflammation in a hepatic I/R rat model. METHODS: Male Wistar rats were allocated to (1) five groups of animals exposed to 60 min of partial ischemia (70%) induced via clamping of the left segmental portal triad, followed by 0, 3, 6, 12 or 24 h of reperfusion (n = 6 in each group); (2) five groups of sham-operated animals with corresponding reperfusion times (n = 5), and (3) a control group sacrificed before ischemia (n = 5). Hepatocellular injury, inflammatory response, rat plasma CRP and IgM levels and immunohistochemical depositions of CRP, IgM and C3 were assessed for each group. RESULTS: Histopathological injury scores of hematoxylin and eosin sections of ischemic liver lobes demonstrated increasing values throughout the reperfusion time with a peak at 12 h. Plasma aminotransferases (alanine aminotransferase and aspartate aminotransferase) significantly increased after 3 h of reperfusion, peaking at 6 h (3,100 ± 800 U/l; p < 0.05). Hepatic neutrophil influx significantly increased from 3 to 6 h of reperfusion (p < 0.05) and demonstrated the highest value at 12 h (1.1 ± 0.2 U/mg of protein). Plasma IL-6 levels in the ischemia groups showed peak values after 6 h of reperfusion, decreasing significantly thereafter (p < 0.05). Plasma CRP values reached highest levels after 3 h of reperfusion (mean 91 ± 5% of control pool), decreasing significantly thereafter. Rat IgM concentrations in plasma did not significantly change throughout the reperfusion time. Immunohistochemical depositions of IgM, CRP and C3 in ischemic lobes demonstrated a similar pattern in time, reaching maximum values at 12 h of reperfusion. The percentages of depositions of CRP and IgM were significantly correlated [r(S) = 0.569; p < 0.001; Spearman test]. The time course of C3 and CRP depositions throughout reperfusion and C3 and IgM staining were significantly similar [r(S) = 0.797 and r(S) = 0.656, respectively; p < 0.0001; ANOVA]. CONCLUSIONS: CRP and IgM depositions demonstrate a parallel time course throughout the reperfusion to hepatocellular damage, inflammatory response and activated complement deposition in this rat hepatic I/R model. Furthermore, the time course of CRP and IgM depositions was significantly similar to that of activated complement depositions.


Subject(s)
C-Reactive Protein/metabolism , Complement Activation , Immunoglobulin M/blood , Liver/immunology , Liver/injuries , Reperfusion Injury/blood , Reperfusion Injury/immunology , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Hepatocytes/immunology , Hepatocytes/metabolism , Hepatocytes/pathology , Interleukin-6/blood , Liver/pathology , Male , Neutrophils/immunology , Neutrophils/pathology , Rats , Rats, Wistar
8.
J Appl Microbiol ; 115(5): 1212-21, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23910098

ABSTRACT

AIMS: To develop a staining method for specific detection of metabolically active (viable) cells in biofilms of the foodborne pathogen Campylobacter jejuni. METHODS AND RESULTS: Conversion of 2,3,5 triphenyltetrazolium chloride (TTC) to insoluble, red 1,3,5-triphenylformazan (TPF) was dependent on metabolic activity of Camp. jejuni. When used with chicken juice, TTC staining allowed quantification of Camp. jejuni biofilm levels, whereas the commonly used dye, crystal violet, gave high levels of nonspecific staining of food matrix components (chicken juice). The assay was optimized to allow for monitoring of biofilm levels and adapted to monitor levels of Camp. jejuni in broth media. CONCLUSIONS: Staining with TTC allows for the quantification of metabolically active Camp. jejuni and thus allows for quantification of viable cells in biofilms and food matrices. The TTC staining method can be adapted to quantify bacterial cell concentration in a food matrix model, where the accepted method of A600 measurement is not suitable due to interference by components of the food matrix. SIGNIFICANCE AND IMPACT OF THE STUDY: 2,3,5 Triphenyltetrazolium chloride (TTC) staining is a low-cost technique suitable for use in biofilm analysis, allowing rapid and simple imaging of metabolically active cells and increasing the methods available for biofilm assessment and quantification.


Subject(s)
Biofilms , Campylobacter jejuni/metabolism , Food Contamination/analysis , Food Microbiology/methods , Staining and Labeling/methods , Tetrazolium Salts/metabolism , Animals , Campylobacter jejuni/growth & development , Chickens/microbiology , Formazans/metabolism , Gentian Violet , Meat/microbiology , Microbial Viability , Reproducibility of Results , Sensitivity and Specificity
9.
Eur J Clin Microbiol Infect Dis ; 32(2): 207-26, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22945471

ABSTRACT

Guillain-Barré syndrome (GBS) is a post-infectious disease in which the human peripheral nervous system is affected after infection by specific pathogenic bacteria, including Campylobacter jejuni. GBS is suggested to be provoked by molecular mimicry between sialylated lipooligosaccharide (LOS) structures on the cell envelope of these bacteria and ganglioside epitopes on the human peripheral nerves, resulting in autoimmune-driven nerve destruction. Earlier, the C. jejuni sialyltransferase (Cst-II) was found to be linked to GBS and demonstrated to be involved in the biosynthesis of the ganglioside-like LOS structures. Apart from a role in pathogenicity, we report here that Cst-II-generated ganglioside-like LOS structures confer efficient bacteriophage resistance in C. jejuni. By bioinformatic analysis, it is revealed that the presence of sialyltransferases in C. jejuni and other potential GBS-related pathogens correlated significantly with the apparent degeneration of an alternative anti-virus system: type II Clusters of Regularly Interspaced Short Palindromic Repeat and associated genes (CRISPR-Cas). Molecular analysis of the C. jejuni CRISPR-Cas system confirmed the bioinformatic investigation. CRISPR degeneration and mutations in the cas genes cas2, cas1 and csn1 were found to correlate with Cst-II sialyltransferase presence (p < 0.0001). Remarkably, type II CRISPR-Cas systems are mainly found in mammalian pathogens. To study the potential involvement of this system in pathogenicity, we inactivated the type II CRISPR-Cas marker gene csn1, which effectively reduced virulence in primarily cst-II-positive C. jejuni isolates. Our findings indicate a novel link between viral defence, virulence and GBS in a pathogenic bacterium.


Subject(s)
Bacteriophages/growth & development , Campylobacter Infections/complications , Campylobacter jejuni/pathogenicity , Gangliosides/metabolism , Guillain-Barre Syndrome/microbiology , Virulence Factors/metabolism , Campylobacter Infections/immunology , Campylobacter Infections/microbiology , Campylobacter jejuni/genetics , Campylobacter jejuni/immunology , Campylobacter jejuni/virology , Computational Biology , DNA, Bacterial/genetics , Gangliosides/immunology , Humans , Virulence Factors/immunology
10.
Antimicrob Agents Chemother ; 56(8): 4525-8, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22664976

ABSTRACT

IDX375 is a potent and selective palm-binding nonnucleoside inhibitor of the hepatitis C virus (HCV) genotype 1 polymerase. This first-in-human study evaluated the safety, tolerability, and pharmacokinetics of IDX375 in healthy volunteers, as well as its antiviral activity in HCV-infected patients. IDX375, as a choline salt, was administered for 1 day to 40 healthy male volunteers (25- to 200-mg IDX375-equivalent single ascending doses and a 200-mg twice-daily [BID] dose) and three patients chronically infected with HCV genotype 1 (200 mg BID only). IDX375 was well absorbed and well tolerated by all of the study participants. A single-day 200-mg BID dose resulted in exposure-related anti-HCV activity with maximal 0.5 to 1.1 log(10) reductions in plasma HCV RNA. These observations support further clinical investigations of IDX375.


Subject(s)
Antiviral Agents/pharmacology , Antiviral Agents/pharmacokinetics , Hepacivirus/drug effects , Hepatitis C/virology , Lactams/pharmacology , Lactams/pharmacokinetics , Organophosphorus Compounds/pharmacology , Organophosphorus Compounds/pharmacokinetics , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Adult , Antiviral Agents/adverse effects , Antiviral Agents/therapeutic use , Enzyme Inhibitors/adverse effects , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Female , Hepacivirus/genetics , Hepatitis C/drug therapy , Humans , Lactams/adverse effects , Lactams/therapeutic use , Male , Middle Aged , Organophosphorus Compounds/adverse effects , Organophosphorus Compounds/therapeutic use , RNA, Viral/blood , Viral Load/drug effects
11.
Eur J Microbiol Immunol (Bp) ; 2(1): 12-9, 2012 Mar.
Article in English | MEDLINE | ID: mdl-24611116

ABSTRACT

The bacterial pathogen Campylobacter jejuni is the leading cause of foodborne gastroenteritis in the developed world, with the organism being transmitted by ingestion of contaminated and undercooked poultry. Exposure to acid is an inevitable stressor for C. jejuni during gastric passage, yet the effect of low pH on C. jejuni virulence is still poorly understood. Here, we investigate the effect of acid-shock on C. jejuni viability, gene expression and host-cell invasion. C. jejuni strain NCTC 11168 survived acid exposure at pH 3.5 and above for up to 30 min without a drop in viability, and this exposure induced the expression of flagellar genes transcribed from σ(54)-dependent promoters. Furthermore, acid-shock resulted in increased C. jejuni invasion of m-ICcl2 mouse small intestine crypt cells grown on transwells, but not when the cells were grown on flat-bottomed wells. This suggests that C. jejuni might be invading intestinal epithelial cells at the basolateral side, possibly after paracellular passage. We hypothesize that acid-shock prior to intestinal entry may serve as a signal that primes C. jejuni to express its virulence gene repertoire including flagellar motility genes, but this requires further study in the context of an appropriate colonization or disease model.

12.
Eur J Microbiol Immunol (Bp) ; 2(1): 76-87, 2012 Mar.
Article in English | MEDLINE | ID: mdl-24611124

ABSTRACT

Bacteria belonging to the species Campylobacter are the most common cause of bacterial diarrhoea in humans. The clinical phenotype associated with Campylobacter infections ranges from asymptomatic conditions to severe colitis and bacteremia. In susceptible patients, Campylobacter infections are associated with significant morbidity and mortality, with both host factors and bacterial factors being involved in the pathogenesis of bacteremia. In the host, age, gender and immune-compromising conditions may predispose for Campylobacter infections, whilst the most important bacterial determinants mentioned in the literature are cytotoxin production and flagellar motility. The role of sialylated lipo-oligosaccharide (LOS) and serum resistance in bacteremia is inconclusive at this time, and the clinical significance of Campylobacter bacteremia is not yet fully understood. More emphasis on the detection of Campylobacter species from blood cultures in susceptible patients at risk for Campylobacter infections will increase our understanding of the pathogenesis and the relevance of Campylobacter bacteremia.

13.
Aliment Pharmacol Ther ; 34(4): 443-53, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21707679

ABSTRACT

BACKGROUND: The ANA773 is an oral prodrug of a small-molecule toll-like receptor (TLR)7 agonist. Preclinical and healthy volunteer clinical studies with ANA773 have demonstrated induction of endogenous interferon-α (IFN-α) of multiple subtypes, which supports the potential utility in the treatment of chronic hepatitis C virus (HCV) infection. AIM: To examine safety, tolerability, pharmacodynamics, pharmacokinetics and anti-viral activity of ANA773. METHODS: The ANA773 was investigated in a double-blind, placebo-controlled study in 34 patients chronically infected with HCV of any genotype. Patients were treatment-naïve or had relapsed following previous interferon-based treatment. This dose escalation study was composed of four dose groups (800, 1200, 1600 and 2000mg). In each group, six to eight patients received ANA773 and two received placebo. Patients were dosed with ANA773 every-other-day for either 28 days (800, 1200 or 1600mg) or 10days (2000mg). RESULTS: Mild to moderate adverse events were reported, with an increase in frequency and intensity with increasing dose. No serious AEs were reported and there were no early discontinuations. There were dose-related increases in various markers of IFN-α response. The mean maximum change in serum HCV RNA level from baseline was -0.34, -0.29, -0.40, -0.97 and -1.26log(10) in the placebo, 800, 1200, 1600 and 2000mg cohorts, respectively. At the 2000mg dose, ANA773 significantly (P=0.037) reduced serum HCV RNA levels (range: 0.14 to -3.10log(10) ). CONCLUSION: The ANA773 was generally well tolerated and resulted in a dose-related IFN-dependent response leading to a significant decrease in serum HCV RNA levels in the 2000mg dose group.


Subject(s)
Antiviral Agents/therapeutic use , Hepatitis C, Chronic/drug therapy , Interferon Inducers/therapeutic use , Interferon-alpha/biosynthesis , Prodrugs/therapeutic use , Toll-Like Receptor 7/metabolism , Administration, Oral , Adolescent , Adult , Aged , Analysis of Variance , Antiviral Agents/adverse effects , Antiviral Agents/pharmacokinetics , Double-Blind Method , Female , Hepacivirus/genetics , Humans , Interferon Inducers/adverse effects , Interferon Inducers/pharmacokinetics , Male , Middle Aged , Prodrugs/adverse effects , Prodrugs/pharmacokinetics , RNA/blood , Treatment Outcome , Young Adult
14.
Appl Environ Microbiol ; 77(10): 3182-8, 2011 May.
Article in English | MEDLINE | ID: mdl-21441333

ABSTRACT

The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance.


Subject(s)
Bacterial Proteins/metabolism , Endotoxins/metabolism , Hemolysin Proteins/metabolism , Lepidoptera/drug effects , Microvilli/drug effects , Microvilli/metabolism , Transport Vesicles/metabolism , Animals , Bacillus thuringiensis Toxins , Binding Sites , Protein Binding
15.
Eur J Microbiol Immunol (Bp) ; 1(3): 215-22, 2011 Sep.
Article in English | MEDLINE | ID: mdl-24516727

ABSTRACT

Chronic intestinal and hepatic colonization with the microaerophilic murine pathogen Helicobacter hepaticus can lead to a range of inflammatory diseases of the lower digestive tract. Colonization is associated with an active cellular immune response and production of oxygen radicals. During colonization, H. hepaticus needs to cope with and respond to oxidative stress, and here we report on the role of the H. hepaticus PerR-regulator (HH0942) in the expression of the peroxidase-encoding katA (HH0043) and ahpC (HH1564) genes. Transcription of katA and ahpC was induced by hydrogen peroxide, and by iron restriction of growth media. This iron- and hydrogen peroxide-responsive regulation of katA and ahpC was mediated at the transcriptional level, from promoters directly upstream of the genes. Inactivation of the perR gene resulted in constitutive, iron-independent high-level expression of the katA and ahpC transcripts and corresponding proteins. Finally, inactivation of the katA gene resulted in increased sensitivity of H. hepaticus to hydrogen peroxide and reduced aerotolerance. In H. hepaticus, iron metabolism and oxidative stress defense are intimately connected via the PerR regulatory protein. This regulatory pattern resembles that observed in the enteric pathogen Campylobacter jejuni, but contrasts with the pattern observed in the closely related human gastric pathogen Helicobacter pylori.

16.
Clin Pharmacol Ther ; 88(2): 243-50, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20592721

ABSTRACT

MKC253 is glucagon-like peptide 1 (GLP-1, 7-36 amide) adsorbed onto Technosphere microparticles for oral inhalation. The pharmacokinetics of inhaled GLP-1 and the pharmacokinetic-pharmacodynamic (PK-PD) relationship between inhaled GLP-1 and insulin were analyzed in two trials, one in healthy normal volunteers and the other in patients with type 2 diabetes. Inhaled GLP-1 was absorbed quickly, with peak concentrations occurring within 5 min, and levels returned to baseline within 30 min. Inhaled GLP-1 appeared to produce plasma levels of GLP-1 comparable to those of parenteral administration and sufficient to induce insulin secretion resulting in attenuation of postmeal glucose excursions in subjects with type 2 diabetes. An E(max) (maximum effect) model described the relationship between GLP-1 concentration and insulin release. The variability in the E(max) may be due to differences in baseline glucose levels, differences resulting from genetic polymorphisms in GLP-1 receptors (GLP-1Rs), or the stage of diabetes of the patient.


Subject(s)
Diabetes Mellitus, Type 2/metabolism , Glucagon-Like Peptide 1/pharmacokinetics , Hypoglycemic Agents/pharmacokinetics , Peptide Fragments/pharmacokinetics , Administration, Inhalation , Adult , Aged , Blood Glucose/metabolism , C-Peptide/metabolism , Diabetes Mellitus, Type 2/blood , Dose-Response Relationship, Drug , Drug Delivery Systems , Energy Intake , Female , Glucagon/blood , Glucagon-Like Peptide 1/administration & dosage , Glucagon-Like Peptide 1/adverse effects , Humans , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/adverse effects , Insulin/blood , Male , Middle Aged , Peptide Fragments/administration & dosage , Peptide Fragments/adverse effects
17.
Genome Dyn ; 6: 91-109, 2009.
Article in English | MEDLINE | ID: mdl-19696496

ABSTRACT

The thermophilic Campylobacter species C. jejuni and C. coli are important human pathogens, which are major causes of bacterial gastroenteritis. The recent progress in genomics techniques has allowed for a rapid increase in our knowledge of the molecular biology of Campylobacter species, but needs to be matched by concurrent increases in our understanding of the unique biology of these organisms. Campylobacter species display significant levels of genomic variation via natural transformation, phase variation, plasmid transfer and infection with bacteriophages, and this poses a continuous challenge for studies on pathogenesis, physiology, epidemiology and evolution of Campylobacter. In this chapter we will review the current state of the art of the genomics of thermophilic Campylobacter species, and opportunities where genomics can further contribute to our understanding of the biology of these successful human pathogens.


Subject(s)
Campylobacter jejuni , Campylobacter , Bacteriophages/genetics , Campylobacter/genetics , Campylobacter jejuni/genetics , Evolution, Molecular , Genomics , Humans , Molecular Sequence Data , Plasmids
18.
Langenbecks Arch Surg ; 394(1): 143-50, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18351382

ABSTRACT

BACKGROUND: Hypothermic perfusion (HP) of the liver is applied during total vascular exclusion (TVE) to reduce ischemic injury during liver resection. No studies have been performed comparing different perfusion solutions for HP. The aim of this experimental study was to compare Ringer-lactate solution (RL) with Celsior solution (Cs) for HP in a pig model of 60-min TVE. METHOD: Twenty pigs underwent 60-min TVE of the liver. Groups were TVE without HP (no-HP, n = 9), TVE with HP using RL (n = 6), and TVE with HP using Cs (n = 5). Blood and liver tissue samples were taken before TVE and during 24-h reperfusion. RESULTS: In the no-HP group, plasma aspartate aminotransferase values were significantly increased during reperfusion (p < 0.05), while liver tissue pO(2) levels (p < 0.01) were decreased when compared to the HP groups. After 24-h reperfusion, bile production and liver tissue glutathione content were significantly higher (p < 0.05) in the Cs group (42.0 +/- 1.7 mL/h and 44.9 +/- 2.2 nmol/mg, respectively) as compared to the RL group (31.5 +/- 3.5 mL/h and 19.6 +/- 1.8 nmol/mg, respectively). CONCLUSION: The protective effect of HP during TVE was confirmed in this study. HP with Cs was more effective in reducing ischemic injury as compared to HP with RL.


Subject(s)
Hypothermia, Induced , Isotonic Solutions/pharmacology , Liver/blood supply , Organ Preservation Solutions/pharmacology , Perfusion , Reperfusion Injury/pathology , Animals , Aspartate Aminotransferases/metabolism , Biopsy , Disaccharides/pharmacology , Electrolytes/pharmacology , Glutamates/pharmacology , Glutathione/metabolism , Glutathione/pharmacology , Histidine/pharmacology , Liver/pathology , Mannitol/pharmacology , Oxygen Consumption/drug effects , Prothrombin Time , Ringer's Lactate , Swine
19.
Int J Clin Pharmacol Ther ; 46(9): 443-52, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18793574

ABSTRACT

OBJECTIVE: The safety, tolerability, pharmacokinetics and preliminary pharmacodynamics of single rising doses of a novel GLP-1 analog, CJC-1131, was evaluated. METHODS: CJC-1131 was subcutaneously injected in 8 groups (1.5 - 20.5 microg/kg) of healthy subjects (each group of six subjects included 1 placebo per dose level). CJC-1131 was also injected subcutaneously in 6 groups (1.5 - 12 microg/kg) of Type 2 diabetic patients after a 9-day washout period from their own anti-diabetic medication. Each group of 8 patients included 2 placebo-treated patients. Seven blood glucose measurements were taken daily, and meal tolerance tests were performed on the day before dosing and on Day 3. RESULTS: CJC-1131 was quickly absorbed from the subcutaneous space, and a less than dose-proportional increase was found in Cmax. The half-life of CJC-1131 varied from 8.9 - 14.7 days in healthy subjects and from 9.1 - 13.8 days in patients. The maximum tolerated dose in healthy subjects was established at 12 microg/kg with nausea and vomiting being the dose-limiting events. These events occurred generally in the morning after dosing. Blood glucose levels in patients decreased on Day 1 in proportion with dose, with a maximum average decrease of 4.1 mmol/l in the highest dose group. Higher doses appeared to be related to a slight weight loss in patients. CONCLUSIONS: Conjugation to albumin led to a major prolongation of the half-life of GLP-1. The tolerability of this potential antidiabetic drug seems to be limited only by gastrointestinal complaints.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/administration & dosage , Maleimides/administration & dosage , Peptides/administration & dosage , Adult , Aged , Blood Glucose/drug effects , Dose-Response Relationship, Drug , Double-Blind Method , Female , Glucagon-Like Peptide 1/analogs & derivatives , Half-Life , Humans , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/pharmacokinetics , Injections, Subcutaneous , Male , Maleimides/adverse effects , Maleimides/pharmacokinetics , Maximum Tolerated Dose , Middle Aged , Nausea/chemically induced , Peptides/adverse effects , Peptides/pharmacokinetics , Protein Binding , Serum Albumin/metabolism , Vomiting/chemically induced
20.
Surgery ; 144(1): 22-31, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18571581

ABSTRACT

BACKGROUND: The combination of hepatic ischemia and cholestasis, both identified as risk factors for oxidative stress, potentially enhances postischemic reperfusion (I/R) injury. Preoperative biliary drainage relieves oxidative stress and therefore seems a worthwhile intervention in cholestatic patients undergoing major liver resection. AIM: To assess the effect of biliary decompression on I/R injury in a reversible bile duct ligation (BDL) model in the rat. METHODS: Male Wistar rats were randomized into 3 groups. The first group underwent 30 minutes of partial liver ischemia after 7 days BDL; the second group underwent internal drainage (ID) after 7 days BDL and after 5 days, were subjected to partial liver ischemia. The last group (control animals) underwent 2 sham laparotomies and subsequent ischemia. Inflammatory response (interleukin [IL]-6, IL-10, GRO/KC, and interferon-gamma), hepatic damage and oxidative stress were assessed during 24 hours of reperfusion. RESULTS: Cholestatic rats, as compared with the ID and control groups, showed significantly increased I/R injury as determined by transaminase release, histologic injury score and neutrophil infiltration. Plasma IL-6, IL-10, and GRO/KC (a CXC chemokine) were significantly increased in the BDL group (P < .05 vs control and ID). Moreover, the hepatic antioxidant capacity was strongly decreased in the BDL group (P < .01 vs control and ID). No significant differences for most parameters were seen in the ID group as compared to the control group. CONCLUSION: The cholestatic rat is more susceptible to postischemic liver injury and these injurious effects were significantly attenuated by biliary decompression.


Subject(s)
Cholestasis/surgery , Drainage , Liver Diseases/prevention & control , Reperfusion Injury/prevention & control , Animals , Bile , Bile Ducts/surgery , Cholestasis/complications , Decompression, Surgical , Disease Models, Animal , Hepatectomy/adverse effects , Ligation , Liver Diseases/etiology , Male , Oxidative Stress , Rats , Rats, Wistar , Reperfusion Injury/etiology
SELECTION OF CITATIONS
SEARCH DETAIL
...