34 results on '"Verkade E"'
Search Results
2. On Extreme-Value Theory in the Presence of a Trend
- Author
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De Haan, L. and Verkade, E.
- Published
- 1987
- Full Text
- View/download PDF
3. Dynamics of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus carriage in pig farmers: a prospective cohort study
- Author
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van Cleef, B. A. G. L., van Benthem, B. H. B., Verkade, E. J. M., van Rijen, M., Kluytmans-van den Bergh, M. F. Q., Schouls, L. M., Duim, B., Wagenaar, J. A., Graveland, H., Bos, M. E. H., Heederik, D., Kluytmans, J. A. J. W., and Lina, G.
- Published
- 2014
- Full Text
- View/download PDF
4. Clinical evaluation of Bio-Rad MRSASelect™ medium for the detection of livestock-associated methicillin-resistant Staphylococcus aureus
- Author
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Verkade, E., Verhulst, C., van Cleef, B., and Kluytmans, J.
- Published
- 2011
- Full Text
- View/download PDF
5. In vitro activity of tigecycline against methicillin-resistant Staphylococcus aureus, including livestock-associated strains
- Author
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Verkade, E. J. M., Verhulst, C. J. M. M., Huijsdens, X. W., and Kluytmans, J. A. J. W.
- Published
- 2010
- Full Text
- View/download PDF
6. Performance of Oxoid Brilliance™ MRSA medium for detection of methicillin-resistant Staphylococcus aureus: an in vitro study
- Author
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Verkade, E., Elberts, S., Verhulst, C., and Kluytmans, J.
- Published
- 2009
- Full Text
- View/download PDF
7. Outbreak of Campylobacter fetus infection after consumption of unpasteurized sheep's milk cheeses: how to trace the source?
- Author
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Koppenaal, H, Groenendijk, F, van den Berge, M., Verkade, E., Verduin, K, Zomer, A L, Duim, B, Wagenaar, J A, Tijsma, A S L, Spierenburg, M A H, Te Wierik, Margreet J M, and dI&I I&I-4
- Abstract
Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.
- Published
- 2018
8. Een uitbraak met Campylobacter fetus na het eten van rauwmelkse schapenkaas: Hoe traceer je de bron van een uitbraak?
- Author
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Koppenaal, H, Groenendijk, F, van den Berge, M., Verkade, E., Verduin, K, Zomer, A L, Duim, B, Wagenaar, J A, Tijsma, A S L, Spierenburg, M A H, Te Wierik, Margreet J M, and dI&I I&I-4
- Abstract
Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.
- Published
- 2017
9. Health and health-related quality of life in pig farmers carrying livestock-associated methicillin-resistantStaphylococcus aureus
- Author
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VAN CLEEF, B. A. G. L, primary, VAN BENTHEM, B. H. B., additional, VERKADE, E. J. M., additional, VAN RIJEN, M. M. L., additional, KLUYTMANS-VAN DEN BERGH, M. F. Q., additional, GRAVELAND, H., additional, BOSCH, T., additional, VERSTAPPEN, K. M. H. W., additional, WAGENAAR, J. A., additional, HEEDERIK, D., additional, and KLUYTMANS, J. A. J. W., additional
- Published
- 2016
- Full Text
- View/download PDF
10. Rectal Carriage of Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceae in Hospitalized Patients: Selective Preenrichment Increases Yield of Screening
- Author
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Kluytmans-van den Bergh, M. F. Q., primary, Verhulst, C., additional, Willemsen, L. E., additional, Verkade, E., additional, Bonten, M. J. M., additional, and Kluytmans, J. A. J. W., additional
- Published
- 2015
- Full Text
- View/download PDF
11. Transmission and Persistence of Livestock-Associated Methicillin-Resistant Staphylococcus aureus among Veterinarians and Their Household Members
- Author
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Bosch, T., primary, Verkade, E., additional, van Luit, M., additional, Landman, F., additional, Kluytmans, J., additional, and Schouls, L. M., additional
- Published
- 2015
- Full Text
- View/download PDF
12. Optimization of human immunodeficiency virus type 1 envelope glycoproteins with V1/V2 deleted, using virus evolution
- Author
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Bontjer, I., Land, A., Eggink, D., Verkade, E., Tuin, K., Baldwin, C., Pollakis, G., Paxton, W.A., Braakman, L.J., Berkhout, B., Sanders, R.W., Cellular Protein Chemistry, Dep Scheikunde, and Sub Cellular Protein Chemistry
- Subjects
International (English) ,viruses ,virus diseases - Abstract
The human immunodeficiency virus type 1 envelope glycoprotein (Env) complex is the principal focus of neutralizing antibody-based vaccines. The functional Env complex is a trimer consisting of six individual subunits: three gp120 molecules and three gp41 molecules. The individual subunits have proven unsuccessful as vaccines presumably because they do not resemble the functional Env complex. Variable domains and carbohydrates shield vulnerable neutralization epitopes on the functional Env complex. The deletion of variable loops has been shown to improve gp120's immunogenicity; however, problems have been encountered when introducing such modifications in stabilized Env trimer constructs. To address these issues, we have created a set of V1/V2 and V3 loop deletion variants in the context of complete virus to allow optimization by forced virus evolution. Compensatory second-site substitutions included the addition and/or removal of specific carbohydrates, changes in the disulfide-bonded architecture of the V1/V2 stem, the replacement of hydrophobic residues by hydrophilic and charged residues, and changes in distal parts of gp120 and gp41. These viruses displayed increased sensitivity to neutralizing antibodies, demonstrating the improved exposure of conserved domains. The results show that we can select for functionally improved Env variants with loop deletions through forced virus evolution. Selected evolved Env variants were transferred to stabilized Env trimer constructs and were shown to improve trimer expression and secretion. Based on these findings, we can make recommendations on how to delete the V1/V2 domain from recombinant Env trimers for vaccine and X-ray crystallography studies. In general, virus evolution may provide a powerful tool to optimize Env vaccine antigens
- Published
- 2009
13. Ooutbreak of livestock-associated methicillin-resistant Staphylococcus aureus in a nursing home
- Author
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Verkade, E, primary, Bosch, T, additional, Hendriks, Y, additional, and Kluytmans, J, additional
- Published
- 2011
- Full Text
- View/download PDF
14. Clinical evaluation of Bio-Rad MRSASelect™ medium for the detection of livestock-associated methicillin-resistant Staphylococcus aureus
- Author
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Verkade, E., primary, Verhulst, C., additional, van Cleef, B., additional, and Kluytmans, J., additional
- Published
- 2010
- Full Text
- View/download PDF
15. Rectal Carriage of Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceaein Hospitalized Patients: Selective Preenrichment Increases Yield of Screening
- Author
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Kluytmans-van den Bergh, M. F. Q., Verhulst, C., Willemsen, L. E., Verkade, E., Bonten, M. J. M., and Kluytmans, J. A. J. W.
- Abstract
ABSTRACTThis study evaluated the added value of selective preenrichment for the detection of rectal carriage of extended-spectrum-beta-lactamase-producing Enterobacteriaceae(ESBL-E). ESBL-E rectal carriage was identified in 4.8% of hospitalized patients, and 25.9% of ESBL-E rectal carriers were identified with selective preenrichment only.
- Published
- 2015
- Full Text
- View/download PDF
16. Clinical evaluation of Bio-Rad MRSA Select™ medium for the detection of livestock-associated methicillin-resistant Staphylococcus aureus.
- Author
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Verkade, E., Verhulst, C., Cleef, B., and Kluytmans, J.
- Subjects
METHICILLIN-resistant staphylococcus aureus ,LIVESTOCK infections ,MICROBIAL sensitivity tests ,COMPETITIVE exclusion (Microbiology) ,MICROBIOLOGY ,VACCINATION ,MEDICAL screening - Abstract
Bio-Rad MRSA Select™ medium was evaluated for its ability to recover methicillin-resistant Staphylococcus aureus (MRSA) from nasal samples of pig farmers and their household members. In total, 257 samples were inoculated on Bio-Rad MRSA Select™ medium with and without broth enrichment and on bioMérieux MRSA ID with broth enrichment. A sample was considered to be positive if at least one of the media grew MRSA. The sensitivity of Bio-Rad MRSA Select™ medium without broth enrichment was 63.9%. With broth enrichment, the sensitivity increased to 98.4%. The specificity was 95.4% both with and without broth enrichment. In conclusion, Bio-Rad MRSA Select™ medium as well as MRSA ID medium are reliable methods to detect MRSA carriage when used in combination with broth enrichment. The directly inoculated MRSA Select™ medium was statistically significantly less sensitive than the two media after broth enrichment. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
17. [Outbreak of Campylobacter fetus infection after consumption of unpasteurized sheep's milk cheeses: how to trace the source?]
- Author
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Koppenaal H, Groenendijk F, van den Berge M, Verkade E, Verduin K, Aldert Zomer, Duim B, Ja, Wagenaar, Asl, Tijsma, Mah, Spierenburg, and Mjm, Te Wierik
- Subjects
Male ,Immunocompromised Host ,Campylobacter fetus ,Milk ,Sheep ,Cheese ,Campylobacter Infections ,Animals ,Humans ,Aged ,Disease Outbreaks ,Netherlands - Abstract
Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.
18. Correspondentie van Mr. M. M. Rost van Tonningen. Volume I, 1921-Mei 1942
- Author
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Warmbrunn, Werner, primary and Fraenkel-Verkade, E., additional
- Published
- 1968
- Full Text
- View/download PDF
19. Dynamics of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus carriage in pig farmers: a prospective cohort study.
- Author
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Cleef, B. A. G. L., Benthem, B. H. B., Verkade, E. J. M., Rijen, M., Kluytmans-van den Bergh, M. F. Q., Schouls, L. M., Duim, B., Wagenaar, J. A., Graveland, H., Bos, M. E. H., Heederik, D., and Kluytmans, J. A. J. W.
- Subjects
- *
METHICILLIN-resistant staphylococcus aureus , *SWINE farms , *STAPHYLOCOCCUS aureus infections , *DRUG resistance in bacteria , *COHORT analysis , *THERAPEUTICS - Abstract
Our purpose was to determine the dynamics of livestock-associated methicillin-resistant Staphylococcus aureus ( LA- MRSA) carriage and its determinants in persons working at pig farms, in order to identify targets for interventions. This prospective cohort study surveyed 49 pig farms in the Netherlands on six sampling dates in 1 year (2010-11). Nasal and oropharyngeal swabs were collected, as well as environmental surface samples from stables and house. Of 110 pig farmers, 38% were persistent MRSA nasal carriers. The average cross-sectional MRSA prevalence was 63%. Methicillin-susceptible S. aureus ( MSSA) nasal carriage was associated with fewer MRSA acquisitions (prevalence rate ( PR) = 0.47, p 0.02). In multivariate analysis, an age of 40-49 years ( PR = 2.13, p 0.01), a working week of ≥40 h ( PR=1.89, p 0.01), giving birth assistance to sows ( PR=2.26, p 0.03), removing manure of finisher pigs ( PR=0.48, p 0.02), and wearing a facemask ( PR = 0.13, p 0.02) were significantly related with persistent MRSA nasal carriage. A higher MRSA exposure in stables was associated with MRSA in pig farmers (p <0.0001). This study describes a very high prevalence of LA- MRSA carriage in pig farmers, reflecting extensive exposure during work. We identified the possible protective effects of MSSA carriage and of continuously wearing a facemask during work. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
20. Gut microbiota depletion aggravates bile acid-induced liver pathology in mice with a human-like bile acid composition.
- Author
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Verkade E, Shen W, Hovingh MV, Mulder NL, de Bruyn K, Koehorst M, de Vries HD, Bloks VW, Kuipers F, and de Boer JF
- Subjects
- Humans, Male, Animals, Female, Mice, Bile Acids and Salts metabolism, Steroid 12-alpha-Hydroxylase genetics, Steroid 12-alpha-Hydroxylase metabolism, Liver metabolism, Anti-Bacterial Agents, Mice, Inbred C57BL, Gastrointestinal Microbiome, Cholestasis
- Abstract
Cyp2c70-deficient mice have a human-like bile acid (BA) composition due to their inability to convert chenodeoxycholic acid (CDCA) into rodent-specific muricholic acids (MCAs). However, the hydrophobic BA composition in these animals is associated with liver pathology. Although Cyp2c70-ablation has been shown to alter gut microbiome composition, the impact of gut bacteria on liver pathology in Cyp2c70-/- mice remains to be established. Therefore, we treated young-adult male and female wild-type (WT) and Cyp2c70-/- mice with antibiotics (AB) with broad specificity to deplete the gut microbiota and assessed the consequences on BA metabolism and liver pathology. Female Cyp2c70-/- mice did not tolerate AB treatment, necessitating premature termination of the experiment. Male Cyp2c70-/- mice did tolerate AB but showed markedly augmented liver pathology after 6 weeks of treatment. Dramatic downregulation of hepatic Cyp8b1 expression (-99%) caused a reduction in the proportions of 12α-hydroxylated BAs in the circulating BA pools of AB-treated male Cyp2c70-/- mice. Interestingly, the resulting increased BA hydrophobicity strongly correlated with various indicators of liver pathology. Moreover, genetic inactivation of Cyp8b1 in livers of male Cyp2c70-/- mice increased liver pathology, while addition of ursodeoxycholic acid to the diet prevented weight loss and liver pathology in AB-treated female Cyp2c70-/- mice. In conclusion, depletion of gut microbiota in Cyp2c70-/- mice aggravates liver pathology at least in part by increasing the hydrophobicity of the circulating BA pool. These findings highlight that the potential implications of AB administration to cholestatic patients should be evaluated in a systematic manner., (© 2023 The Author(s).)
- Published
- 2023
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21. Bile Acid Sequestration via Colesevelam Reduces Bile Acid Hydrophobicity and Improves Liver Pathology in Cyp2c70 -/- Mice with a Human-like Bile Acid Composition.
- Author
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Palmiotti A, de Vries HD, Hovingh MV, Koehorst M, Mulder NL, Verkade E, Veentjer MK, van Dijk TH, Bloks VW, Havinga R, Verkade HJ, de Boer JF, and Kuipers F
- Abstract
Bile acids (BAs) and their signaling pathways have been identified as therapeutic targets for liver and metabolic diseases. We generated Cyp2c70
-/- (KO) mice that were not able to convert chenodeoxycholic acid into rodent-specific muricholic acids (MCAs) and, hence, possessed a more hydrophobic, human-like BA pool. Recently, we have shown that KO mice display cholangiopathic features with the development of liver fibrosis. The aim of this study was to determine whether BA sequestration modulates liver pathology in Western type-diet (WTD)-fed KO mice. The BA sequestrant colesevelam was mixed into the WTD (2% w / w ) of male Cyp2c70+/+ (WT) and KO mice and the effects were evaluated after 3 weeks of treatment. Colesevelam increased fecal BA excretion in WT and KO mice and reduced the hydrophobicity of biliary BAs in KO mice. Colesevelam ameliorated diet-induced hepatic steatosis in WT mice, whereas KO mice were resistant to diet-induced steatosis and BA sequestration had no additional effects on liver fat content. Total cholesterol concentrations in livers of colesevelam-treated WT and KO mice were significantly lower than those of untreated controls. Of particular note, colesevelam treatment normalized plasma levels of liver damage markers in KO mice and markedly decreased hepatic mRNA levels of fibrogenesis-related genes in KO mice. Lastly, colesevelam did not affect glucose excursions and insulin sensitivity in WT or KO mice. Our data show that BA sequestration ameliorates liver pathology in Cyp2c70-/- mice with a human-like bile acid composition without affecting insulin sensitivity.- Published
- 2023
- Full Text
- View/download PDF
22. Role of bile acids in inflammatory liver diseases.
- Author
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Evangelakos I, Heeren J, Verkade E, and Kuipers F
- Subjects
- Animals, Bile Acids and Salts, Humans, Liver, Mice, Rats, Signal Transduction, Gastrointestinal Microbiome, Liver Diseases etiology
- Abstract
Bile acids and their signaling pathways are increasingly recognized as potential therapeutic targets for cholestatic and metabolic liver diseases. This review summarizes new insights in bile acid physiology, focusing on regulatory roles of bile acids in the control of immune regulation and on effects of pharmacological modulators of bile acid signaling pathways in human liver disease. Recent mouse studies have highlighted the importance of the interactions between bile acids and gut microbiome. Interfering with microbiome composition may be beneficial for cholestatic and metabolic liver diseases by modulating formation of secondary bile acids, as different bile acid species have different signaling functions. Bile acid receptors such as FXR, VDR, and TGR5 are expressed in a variety of cells involved in innate as well as adaptive immunity, and specific microbial bile acid metabolites positively modulate immune responses of the host. Identification of Cyp2c70 as the enzyme responsible for the generation of hydrophilic mouse/rat-specific muricholic acids has allowed the generation of murine models with a human-like bile acid composition. These novel mouse models will aid to accelerate translational research on the (patho)physiological roles of bile acids in human liver diseases ., (© 2021. The Author(s).)
- Published
- 2021
- Full Text
- View/download PDF
23. A human-like bile acid pool induced by deletion of hepatic Cyp2c70 modulates effects of FXR activation in mice.
- Author
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de Boer JF, Verkade E, Mulder NL, de Vries HD, Huijkman N, Koehorst M, Boer T, Wolters JC, Bloks VW, van de Sluis B, and Kuipers F
- Subjects
- Animals, Mice, Mice, Inbred C57BL, Mice, Transgenic, Bile Acids and Salts metabolism, Cytochrome P-450 Enzyme System metabolism, Liver metabolism, Receptors, Cytoplasmic and Nuclear metabolism
- Abstract
Bile acids (BAs) facilitate intestinal absorption of lipid-soluble nutrients and modulate various metabolic pathways through the farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5. These receptors are targets for therapy in cholestatic and metabolic diseases. However, dissimilarities in BA metabolism between humans and mice complicate translation of preclinical data. Cytochrome P450 family 2 subfamily c polypeptide 70 (CYP2C70) was recently proposed to catalyze the formation of rodent-specific muricholic acids (MCAs). With CRISPR/Cas9-mediated somatic genome editing, we generated an acute hepatic Cyp2c70 knockout mouse model ( Cyp2c70
ako ) to clarify the role of CYP2C70 in BA metabolism in vivo and evaluate whether its activity modulates effects of pharmacologic FXR activation on cholesterol homeostasis. In Cyp2c70ako mice, chenodeoxycholic acid (CDCA) increased at the expense of βMCA, resulting in a more hydrophobic human-like BA pool. Tracer studies demonstrated that, in vivo, CYP2C70 catalyzes the formation of βMCA primarily by sequential 6β-hydroxylation and C7-epimerization of CDCA, generating αMCA as an intermediate metabolite. Physiologically, the humanized BA composition in Cyp2c70ako mice blunted the stimulation of fecal cholesterol disposal in response to FXR activation compared with WT mice, predominantly due to reduced stimulation of transintestinal cholesterol excretion. Thus, deletion of hepatic Cyp2c70 in adult mice translates into a human-like BA pool composition and impacts the response to pharmacologic FXR activation. This Cyp2c70ako mouse model may be a useful tool for future studies of BA signaling and metabolism that informs human disease development and treatment., (Copyright © 2020 de Boer et al.)- Published
- 2020
- Full Text
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24. Targeting senescent cells alleviates obesity-induced metabolic dysfunction.
- Author
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Palmer AK, Xu M, Zhu Y, Pirtskhalava T, Weivoda MM, Hachfeld CM, Prata LG, van Dijk TH, Verkade E, Casaclang-Verzosa G, Johnson KO, Cubro H, Doornebal EJ, Ogrodnik M, Jurk D, Jensen MD, Chini EN, Miller JD, Matveyenko A, Stout MB, Schafer MJ, White TA, Hickson LJ, Demaria M, Garovic V, Grande J, Arriaga EA, Kuipers F, von Zglinicki T, LeBrasseur NK, Campisi J, Tchkonia T, and Kirkland JL
- Subjects
- Adipocytes cytology, Adipocytes drug effects, Adipogenesis physiology, Adipose Tissue drug effects, Aging metabolism, Aging pathology, Animals, Cell Death drug effects, Cell Death genetics, Cell Death physiology, Cell Line, Cellular Senescence genetics, Cellular Senescence physiology, Cyclin-Dependent Kinase Inhibitor p16 metabolism, Dasatinib pharmacology, Female, Ganciclovir pharmacology, Glucose metabolism, Humans, Macrophages drug effects, Macrophages metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Quercetin pharmacology, Adipocytes metabolism, Adipogenesis drug effects, Adipose Tissue metabolism, Cellular Senescence drug effects, Inflammation metabolism, Insulin Resistance physiology, Obesity metabolism
- Abstract
Adipose tissue inflammation and dysfunction are associated with obesity-related insulin resistance and diabetes, but mechanisms underlying this relationship are unclear. Although senescent cells accumulate in adipose tissue of obese humans and rodents, a direct pathogenic role for these cells in the development of diabetes remains to be demonstrated. Here, we show that reducing senescent cell burden in obese mice, either by activating drug-inducible "suicide" genes driven by the p16
Ink4a promoter or by treatment with senolytic agents, alleviates metabolic and adipose tissue dysfunction. These senolytic interventions improved glucose tolerance, enhanced insulin sensitivity, lowered circulating inflammatory mediators, and promoted adipogenesis in obese mice. Elimination of senescent cells also prevented the migration of transplanted monocytes into intra-abdominal adipose tissue and reduced the number of macrophages in this tissue. In addition, microalbuminuria, renal podocyte function, and cardiac diastolic function improved with senolytic therapy. Our results implicate cellular senescence as a causal factor in obesity-related inflammation and metabolic derangements and show that emerging senolytic agents hold promise for treating obesity-related metabolic dysfunction and its complications., (© 2019 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)- Published
- 2019
- Full Text
- View/download PDF
25. New insights in the multiple roles of bile acids and their signaling pathways in metabolic control.
- Author
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de Boer JF, Bloks VW, Verkade E, Heiner-Fokkema MR, and Kuipers F
- Subjects
- Aging genetics, Aging pathology, Animals, Cholesterol metabolism, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 pathology, Humans, Mice, Mice, Transgenic, Receptors, Cytoplasmic and Nuclear genetics, Receptors, G-Protein-Coupled genetics, Aging metabolism, Bile Acids and Salts metabolism, Diabetes Mellitus, Type 2 metabolism, Receptors, Cytoplasmic and Nuclear metabolism, Receptors, G-Protein-Coupled metabolism, Signal Transduction
- Abstract
Purpose of Review: There is a growing awareness that individual bile acid species exert different physiological functions, beyond their classical roles in bile formation and fat absorption, due to differential stimulatory effects on the bile-acid-activated receptors farnesoid X receptor (FXR) and takeda G receptor 5 (TGR5). This review integrates recent findings on the role of individual bile acids and their receptors in metabolic control, with special emphasis on cholesterol homeostasis., Recent Findings: The consequences of altered bile acid metabolism, for example, in type 2 diabetes and during aging, on metabolic control is increasingly recognized but full impact hereof remains to be elucidated. These effects interact with those of newly developed pharmacological FXR and TGR5 modulators that aim to improve metabolic health. Studies in genetically modified mice have provided important new insights, for example, establishment of the role of intestinal FXR in control of the transintestinal cholesterol excretion pathway. However, translation from mice to men is hampered by the presence of rodent-specific bile acid species with special features., Summary: Specific bile acids and their signaling pathways play important roles in control of (cholesterol) metabolism. Deeper insight into the interactions between endogenous (i.e., bile acids) and pharmacological modulators of FXR and TGR5 is needed to optimize therapeutic benefit of the latter. The recent identification of cytochrome P450 2C70 as key enzyme in the formation of rodent-specific hydrophilic muricholic acids allows for the development of adequate mouse models for this purpose.
- Published
- 2018
- Full Text
- View/download PDF
26. [Outbreak of Campylobacter fetus infection after consumption of unpasteurized sheep's milk cheeses: how to trace the source?]
- Author
-
Koppenaal H, Groenendijk F, van den Berge M, Verkade E, Verduin K, Zomer AL, Duim B, Wagenaar JA, Tijsma ASL, Spierenburg MAH, and te Wierik MJM
- Subjects
- Aged, Animals, Disease Outbreaks, Humans, Immunocompromised Host, Male, Milk microbiology, Netherlands epidemiology, Sheep, Campylobacter Infections epidemiology, Campylobacter fetus isolation & purification, Cheese microbiology
- Abstract
Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.
- Published
- 2017
27. Transmission of methicillin-resistant Staphylococcus aureus CC398 from livestock veterinarians to their household members.
- Author
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Verkade E, Kluytmans-van den Bergh M, van Benthem B, van Cleef B, van Rijen M, Bosch T, Schouls L, and Kluytmans J
- Subjects
- Animals, Family, Female, Genotype, Humans, Livestock microbiology, Male, Methicillin-Resistant Staphylococcus aureus pathogenicity, Staphylococcal Infections microbiology, Staphylococcal Infections transmission, Tandem Repeat Sequences genetics, Methicillin-Resistant Staphylococcus aureus genetics, Staphylococcal Infections genetics, Staphylococcal Protein A genetics, Veterinarians
- Abstract
There are indications that livestock-associated MRSA CC398 has a reduced human-to-human transmissibility, limiting its impact on public health and justifying modified control measures. This study determined the transmissibility of MRSA CC398 from livestock veterinarians to their household members in the community as compared to MRSA non-CC398 strains. A one-year prospective cohort study was performed to determine the presence of MRSA CC398 in four-monthly nasal and oropharyngeal samples of livestock veterinarians (n = 137) and their household members (n = 389). In addition, a cross-sectional survey was performed to detect the presence of MRSA non-CC398 in hospital derived control patients (n = 20) and their household members (n = 41). Staphylococcus aureus isolates were genotyped by staphylococcal protein A (spa) typing and multiple-locus variable-number tandem repeat analysis (MLVA). Mean MRSA CC398 prevalence over the study period was 44% (range 41.6-46.0%) in veterinarians and 4.0% (range 2.8-4.7%) in their household members. The MRSA CC398 prevalence in household members of veterinarians was significantly lower than the MRSA non-CC398 prevalence in household members of control patients (PRR 6.0; 95% CI 2.4-15.5), indicating the reduced transmissibility of MRSA CC398. The impact of MRSA CC398 appears to be low at the moment. However, careful monitoring of the human-to-human transmissibility of MRSA CC398 remains important.
- Published
- 2014
- Full Text
- View/download PDF
28. Livestock-associated Staphylococcus aureus CC398: animal reservoirs and human infections.
- Author
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Verkade E and Kluytmans J
- Subjects
- Animals, Biological Evolution, Genome, Bacterial, Humans, Meat microbiology, Methicillin-Resistant Staphylococcus aureus classification, Methicillin-Resistant Staphylococcus aureus pathogenicity, Staphylococcal Infections epidemiology, Staphylococcal Infections microbiology, Virulence Factors genetics, Virulence Factors metabolism, Livestock microbiology, Methicillin-Resistant Staphylococcus aureus genetics, Staphylococcal Infections transmission
- Abstract
Over the past 15 years the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) has changed significantly. Being initially a nosocomial pathogen, other clones have been detected in the community, leading to infections in relatively young and healthy individuals lacking contact with healthcare. More recently, a specific clone of MRSA CC398 emerged, which has spread extensively in livestock animals and is also found in retail meat. People in contact with food production animals are at high risk of colonization. The ways in which MRSA CC398 can be transmitted to humans are direct contact with animals, environmental contamination, and eating or handling contaminated meat. The role of MRSA CC398 as a food pathogen needs further research. Recently, whole genome sequencing and other genetic analyses have shown that livestock-associated strains are distinct from human-derived strains. However, there is also an exchange of strains between the reservoirs. Livestock-associated and human-associated strains of CC398 share some virulence factors, but there are also distinct virulence factors that appear to be important in host adaptation. Exchange of genes encoding these virulence factors between strains may expand the host range and thereby threaten public health. Since the emergence of MRSA CC398 in humans, approximately 10 years ago, this clone has shown a remarkable evolution, which is described in this review., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2014
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29. Dynamics and determinants of Staphylococcus aureus carriage in livestock veterinarians: a prospective cohort study.
- Author
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Verkade E, van Benthem B, den Bergh MK, van Cleef B, van Rijen M, Bosch T, and Kluytmans J
- Subjects
- Adult, Animal Husbandry, Animals, Carrier State microbiology, Cohort Studies, Female, Genotype, Humans, Livestock, Male, Middle Aged, Minisatellite Repeats, Molecular Typing, Netherlands epidemiology, Nose microbiology, Oropharynx microbiology, Prevalence, Prospective Studies, Staphylococcal Infections microbiology, Staphylococcal Protein A genetics, Staphylococcus aureus classification, Staphylococcus aureus genetics, Carrier State epidemiology, Occupational Exposure, Staphylococcal Infections epidemiology, Staphylococcus aureus isolation & purification, Veterinarians
- Abstract
Background: Since 2003, a new clade of methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex (CC) 398 and associated with animal husbandry has emerged in the Netherlands. The purpose of this study was to determine the dynamics of carriage in persons with direct contact to livestock., Methods: A 2-year prospective cohort study was performed in which the anterior nares and oropharynx of 137 livestock veterinarians were sampled for the presence of S. aureus every 4 months during the first year and again 1 year later. All S. aureus isolates were genotyped by staphylococcal protein A (spa) typing and with multilocus variable-number tandem repeat analysis (MLVA)., Results: The mean prevalence of MRSA CC398 carriage was 44% (range, 42%-46%), and for S. aureus the prevalence was 72% (range, 69%-75%). Thirty-two veterinarians (23%) were always carrying MRSA CC398 and 18 of those (56%, 13% of all veterinarians) had identical MLVA types at all sampling moments., Conclusions: A high proportion of veterinarians had persistent MRSA CC398 carriage during the 2-year study period, indicating that this variant may colonize humans for prolonged periods. Furthermore, prevalence of S. aureus carriage was extremely high, indicating that MRSA CC398 is not replacing the susceptible strains, but comes on top of it.
- Published
- 2013
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30. High Resolution Typing by Whole Genome Mapping Enables Discrimination of LA-MRSA (CC398) Strains and Identification of Transmission Events.
- Author
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Bosch T, Verkade E, van Luit M, Pot B, Vauterin P, Burggrave R, Savelkoul P, Kluytmans J, and Schouls L
- Subjects
- Animals, Disease Outbreaks, Livestock microbiology, Methicillin-Resistant Staphylococcus aureus isolation & purification, Netherlands, Bacterial Typing Techniques methods, Chromosome Mapping, Genome, Bacterial, Methicillin-Resistant Staphylococcus aureus classification, Methicillin-Resistant Staphylococcus aureus genetics, Staphylococcal Infections classification, Staphylococcal Infections genetics, Staphylococcal Infections transmission, Staphylococcal Infections veterinary
- Abstract
After its emergence in 2003, a livestock-associated (LA-)MRSA clade (CC398) has caused an impressive increase in the number of isolates submitted for the Dutch national MRSA surveillance and now comprises 40% of all isolates. The currently used molecular typing techniques have limited discriminatory power for this MRSA clade, which hampers studies on the origin and transmission routes. Recently, a new molecular analysis technique named whole genome mapping was introduced. This method creates high-resolution, ordered whole genome restriction maps that may have potential for strain typing. In this study, we assessed and validated the capability of whole genome mapping to differentiate LA-MRSA isolates. Multiple validation experiments showed that whole genome mapping produced highly reproducible results. Assessment of the technique on two well-documented MRSA outbreaks showed that whole genome mapping was able to confirm one outbreak, but revealed major differences between the maps of a second, indicating that not all isolates belonged to this outbreak. Whole genome mapping of LA-MRSA isolates that were epidemiologically unlinked provided a much higher discriminatory power than spa-typing or MLVA. In contrast, maps created from LA-MRSA isolates obtained during a proven LA-MRSA outbreak were nearly indistinguishable showing that transmission of LA-MRSA can be detected by whole genome mapping. Finally, whole genome maps of LA-MRSA isolates originating from two unrelated veterinarians and their household members showed that veterinarians may carry and transmit different LA-MRSA strains at the same time. No such conclusions could be drawn based spa-typing and MLVA. Although PFGE seems to be suitable for molecular typing of LA-MRSA, WGM provides a much higher discriminatory power. Furthermore, whole genome mapping can provide a comparison with other maps within 2 days after the bacterial culture is received, making it suitable to investigate transmission events and outbreaks caused by LA-MRSA.
- Published
- 2013
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31. Outbreak of methicillin-resistant Staphylococcus aureus ST398 in a Dutch nursing home.
- Author
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Verkade E, Bosch T, Hendriks Y, and Kluytmans J
- Subjects
- Bacterial Typing Techniques, Cross Infection diagnosis, Cross Infection prevention & control, Electrophoresis, Gel, Pulsed-Field, Humans, Infection Control, Methicillin-Resistant Staphylococcus aureus classification, Netherlands, Prospective Studies, Staphylococcal Infections diagnosis, Staphylococcal Infections prevention & control, Cross Infection epidemiology, Disease Outbreaks prevention & control, Methicillin-Resistant Staphylococcus aureus isolation & purification, Nursing Homes, Staphylococcal Infections epidemiology
- Abstract
We describe an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) ST398 in a nursing home in the Netherlands. Seven residents and 4 healthcare workers were identified with MRSA ST398, but 2 of the healthcare workers carried other strains. This study demonstrates that MRSA ST398 can spread in nursing homes.
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- 2012
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32. Recent emergence of Staphylococcus aureus clonal complex 398 in human blood cultures.
- Author
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Verkade E, Bergmans AM, Budding AE, van Belkum A, Savelkoul P, Buiting AG, and Kluytmans J
- Subjects
- Animals, Anti-Bacterial Agents therapeutic use, Bacteremia drug therapy, Bacteremia microbiology, Clone Cells, DNA, Ribosomal Spacer genetics, Disease Reservoirs, Female, Humans, Male, Methicillin therapeutic use, Methicillin-Resistant Staphylococcus aureus drug effects, Methicillin-Resistant Staphylococcus aureus genetics, Microbial Sensitivity Tests, Netherlands epidemiology, Polymerase Chain Reaction, Prevalence, Staphylococcal Infections drug therapy, Staphylococcal Infections microbiology, Swine, Swine Diseases microbiology, Bacteremia epidemiology, Bacteremia veterinary, DNA, Ribosomal Spacer analysis, Methicillin-Resistant Staphylococcus aureus isolation & purification, Staphylococcal Infections epidemiology, Staphylococcal Infections veterinary, Swine Diseases epidemiology
- Abstract
Background: Recently, a clone of MRSA with clonal complex 398 (CC398) has emerged that is related to an extensive reservoir in animals, especially pigs and veal calves. It has been reported previously that methicillin-susceptible variants of CC398 circulate among humans at low frequency, and these have been isolated in a few cases of bloodstream infections (BSI). The purpose of this study was to determine the prevalence of S. aureus CC398 in blood cultures taken from patients in a geographic area with a high density of pigs., Methodology/principal Findings: In total, 612 consecutive episodes of S. aureus BSI diagnosed before and during the emergence of CC398 were included. Three strains (2 MSSA and 1 MRSA) that were isolated from bacteremic patients between 2010-2011 were positive in a CC398 specific PCR. There was a marked increase in prevalence of S. aureus CC398 BSI isolated between 2010-2011 compared to the combined collections that were isolated between 1996-1998 and 2002-2005 (3/157, 1.9% vs. 0/455, 0.0%; p = 0.017)., Conclusions/significance: In conclusion, in an area with a relative high density of pigs, S. aureus CC398 was found as a cause of BSI in humans only recently. This indicates that S. aureus CC398 is able to cause invasive infections in humans and that the prevalence is rising. Careful monitoring of the evolution and epidemiology of S. aureus CC398 in animals and humans is therefore important.
- Published
- 2012
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33. Clinical evaluation of Oxoid Brilliance MRSA Agar in comparison with bioMerieux MRSA ID medium for detection of livestock-associated meticillin-resistant Staphylococcus aureus.
- Author
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Verkade E, Ferket M, and Kluytmans J
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Culture Media pharmacology, Humans, Livestock microbiology, Methicillin pharmacology, Methicillin Resistance, Methicillin-Resistant Staphylococcus aureus drug effects, Nose microbiology, Occupational Exposure, Pharynx microbiology, Sensitivity and Specificity, Swine, Culture Media chemistry, Methicillin-Resistant Staphylococcus aureus isolation & purification, Occupational Diseases microbiology, Staphylococcal Infections microbiology, Veterinarians
- Abstract
Oxoid Brilliance MRSA Agar and bioMérieux MRSA ID medium were evaluated for their ability to identify meticillin-resistant Staphylococcus aureus (MRSA) in clinical samples. Nasal and throat samples (n = 629) were taken from veterinarians and their household members. The sensitivities of Brilliance MRSA Agar and MRSA ID medium after 20 h of incubation were 63.6 and 64.5 %, and the specificities were 94.1 and 99.4 %, respectively. After an enrichment step, the sensitivities increased to 96.3 and 97.2 %, but the specificities decreased to 88.7 and 98.5 %, respectively. Brilliance MRSA Agar and MRSA ID medium are both sensitive methods for the screening of MRSA in combination with broth enrichment, but positive results require confirmation.
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- 2011
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34. Optimization of human immunodeficiency virus type 1 envelope glycoproteins with V1/V2 deleted, using virus evolution.
- Author
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Bontjer I, Land A, Eggink D, Verkade E, Tuin K, Baldwin C, Pollakis G, Paxton WA, Braakman I, Berkhout B, and Sanders RW
- Subjects
- HIV Antibodies immunology, HIV Antigens genetics, HIV Antigens immunology, HIV-1 growth & development, HIV-1 immunology, Humans, Models, Molecular, Neutralization Tests, Protein Structure, Tertiary, Sequence Deletion, Directed Molecular Evolution, HIV-1 genetics, HIV-1 isolation & purification, Mutation, env Gene Products, Human Immunodeficiency Virus genetics, env Gene Products, Human Immunodeficiency Virus immunology
- Abstract
The human immunodeficiency virus type 1 envelope glycoprotein (Env) complex is the principal focus of neutralizing antibody-based vaccines. The functional Env complex is a trimer consisting of six individual subunits: three gp120 molecules and three gp41 molecules. The individual subunits have proven unsuccessful as vaccines presumably because they do not resemble the functional Env complex. Variable domains and carbohydrates shield vulnerable neutralization epitopes on the functional Env complex. The deletion of variable loops has been shown to improve gp120's immunogenicity; however, problems have been encountered when introducing such modifications in stabilized Env trimer constructs. To address these issues, we have created a set of V1/V2 and V3 loop deletion variants in the context of complete virus to allow optimization by forced virus evolution. Compensatory second-site substitutions included the addition and/or removal of specific carbohydrates, changes in the disulfide-bonded architecture of the V1/V2 stem, the replacement of hydrophobic residues by hydrophilic and charged residues, and changes in distal parts of gp120 and gp41. These viruses displayed increased sensitivity to neutralizing antibodies, demonstrating the improved exposure of conserved domains. The results show that we can select for functionally improved Env variants with loop deletions through forced virus evolution. Selected evolved Env variants were transferred to stabilized Env trimer constructs and were shown to improve trimer expression and secretion. Based on these findings, we can make recommendations on how to delete the V1/V2 domain from recombinant Env trimers for vaccine and X-ray crystallography studies. In general, virus evolution may provide a powerful tool to optimize Env vaccine antigens.
- Published
- 2009
- Full Text
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