18 results on '"Dengler F"'
Search Results
2. CO2 and aerosol concentration during manual and mechanical chest compression while cardiopulmonary resuscitation.
- Author
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Heymer J, Dengler F, Hein A, Krohn A, Jaki C, Echterdiek F, Schmid S, Müller-Schilling M, Schilling T, and Ott M
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- Humans, Infectious Disease Transmission, Patient-to-Professional prevention & control, SARS-CoV-2, Health Personnel, Heart Massage methods, Cardiopulmonary Resuscitation methods, COVID-19 transmission, COVID-19 prevention & control, Aerosols, Carbon Dioxide analysis
- Abstract
Background: This study investigates the staff-to-staff transmission risk of Coronavirus disease 2019 during cardiopulmonary resuscitation in an ambulance vehicle., Methods: Comparing manual and mechanical chest compressions, CO2 concentrations were monitored as a proxy for infection risk., Results: Results suggest that mechanical chest compressions generate lower CO2 levels, indicating a reduced risk of infection among healthcare workers compared to manual compressions., Conclusions: These findings highlight the potential benefits of employing mechanical chest compressions to mitigate staff-to-staff infections in small, confined spaces during aerosol-transmitted diseases., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2025 the Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2025
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3. Cryptosporidium parvum infection alters the intestinal mucosa transcriptome in neonatal calves: impacts on epithelial barriers and transcellular transport systems.
- Author
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Veshkini A, Kühn C, Dengler F, Bachmann L, Liermann W, Helm C, Ulrich R, Delling C, and Hammon HM
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- Animals, Cattle, Male, Diarrhea parasitology, Diarrhea veterinary, Gene Expression Profiling, Biological Transport, Epithelial Cells parasitology, Epithelial Cells metabolism, Jejunum parasitology, Jejunum metabolism, Transcytosis, Cryptosporidiosis parasitology, Cryptosporidium parvum genetics, Intestinal Mucosa metabolism, Intestinal Mucosa parasitology, Transcriptome, Animals, Newborn, Cattle Diseases parasitology, Cattle Diseases metabolism
- Abstract
Introduction: Cryptosporidium parvum (C. parvum) is the most prevalent enteric protozoan parasite causing infectious diarrhea in neonatal calves worldwide with a direct negative impact on their health and welfare. This study utilized next-generation sequencing (NGS) to deepen our understanding of intestinal epithelial barriers and transport mechanisms in the pathophysiology of infectious diarrhea in neonatal calves, which could potentially unveil novel solutions for treatment., Methods: At day 1 of life, male Holstein-Friesian calves were either orally infected (n = 5) or not (control group, n = 5) with C. parvum oocysts (in-house strain LE-01-Cp-15). On day 8 after infection, calves were slaughtered and jejunum mucosa samples were taken. The RNA was extracted from collected samples and subjected to sequencing. Differentially expressed genes (DEG) between the infected and CTRL groups were assessed using DESeq2 at a false discovery rate < 0.05 and used for gene ontology (GO) and pathway enrichment analysis in Cytoscape (v3.9.1)., Results and Discussion: To study the pathophysiology of infectious diarrhea on intestinal permeability, 459 genes related to epithelial cell barrier integrity and paracellular and transmembrane transport systems were selected from 12,908 identified genes in mucus. Among, there were 61 increased and 109 decreased gene transcripts belonged to adhesion molecules (e.g. ADGRD1 and VCAM1), ATP-binding cassette (ABC, e.g. ABCC2 and ABCD1) and solute carrier (SLC, e.g. SLC28A2 and SLC38A3) transporters, and ion channels (e.g. KCNJ15). Our results suggest deregulation of cellular junctions and thus a possibly increased intestinal permeability, whereas deregulation of ABC and SLC transporters and ion channels may influence the absorption/secretion of amino acids, carbohydrates, fats, and organic compounds, as well as acid-based balance and osmotic hemostasis. Besides pathogen-induced gene expression alterations, part of the DEG may have been triggered or consequently affected by inflammatory mechanisms. The study provided a deeper understanding of the pathophysiology of infectious diarrhea in neonatal calves and the host-pathogen interactions at the transcript level. For further studies with a particular focus on the transport system, these results could lead to a new approach to elucidating pathophysiological regulatory mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Veshkini, Kühn, Dengler, Bachmann, Liermann, Helm, Ulrich, Delling and Hammon.)
- Published
- 2024
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4. Homeless Persons in the Emergency Room—A Single-Center Study on the Performance and Completeness of Recommended Diagnostic Tests.
- Author
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Heymer J, Hein AS, Ott M, Müller-Schilling M, Schilling T, Krohn A, and Dengler F
- Published
- 2024
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5. Site Matters: Differences in Gene Expression Profiles Along the Bovine Rumen Papilla During Subacute Rumen Acidosis.
- Author
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Sener-Aydemir A, Dengler F, Larsberg F, Rivera-Chacon R, Castillo-Lopez E, Zebeli Q, and Kreuzer-Redmer S
- Subjects
- Animals, Cattle, Female, Transcriptome, Cattle Diseases genetics, Cattle Diseases metabolism, Animal Feed adverse effects, Gene Expression Profiling, Diet veterinary, Rumen metabolism, Acidosis veterinary, Acidosis genetics, Acidosis metabolism
- Abstract
Subacute rumen acidosis (SARA) is a significant concern in dairy cattle fed grain-rich diets. To elucidate the underlying pathophysiological mechanisms, ruminal papilla biopsies are often used. This study aimed to assess how the sampling site along the ruminal papilla influences gene expression profiles in rumen epithelium during SARA. Rumen biopsies from five ruminal-cannulated non-lactating Holstein cows were collected during feeding of a forage diet (FD) and seven (wk1) and 21 days (wk3) after transition to high-grain (HG) feeding. Gene expression in apical (AP), basal (BP), and total length (TP) papillae were compared using RT-qPCR. Significant diet-induced effects were observed in AP for DSG1 (wk3, p = 0.0317), ZO1 (wk1 and wk3, p = 0.0159), GLUT3 (wk3, p = 0.0159), TLR4 (wk3, p = 0.0635), and NFKB (wk1, p = 0.0159), but hardly in BP or TP. Within wk1, TP showed higher transcript levels of ZO1 and TLR4 ( p = 0.0079) and SGLT1 ( p = 0.0317) compared to AP and BP independently from diet effects. These findings suggest that the apical parts of rumen papillae biopsies are most suitable for gene expression analyses to investigate diet-induced effects on rumen physiology and underscore the importance of considering the sampling site for accurate gene expression studies in rumen epithelium during SARA, providing valuable insights for future research and diagnostic approaches in managing rumen health in dairy cattle.
- Published
- 2024
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6. Serum Transcobalamin Concentration in Cats-Method Validation and Evaluation in Chronic Enteropathies and Other Conditions.
- Author
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Kunath T, Kather S, Dengler F, Nexo E, Pfannkuche H, and Heilmann RM
- Abstract
Hypocobalaminemia is common in cats with chronic enteropathy (FCE). However, the disruptions in cobalamin metabolism are not fully understood and may vary across species. Cobalamin is distributed to target tissues via binding to transcobalamin (TC) in blood, which has not been evaluated in cats. Thus, an in-house sandwich-ELISA was established to evaluate serum total TC concentrations in cats with FCE. Surplus sera served to analytically validate the assay, and serum TC concentrations were compared among cats with FCE and other diseases (gastrointestinal neoplasia, cholangiohepatopathy, and other neoplastic or non-neoplastic conditions) and healthy controls. Observed-to-expected ratios for serial dilutions ranged from 72.4 to 145.6% and were 75.1-126.7% for spiking-and-recovery. Intra- and inter-assay variability was <17.7% and <17.2% and the preliminary reference interval for feline serum TC was <160-2795 aU/L (lower detection limit: 160 aU/L). Serum TC levels were significantly decreased ( p = 0.0067) but not correlated with paired cobalamin concentrations in FCE. Hypertranscobalaminemia predominated with hypercobalaminemia, reaching the highest levels in advanced-stage chronic kidney disease (CKD) cases. TC variations in cobalamin deficiency states with FCE may be linked to inflammation or autoantibodies. This and possible links between serum TC variation in FCE, intracellular cobalamin availability, response to supplementation, and concurrent CKD require further exploration.
- Published
- 2024
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7. Beliefs, preferences, and acceptance of personal protective equipment for a shock room team in a tertiary care center.
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Ott M, Hein AS, Krohn A, Jaki C, Dengler F, Schilling T, and Heymer J
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- Humans, Male, Female, Adult, Health Personnel education, Coronavirus Infections prevention & control, Coronavirus Infections epidemiology, Germany, Pneumonia, Viral prevention & control, Pneumonia, Viral epidemiology, Surveys and Questionnaires, Attitude of Health Personnel, Infectious Disease Transmission, Patient-to-Professional prevention & control, Betacoronavirus, Middle Aged, Infection Control methods, COVID-19 prevention & control, COVID-19 epidemiology, Personal Protective Equipment, Tertiary Care Centers, SARS-CoV-2, Pandemics prevention & control
- Abstract
Background: During coronavirus disease of 2019 pandemic a standard usage of personal protective equipment (PPE) in healthcare was mandatory, while actually the usage of PPE is currently decreasing. This raises the question about the further use of PPE in the clinical setting because healthcare workers (HCW) are at greater risk of being infected with SARS-CoV-2 than the general population. The primary objective of this study is to determine the proportion of shock room team members approving the further use of PPE including a FFP2 respirator in simulation training and reality. The secondary objectives are to describe the expertise and difficulties faced while using PPE in the shock room care., Methods: Fifty-four HCW participated in a shock room simulation training at a large urban tertiary care hospital in Germany, utilizing a PPE comprising an FFP2 mask, gloves, goggles, and gown. Subsequently, participants completed an online questionnaire featuring 15 questions presented on a 5-point Likert scale or as multiple-choice questions with predefined answers., Results: Sixty-eight point five percent of our participants voted for an established standard PPE in shock room care. The largest fraction of our participants (40.7%) favors a standard PPE consisting of FFP2 mask, gown, and gloves. Less HCW (31.5%) want to wear PPE in shock room simulation training. Except for goggles we could not detect relevant difficulties faced while using PPE in the shock room environment. Incorrect use of PPE was observed in 14.8%., Conclusion: A majority of our participants favored a standard PPE including a FFP2 respirator in shock room care. In addition, we recommend the use of PPE in shock room simulation training, while further awareness of and training in proper use of PPE seems to be necessary to reduce risk of infectious diseases for HCW., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2024
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8. Colostrum as a source of ESBL-Escherichia coli in feces of newborn calves.
- Author
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Bachmann L, Weber L, Liermann W, Hammon HM, Delling C, Dengler F, Schaufler K, Schwabe M, Eger E, Becker K, Schütz A, and Homeier-Bachmann T
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- Animals, Cattle, Male, Escherichia coli Infections microbiology, Escherichia coli Infections veterinary, Female, Bacterial Proteins genetics, Bacterial Proteins metabolism, Colostrum microbiology, Escherichia coli isolation & purification, Escherichia coli genetics, Feces microbiology, beta-Lactamases genetics, beta-Lactamases metabolism, Animals, Newborn
- Abstract
The aim of the present study was to determine if colostrum and the equipment for harvesting and feeding colostrum are sources of fecal ESBL/AmpC-producing Escherichia coli (ESBL/AmpC-E. coli) in calves. Therefore, 15 male calves fed with pooled colostrum on a dairy farm and held individually in an experimental barn, the colostrum pool and the equipment for harvesting and feeding colostrum were sampled and analyzed for the occurrence of ESBL/AmpC-E. coli. The ESBL-AmpC-E. coli suspicious isolates were subjected to whole-genome sequence analysis. Forty-three of 45 fecal samples were tested positive for ESBL/AmpC-E. coli. In the colostrum sample and in the milking pot, we also found ESBL/AmpC-E. coli. All 45 E. coli isolates were ESBL-producers, mainly commensal sequence type (ST) 10, but also human-extraintestinal pathogenic E. coli ST131 and ST117 were found. The clonal identity of six fecal isolates with the ESBL-E. coli isolate from the colostrum and of five fecal isolates with the strain from the milking pot demonstrates that the hygiene of colostrum or the colostrum equipment can play a significant role in the spread of ESBL-E. coli. Effective sanitation procedures for colostrum harvesting and feeding equipment are crucial to reduce the ESBL-E. coli shedding of neonatal dairy calves., (© 2024. The Author(s).)
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- 2024
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9. A matter of differentiation: equine enteroids as a model for the in vivo intestinal epithelium.
- Author
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Windhaber C, Heckl A, Csukovich G, Pratscher B, Burgener IA, Biermann N, and Dengler F
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- Animals, Horses, Intestinal Mucosa, Intestines, Cell Differentiation, RNA, Messenger, Gastrointestinal Diseases veterinary, Horse Diseases
- Abstract
Epithelial damage due to gastrointestinal disorders frequently causes severe disease in horses. To study the underlying pathophysiological processes, we aimed to establish equine jejunum and colon enteroids (eqJE, eqCE) mimicking the in vivo epithelium. Therefore, enteroids were cultivated in four different media for differentiation and subsequently characterized histomorphologically, on mRNA and on protein level in comparison to the native epithelium of the same donor horses to identify ideal culture conditions for an in vitro model system. With increasing enterocyte differentiation, the enteroids showed a reduced growth rate as well as a predominantly spherical morphology and less budding compared to enteroids in proliferation medium. Combined or individual withdrawal of stem cell niche pathway components resulted in lower mRNA expression levels of stem cell markers and concomitant differentiation of enterocytes, goblet cells and enteroendocrine cells. For eqCE, withdrawal of Wnt alone was sufficient for the generation of differentiated enterocytes with a close resemblance to the in vivo epithelium. Combined removal of Wnt, R-spondin and Noggin and the addition of DAPT stimulated differentiation of eqJE at a similar level as the in vivo epithelium, particularly with regard to enterocytes. In summary, we successfully defined a medium composition that promotes the formation of eqJE and eqCE consisting of multiple cell types and resembling the in vivo epithelium. Our findings emphasize the importance of adapting culture conditions to the respective species and the intestinal segment. This in vitro model will be used to investigate the pathological mechanisms underlying equine gastrointestinal disorders in future studies., (© 2024. The Author(s).)
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- 2024
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10. Cryptosporidium parvum infection alters the intestinal mucosa transcriptome in neonatal calves: implications for immune function.
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Veshkini A, Dengler F, Bachmann L, Liermann W, Helm C, Ulrich R, Delling C, Kühn C, and Hammon HM
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- Animals, Cattle, Male, Humans, Transcriptome, Intestinal Mucosa, Tumor Necrosis Factor-alpha genetics, Adaptive Immunity, Cryptosporidiosis, Cryptosporidium parvum genetics, Cryptosporidium genetics, Cattle Diseases genetics, Immune System Phenomena
- Abstract
One of the leading causes of infectious diarrhea in newborn calves is the apicomplexan protozoan Cryptosporidium parvum ( C. parvum ). However, little is known about its immunopathogenesis. Using next generation sequencing, this study investigated the immune transcriptional response to C. parvum infection in neonatal calves. Neonatal male Holstein-Friesian calves were either orally infected (N = 5) or not (CTRL group, N = 5) with C. parvum oocysts (gp60 subtype IIaA15G2R1) at day 1 of life and slaughtered on day 7 after infection. Total RNA was extracted from the jejunal mucosa for short read. Differentially expressed genes (DEGs) between infected and CTRL groups were assessed using DESeq2 at a false discovery rate < 0.05. Infection did not affect plasma immunohematological parameters, including neutrophil, lymphocyte, monocyte, leucocyte, thrombocyte, and erythrocyte counts as well as hematocrit and hemoglobin concentration on day 7 post infection. The immune-related DEGs were selected according to the UniProt immune system process database and were used for gene ontology (GO) and pathway enrichment analysis using Cytoscape (v3.9.1). Based on GO analysis, DEGs annotated to mucosal immunity, recognizing and presenting antigens, chemotaxis of neutrophils, eosinophils, natural killer cells, B and T cells mediated by signaling pathways including toll like receptors, interleukins, tumor necrosis factor, T cell receptor, and NF-KB were upregulated, while markers of macrophages chemotaxis and cytosolic pattern recognition were downregulated. This study provides a holistic snapshot of immune-related pathways induced by C. parvum in calves, including novel and detailed feedback and feedforward regulatory mechanisms establishing the crosstalk between innate and adaptive immune response in neonate calves, which could be utilized further to develop new therapeutic strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Veshkini, Dengler, Bachmann, Liermann, Helm, Ulrich, Delling, Kühn and Hammon.)
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- 2024
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11. Expression of the cobalamin transporters cubam and MRP1 in the canine ileum-Upregulation in chronic inflammatory enteropathy.
- Author
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Kather S, Kacza J, Pfannkuche H, Böttcher D, Sung CH, Steiner JM, Gäbel G, Dengler F, and Heilmann RM
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- Humans, Dogs, Animals, Vitamin B 12, Up-Regulation, Ileum metabolism, Membrane Transport Proteins genetics, Membrane Transport Proteins metabolism, Vitamin B 12 Deficiency genetics, Vitamin B 12 Deficiency veterinary, Inflammatory Bowel Diseases pathology, Dog Diseases genetics, Multidrug Resistance-Associated Proteins
- Abstract
Chronic inflammatory enteropathy (CIE) in dogs, a spontaneous model of human inflammatory bowel disease (IBD), is associated with a high rate of cobalamin deficiency. The etiology of hypocobalaminemia in human IBD and canine CIE remains unknown, and compromised intestinal uptake of cobalamin resulting from ileal cobalamin receptor deficiency has been proposed as a possible cause. Here, we evaluated the intestinal expression of the cobalamin receptor subunits, amnionless (AMN) and cubilin (CUBN), and the basolateral efflux transporter multi-drug resistance protein 1 (MRP1) in 22 dogs with CIE in comparison to healthy dogs. Epithelial CUBN and AMN levels were quantified by confocal laser scanning microscopy using immunohistochemistry in endoscopic ileal biopsies from dogs with (i) CIE and normocobalaminemia, (ii) CIE and suboptimal serum cobalamin status, (iii) CIE and severe hypocobalaminemia, and (iv) healthy controls. CUBN and MRP1 expression was quantified by RT-qPCR. Receptor expression was evaluated for correlation with clinical patient data. Ileal mucosal protein levels of AMN and CUBN as well as mRNA levels of CUBN and MRP1 were significantly increased in dogs with CIE compared to healthy controls. Ileal cobalamin receptor expression was positively correlated with age, clinical disease activity index (CCECAI) score, and lacteal dilation in the ileum, inversely correlated with serum folate concentrations, but was not associated with serum cobalamin concentrations. Cobalamin receptor downregulation does not appear to be the primary cause of hypocobalaminemia in canine CIE. In dogs of older age with severe clinical signs and/or microscopic intestinal lesions, intestinal cobalamin receptor upregulation is proposed as a mechanism to compensate for CIE-associated hypocobalaminemia. These results support oral supplementation strategies in hypocobalaminemic CIE patients., Competing Interests: Dr. Joerg Steiner is the director of the Gastrointestinal Laboratory at Texas A&M University where serum cobalamin analysis is offered on a fee-for-service basis. The authors declare no further conflicting interests in relation to the contents of the study., (Copyright: © 2024 Kather et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2024
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12. Dysregulation of intestinal epithelial electrolyte transport in canine chronic inflammatory enteropathy and the role of the renin-angiotensin-aldosterone-system.
- Author
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Dengler F, Domenig O, Kather S, Burgener IA, Steiner JM, and Heilmann RM
- Abstract
Chronic diarrhea is a hallmark sign of canine chronic inflammatory enteropathy (CIE), leading to fluid and electrolyte losses. Electrolyte homeostasis is regulated by the renin-angiotensin-aldosterone-system (RAAS), which might be involved in (counter-)regulating electrolyte losses in canine CIE. Whether and which electrolyte transporters are affected or if RAAS is activated in canine CIE is unknown. Thus, intestinal electrolyte transporters and components of the RAAS were investigated in dogs with CIE. Serum RAAS fingerprint analysis by mass spectrometry was performed in 5 CIE dogs and 5 healthy controls, and mRNA levels of intestinal electrolyte transporters and local RAAS pathway components were quantified by RT-qPCR in tissue biopsies from the ileum (7 CIE, 10 controls) and colon (6 CIE, 12 controls). Concentrations of RAAS components and mRNA expression of electrolyte transporters were compared between both groups of dogs and were tested for associations among each other. In dogs with CIE, associations with clinical variables were also tested. Components of traditional and alternative RAAS pathways were higher in dogs with CIE than in healthy controls, with statistical significance for Ang I, Ang II, and Ang 1-7 (all p < 0.05). Expression of ileal, but not colonic electrolyte transporters, such as Na
+ /K+ -ATPase, Na+ /H+ -exchanger 3, Cl- channel 2, down-regulated in adenoma, and Na+ -glucose-cotransporter (all p < 0.05) was increased in CIE. Our results suggest that the dys- or counter-regulation of intestinal electrolyte transporters in canine CIE might be associated with a local influence of RAAS. Activating colonic absorptive reserve capacities may be a promising therapeutic target in canine CIE., Competing Interests: OD is employed by Attoquant Diagnostics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Dengler, Domenig, Kather, Burgener, Steiner and Heilmann.)- Published
- 2023
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13. Time to eRAASe chronic inflammation: current advances and future perspectives on renin-angiotensin-aldosterone-system and chronic intestinal inflammation in dogs and humans.
- Author
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Heilmann RM, Csukovich G, Burgener IA, and Dengler F
- Abstract
Chronic idiopathic intestinal inflammation is an increasing worldwide problem that affects companion animals, especially dogs, and human patients. Although these disease entities have been intensely investigated recently, many questions remain, and alternative therapeutic options are needed. Diarrhea caused by dysregulation of intestinal electrolyte transport and subsequent fluid and electrolyte losses often leads to secondary consequences for the patient. Currently, it is not exactly clear which mechanisms are involved in the dysregulation of intestinal fluid absorption, but differences in intestinal electrolyte shifts between human and canine patients suggest species-specific regulatory or counterregulatory mechanisms. Several intestinal electrolyte transporters are differentially expressed in human patients with inflammatory bowel disease (IBD), whereas there are virtually no studies on electrolyte transporters and their endocrine regulation in canine chronic inflammatory enteropathy. An important mechanism involved in regulating fluid and electrolyte homeostasis is the renin-angiotensin-aldosterone-system (RAAS), which may affect intestinal Na
+ transport. While RAAS has previously been considered a systemic regulator of blood pressure, additional complex roles of RAAS in inflammatory processes have been unraveled. These alternative RAAS pathways may pose attractive therapeutic targets to address diarrhea and, thus, electrolyte shifts in human IBD and canine chronic inflammatory enteropathy. This article comparatively summarizes the current knowledge about electrolyte transport in human IBD and canine chronic inflammatory enteropathy and the role of RAAS and offers perspectives for novel therapeutic avenues., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Heilmann, Csukovich, Burgener and Dengler.)- Published
- 2023
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14. Cryptosporidium parvumcompetes with the intestinal epithelial cells for glucose and impairs systemic glucose supply in neonatal calves.
- Author
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Dengler F, Hammon HM, Liermann W, Görs S, Bachmann L, Helm C, Ulrich R, and Delling C
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- Animals, Cattle, Animals, Newborn metabolism, Animals, Newborn parasitology, Blood Glucose metabolism, Jejunum metabolism, Male, Cattle Diseases metabolism, Cattle Diseases parasitology, Cryptosporidiosis metabolism, Cryptosporidiosis parasitology, Cryptosporidium parvum metabolism, Glucose metabolism, Intestinal Mucosa metabolism
- Abstract
Cryptosporidiosis is one of the main causes of diarrhea in children and young livestock. The interaction of the parasite with the intestinal host cells has not been characterized thoroughly yet but may be affected by the nutritional demand of the parasite. Hence, we aimed to investigate the impact of C. parvum infection on glucose metabolism in neonatal calves. Therefore, N = 5 neonatal calves were infected with C. parvum on the first day of life, whereas a control group was not (N = 5). The calves were monitored clinically for one week, and glucose absorption, turnover and oxidation were assessed using stable isotope labelled glucose. The transepithelial transport of glucose was measured using the Ussing chamber technique. Glucose transporters were quantified on gene and protein expression level using RT-qPCR and Western blot in the jejunum epithelium and brush border membrane preparations. Plasma glucose concentration and oral glucose absorption were decreased despite an increased electrogenic phlorizin sensitive transepithelial transport of glucose in infected calves. No difference in the gene or protein abundance of glucose transporters, but an enrichment of glucose transporter 2 in the brush border was observed in the infected calves. Furthermore, the mRNA for enzymes of the glycolysis pathway was increased indicating enhanced glucose oxidation in the infected gut. In summary, C. parvum infection modulates intestinal epithelial glucose absorption and metabolism. We assume that the metabolic competition of the parasite for glucose causes the host cells to upregulate their uptake mechanisms and metabolic machinery to compensate for the energy losses., (© 2023. The Author(s).)
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- 2023
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15. Hypoxia signaling in the equine small intestine: Expression and distribution of hypoxia inducible factors during experimental ischemia.
- Author
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Verhaar N, de Buhr N, von Köckritz-Blickwede M, Dümmer K, Hewicker-Trautwein M, Pfarrer C, Dengler F, and Kästner S
- Abstract
Introduction: Hypoxia inducible factors (HIF) are widely researched in human medicine for their role in different disease processes. The aim of this study was to investigate the expression and distribution of HIF in experimental small intestinal ischemia in the horse., Methods: In 14 horses under general anesthesia, segmental jejunal ischemia with 90% reduction in blood flow was induced. The horses were randomly divided into two groups of seven horses, one subjected to ischemic postconditioning (IPoC) by delayed reperfusion, and a control group (group C) undergoing undelayed reperfusion. Intestinal samples were taken pre-ischemia, after ischemia and after reperfusion. Following immunohistochemical staining for HIF1α and -2α, the immunoreactivity pattern in the small intestine was evaluated by light microscopy, and the mucosal enterocyte and muscularis staining were semi-quantitatively scored. Additionally, mucosal HIF1α protein levels were determined by an Enzyme Linked Immunosorbent Assay (ELISA), and mRNA levels of HIF1α and its target genes by a two-step real-time Reverse Transcriptase Polymerase Chain Reaction. Statistical comparison was performed between the groups and time points using parametric and non-parametric tests ( p < 0.05)., Results: All cell types exhibited cytoplasmic and nuclear immunoreactivity for HIF1α. After reperfusion, the cytoplasmic staining of the crypt and villus enterocytes as well as the villus nuclear staining significantly increased, whereas the perinuclear granules in the crypts decreased. The protein levels showed a significant decrease in group C at reperfusion, with lower HIF1α levels in group C compared to group IPoC during ischemia and reperfusion. No other group differences could be detected. In the HIF2α stained slides, mild to moderate cytoplasmic staining yet no nuclear immunoreactivity of the enterocytes was observed, and no significant changes over time were noted., Discussion: the changes in HIF1α immunoreactivity pattern and expression over time suggest that this transcription factor plays a role in the intestinal response to ischemia in horses. However, the current study could not identify an effect of IPoC on HIF distribution or expression., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Verhaar, de Buhr, von Köckritz-Blickwede, Dümmer, Hewicker-Trautwein, Pfarrer, Dengler and Kästner.)
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- 2023
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16. Simulation of Aerosol and Droplet Spread during Upper Airway and Gastrointestinal Endoscopy.
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Heymer J, Dengler F, Krohn A, Jaki C, Schilling T, Mueller-Schilling M, Kandulski A, and Ott M
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- Humans, SARS-CoV-2, Pandemics prevention & control, Infectious Disease Transmission, Patient-to-Professional prevention & control, Respiratory Aerosols and Droplets, Endoscopy, Endoscopy, Gastrointestinal, COVID-19
- Abstract
Background and Aims: Aerosols and droplets are the main vectors in transmission of highly contagious SARS-CoV-2. Invasive diagnostic procedures like upper airway and gastrointestinal endoscopy have been declared as aerosol-generating procedures. Protection of healthcare workers is crucial in times of the COVID-19 pandemic., Methods: We simulated aerosol and droplet spread during upper airway and gastrointestinal endoscopy with and without physico-mechanical barriers using a simulation model., Results: A clear plastic drape as used for central venous access markedly reduced visualized aerosol and droplet spread during endoscopy., Conclusion: A simple and cheap drape has the potential to reduce aerosol and droplet spread during endoscopy. In terms of healthcare worker protection, this may be important particularly in low- or moderate-income countries., (© 2022 S. Karger AG, Basel.)
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- 2023
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17. The intraruminal redox potential is stabilised by opposing influences during fermentation.
- Author
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Rietmann SJ, Gäbel G, and Dengler F
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- Cattle, Animals, Sheep, Fermentation, Ruminants, Fatty Acids, Volatile metabolism, Oxidation-Reduction, Rumen metabolism, Diet veterinary, Animal Feed analysis
- Abstract
An optimal fermentation process in the forestomach is pivotal for the wellbeing and performance of ruminants. Complex carbohydrates are broken down into short-chain fatty acids (SCFA) which form the major energy source for the animal. A strong interrelationship of this process with intraruminal pH and redox potential (Eh) exists. These parameters can be measured with intraruminal sensors, but the interpretation of the measurements, especially of Eh, and their meaning for intraruminal homeostasis is not completely clear. In this study, factors influencing intraruminal Eh were elucidated. We hypothesised that intraruminal Eh is influenced by the fermentation process as such, but not by its end products SCFA. We measured Eh and pH in ruminal fluid from fasting cannulated sheep after the addition of 0.06 m Na-acetate, -propionate, -butyrate or glucose in vitro. Furthermore, we assessed the interrelation of pH and Eh. Basal Eh and pH values were -120 ± 41 mV and 7.0 ± 0.3, respectively, in native ruminal fluid in vitro. While the addition of SCFA did not induce any changes, glucose addition caused a significant decrease in both pH and Eh compared to the values before the addition (paired Student's t-test, p < 0.05). We attribute the decrease in Eh to an increased production of H
2 in the process of generating SCFA, predominantly acetate. By titrating both native and particle-free ruminal fluid to more acidic and basic pH values (4.5-8.5), we found a non-linear inverse correlation of pH and Eh, counteracting the H2 -driven decrease of Eh during fermentation. Thus, the intraruminal Eh is influenced by pH and H2 output during SCFA formation. The opposed character of these factors stabilises the intraruminal homeostasis which might help maintain symbiotic microbiota in the rumen. Understanding, monitoring, and supporting this system will be an essential part of modern cattle production., (© 2022 The Authors. Journal of Animal Physiology and Animal Nutrition published by Wiley-VCH GmbH.)- Published
- 2023
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18. Adaptive mechanisms in no flow vs. low flow ischemia in equine jejunum epithelium: Different paths to the same destination.
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Dengler F, Sternberg F, Grages M, Kästner SB, and Verhaar N
- Abstract
Intestinal ischemia reperfusion injury (IRI) is a frequent complication of equine colic. Several mechanisms may be involved in adaptation of the intestinal epithelium to IRI and might infer therapeutic potential, including hypoxia-inducible factor (HIF) 1α, AMP-activated protein kinase (AMPK), nuclear factor-erythroid 2-related factor 2 (NRF2), and induction of autophagy. However, the mechanisms supporting adaptation and thus cellular survival are not completely understood yet. We investigated the activation of specific adaptation mechanisms in both no and low flow ischemia and reperfusion simulated in equine jejunum epithelium in vivo . We found an activation of HIF1α in no and low flow ischemia as indicated by increased levels of HIF1α target genes and phosphorylation of AMPKα tended to increase during ischemia. Furthermore, the protein expression of the autophagy marker LC3B in combination with decreased expression of nuclear-encoded mitochondrial genes indicates an increased rate of mitophagy in equine intestinal IRI, possibly preventing damage by mitochondria-derived reactive oxygen species (ROS). Interestingly, ROS levels were increased only shortly after the onset of low flow ischemia, which may be explained by an increased antioxidative defense, although NFR2 was not activated in this setup. In conclusion, we could demonstrate that a variety of adaptation mechanisms manipulating different aspects of cellular homeostasis are activated in IRI irrespective of the ischemia model, and that mitophagy might be an important factor for epithelial survival following small intestinal ischemia in horses that should be investigated further., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dengler, Sternberg, Grages, Kästner and Verhaar.)
- Published
- 2022
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