Michael H. Stoffel | University of Bern (original) (raw)

Papers by Michael H. Stoffel

Research paper thumbnail of Time-Dependent Internalization of Polymer-Coated Silica Nanoparticles in Brain Endothelial Cells and Morphological and Functional Effects on the Blood-Brain Barrier

International Journal of Molecular Sciences

Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages com... more Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages compared to conventional microsuturing, especially in the brain. In this study, effects of polymer-coated silica NPs used in LTS were investigated in human brain endothelial cells (ECs) and blood-brain barrier models. In the co-culture setting with ECs and pericytes, only the cell type directly exposed to NPs displayed a time-dependent internalization. No transfer of NPs between the two cell types was observed. Cell viability was decreased relatively to NP exposure duration and concentration. Protein expression of the nuclear factor ĸ-light-chain-enhancer of activated B cells and various endothelial adhesion molecules indicated no initiation of inflammation or activation of ECs after NP exposure. Differentiation of CD34+ ECs into brain-like ECs co-cultured with pericytes, blood-brain barrier (BBB) characteristics were obtained. The established endothelial layer reduced the passage of integr...

Research paper thumbnail of Removal of a subset of non-essential genes fully attenuates a highly virulent Mycoplasma strain

Mycoplasmas are the smallest free-living organisms and cause a number of economically important d... more Mycoplasmas are the smallest free-living organisms and cause a number of economically important diseases affecting humans, animals, insects and plants. Here, we demonstrate that highly virulent Mycoplasma mycoides subspecies capri (Mmc) can be fully attenuated via targeted deletion of non-essential genes encoding, among others, potential virulence traits. Five genomic regions, representing approximately ten percent of the original Mmc genome, were successively deleted using Saccharomyces cerevisiae as an engineering platform. Specifically, a total of 68 genes out of the 432 genes verified to be individually nonessential in the JCVI-Syn3.0 minimal cell, were excised from the genome. In vitro characterization showed that this mutant was similar to its parental strain in terms of its doubling time, even though ten percent of the genome content were removed. A novel in vivo challenge model in goats revealed that the wild-type parental strain caused marked necrotizing inflammation at the...

Research paper thumbnail of Histologie-Kurs Veterin�rmediziner

Schweiz Arch Tierheilkd, 2010

Research paper thumbnail of Topographische und klinisch-funktionelle Anatomie des Zentralnervensystems

Research paper thumbnail of Atlas der angewandten Anatomie der Haustiere

Schweizer Archiv für Tierheilkunde, 2004

Bauchhöhle eines Hundes, Ansicht von ventral, großes Netz nach kranial gelegt 142 Abb. 67 Bauchhö... more Bauchhöhle eines Hundes, Ansicht von ventral, großes Netz nach kranial gelegt 142 Abb. 67 Bauchhöhle eines Hundes, Ansicht von ventral, Darmkonvolut mit Ausnahme von Duodenum und Colon descendens nach links verlagert .

Research paper thumbnail of Histologie-Kurs Veterinärmediziner

Schweizer Archiv für Tierheilkunde, 2010

Research paper thumbnail of The Small-Compound Inhibitor K22 Displays Broad Antiviral Activity against Different Members of the Family Flaviviridae and Offers Potential as a Panviral Inhibitor

Antimicrobial agents and chemotherapy, 2018

The virus family encompasses several viruses, including (re)emerging viruses which cause widespre... more The virus family encompasses several viruses, including (re)emerging viruses which cause widespread morbidity and mortality throughout the world. Members of this virus family are positive-strand RNA viruses and replicate their genome in close association with reorganized intracellular host cell membrane compartments. This evolutionarily conserved strategy facilitates efficient viral genome replication and contributes to evasion from host cell cytosolic defense mechanisms. We have previously described the identification of a small-compound inhibitor, K22, which exerts a potent antiviral activity against a broad range of coronaviruses by targeting membrane-bound viral RNA replication. To analyze the antiviral spectrum of this inhibitor, we assessed the inhibitory potential of K22 against several members of the family, including the reemerging Zika virus (ZIKV). We show that ZIKV is strongly affected by K22. Time-of-addition experiments revealed that K22 acts during a postentry phase o...

Research paper thumbnail of Isolation of Human Small Extracellular Vesicles and Tracking of Their Uptake by Retinal Pigment Epithelial Cells In Vitro

International Journal of Molecular Sciences

Small extracellular vesicles (EVs) are among the most frequently investigated EVs and play major ... more Small extracellular vesicles (EVs) are among the most frequently investigated EVs and play major roles in intercellular communication by delivering various cargo molecules to target cells. They could potentially represent an alternative delivery strategy to treat ocular toxoplasmosis, a parasitosis affecting the retinal pigment epithelium (RPE). To date, the uptake of human small EVs by RPE cells has never been reported. In this study, we report on the intracellular uptake of fluorescently labelled human urine and fibroblast-derived small EVs by human RPE cells. In summary, both dye-labelled urinary small EVs and small EVs obtained from fibroblasts stably expressing membrane-bound green fluorescent protein were successfully internalized by RPE cells as revealed by immunohistochemistry. In recipient ARPE19 cells, BODIPY-labelled small EVs were found in close vicinity to the parasite Toxoplasma gondii. Additionally, an ultrastructural method was enabled to distinguish between labelled...

Research paper thumbnail of Treponema phagedenis (ex Noguchi 1912) Brumpt 1922 sp. nov., nom. rev., isolated from bovine digital dermatitis

International Journal of Systematic and Evolutionary Microbiology

‘ Treponema phagedenis ’ was originally described in 1912 by Noguchi but the name was not validly... more ‘ Treponema phagedenis ’ was originally described in 1912 by Noguchi but the name was not validly published and no type strain was designated. The taxon was not included in the Approved Lists of Bacterial Names and hence has no standing in nomenclature. Six Treponema strains positive in a ‘ T. phagedenis ’ phylogroup-specific PCR test were isolated from digital dermatitis (DD) lesions of cattle and further characterized and compared with the human strain ‘ T. phagedenis ’ ATCC 27087. Results of phenotypic and genotypic analyses including API ZYM, VITEK2, MALDI-TOF and electron microscopy, as well as whole genome sequence data, respectively, showed that they form a cluster of species identity. Moreover, this species identity was shared with ‘ T. phagedenis ’-like strains reported in the literature to be regularly isolated from bovine DD. High average nucleotide identity values between the genomes of bovine and human ‘ T. phagedenis ’ were observed. Slight genomic as well as phenotypic variations allowed us to differentiate bovine from human isolates, indicating host adaptation. Based on the fact that this species is regularly isolated from bovine DD and that the name is well dispersed in the literature, we propose the species Treponema phagedenis sp. nov., nom. rev. The species can phenotypically and genetically be identified and is clearly separated from other Treponema species. The valid species designation will allow to further explore its role in bovine DD. The type strain for Treponema phagedenis sp. nov., nom. rev. is B43.1T (=DSM 110455T=NCTC 14362T) isolated from a bovine DD lesion in Switzerland.

Research paper thumbnail of Abnormal keratinocyte differentiation in the nasal planum of Labrador Retrievers with hereditary nasal parakeratosis (HNPK)

PLOS ONE

Hereditary nasal parakeratosis (HNPK) is an inherited disorder described in Labrador Retrievers a... more Hereditary nasal parakeratosis (HNPK) is an inherited disorder described in Labrador Retrievers and Greyhounds. It has been associated with breed-specific variants in the SUV39H2 gene encoding a histone 3 methyltransferase involved in epigenetic silencing. Formalin-fixed biopsies of the nasal planum of Labrador Retrievers were screened by immunofluorescence microscopy for the presence and distribution of epidermal proliferation and differentiation markers. Gene expression of these markers was further analysed using RNA sequencing (RNA-seq) and ultrastructural epidermal differences were investigated by electron microscopy. Differentiation of the nasal planum in the basal and suprabasal epidermal layers of HNPK-affected dogs (n = 6) was similar compared to control dogs (n = 6). In the upper epidermal layers, clear modifications were noticed. Loricrin protein was absent in HNPK-affected nasal planum sections in contrast to sections of the same location of control dogs. However, loricrin was present in the epidermis of paw pads and abdominal skin from HNPK dogs and healthy control dogs. The patterns of keratins K1, K10 and K14, were not markedly altered in the nasal planum of HNPK-affected dogs while the expression of the terminal differentiation marker involucrin appeared less regular. Based on RNA-seq, LOR and IVL expression levels were significantly decreased, while KRT1, KRT10 and KRT14 levels were up-regulated (log2fold-changes of 2.67, 3.19 and 1.71, respectively) in HNPK-affected nasal planum (n = 3) compared to control dogs (n = 3). Electron microscopical analysis revealed structural alterations in keratinocytes and stratum corneum, and disrupted keratinocyte adhesions and distended intercellular spaces in lesional samples (n = 3) compared PLOS ONE

Research paper thumbnail of The embryonic development of the bovine stomach revisited

Anatomia, Histologia, Embryologia

Research paper thumbnail of Effect of Clostridium perfringens β-Toxin on Platelets

Toxins

Clostridium perfringens β-toxin (CPB) is the major virulence factor of C. perfringens type C caus... more Clostridium perfringens β-toxin (CPB) is the major virulence factor of C. perfringens type C causing a hemorrhagic enteritis in animals and humans. In experimentally infected pigs, endothelial binding of CPB was shown to be associated with early vascular lesions and hemorrhage but without obvious thrombosis of affected vessels, suggesting altered hemostasis in the early phase of the disease. The objective of the present study was to investigate the effect of CPB on platelets, with respect to primary hemostasis. Our results demonstrate that CPB binds to porcine and human platelets and forms oligomers resulting in a time-and dose-dependent cell death. Platelets showed rapid ultrastructural changes, significantly decreased aggregation and could no longer be activated by thrombin. This indicates that CPB affects the physiological function of platelets and counteracts primary hemostasis. Our results add platelets to the list of target cells of CPB and extend the current hypothesis of its role in the pathogenesis of C. perfringens type C enteritis.

Research paper thumbnail of Bufonid herpesvirus 1 (BfHV1) associated dermatitis and mortality in free ranging common toads (Bufo bufo) in Switzerland

Scientific reports, Jan 3, 2018

Here we report the discovery and partial characterization of a novel herpesvirus tentatively name... more Here we report the discovery and partial characterization of a novel herpesvirus tentatively named Bufonid herpesvirus 1 (BfHV1) from severe dermatitis in free ranging common toads (Bufo bufo) in Switzerland. The disease has been observed in toads every year since 2014, in spring, during the mating season, at different and distant locations. The virus is found in the skin and occasionally in the brain of infected toads. The genome of the virus is at least 158 Kb long and contains at least 152 open reading frames with a minimal length of 270 nt. The genome of BfHV1 contains all the signature genes that are present in alloherpesviruses. Phylogenetic analysis based on the amino acid sequence of the DNA polymerase and terminase proteins positions the novel virus among the members of the genus Batrachovirus, family Alloherpesviridae. This is the first herpesvirus ever characterized in common toads.

Research paper thumbnail of A stereotaxic breed-averaged, symmetric T2w canine brain atlas including detailed morphological and volumetrical data sets

NeuroImage, Jan 31, 2018

Stereotaxic systems and automatic tissue segmentation routines enable neuronavigation as well as ... more Stereotaxic systems and automatic tissue segmentation routines enable neuronavigation as well as reproducible processing of neuroimage datasets. Such systems have been developed for humans, non-human-primates, sheep, and rodents, but not for dogs. Although dogs share important neurofunctional and -anatomical features with humans, and in spite of their importance in translational neuroscience, little is known about the variability of the canine brain morphology and, possibly related, function. Moreover, we lack templates, tissue probability maps (TPM), and stereotaxic brain labels for implementation in standard software utilities such as Statistical Parametric Mapping (SPM). Hence, objective and reproducible, image-based investigations are currently impeded in dogs. We have created a detailed stereotaxic reference frame for dogs including TPM and tissue labels, enabling inter-individual and cross-study neuroimage analysis. T2w datasets were acquired from 16 neurologically inconspicuo...

Research paper thumbnail of Binding of indocyanine green in polycaprolactone fibers using blend electrospinning for in vivo laser-assisted vascular anastomosis

Lasers in Surgery and Medicine

The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and lo... more The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and low bonding strengths as well as tedious handling during microvascular surgery. The challenge to be met arises from the flow-off of the chromophore during soldering that changes the absorption and stains the surrounding tissue, leading to an uncontrollable thermal damage zone. In this study, we investigated the feasibility to produce an indocyanine green (ICG)-loaded patch by electrospinning and tested its applicability to both in vitro and in vivo microvascular laser soldering. A blend of polycaprolactone and ICG was electrospun to produce a pliable patch. Prior to soldering, the patch was soaked in 40% wt. bovine serum albumin solution. The solder patch was wrapped in vitro around blood vessel stumps of rabbit aortas. An intraluminal balloon catheter enabled an easy alignment and held the setup in place. The soldering energy was delivered via a diffusor fiber from the vessel lumen using a diode laser at 810 nm. During the procedure, the surface temperature was observed with an infrared camera. Afterward, samples were embedded in methylmethacrylate and epon to study thermal damage. The quality of the fusion was assessed by measuring the tensile strength. After in vitro tests with rabbit aortas, eight large white pigs were subjected to an acute in vivo experiment, and the artery of the latissimus dorsi flap was anastomosed to the distal femoral artery. The ICG-loaded patch, produced by electrospinning, has a thickness of 279 ± 62 μm, a fiber diameter of 1.20 ± 0.19 μm, and an attenuation coefficient of 1,119 ± 183 cm(-1) at a wavelength of 790 nm. The patch was pliable and easy to handle during surgery. No leakage of the chromophore was observed. Thermal damage was restricted to the Tunica adventitia and Tunica media and the area of the vessel wall that was covered with the patch. Six pigs were successfully treated, without any bleeding and with a continuous blood flow. The in vivo flap model yielded a similar tensile strength compared to in vitro laser-assisted vascular anastomoses (138 ± 52 vs. 117 ± 30 mN/mm(2) ). Our study demonstrated the applicability of the ICG-loaded patch for laser-assisted vascular anastomosis. By using electrospinning, ICG could be bound to polymer fibers, avoiding its flow-off and the staining of the surrounding tissue. This patch demonstrated several advantages over liquid solder as it was easier to apply, ensured a high and reliable bonding strength while maintaining a constant concentration of ICG concentration during the surgery. Lasers Surg. Med. © 2017 Wiley Periodicals, Inc.

Research paper thumbnail of Assessment of a specifically developed bullet casing gun for the stunning of water buffaloes

Research paper thumbnail of Uptake of silica nanoparticles in the brain and effects on neuronal differentiation using different in vitro models

Nanomedicine : nanotechnology, biology, and medicine, 2017

Nanomedicine offers a promising tool for therapies of brain diseases, but they may be associated ... more Nanomedicine offers a promising tool for therapies of brain diseases, but they may be associated with potential adverse effects. The aim of this study was to investigate the uptake of silica-nanoparticles engineered for laser-tissue soldering in the brain using SH-SY5Y cells, dissociated and organotypic slice cultures from rat hippocampus. Nanoparticles were predominantly taken up by microglial cells in the hippocampal cultures but nanoparticles were also found in differentiated SH-SY5Y cells. The uptake was time- and concentration-dependent in primary hippocampal cells. Transmission electron microscopy experiments demonstrated nanoparticle aggregates and single particles in the cytoplasm. Nanoparticles were found in the endoplasmic reticulum, but not in other cellular compartments. Nanoparticle exposure did not impair cell viability and neuroinflammation in primary hippocampal cultures at all times investigated. Neurite outgrowth was not significantly altered in SH-SY5Y cells, but ...

Research paper thumbnail of Effects of stimulus with proinflammatory mediators on nitric oxide production and matrix metalloproteinase activity in explants of cranial cruciate ligaments obtained from dogs

Http Dx Doi Org 10 2460 Ajvr 2002 63 1423, Dec 14, 2005

To evaluate the origin and degree of activity of nitric oxide (NO) and matrix metalloproteinase (... more To evaluate the origin and degree of activity of nitric oxide (NO) and matrix metalloproteinase (MMP) in explants of cranial cruciate ligaments (CCLs) obtained from dogs and cultured with and without inflammatory activators. Tissue specimens obtained from 7 healthy adult Beagles that were (mean +/- SD) 4.5 +/- 0.5 years old and weighed 12.5 +/- 0.8 kg. The CCLs were harvested immediately after dogs were euthanatized, and specimens were submitted for explant culture. Cultures were stimulated by incubation with a combination of interleukin-1, tumor necrosis factor-alpha, and lipopolysaccharide, or they were not stimulated. Culture supernatants were examined for production of NO nitrite-nitrate metabolites (NOts) and activity of MMP Cultured specimens were evaluated by use of immunohistochemical analysis to detect activity of inducible NO synthase (iNOS). All ligament explants produced measurable amounts of NOts. Stimulated cultures produced significantly more NOts after incubation for 24 and 48 hours, compared with nonstimulated cultures. Production of MMP in supernatants after incubation for 48 hours was significantly higher in stimulated cultures than in nonstimulated cultures. Cells with positive staining for iNOS were detected on all slides. Positively stained cells were predominantly chondroid metaplastic. There was a significant difference in intensity of cell staining between stimulated and non-stimulated cultures. Explant cultures of intact CCLs obtained from dogs produce iNOS-induced NO. Stimulation of chondroid metaplastic cells in CCL of dogs by use of inflammatory activators can increase production of iNOS, NOts, and MMP.

Research paper thumbnail of Vascularization of the epididymis in boars with special reference to the perfusion and fixation technique

Schweizer Archiv Fur Tierheilkunde, 1990

Research paper thumbnail of Erratum for Henke et al., Listeria monocytogenes Spreads within the Brain by Actin-Based Intra-Axonal Migration

Infection and Immunity, 2016

Oevermann A. 2016. Erratum for Henke et al., Listeria monocytogenes spreads within the brain by a... more Oevermann A. 2016. Erratum for Henke et al., Listeria monocytogenes spreads within the brain by actin-based intra-axonal migration. Infect Immun 84:866.

Research paper thumbnail of Time-Dependent Internalization of Polymer-Coated Silica Nanoparticles in Brain Endothelial Cells and Morphological and Functional Effects on the Blood-Brain Barrier

International Journal of Molecular Sciences

Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages com... more Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages compared to conventional microsuturing, especially in the brain. In this study, effects of polymer-coated silica NPs used in LTS were investigated in human brain endothelial cells (ECs) and blood-brain barrier models. In the co-culture setting with ECs and pericytes, only the cell type directly exposed to NPs displayed a time-dependent internalization. No transfer of NPs between the two cell types was observed. Cell viability was decreased relatively to NP exposure duration and concentration. Protein expression of the nuclear factor ĸ-light-chain-enhancer of activated B cells and various endothelial adhesion molecules indicated no initiation of inflammation or activation of ECs after NP exposure. Differentiation of CD34+ ECs into brain-like ECs co-cultured with pericytes, blood-brain barrier (BBB) characteristics were obtained. The established endothelial layer reduced the passage of integr...

Research paper thumbnail of Removal of a subset of non-essential genes fully attenuates a highly virulent Mycoplasma strain

Mycoplasmas are the smallest free-living organisms and cause a number of economically important d... more Mycoplasmas are the smallest free-living organisms and cause a number of economically important diseases affecting humans, animals, insects and plants. Here, we demonstrate that highly virulent Mycoplasma mycoides subspecies capri (Mmc) can be fully attenuated via targeted deletion of non-essential genes encoding, among others, potential virulence traits. Five genomic regions, representing approximately ten percent of the original Mmc genome, were successively deleted using Saccharomyces cerevisiae as an engineering platform. Specifically, a total of 68 genes out of the 432 genes verified to be individually nonessential in the JCVI-Syn3.0 minimal cell, were excised from the genome. In vitro characterization showed that this mutant was similar to its parental strain in terms of its doubling time, even though ten percent of the genome content were removed. A novel in vivo challenge model in goats revealed that the wild-type parental strain caused marked necrotizing inflammation at the...

Research paper thumbnail of Histologie-Kurs Veterin�rmediziner

Schweiz Arch Tierheilkd, 2010

Research paper thumbnail of Topographische und klinisch-funktionelle Anatomie des Zentralnervensystems

Research paper thumbnail of Atlas der angewandten Anatomie der Haustiere

Schweizer Archiv für Tierheilkunde, 2004

Bauchhöhle eines Hundes, Ansicht von ventral, großes Netz nach kranial gelegt 142 Abb. 67 Bauchhö... more Bauchhöhle eines Hundes, Ansicht von ventral, großes Netz nach kranial gelegt 142 Abb. 67 Bauchhöhle eines Hundes, Ansicht von ventral, Darmkonvolut mit Ausnahme von Duodenum und Colon descendens nach links verlagert .

Research paper thumbnail of Histologie-Kurs Veterinärmediziner

Schweizer Archiv für Tierheilkunde, 2010

Research paper thumbnail of The Small-Compound Inhibitor K22 Displays Broad Antiviral Activity against Different Members of the Family Flaviviridae and Offers Potential as a Panviral Inhibitor

Antimicrobial agents and chemotherapy, 2018

The virus family encompasses several viruses, including (re)emerging viruses which cause widespre... more The virus family encompasses several viruses, including (re)emerging viruses which cause widespread morbidity and mortality throughout the world. Members of this virus family are positive-strand RNA viruses and replicate their genome in close association with reorganized intracellular host cell membrane compartments. This evolutionarily conserved strategy facilitates efficient viral genome replication and contributes to evasion from host cell cytosolic defense mechanisms. We have previously described the identification of a small-compound inhibitor, K22, which exerts a potent antiviral activity against a broad range of coronaviruses by targeting membrane-bound viral RNA replication. To analyze the antiviral spectrum of this inhibitor, we assessed the inhibitory potential of K22 against several members of the family, including the reemerging Zika virus (ZIKV). We show that ZIKV is strongly affected by K22. Time-of-addition experiments revealed that K22 acts during a postentry phase o...

Research paper thumbnail of Isolation of Human Small Extracellular Vesicles and Tracking of Their Uptake by Retinal Pigment Epithelial Cells In Vitro

International Journal of Molecular Sciences

Small extracellular vesicles (EVs) are among the most frequently investigated EVs and play major ... more Small extracellular vesicles (EVs) are among the most frequently investigated EVs and play major roles in intercellular communication by delivering various cargo molecules to target cells. They could potentially represent an alternative delivery strategy to treat ocular toxoplasmosis, a parasitosis affecting the retinal pigment epithelium (RPE). To date, the uptake of human small EVs by RPE cells has never been reported. In this study, we report on the intracellular uptake of fluorescently labelled human urine and fibroblast-derived small EVs by human RPE cells. In summary, both dye-labelled urinary small EVs and small EVs obtained from fibroblasts stably expressing membrane-bound green fluorescent protein were successfully internalized by RPE cells as revealed by immunohistochemistry. In recipient ARPE19 cells, BODIPY-labelled small EVs were found in close vicinity to the parasite Toxoplasma gondii. Additionally, an ultrastructural method was enabled to distinguish between labelled...

Research paper thumbnail of Treponema phagedenis (ex Noguchi 1912) Brumpt 1922 sp. nov., nom. rev., isolated from bovine digital dermatitis

International Journal of Systematic and Evolutionary Microbiology

‘ Treponema phagedenis ’ was originally described in 1912 by Noguchi but the name was not validly... more ‘ Treponema phagedenis ’ was originally described in 1912 by Noguchi but the name was not validly published and no type strain was designated. The taxon was not included in the Approved Lists of Bacterial Names and hence has no standing in nomenclature. Six Treponema strains positive in a ‘ T. phagedenis ’ phylogroup-specific PCR test were isolated from digital dermatitis (DD) lesions of cattle and further characterized and compared with the human strain ‘ T. phagedenis ’ ATCC 27087. Results of phenotypic and genotypic analyses including API ZYM, VITEK2, MALDI-TOF and electron microscopy, as well as whole genome sequence data, respectively, showed that they form a cluster of species identity. Moreover, this species identity was shared with ‘ T. phagedenis ’-like strains reported in the literature to be regularly isolated from bovine DD. High average nucleotide identity values between the genomes of bovine and human ‘ T. phagedenis ’ were observed. Slight genomic as well as phenotypic variations allowed us to differentiate bovine from human isolates, indicating host adaptation. Based on the fact that this species is regularly isolated from bovine DD and that the name is well dispersed in the literature, we propose the species Treponema phagedenis sp. nov., nom. rev. The species can phenotypically and genetically be identified and is clearly separated from other Treponema species. The valid species designation will allow to further explore its role in bovine DD. The type strain for Treponema phagedenis sp. nov., nom. rev. is B43.1T (=DSM 110455T=NCTC 14362T) isolated from a bovine DD lesion in Switzerland.

Research paper thumbnail of Abnormal keratinocyte differentiation in the nasal planum of Labrador Retrievers with hereditary nasal parakeratosis (HNPK)

PLOS ONE

Hereditary nasal parakeratosis (HNPK) is an inherited disorder described in Labrador Retrievers a... more Hereditary nasal parakeratosis (HNPK) is an inherited disorder described in Labrador Retrievers and Greyhounds. It has been associated with breed-specific variants in the SUV39H2 gene encoding a histone 3 methyltransferase involved in epigenetic silencing. Formalin-fixed biopsies of the nasal planum of Labrador Retrievers were screened by immunofluorescence microscopy for the presence and distribution of epidermal proliferation and differentiation markers. Gene expression of these markers was further analysed using RNA sequencing (RNA-seq) and ultrastructural epidermal differences were investigated by electron microscopy. Differentiation of the nasal planum in the basal and suprabasal epidermal layers of HNPK-affected dogs (n = 6) was similar compared to control dogs (n = 6). In the upper epidermal layers, clear modifications were noticed. Loricrin protein was absent in HNPK-affected nasal planum sections in contrast to sections of the same location of control dogs. However, loricrin was present in the epidermis of paw pads and abdominal skin from HNPK dogs and healthy control dogs. The patterns of keratins K1, K10 and K14, were not markedly altered in the nasal planum of HNPK-affected dogs while the expression of the terminal differentiation marker involucrin appeared less regular. Based on RNA-seq, LOR and IVL expression levels were significantly decreased, while KRT1, KRT10 and KRT14 levels were up-regulated (log2fold-changes of 2.67, 3.19 and 1.71, respectively) in HNPK-affected nasal planum (n = 3) compared to control dogs (n = 3). Electron microscopical analysis revealed structural alterations in keratinocytes and stratum corneum, and disrupted keratinocyte adhesions and distended intercellular spaces in lesional samples (n = 3) compared PLOS ONE

Research paper thumbnail of The embryonic development of the bovine stomach revisited

Anatomia, Histologia, Embryologia

Research paper thumbnail of Effect of Clostridium perfringens β-Toxin on Platelets

Toxins

Clostridium perfringens β-toxin (CPB) is the major virulence factor of C. perfringens type C caus... more Clostridium perfringens β-toxin (CPB) is the major virulence factor of C. perfringens type C causing a hemorrhagic enteritis in animals and humans. In experimentally infected pigs, endothelial binding of CPB was shown to be associated with early vascular lesions and hemorrhage but without obvious thrombosis of affected vessels, suggesting altered hemostasis in the early phase of the disease. The objective of the present study was to investigate the effect of CPB on platelets, with respect to primary hemostasis. Our results demonstrate that CPB binds to porcine and human platelets and forms oligomers resulting in a time-and dose-dependent cell death. Platelets showed rapid ultrastructural changes, significantly decreased aggregation and could no longer be activated by thrombin. This indicates that CPB affects the physiological function of platelets and counteracts primary hemostasis. Our results add platelets to the list of target cells of CPB and extend the current hypothesis of its role in the pathogenesis of C. perfringens type C enteritis.

Research paper thumbnail of Bufonid herpesvirus 1 (BfHV1) associated dermatitis and mortality in free ranging common toads (Bufo bufo) in Switzerland

Scientific reports, Jan 3, 2018

Here we report the discovery and partial characterization of a novel herpesvirus tentatively name... more Here we report the discovery and partial characterization of a novel herpesvirus tentatively named Bufonid herpesvirus 1 (BfHV1) from severe dermatitis in free ranging common toads (Bufo bufo) in Switzerland. The disease has been observed in toads every year since 2014, in spring, during the mating season, at different and distant locations. The virus is found in the skin and occasionally in the brain of infected toads. The genome of the virus is at least 158 Kb long and contains at least 152 open reading frames with a minimal length of 270 nt. The genome of BfHV1 contains all the signature genes that are present in alloherpesviruses. Phylogenetic analysis based on the amino acid sequence of the DNA polymerase and terminase proteins positions the novel virus among the members of the genus Batrachovirus, family Alloherpesviridae. This is the first herpesvirus ever characterized in common toads.

Research paper thumbnail of A stereotaxic breed-averaged, symmetric T2w canine brain atlas including detailed morphological and volumetrical data sets

NeuroImage, Jan 31, 2018

Stereotaxic systems and automatic tissue segmentation routines enable neuronavigation as well as ... more Stereotaxic systems and automatic tissue segmentation routines enable neuronavigation as well as reproducible processing of neuroimage datasets. Such systems have been developed for humans, non-human-primates, sheep, and rodents, but not for dogs. Although dogs share important neurofunctional and -anatomical features with humans, and in spite of their importance in translational neuroscience, little is known about the variability of the canine brain morphology and, possibly related, function. Moreover, we lack templates, tissue probability maps (TPM), and stereotaxic brain labels for implementation in standard software utilities such as Statistical Parametric Mapping (SPM). Hence, objective and reproducible, image-based investigations are currently impeded in dogs. We have created a detailed stereotaxic reference frame for dogs including TPM and tissue labels, enabling inter-individual and cross-study neuroimage analysis. T2w datasets were acquired from 16 neurologically inconspicuo...

Research paper thumbnail of Binding of indocyanine green in polycaprolactone fibers using blend electrospinning for in vivo laser-assisted vascular anastomosis

Lasers in Surgery and Medicine

The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and lo... more The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and low bonding strengths as well as tedious handling during microvascular surgery. The challenge to be met arises from the flow-off of the chromophore during soldering that changes the absorption and stains the surrounding tissue, leading to an uncontrollable thermal damage zone. In this study, we investigated the feasibility to produce an indocyanine green (ICG)-loaded patch by electrospinning and tested its applicability to both in vitro and in vivo microvascular laser soldering. A blend of polycaprolactone and ICG was electrospun to produce a pliable patch. Prior to soldering, the patch was soaked in 40% wt. bovine serum albumin solution. The solder patch was wrapped in vitro around blood vessel stumps of rabbit aortas. An intraluminal balloon catheter enabled an easy alignment and held the setup in place. The soldering energy was delivered via a diffusor fiber from the vessel lumen using a diode laser at 810 nm. During the procedure, the surface temperature was observed with an infrared camera. Afterward, samples were embedded in methylmethacrylate and epon to study thermal damage. The quality of the fusion was assessed by measuring the tensile strength. After in vitro tests with rabbit aortas, eight large white pigs were subjected to an acute in vivo experiment, and the artery of the latissimus dorsi flap was anastomosed to the distal femoral artery. The ICG-loaded patch, produced by electrospinning, has a thickness of 279 ± 62 μm, a fiber diameter of 1.20 ± 0.19 μm, and an attenuation coefficient of 1,119 ± 183 cm(-1) at a wavelength of 790 nm. The patch was pliable and easy to handle during surgery. No leakage of the chromophore was observed. Thermal damage was restricted to the Tunica adventitia and Tunica media and the area of the vessel wall that was covered with the patch. Six pigs were successfully treated, without any bleeding and with a continuous blood flow. The in vivo flap model yielded a similar tensile strength compared to in vitro laser-assisted vascular anastomoses (138 ± 52 vs. 117 ± 30 mN/mm(2) ). Our study demonstrated the applicability of the ICG-loaded patch for laser-assisted vascular anastomosis. By using electrospinning, ICG could be bound to polymer fibers, avoiding its flow-off and the staining of the surrounding tissue. This patch demonstrated several advantages over liquid solder as it was easier to apply, ensured a high and reliable bonding strength while maintaining a constant concentration of ICG concentration during the surgery. Lasers Surg. Med. © 2017 Wiley Periodicals, Inc.

Research paper thumbnail of Assessment of a specifically developed bullet casing gun for the stunning of water buffaloes

Research paper thumbnail of Uptake of silica nanoparticles in the brain and effects on neuronal differentiation using different in vitro models

Nanomedicine : nanotechnology, biology, and medicine, 2017

Nanomedicine offers a promising tool for therapies of brain diseases, but they may be associated ... more Nanomedicine offers a promising tool for therapies of brain diseases, but they may be associated with potential adverse effects. The aim of this study was to investigate the uptake of silica-nanoparticles engineered for laser-tissue soldering in the brain using SH-SY5Y cells, dissociated and organotypic slice cultures from rat hippocampus. Nanoparticles were predominantly taken up by microglial cells in the hippocampal cultures but nanoparticles were also found in differentiated SH-SY5Y cells. The uptake was time- and concentration-dependent in primary hippocampal cells. Transmission electron microscopy experiments demonstrated nanoparticle aggregates and single particles in the cytoplasm. Nanoparticles were found in the endoplasmic reticulum, but not in other cellular compartments. Nanoparticle exposure did not impair cell viability and neuroinflammation in primary hippocampal cultures at all times investigated. Neurite outgrowth was not significantly altered in SH-SY5Y cells, but ...

Research paper thumbnail of Effects of stimulus with proinflammatory mediators on nitric oxide production and matrix metalloproteinase activity in explants of cranial cruciate ligaments obtained from dogs

Http Dx Doi Org 10 2460 Ajvr 2002 63 1423, Dec 14, 2005

To evaluate the origin and degree of activity of nitric oxide (NO) and matrix metalloproteinase (... more To evaluate the origin and degree of activity of nitric oxide (NO) and matrix metalloproteinase (MMP) in explants of cranial cruciate ligaments (CCLs) obtained from dogs and cultured with and without inflammatory activators. Tissue specimens obtained from 7 healthy adult Beagles that were (mean +/- SD) 4.5 +/- 0.5 years old and weighed 12.5 +/- 0.8 kg. The CCLs were harvested immediately after dogs were euthanatized, and specimens were submitted for explant culture. Cultures were stimulated by incubation with a combination of interleukin-1, tumor necrosis factor-alpha, and lipopolysaccharide, or they were not stimulated. Culture supernatants were examined for production of NO nitrite-nitrate metabolites (NOts) and activity of MMP Cultured specimens were evaluated by use of immunohistochemical analysis to detect activity of inducible NO synthase (iNOS). All ligament explants produced measurable amounts of NOts. Stimulated cultures produced significantly more NOts after incubation for 24 and 48 hours, compared with nonstimulated cultures. Production of MMP in supernatants after incubation for 48 hours was significantly higher in stimulated cultures than in nonstimulated cultures. Cells with positive staining for iNOS were detected on all slides. Positively stained cells were predominantly chondroid metaplastic. There was a significant difference in intensity of cell staining between stimulated and non-stimulated cultures. Explant cultures of intact CCLs obtained from dogs produce iNOS-induced NO. Stimulation of chondroid metaplastic cells in CCL of dogs by use of inflammatory activators can increase production of iNOS, NOts, and MMP.

Research paper thumbnail of Vascularization of the epididymis in boars with special reference to the perfusion and fixation technique

Schweizer Archiv Fur Tierheilkunde, 1990

Research paper thumbnail of Erratum for Henke et al., Listeria monocytogenes Spreads within the Brain by Actin-Based Intra-Axonal Migration

Infection and Immunity, 2016

Oevermann A. 2016. Erratum for Henke et al., Listeria monocytogenes spreads within the brain by a... more Oevermann A. 2016. Erratum for Henke et al., Listeria monocytogenes spreads within the brain by actin-based intra-axonal migration. Infect Immun 84:866.