367 research outputs found
Relevance of mycotoxins to product quality and animal health in organic farming
Organic farming is not generally more endangered by the risk of contamination of the products with mycotoxins than other farming systems. Knowledge about the influence of litter beddings on mycotoxin exposure of livestock is rare. Due to restrictions on silage additives and fungicides, organic farms are limited in their possibilities to prevent and to cure fungal diseases. But the organic production system offers several important factors for lowering infections with mycotoxin producing fungi
TRPC Channels in the Physiology and Pathophysiology of the Renal Tubular System: What Do We Know?
The study of transient receptor potential (TRP) channels has dramatically increased during
the past few years. TRP channels function as sensors and effectors in the cellular adaptation to
environmental changes. Here, we review literature investigating the physiological and pathophysiological roles of TRPC channels in the renal tubular system with a focus on TRPC3 and TRPC6.
TRPC3 plays a key role in Ca2+ homeostasis and is involved in transcellular Ca2+ reabsorption in the
proximal tubule and the collecting duct. TRPC3 also conveys the osmosensitivity of principal cells of
the collecting duct and is implicated in vasopressin-induced membrane translocation of AQP-2. Autosomal dominant polycystic kidney disease (ADPKD) can often be attributed to mutations of the PKD2
gene. TRPC3 is supposed to have a detrimental role in ADPKD-like conditions. The tubule-specific
physiological functions of TRPC6 have not yet been entirely elucidated. Its pathophysiological role
in ischemia-reperfusion injuries is a subject of debate. However, TRPC6 seems to be involved in
tumorigenesis of renal cell carcinoma. In summary, TRPC channels are relevant in multiples conditions of the renal tubular system. There is a need to further elucidate their pathophysiology to
better understand certain renal disorders and ultimately create new therapeutic targets to improve
patient care
Observationes microchemicae circa nonnullas animalium telas : dissertatio inauguralis
http://tartu.ester.ee/record=b2522434~S1*es
Eiweiß- und Aminosäurenversorgung in der Fütterung der Monogastrier im Ökologischen Landbau
Die bedarfsgerechte Versorgung von Monogastriern mit den essentiellen und limitierenden Aminosäuren ist von großer Bedeutung. Im Ökologischen Landbau wirft dies aufgrund von unbefriedigenden Aminosäureprofilen der zur Verfügung stehenden Getreide- und Körnerleguminosenarten sowie der fehlenden Verfügbarkeit alternativer Einzel- und Ergänzungsfuttermittel Probleme auf. Durch die Differenz zwischen Aminosäurebedarf und –versorgung entsteht die sog. Aminosäurelücke. Um diese zu füllen, ist es nach EU Öko-Verordnung (EG 834/2007, EG 889/2008 und EU 505/2012) gestattet, die Ration für monogastrische Nutztiere aufzuwerten, indem 5 % der landwirtschaftlich erzeugten Proteinfuttermittel konventioneller Herkunft sein dürfen. Diese Ausnahmegenehmigung läuft zum Ende des Jahres 2014 aus. Es sollte herausgefunden werden welche Probleme bei der Versorgung der Tiere und im Marktgeschehen bei einer 100%-Biofütterung gesehen werden.
Insgesamt scheint eine 100%-Biofütterung für Jungtiere und Mastgeflügel, unter den gegenwärtigen Bedingungen schwierig. Es besteht noch immer ein erheblicher Forschungs- und Entwicklungsbedarf zur Versorgung monogastrischer Nutztiere mit Aminosäuren. Als praxistauglicher Lösungsansatz wurde das Beibehalten der 5%-Regelung für Jungtiere und Geflügel und Regelungen für ein allmähliches „Ausschleichen“ favorisiert, welches die Marktentwicklung für ökologische Proteinkomponenten fördert
Insights into the Microstructural Origin of Brain Viscoelasticity : Prospects for Microstructure-Informed Constitutive Modeling
Mechanical aspects play an important role in brain development, function, and disease. Therefore, continuum-mechanics-based computational models are a valuable tool to advance our understanding of mechanics-related physiological and pathological processes in the brain. Currently, mainly phenomenological material models are used to predict the behavior of brain tissue numerically. The model parameters often lack physical interpretation and only provide adequate estimates for brain regions which have a similar microstructure and age as those used for calibration. These issues can be overcome by establishing advanced constitutive models that are microstructurally motivated and account for regional heterogeneities through microstructural parameters.
In this work, we perform simultaneous compressive mechanical loadings and microstructural analyses of porcine brain tissue to identify the microstructural mechanisms that underlie the macroscopic nonlinear and time-dependent mechanical response. Based on experimental insights into the link between macroscopic mechanics and cellular rearrangements, we propose a microstructure-informed finite viscoelastic constitutive model for brain tissue. We determine a relaxation time constant from cellular displacement curves and introduce hyperelastic model parameters as linear functions of the cell density, as determined through histological staining of the tested samples. The model is calibrated using a combination of cyclic loadings and stress relaxation experiments in compression. The presented considerations constitute an important step towards microstructure-based viscoelastic constitutive models for brain tissue, which may eventually allow us to capture regional material heterogeneities and predict how microstructural changes during development, aging, and disease affect macroscopic tissue mechanics
Wound healing in rabbit corneas after flapless refractive lenticule extraction with a 345 nm ultraviolet femtosecond laser
Purpose
To characterize corneal wound healing in a rabbit model after flapless refractive lenticule extraction with a 345 nm ultraviolet femtosecond laser.
Setting
Departments of Ophthalmology and Anatomy II, University of Erlangen-Nürnberg and Wavelight GmbH, Erlangen, Germany.
Design
Methods
Flapless refractive lenticule extraction was performed in 1 eye each of 20 New Zealand white rabbits (−5.0 diopters). Groups of 4 animals were euthanized after 48 hours, 1 week, 2 weeks, 4 weeks, and 3 months, respectively. Corneal samples were prepared for histology and fluorescence microscopy. To assess corneal cell death, proliferation, and myofibroblastic transdifferentiation, terminal uridine deoxynucleotidyl nick end-labeling (TUNEL) assay as well as immunostaining for Ki67 and α-smooth muscle actin (αSMA) were performed on sagittal cryosections.
Results
Histology revealed a zone of keratocyte depletion with a thickness of approximately 50 μm around the extraction site. At 48 hours, pronounced TUNEL staining of keratocytes was detected around the interface (159.9 cells/mm ± 18.4 [SD]), which steadily decreased to 74.9 ± 19.8 cells/mm at 1 week and 5.7 ± 4.8 cells/mm at 2 weeks. Ki67 staining of keratocytes was evident at 48 hours (10.0 ± 3.8 cells/mm), which then decreased at 1 week (5.2 ± 1.7 cells/mm) and 2 weeks (0.4 ± 0.5 cells/mm). From 4 weeks onward, no TUNEL or Ki67 staining was detected. The corneal stroma was αSMA-negative at all timepoints.
Conclusion
Application of the 345 nm laser showed no signs of problematic repair processes in the cornea, which supports the initiation of the clinical phase
TRPC6 Is Found in Distinct Compartments of the Human Kidney
In the context of renal proteinuric diseases, TRPC6 has been shown to play an important
role in ultrafiltration associated with the slit diaphragm through the control of the intracellular Ca2+
concentration in the podocytes of glomeruli. However, to date, the properties of TRPC6 have been
studied mainly in cell lines or in animal models. Therefore, the aim of the study presented here was to
investigate the presence and distribution of TRPC6 in human kidneys in order to possibly verify the
applicability of the results previously obtained in nonhuman experiments. For this purpose, kidneys
from nine cadavers were prepared for immunohistochemical staining and were supplemented with a
fresh human kidney obtained by nephrectomy. TRPC6 was detected in glomeruli and in the parietal
epithelial cells of Bowman’s capsule. Larger amounts were detected in the tubular system and
collecting ducts. In contrast to the peritubular capillary bed, which showed no immune reaction, the
cortical resistance vessels showed mild TRPC6 staining. In conclusion, our studies on the expression
of TRPC6 in human kidney tissue support the translational concept of the involvement of TRPC6 in
various renal diseases and reveal new aspects of the distribution of TRPC6 in the human kidney
A three-headed plantaris muscle fused with Kaplan fibers: potential clinical significance
The plantaris is a short, small muscle that usually originates at the popliteal surface of the femur and has a long, thin tendon that typically inserts into the calcaneal tuberosity. Its role and degree of development have been objects of debate for years. Some authors consider it a vestigial muscle while others believe it is a process of its development. The clinical significance of plantaris muscle is usually related to its morphological variation, which is common and well described in the literature. These variations are often a risk factor for many ailments and disorders. We would like to present another, very rare case of three-headed plantaris muscle (fused with distal Kaplan fibers), and consider what clinical implications it may have
Recombinant human gelsolin promotes the migration of human articular cartilage chondrocytes by regulating gene expression in vitro
Objective
It is known that recombinant human gelsolin (rhuGSN) supports wound closure and migration processes in avascular tissue. Since articular cartilage degradation plays an important role in osteoarthritis (OA), we are investigating how rhuGSN affects regeneration processes in human articular cartilage and represents a promising new therapeutic approach for the treatment of OA.
Methods
Primary human chondrocytes (phCs) from articular knee cartilage were cultured with different concentrations of rhuGSN to analyse its direct effect in vitro. In addition, phCs were stimulated with 10 ng/mL IL-1β or TNF-α to simulate osteoarthritis in vitro and treated with different concentrations of rhuGSN to investigate the beneficial effect in disease treatment. Cytokine secretion and gene expression as well as wound assays were performed.
Results
GSN significantly promotes wound closure in phCs after 60 h compared to untreated cells. After 24 h treatment with 30 μg/mL rhuGSN, TGF-β secretion increases significantly in the in vitro osteoarthritis model. Gene expression of MMP1 as well as SPARC is reduced in chondrocytes due to treatment with GSN in the OA model. At the same time, CXCR4 expression increases significantly after 24 h treatment with 3 μg/mL GSN.
Conclusion
In the in vitro model of osteoarthritis, rhuGSN promotes wound closure of chondrocytes by a supported migration as well as expression of reconstructive and down regulated expression of deconstructive genes concentration dependently. Further experiments are needed to fully understand the beneficial effect of gelsolin on human chondrocytes and to verify this promising approach for a pharmacological treatment of osteoarthritis
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