Contaminating white blood cells (WBCs) in stored platelet concentrates (PC) are the main source of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin- 8 (IL-8) and tumour necrosis ...factor-alpha (TNF-alpha) that are implicated in transfusion reactions. We compared the levels of these cytokines in stored platelet preparations prepared by two methods. Effect of pre-storage leucofiltration on these cytokine levels was also studied.
Twelve units of pooled PCs were prepared by platelet rich plasma (PRP) method and buffy-coat (BC) method each and stored for 5 days. IL-6, IL-8 and TNF-alpha levels were measured in platelet supernatants on day 0, 1, 3 and 5 of the storage using commercially available immunoassays. Pre-storage leucofiltration was done in 4-pooled units of PRP-PC and cytokine levels compared with unfiltered PCs.
Median IL-6 levels increased from day 0 to day 5 in both PRP-PC and BC-PC. In PRP-PC, IL-8 increased from <3 pg/ml on day 0 to 817 pg/ml on day 5, while in BC-PC the corresponding levels were 10 and 346.5 pg/ml, respectively. No significant increase in levels of TNF-alpha was observed in BC-PC during storage period, while levels increased significantly in PRP-PC on day 1 only. There was no significant change in the levels of all three cytokines in leucofiltered PCs over 5 days of storage.
Findings of our study showed that method of preparation and WBC content are the critical factors in determining the cytokine levels in stored PCs.
This study evaluated the ultra-morphological effects of ortophosforic acid and Er.Cr: YSGGLASER on human dentin by means of a field emission in-lens scanning electron microscope. The study was ...conducted in vitro on human teeth extracted for orthodontic or periodontal reasons, after obtaining informed consent of patients. The samples were sectioned mesial-distal in the longitudinal direction (diamond discs) finished 400, 600, 1200 and 2400 grit SiC paper, polished with gums and abrasive paste 6, 3, 1 and 0,25 mm under continuous irrigation. The samples were divided in five groups depending on the type of conditioning as follows: GR.1= 5 s; GR.2= 10 s; GR.3= 15 s; GR.4= 20 s; GR.5= Er,Cr: YSGGlaser irradiating at 30% water and 60% air at 3W/15 Hz. The materials used for conditioning the teeth were SE 35% (Scotchbond Etchant Phosphoric Acid -3M ESPE-Seefeld, Germany) and MG6-MZ6 tipswith Er, Cr: YSGGlaser (Biolase Waterlase-MD), according to manufacturer s instructions. The specimens were prepared for observation under SEM with 1,000 and 4,000 magnifications. The acid type, concentration and time of action determines dentin demineralization and modifying or removing smear layer. Er.Cr: YSGG laser treatment of non-carious dentin, a laser power of 3 W is found to be the optimal to improve the micromorphology of dentin.
Systemic amyloidosis refers to a group of diseases that are caused by the misfolding of proteins and their deposition as amyloid fibrils in various organs. Here we present an overview of the progress ...made in the understanding of the biochemical and structural characteristics of the pathogenic agents of these diseases, obtained by using cryo-electron microscopy. The observed structures provided insights in the molecular etiology of the diseases and helped to shed light on the mechanism of misfolding in the affected patients.
Osteomodulin (OMD) is a member of the small leucine-rich repeat proteoglycan family, which is involved in the organization of the extracellular matrix. OMD is located in bone tissue and is reportedly ...important for bone mineralization. However, the details of OMD function in bone formation are poorly understood. Using the baculovirus expression system, we produced recombinant human OMD and analyzed its interaction with type I collagen, which is abundant in bone. In this result, OMD directly interacted with purified immobilized collagen and OMD suppressed collagen fibril formation in a turbidity assay. Morphological analysis of collagen in the presence or absence of OMD demonstrated that OMD reduces the diameter and changes the shape of collagen fibrils. We conclude that OMD regulates the extracellular matrix during bone formation.
•Osteomodulin (OMD) directly binds to type I collagen.•OMD suppresses formation of collagen fibrils.•The diameter of collagen fibrils is reduced in the presence of OMD.•The shape of collagen fibrils is altered to straight one by OMD.
RESUMO O colágeno é sintetizado e segregado no espaço extracelular e organizados em fibrilas estriadas de acordo com o tipo de tecido. Utilizaram-se 24 coelhos brancos da raça Nova Zelândia, com ...idade de 12 meses e com 3,0kg de peso corporal, para avaliar a porcentagem de colágeno das feridas cutâneas tratadas com plasma rico em plaquetas de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A. Os animais foram separados em quatro grupos de igual número e submetidos à remoção de pele na região das linhas médias dorsal torácica (feridas tratadas) e lombar (feridas controle). As feridas torácicas foram tratadas com plasma rico em plaqueta de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A, e as do grupo controle somente com a pomada. Dos animais do grupo I, foi coletado tecido cutâneo, para a avaliação histológica e a ultraestrutural, com três dias de pós-operatório; dos animais do grupo II, com sete dias; do grupo III, com 14 dias; e do grupo IV, com 21 dias. Decorrido o período de avaliação de cada grupo, foi coletado fragmento de pele para avaliação da porcentagem de colágeno, bem como do diâmetro e da densidade da fibrila de colágeno por microscopia eletrônica de transmissão. O tratamento com PRP de equino associado à aplicação tópica da pomada mostrou-se eficaz na maturação das fibrilas colágenas e na antecipação do processo cicatricial.
ABSTRACT Collagen is synthesized and secreted into the extracellular space and organized into striated fibrils according to the tissue type. This study evaluated the concentration of collagen in rabbit skin wounds treated with equine platelet-rich plasma (PRP) and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A. Twenty-four New Zealand white rabbits aged 2 to 12 months and weighing 3.0kg were included. The animals were allocated equally into four groups and the skin was removed from the thoracic dorsal midline (treated wound) and lumbar (control wound) regions. The thoracic wounds were treated with equine PRP and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A, and the control group was treated with the ointment alone. For histological and ultrastructural assessment, cutaneous tissue was collected on postoperative days 3 (group I), 7 (group II), 14 (group III), and 21 (group IV). After the evaluation period, in each group, a skin fragment was collected for analysis of the collagen concentration, as well as the collagen fibril diameter and density by transmission electron microscopy. The results indicated that treatment with equine PRP combined with topical application of the ointment was effective in facilitating the maturation of collagen fibrils and the wound healing process.
Type I interferon (IFN) is a key cytokine that curbs viral infection and cell malignancy. Previously, we demonstrated a potent IFN immunogenicity of nucleic acid-containing (NA-containing) amyloid ...fibrils in the periphery. Here, we investigated whether IFN is associated with β-amyloidosis inside the brain and contributes to neuropathology. An IFN-stimulated gene (ISG) signature was detected in the brains of multiple murine Alzheimer disease (AD) models, a phenomenon also observed in WT mouse brain challenged with generic NA-containing amyloid fibrils. In vitro, microglia innately responded to NA-containing amyloid fibrils. In AD models, activated ISG-expressing microglia exclusively surrounded NA+ amyloid β plaques, which accumulated in an age-dependent manner. Brain administration of rIFN-β resulted in microglial activation and complement C3-dependent synapse elimination in vivo. Conversely, selective IFN receptor blockade effectively diminished the ongoing microgliosis and synapse loss in AD models. Moreover, we detected activated ISG-expressing microglia enveloping NA-containing neuritic plaques in postmortem brains of patients with AD. Gene expression interrogation revealed that IFN pathway was grossly upregulated in clinical AD and significantly correlated with disease severity and complement activation. Therefore, IFN constitutes a pivotal element within the neuroinflammatory network of AD and critically contributes to neuropathogenic processes.
Lysyl oxidases (LOXs) are a family of copper-dependent oxido-deaminases that can modify the side chain of lysyl residues in collagen and elastin, thereby leading to the spontaneous formation of ...non-reducible aldehyde-derived interpolypeptide chain cross-links. The consequences of LOX inhibition in producing lathyrism are well documented, but the consequences on collagen fibril formation are less clear. Here we used β-aminoproprionitrile (BAPN) to inhibit LOX in tendon-like constructs (prepared from human tenocytes), which are an experimental model of cell-mediated collagen fibril formation. The improvement in structure and strength seen with time in control constructs was absent in constructs treated with BAPN. As expected, BAPN inhibited the formation of aldimine-derived cross-links in collagen, and the constructs were mechanically weak. However, an unexpected finding was that BAPN treatment led to structurally abnormal collagen fibrils with irregular profiles and widely dispersed diameters. Of special interest, the abnormal fibril profiles resembled those seen in some Ehlers-Danlos Syndrome phenotypes. Importantly, the total collagen content developed normally, and there was no difference in COL1A1 gene expression. Collagen type V, decorin, fibromodulin, and tenascin-X proteins were unaffected by the cross-link inhibition, suggesting that LOX regulates fibrillogenesis independently of these molecules. Collectively, the data show the importance of LOX for the mechanical development of early collagenous tissues and that LOX is essential for correct collagen fibril shape formation.
Background: Lysyl oxidase catalyzes collagen cross-link formation, which is essential for mechanically strong collagen fibrils.
Results: LOX inhibition stops early mechanical development of tendon constructs and leads to irregularly shaped collagen fibrils.
Conclusion: Collagen cross-linking is essential for successful fibrillogenesis and regulates fibril shape.
Significance: LOX activity is required in the control of collagen fibril architecture by a mechanism that remains to be explained.
Proteine In der Zuschrift auf S.2386ff. schildern V. Forge, R. Antoine etal. den Einsatz der Ladungsdetektions-Massenspektrometrie zur Charakterisierung von Amyloidfibrillen. Mit dieser Methode kann ...die Proteinaggregation in Echtzeit verfolgt werden.
Fibril Assemblies in Aqueous Whey Protein Mixtures Bolder, Suzanne G; Hendrickx, Hanneke; Sagis, Leonard M. C ...
Journal of agricultural and food chemistry,
06/2006, Letnik:
54, Številka:
12
Journal Article
Recenzirano
Fibril formation in mixtures of whey proteins upon heating at pH 2 was investigated. Fibrils were found to coexist with other structures, such as spherulites. These spherulites consist of radially ...oriented fibrils. At total protein concentrations above 6 wt %, transparent gels were formed. Changing the ratio between the various whey proteins did not affect this gelation concentration as long as β-lactoglobulin (β-lg) was present, suggesting that β-lg was dominant in the gelation. Pure α-lactalbumin and pure bovine serum albumin did not form fibrils, nor did they gel upon heating at pH 2 and 80 °C for up to 10 h. They did however induce a decrease in the β-lg concentration needed for gel formation upon heating at pH 2. Our results suggest that β-lg is the only fibril forming protein at the conditions used and that no mixed fibrils are formed. Keywords: Heat-induced aggregation; heat-set gelation; fibrils; whey proteins; β-lactoglobulin
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