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Query: UMLS:C0205700 (ash)
 15,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of fly ash from a coal-fired power plant on tracheal epithelium of crRGH (SYR) Syrian golden hamsters were studied in organ cultures and after in vivo exposures. The tracheal epithelium of animals receiving 5-9 daily (5 d/wk) 3-h exposures to 2 mg fly ash per cubic meter showed large areas of basal cell hyperplasia and stratification. Surface alterations characteristic of stratified metaplasia were observed. Exposure to 1 mg/m3 produced diffuse basal cell hyperplasia. Hamster tracheal ring cultures exposed in vitro to 50 micrograms/ml fly ash for 1 h/d or to 10 micrograms/ml for 3h/d showed epithelial changes similar to those observed in vivo. Whole suckling hamster tracheas in organ culture exposed to fly ash at concentrations of 10 and 50 micrograms/ml for 1 or 3 h/d exhibited cornifying epidermoid metaplasia after 7 exposures. The most characteristic findings in surface cells were broad metaplastic areas with keratin formation.
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PMID:Fly ash-induced changes in hamster tracheal epithelium in vivo and in vitro. 734 67

Alcoholic (ASH) and nonalcoholic (NASH) steatohepatitis show an almost identical morphology. Since the clinical picture is not characteristic, liver biopsy is still the diagnostic gold standard. ASH and NASH are morphologically characterized by a combination of steatosis, hepatocellular injury (ballooning degeneration, apoptosis, necrosis), perivenular and pericellular fibrosis, and inflammation (mostly neutrophils). A definitive differentiation of ASH and NASH is only possible by exclusion of alcohol abuse. Although NASH comprises a syndrome with a multifactorial etiology, adipositas seems to be the most constant associated causal factor. The pathogenesis of both diseases is still unclear. Clinical evidence and experimental studies suggest an important toxic role of reactive oxygen species (oxidative stress). According to our experience, ballooning of hepatocytes is a constant morphologic feature of ASH and NASH and already present in the early stages of disease. Ballooned cells often (but not always) contain Mallory bodies (alcoholic hyalin), which are irregular cytoplasmic inclusions consisting of keratins and nonkeratin components, including ubiquitin. Ballooning is associated with a disturbance and finally almost disappearance of the keratin-intermediate filament cytoskeleton. In our studies on the pathogenesis of ASH and NASH, we concentrated on these cytoskeletal alterations and Mallory body formation. It could be shown that in the early stages overexpression and hyperphosphorylation of keratins take place. Moreover, the 1:1 ratio of keratin type I (keratin 18) and type II (keratin 8) necessary for the assembly of intermediate filaments is disturbed and the equilibrium shifted toward keratin 8. Thus, the pool of soluble keratin 8 increases. The resulting keratin monomers are sensitive to misfolding and either degraded or aggregated as inclusion bodies. If the proteolytic capacity is impaired (e.g., by inhibition of the proteasomal system) in the chronically stressed cell aggregation prevails,finally leading to Mallory body formation. Convincing evidence exists on the basis of clinical and experimental studies that keratins exert a nonskeletal protective function in simple epithelia (e.g., liver cells). Disturbance of the keratin system may thus significantly contribute to cell damage.
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PMID:[Alcoholic and nonalcoholic steatohepatitis. Histopathologic and pathogenetic considerations]. 1176 38

We have fixed optimal conditions for preparation to analysis of waste keratin material (bristle, cerebellum and hoof), which then description of the chemical character define in there fat, moisture and ash content, nitrogen: total and ammonium and qualitative and quantitative composition amino acids. Results, which we obtained indicate to possibility utilization waste keratin material to obtain of full value, dyeability protein products.
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PMID:[Hydrolysis of waste keratin material for use of certain sulfonated acids. I. Chemical characteristics of protein waste products]. 1295 47

The keratin intermediate filament (IF) cytoskeleton of hepatocytes has continuously gained medical relevance over the last two decades. Originally it was mainly recognized as a differentiation marker for diagnostic purposes in pathology. However, keratin IFs were soon identified as major cellular structures to be affected in a variety of chronic liver diseases, such as alcoholic and non-alcoholic steatohepatitis (ASH, NASH), copper toxicosis, and cholestasis. Based on observations in keratin gene knock-out mice, the insight into the functional role of keratins was extended from a mere structural role providing mechanical stability to hepatocytes, to an additional role as target and modulator of toxic stress and apoptosis. The functional relevance of keratins in human diseases has recently been underlined by the identification of mutations in keratin genes in patients with liver cirrhosis.
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PMID:The keratin cytoskeleton in liver diseases. 1549 50

Misfolded and aggregated proteins are a characteristic feature of a variety of chronic diseases. Examples include neurofibrillary tangles in Alzheimer disease, Lewy bodies in Parkinson disease and Mallory bodies (MBs) in chronic liver diseases, particularly alcoholic and non-alcoholic steatohepatitis (ASH and NASH). MB formation is at least in part the result of chronic oxidative cell stress in hepatocytes and can be induced in mice by long-term intoxication with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Proteomic analysis revealed that MBs consist of ubiquitinated keratins and the stress proteins Hsp70, Hsp25, and p62. Furthermore, marked overexpression of clusterin, which shares functional properties with small heat shock proteins, was identified by gene expression profiling of DDC-treated mice livers. To investigate whether clusterin has a function in the stress response to misfolded keratins, we performed transfection studies utilizing expression constructs encoding ubiquitin, p62, Hsp27, clusterin, keratin 8, and keratin 18. Ubiquitin was found in a strong and constant association with keratin aggregates, whereas binding of p62 to keratin was variable. Hsp27 did not colocalize with keratin aggregates under these experimental conditions. In contrast, clusterin associated with misfolded keratin only if its signal peptide was deleted and its secretion inhibited. This suggests that clusterin has ability to bind misfolded proteins, including keratins but its physiological function is restricted to the extracellular space. The extracellular localization of clusterin was underlined by immunohistochemical studies in Alzheimer disease brains, where clusterin was constantly found in association with amyloid plaques; in contrast, cytoplasmic inclusions such as neurofibrillary tangles as well as MBs in ASH were negative. Furthermore, we found clusterin in association with elastic fibers in the extracellular matrix in several chronic liver diseases, including ASH and alpha1-antitrypsin deficiency, implying a possible role of clusterin in liver fibrosis.
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PMID:Interaction of stress proteins with misfolded keratins. 1581 11

Horns are permanent structures projecting from the head of bovids, consisting of a bony horncore covered with a layer of skin and then a sheath of keratinous material showing variability of growth intensity based on nutrition. From the point of view of the horn's mechanical properties, the keratin sheath has been widely studied, but only a few studies have considered the complete structure of the horn and fewer studies have focused on the bony horncore and its characteristics. The latter showed the important role of the bony core, when cranial appendages are subject to mechanical stress (as happens during fighting). The mechanical properties of bone material, along with its mineral profile, are also important, because they can show effects of different factors, such as nutrition and mineral deficiencies in diet. For this reason, eight horncores of captive common eland male were sampled at four positions along the vertical axis of the horn. The main aim was to study variation in mechanical properties and the mineral content along the vertical axis of the horncores. We further analysed whether the spiral bony ridge present on eland horncores differs in any of the studied properties from adjacent parts of the horncore. In other antelopes, spiral ridges on the horns have been proposed to increase grip during wrestling between males. Cross-sections of the horncores were performed at four positions along the longitudinal axis and, for each position, two bone bars were extracted to be tested in impact and bending. Moreover, in the first sampling position (the closest position to the base) two bars were extracted from the spiralled bony area. The resulting fragments were used to measure ash content, bone density and mineral content. Results showed that horn bone decreased along the vertical axis, in ash (-36%), density (-32%), and in impact work 'U' (marginally significant but large effect: -48%). The concentration of several minerals decreased significantly (Mg, Cr, Mn and Tl by -33%, -25%, -31%, -43%, respectively) between the basal and the uppermost sampling site. The bone tissue of the horncore spiral compared with non-spiral bone of the same position showed a lower ash content (53% vs. 57%), Mg and Mn; in addition to showing approximately half values in work to peak force 'W', bending strength 'BS' and 'U', but not in Young's modulus of elasticity 'E'. In conclusion, similarly to the results in a totally different fighting bony structure, the antlers, the horncore of eland shows advantageous parameters in bone tissue of the base in respect to the tip, with higher values for mechanical properties, density and mineral profile. Moreover, the spiral bone tissue showed lower material mechanical properties. Probably the spiral tissue of the horn may have a role in deflecting potential cross-sectional fractures during wrestling. In addition, it may serve to improve the grip during wrestling, and we propose that it may also prevent risk of rotation of sheath with respect to internal bone not only in this, but also in other straight bovid horns.
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PMID:The bony horncore of the common eland (Taurotragus oryx): composition and mechanical properties of a spiral fighting structure. 2902 90