179,595 research outputs found
Pseudoxanthoma elasticum (PXE): ultrastructural and biochemical study on proteoglycan and proteoglycan-associated material produced by skin fibroblasts in vitro.
No full textPseudoxanthoma elasticum is a genetic disease characterized by progressive mineralization of elastic fibers. Previous studies suggested that other components, apart from elastin, might be involved in the alterations of this connective tissue disorder (Martinez-Hernandez and Huffer, 1974; Pasquali Ronchetti et al., 1981; 1986). Evidence is presented that proteoglycan metabolism is altered in PXE-affected patient. Urinary GAGs suggests an increased degradation of glucosamine-containing GAGs in the patient. Pulse and chase experiments on in vitro skin fibroblasts indicated a decreased rate of synthesis of [35SO4] containing GAGs or an increase of their turnover rate in PXE. Moreover, when PGs produced from skin fibroblasts were identified by ultracentrifugation and gel filtration in associative conditions, PXE fibroblasts produced a significantly higher amount of the high molecular weight fraction of sulfated PGs. This high molecular weight material was present both in the medium and in the matrix and disappeared under dissociative conditions or after treatment with hyaluronidase or with pancreas elastase. By electron microscopy, PXE fibroblasts appeared to produce and secrete an enormous amount of toluidine blue 0 positive material organized as filaments and amorphous masses. These data are in agreement with previous observations of the presence of abnormal masses of microfilaments, in the dermis of PXE patients, which were sensitive to hyaluronidase and partially to trypsin and elastase (Pasquali Ronchetti et al., 1986). The results seem to confirm that at least some of the alterations of connective tissues in PXE are due to abnormal PGs metabolism and to their tendency to form abnormal aggregates in the extracellular space
B. L. Pasternak; E. A. Popov; I. B. Ratušinskaja; E. P. Rostopčina; V. V. Rozanov; R. I. Roždestvenskij; A. N. Rybakov; A. A. Šachovskoj; V. T. Šalamov; D. S. Samojlov; G. V. Sapgir; B. V. Savinkov; O. A. Sedakova; Ju. S. Semenov; O. I. Senkovskij
No full textVoci per l'enciclopedia italiana "La Piccola Treccani" relative agli autori russi: B. L. Pasternak; E. A. Popov; I. B. Ratušinskaja; E. P. Rostopčina; V. V. Rozanov; R. I. Roždestvenskij; A. N. Rybakov; A. A. Šachovskoj; V. T. Šalamov; D. S. Samojlov; G. V. Sapgir; B. V. Savinkov; O. A. Sedakova; Ju. S. Semenov; O. I. SenkovskijEntries for the Italian encyclopedia "La Piccola Treccani" relating to Russian authors: L. B. Pasternak; E. A. Popov; I. B. Ratushinskaya; E. P. Rostopchina; V. V. Rozanov; R. I. Rozhdestvensky; A. N. Rybakov; A. A. Shakhovskoi; V. T. Shalamov; D. S. Samoilov; G. V. Sapgir; B. V. Savinkov; O. A. Sedakova; Ju. S. Semenov; O. I. Senkovsk
Synthesis of enantiomerically pure 24-alkylsterol side chains, in both enantiomeric forms, starting from (R)-(+)-limonene
No full textThree couples of enantiomeric synthons corresponding to six 24-alkylsterol side chains, (R)- and (S)-1-bromo-3,4-dimethylpentane, (R)- and (S)-1-bromo-3-ethyl-4-methylpentane, and (R)- and (S)-5-(acetyloxy)-1-bromo-3-(1-methylethyl)pentane, were synthesized from the same chiral intermediate, (R)-5-(acyloxy)-3-(1-methylethyl)pentan-1-ol, readily obtainable from (R)-(+)-limonene
asthma self-management programmes in population of italian children: a multicentric study
No full textSIGNIFICATO CLINICO-EPIDEMIOLOGICO DELLE DETERMINAZIONI SIEROLOGICHE E DI TEST DI POLYMERASE CHAIN REACTION IN UNA POPOLAZIONE PEDIATRICA OSPEDALIZZATA PER FLOGOSI DELLE BASSE VIE RESPIRATORIE
No full textAortic elastin abnormalities in osteogenesis imperfecta type II.
No full textSkin and aortic samples from two patients who died by lethal perinatal Osteogenesis Imperfecta (O.I.) were studied by optical and electron microscopy and compared with similar samples from two normal human fetuses and one newborn child. No significant abnormalities were observed in the dermis of O.I. patients apart from small differences in the diameter of reticular collagen fibrils. On the contrary, in the aortas of both patients collagen fibrils were significantly smaller than in the controls; moreover, elastin lamellae were deeply altered and consisted of roundish aggregates of elastin, massively permeated by cytochemically recognizable glycosaminoglycans. As identical features were described in experimental lathyrism by using inhibitors of the enzyme lysyl oxidase (Pasquali Ronchetti et al., 1984), the conclusion is reached that in the two cases of lethal perinatal O.I. examined, a severe lysyl oxidase deficiency could account for the observed ultrastructural abnormalities of elastin and that, besides defects of collagen type I, additional alterations of cellular metabolism might be responsible for the clinical heterogeneity of the disease
Aortic Elastin Abnormalities in Osteogenesis Imperfecta Type II
No full textSkin and aortic samples from two patients who died by lethal perinatal Osteogenesis Imperfecta (O. I.) were studied by optical and electron microscopy and compared with similar samples from two normal human fetuses and one newborn child. No significant abnormalities were observed in the dermis of O. I. patients apart from small differences in the diameter of reticular collagen fibrils. On the contrary, in the aortas of both patients collagen fibrils were significantly smaller than in the controls; moreover, elastin lamellae were deeply altered and consisted of roundish aggregates of elastin, massively permeated by cytochemically recognizable glycosaminoglycans. As identical features were described in experimental lathyrism by using inhibitors of the enzyme lysyl oxidase (Pasquali Ronchetti et al., 1984), the conclusion is reached that in the two cases of lethal perinatal O. I. examined, a severe lysyl oxidase deficiency could account for the observed ultrastructural abnormalities of elastin and that, besides defects of collagen type I, additional alterations of cellular metabolism might be responsible for the clinical heterogeneity of the diesease. © 1986, Gustav Fischer Verlag · Stuttgart · New York. All rights reserved
Stereospecific introduction of a 24-pro-R-hydrogen in the biosynthesis of tigogenin in Digitalis lanata
No full textIn tigogenin biosynthesized in Digitalis lanata a 4-pro-R-hydrogen of mevalonic acid (MVA) occupies the 24-pro-S-position
Composizioni: linee, forme e colori
No full textLeggere, pensare e progettare contesti di apprendimento alla scuola dell’infanzia implica possedere la capacità di stare in ascolto di ciò che i bambini sono in grado di comunicarci nella quotidianità. Parole e azioni dei bambini che testimoniano un pensiero fortemente dinamico che connette campi esperienziali differenti e differenti linguaggi. Il presente saggio raccoglie riflessioni di un’esperienza realizzata all’interno della Scuola Comunale dell’Infanzia Gianni Rodari di Scandiano (Reggio Emilia
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