INT186461
From wiki-pain
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Sentences Mentioned In
Key: | Protein | Mutation | Event | Anatomy | Negation | Speculation | Pain term | Disease term |
Although SP-B was abundantly present and mutations of SFTPB were excluded [18], alterations of SP-B processing from other causes have not been excluded. | |||||||||||||||
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Thus, this intermediate represents a normal pro-SP-B processing intermediate of SP-B biosynthesis and could result from either constitutive secretion of this form by type II cells or from the physiologic release of 25 kD pro-SP-B into the airways by Clara cells. | |||||||||||||||
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SP-B is synthesized as a proprotein by alveolar type II epithelial cells and non-ciliated bronchiolar (Clara) cells; however, complete processing of the precursor to the biologically active, mature peptide occurs only in type II cells. | |||||||||||||||
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In addition, mutations of surfactant protein B gene and other known external or syndromic causes of PAP, including LPI, were ruled out in this cohort of paediatric patients. | |||||||||||||||
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Of the 6 patients with SP-B deficiency defined as a lack of mature SP-B on Western blotting, 4 had mutations in SFTPB (Tab. 3). | |||||||||||||||
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Mature SP-B was regularly detected in all lavages from normal children and from those with chronic bronchitis at a median molecular weight of 7 kDa (Tab. 1, Fig. 2). | |||||||||||||||
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SP-B is synthesized by alveolar type II cells to the mature 8 kDa protein and secreted into the alveolar space, where it is mainly found as a dimer [5]. | |||||||||||||||
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Pro-SP-B was found in 60 of 64 samples and was therefore commonly abundant in all groups, which corresponds to previous results [10]. | |||||||||||||||
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Pro-SP-B was found in 60 of 64 samples and was therefore commonly abundant in all groups, which corresponds to previous results [10]. | |||||||||||||||
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SP-B was detected in BAL of all 64 patients, whereas SP-C was found in BAL of all but 3 children; those three BAL fluids had more than 80% neutrophils, and in two patients, who were re-lavaged later, SP-C was then present and the neutrophil count was lower. | |||||||||||||||
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SP-B was mainly present as a dimer, SP-C as a monomer. | |||||||||||||||
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SP-B was detected regularly at molecular weights of 8 kDa in monomeric respectively 1618 kDa in dimeric form, additional partly at approximately 30 kDa under non reducing conditions, suggesting the presence of oligomers in smaller amounts. | |||||||||||||||
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Bronchoalveolar Clara cells also express pro-SP-B, but do not process it to the mature form. | |||||||||||||||
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In line with our data, they found decreased SP-A and SP-B levels compared to controls, but SP-A remained consistently low during the observation period (14 days). | |||||||||||||||
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An important finding of this study is the regular detection of certain pro-SP-B peptides in BAL from children without bronchoalveolar disease. | |||||||||||||||
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It has also to be noted that our currently applied technique for measurement of SP-B and SP-C does not allow for the differentiation between intact mature SP-B/C and degradation products of these proteins, the generation of which may additionally exert a detrimental effect on surface activity of the LA fraction. | |||||||||||||||
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General Comments
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