RESUMEN
For 9 years we have observed a girl who has ossification in the dermis with a strikingly limited distribution. Recently a second girl with similar dermal ossification restricted to a single extremity was identified. The ectopic bone is histologically identical to normal membranous bone. These two patients have no obvious underlying cause for soft tissue bone formation, and no disorder of calcium or phosphate metabolism. Ossification first involved the dermal and subcutaneous connective tissue, and with time advanced locally in the affected areas to bridge joints and limit mobility. The ossification has now extended to involve muscle fascia but has not involved the muscle itself. This disease appears to represent a heretofore unrecognized disorder of mesenchymal differentiation.
Asunto(s)
Osificación Heterotópica/patología , Enfermedades de la Piel/patología , Huesos/diagnóstico por imagen , Huesos/metabolismo , Niño , Preescolar , Femenino , Humanos , Minerales/metabolismo , Osificación Heterotópica/diagnóstico por imagen , Osificación Heterotópica/metabolismo , Radiografía , Piel/patología , Enfermedades de la Piel/diagnóstico por imagen , Enfermedades de la Piel/metabolismoRESUMEN
"Amyloid" fibrils have been created from some human Bence Jones proteins by proteolytic digestion under physiologic conditions. These fibrils with an antiparallel, â-pleated sheet conformation consist of only a portion of the variable region of the immunoglobulin light polypeptide chain and share the physical properties of amyloid fibrils. The relation between amyloidosis and immunoglobulins is thus more firmly established and pathogenetic mechanism for amyloid fibril formation is suggested.
Asunto(s)
Amiloide/biosíntesisRESUMEN
Murine amyloid has been produced by four different induction methods (Mycobacterium butyricum, casein, casein plus Freund's adjuvant and endotoxin-induced mouse amyloidosis) in several strains ans obtained from mice with "spontaneous" amyloidosis. The amyloid fibrils have been concentrated from spleen and liver. Electrom microscopy of all of these preparations reveals the amyloid fibril to be 100 Å in width and having the appearance of a twisted ribbon. X-ray diffraction of all preparations reveals a "backbone" spacing at 4.75 Å and a "side chain" spacing at 11 Å indicating a "β-pleated sheet" structure. Identification of the major protein component of amyloid fibril concentrates was made by combined use of sodium dodecyl sulfate polyacrylamide disc electropheresis, labeling of the protein with 3-Htryptophan and Sepharose 4B gel filtration with 5 M guanidine in 1 N acetic acid on Sephorese 4B and Sephadex G-100 or G-75 columns. The material is a unique glycoprotein with a molecular weight of 7200, a high content of dicarboxylic and short chain amino acids, a significant amount of tryptophan and an unreactive NH2-terminal amino-acid, tentatively identified as pyrrolid-2-one-5-carboxylic acid. There are no methionine, half-cystine, hydroxylysine or hydroxyproline residues. Murine amyloid protein, therefore, has strikin similarities to many human amyloid protein preparations. It differs from the human proteins in the similarity of molecular weights of different preparations.