RESUMO
Four children with Down syndrome who had developed atlantoaxial dislocation and myelopathy underwent occipitocervical fusion with Luque loop rod instrumentation and decompressive laminectomy of C1. The postoperative results are presented and the indications discussed. This procedure provides many advantages in the surgical treatment of Down syndrome compared with the conventional procedures, because of the associated mental retardation that makes the postoperative management very complicated.
Assuntos
Articulação Atlantoaxial/cirurgia , Síndrome de Down/complicações , Luxações Articulares/cirurgia , Fusão Vertebral/instrumentação , Articulação Atlantoaxial/diagnóstico por imagem , Articulação Atlantoaxial/patologia , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Criança , Pré-Escolar , Feminino , Humanos , Luxações Articulares/complicações , Masculino , Osso Occipital/diagnóstico por imagem , Osso Occipital/cirurgia , Complicações Pós-Operatórias/fisiopatologia , Radiografia , Fusão Vertebral/métodos , Resultado do TratamentoRESUMO
An acyl-coenzyme A carboxylase that carboxylates acetyl-CoA, butyryl-CoA, propionyl-CoA, and succinyl-CoA was purified from Myxococcus xanthus. Since the enzyme showed maximal rates of carboxylation with propionyl-CoA, the enzyme is thought to be propionyl-CoA carboxylase. The apparent Km values for acetyl-CoA, butyryl-CoA, propionyl-CoA, and succinyl-CoA were found to be 0.2, 0. 2, 0.03, and 1.0 mM, respectively. The native enzyme has a molecular mass of 605-615 kDa and is composed of nonidentical subunits (alpha and beta) with molecular masses of 53 and 56 kDa, respectively. The enzyme showed maximal activity at pH 7.0-7.5 and at 25-30 degrees C, and was affected by variation in concentrations of ATP and Mg2+. During development of M. xanthus, the propionyl-CoA carboxylase activity increased gradually, with maximum activity observed during the sporulation stage. Previous work has shown that a propionyl-CoA-carboxylase-deficient mutant of M. xanthus reduces levels of long-chain fatty acids. These results suggest that the propionyl-CoA carboxylase is also responsible for the carboxylation of acetyl-CoA to malonyl-CoA used for the synthesis of long-chain fatty acids during development.
Assuntos
Carboxiliases/química , Carboxiliases/metabolismo , Myxococcus xanthus/enzimologia , Trifosfato de Adenosina/farmacologia , Sequência de Aminoácidos , Western Blotting , Carbono-Nitrogênio Ligases , Carboxiliases/isolamento & purificação , Catálise , Cromatografia em Gel , Cromatografia por Troca Iônica , Cinética , Cloreto de Magnésio/farmacologia , Metilmalonil-CoA Descarboxilase , Dados de Sequência Molecular , Peso Molecular , Myxococcus xanthus/crescimento & desenvolvimento , Alinhamento de Sequência , Esporos Bacterianos/fisiologiaRESUMO
A severe case of placental mesenchymal dysplasia occurred in association with intrauterine fetal death (IUFD). The gravida-1, para-1 mother was a 26-year-old Japanese. The first pregnancy was unremarkable and a healthy female infant was delivered. The present pregnancy had been uneventful until 34 weeks of gestation when IUFD was detected. The 1516-g (mean +/- SD, 2050 +/- 387 g) stillborn infant had no external abnormalities and the karyotype was 46,XX. The placenta was markedly enlarged (1050 g; mean +/- SD, 452 +/- 202 g), and approximately 80% was occupied by extraordinary enlarged villous structures with a myxoid appearance. Histologically, the dysplastic villi had myxoid stroma and a decreased number of, occasionally obliterated, fetal vessels. There was no abnormal trophoblastic proliferation. Large-sized fetal vessels in the chorionic plate frequently contained organized thrombi. This is the first case of placental mesenchymal dysplasia, which possibly lead to the IUFD.