RESUMEN
Main complications of the remote 2-35 years period after coarctation of the aorta repair are studied up. Of 2746 patients 2464 (89.7%) were operated upon at the age of 2-25 years old. In 841 (30.61%) of patients were determined coexistent heart diseases, more often aortic valve lesion. End-to-end anastomosis was fulfilled in 44.6% of operations and patch repair was done in 43.6%. The most frequent complication of the remote period was the aortic aneurysm-in 61 (2.2%) of cases. It occurred seven times more frequently after the patch repair (4.1%) then after anastomosis end-to-end conduction (0.6%). Late postoperative mortality equaled 1.5%. The main reasons of it were aneurysms at the site of repair--in 12 patients, aneurysms of the ascending aorta--in 4 and progressing of the coexisting heart diseases--in 10.
Asunto(s)
Coartación Aórtica/cirugía , Complicaciones Posoperatorias/diagnóstico , Adolescente , Adulto , Niño , Preescolar , Humanos , Factores de TiempoRESUMEN
The possibility of transfection of bacterial cells by phage M13 DNA entrapped into phospholipid vesicles (liposomes) has been studied. Two types of liposomes differing in size were used. Entrapped DNA was transferred by liposomes into Ca2+-treated E. coli cells. Efficiency of the transfection in the case of small (ca. 400 A) liposomes was 2--3 orders of magnitude higher than that of free DNA extracted from such liposomes.
Asunto(s)
Colifagos/genética , ADN Viral/genética , Escherichia coli/genética , Liposomas , Transfección , Calcio/farmacología , Escherichia coli/efectos de los fármacos , Conformación MolecularRESUMEN
Polynucleotides adsorb on natural and model phospholipid membranes in the presence of Mg2+-cations. Adsorption of nucleic acids on membranes results in a considerable change of their secondary structure. The presence of model phosphatidylcholine membranes greatly stimulates the rate of the synthesis of RNA by E. coli RNA-polymerase on DNA template.
Asunto(s)
Liposomas/metabolismo , Mitocondrias Hepáticas/metabolismo , Polinucleótidos/metabolismo , Animales , ADN/metabolismo , ARN Polimerasas Dirigidas por ADN/metabolismo , Escherichia coli/enzimología , Calor , Membranas Intracelulares/metabolismo , Metilación , Fosfatidilcolinas/metabolismo , Fosfolípidos/metabolismo , ARN/biosíntesis , ARN/metabolismo , RatasRESUMEN
The interaction between labelled polynucleotides and the mitochondrial membrane was studied. It was shown that DNA and mRNA form a complex with the mitochondria and mitoplasts (i. e. mitochondria devoid of the outer membrane); this process does not depend on the energy state of mitochondria. Within the complex polynucleotides are accessible to the effects of nucleases. The complex formation strongly depends on the concentration of Mg2+ and is inhibited by Na+. It was found that polynucleotides are effectively bound to protein-free artificial membranes isolated from the total mitochondrial lipids. The data obtained suggest that in the presence of Mg2+ polynucleotides form a complex with the lipid components of the mitochondrial membrane.
Asunto(s)
Mitocondrias Hepáticas/metabolismo , Polinucleótidos/metabolismo , Animales , ADN/metabolismo , Membranas Intracelulares/metabolismo , Magnesio/farmacología , Lípidos de la Membrana/metabolismo , Membranas Artificiales , ARN Mensajero/metabolismo , Ratas , Sodio/farmacologíaRESUMEN
The ribosomal RNA transport from a nucleus to a perinuclear cytoplasm and its following distribution in the cytoplasm of Acetabularia mediterranea cells were studied using transplantation of RNA-labeled rhizoid into unlabeled stalk. In addition rifamycin treatment was used for inhibition of cytoplasmic RNA synthesis. Acetabularia nuclei contain the stable RNA fractions similar to those present in some other eukaryotes. Nuclear 25S and 17S ribosomal RNA rapidly enter the rhizoid cytoplasm whereas the following trasfer of them to other regions of the cell is a very slow process. Within two days only an insignificant part of 25S and 17S ribosomal RNA is transferred from the rhizoid to the stalk and is distributed there over the base-apical gradient. No preferential transfer of the nuclear ribosomal RNA to the apical region was observed.
Asunto(s)
Acetabularia/metabolismo , Núcleo Celular/metabolismo , Chlorophyta/metabolismo , ARN Ribosómico/metabolismo , Acetabularia/efectos de los fármacos , Transporte Biológico , Peso Molecular , ARN/metabolismo , Rifamicinas/farmacologíaRESUMEN
RNA synthesis and distribution in cytoplasm of Acetabularia mediterranea cell were studied by radiochemical and ultramicrobiochemical methods. Existance of an apico-basal gradient of RNA concentration in the cytoplasm was shown. Variations in the rate of the RNA synthesis in different regions of the cytoplasm are of great importance for the formation of this gradient whereas a contribution of nuclear RNA transport is insignificant. Sedimentation coefficients of about 23S and 16S were detected for the most part of the synthesized cytoplasmic RNAs. Evidently these RNAs represent rRNA of chloroplast ribosomes. Basal region of cytoplasm contains a relatively large amount of low molecular weight RNA. The differences in stability of newly-synthesized RNA were found in cytoplasmic regions under examination.
Asunto(s)
Acetabularia/metabolismo , Chlorophyta/metabolismo , ARN/metabolismo , Transporte Biológico , Centrifugación por Gradiente de Densidad , Electroforesis Discontinua , ARN/biosíntesis , ARN/aislamiento & purificación , Uridina/metabolismoRESUMEN
The species specificity of the factors controlling the cap development was established in the experiments with the transplantation of both the intact and centrifuged in the basal direction apical regions of Acetabularia meditteranea on nuclear basal regions of A. crenulata. These factors are found at the stage of 72 hrs of regeneration primarily in the cytoplasmic zone adjacent to the cell membrane which is not displaced during centrifugation. Using direct measurements and radiochemical method, we have shown that the accumulation of proteins proceeded in this zone due, mainly, to their transition from the cytoplasmic zone displaced during centrifugation.
Asunto(s)
Acetabularia/citología , Chlorophyta/citología , Acetabularia/crecimiento & desarrollo , Membrana Celular/metabolismo , Citoplasma/metabolismo , Proteínas de la Membrana/biosíntesis , Morfogénesis , ARN/biosíntesis , Especificidad de la EspecieAsunto(s)
Escherichia coli/análisis , ARN Bacteriano/análisis , ARN Ribosómico/análisis , ARN de Transferencia/análisis , Saccharomyces cerevisiae/análisis , Electroforesis en Gel de Poliacrilamida , Indicadores y Reactivos , Métodos , Microquímica , Sefarosa , Espectrofotometría , Espectrofotometría Ultravioleta , Factores de TiempoRESUMEN
The distribution of total RNA and its individual fractions in two regions of Acetabularia mediterranea stem during regeneration was investigated. During regeneration of both the nuclear and enucleated cells, RNA concentration increases in the cytoplasm of growth zone whereas it changes insignificantly in the central stem region. A study of the qualitative RNA composition in the same stem regions has shown that during regeneration high molecular weight RNA fractions (main peaks - 0,56-10(6) and 1.04-10(6) Dalton) are found in the growth zone and are practically absent from the central cell region. Low molecular weight RNA (supposedly, tRNA and products of RNA destruction) are present in both the cell regions under study.