RESUMEN
The centrosome is the primary microtubule-organizing center (MTOC) of most animal cells; however, this organelle is absent during early mammalian development. Therefore, the mechanism by which the mammalian embryo organizes its microtubules (MTs) is unclear. We visualize MT bridges connecting pairs of cells and show that the cytokinetic bridge does not undergo stereotypical abscission after cell division. Instead, it serves as scaffold for the accumulation of the MT minus-end-stabilizing protein CAMSAP3 throughout interphase, thereby transforming this structure into a noncentrosomal MTOC. Transport of the cell adhesion molecule E-cadherin to the membrane is coordinated by this MTOC and is required to form the pluripotent inner mass. Our study reveals a noncentrosomal form of MT organization that directs intracellular transport and is essential for mammalian development.
Asunto(s)
Embrión de Mamíferos/metabolismo , Centro Organizador de los Microtúbulos/metabolismo , Animales , Transporte Biológico , Cadherinas/metabolismo , División Celular , Centrosoma/metabolismo , Embrión de Mamíferos/citología , Desarrollo Embrionario , Interfase , Ratones , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismoRESUMEN
Eating disorders are typical diseases of adolescence and early adulthood. About 1-3% of female juveniles suffer from anorexia nervosa (AN) or bulimia nervosa (BN). Today AN is still the psychiatric disease with the highest mortality rate. The peri-operative mortality rate of patients suffering from AN is in the range up to 15%. The beginning of AN is a lingering process and the majority of patients show increasingly restrictive eating habits ending in cachexia. Patients are obsessed by the predominant idea of being obese in spite of having a significant underweight. Patients suffering from bulimia break the strict regimen by eating enormous amounts of high calorie food. Such eating attacks are followed by weight reducing measures, mostly vomiting. Most of the physical changes caused by AN are due to starvation and loss of weight. The most significant medical complications are alterations of the cardiovascular system accompanied by decreasing contractility of the heart, bradycardia, electrocardiographic changes as well as disequilibrium of electrolytic and water balance. Most of these symptoms can be reversed by putting on weight.
Asunto(s)
Anestesia , Anorexia Nerviosa/complicaciones , Bulimia/complicaciones , Anestesia/efectos adversos , Anorexia Nerviosa/diagnóstico , Anorexia Nerviosa/fisiopatología , Bulimia/diagnóstico , Bulimia/fisiopatología , Fenómenos Fisiológicos Cardiovasculares , Deshidratación/terapia , Electrólitos/uso terapéutico , Femenino , Fluidoterapia , Cardiopatías/etiología , Cardiopatías/fisiopatología , Cardiopatías/terapia , Humanos , Masculino , Cuidados Posoperatorios , Cuidados Preoperatorios , Delgadez/fisiopatologíaRESUMEN
Cranio-orbital facial scoliosis is the result of unilateral premature stenosis of the craniofacial skeleton. Plagiocephaly is only a subform of the syndrome. The deformity progresses unless operative treatment is given. Operative treatment is indicated for functional, aesthetic, and psychosocial reasons. We advocate early operation in infancy (3 to 6 months) consisting of wide resection of the stenosed sutures of the cranium and orbit, repositioning, and remodeling relying on the spontaneous autodynamic reshaping of the nasoethmoidal complex and the midface structures during the course of further growth. In adolescents and adults, multisegmental osteotomies and remodeling into a definitive position are necessary.
Asunto(s)
Disostosis Craneofacial , Disostosis Craneofacial/diagnóstico , Disostosis Craneofacial/diagnóstico por imagen , Disostosis Craneofacial/cirugía , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Masculino , Métodos , RadiografíaRESUMEN
Craniofacial dysostosis is encountered in different congenital malformations such as Kleeblattschädel deformity, Crouzon's disease, and Apert's, Chotzen's, Pfeiffer's, and Carpenter's syndromes. Premature closure of cranial and facial sutures leads to characteristic disfigurement of the skull with orbital and maxillary hypoplasia. Operative treatment should be performed as early in life as possible to prevent further functional and esthetic deficiencies, and psychosocial problems. Correction is done by an intracranial approach with mobilization, remodeling, and advancement of the deformed skull. Thirty-two children have been operated during the first year of life with a maximum follow-up of 8 years. Most favorable results were obtained in 28 cases. The rate of complications were lower than in a series of children operated on later in life. We advocate that complex 1-stage corrections of craniofacial syndromes may be safely carried out during infancy utilizing modern techniques, expert pediatric anesthesia, and postoperative intensive care.
Asunto(s)
Disostosis Craneofacial/cirugía , Preescolar , Disostosis Craneofacial/complicaciones , Disostosis Craneofacial/patología , Humanos , LactanteRESUMEN
The radical treatment of craniofacial anomalies in infancy is indicated for medical, technical, and psychosocial reasons. The major problems around the cranium, the orbits, and the face may be safely corrected by osteotomy, suture resection and disjunction, mobilization, repositioning, and reshaping of the various skeletal segments. This radical approach has been possible through the introduction of miniplate fixation. The plates and screws are removed after 3 to 6 months to take optimal advantage of the great formative power of the growing brain, which expands rapidly within the first 2 years of life. In infants, disjunction is more important than advancement, making this approach a dynamic one in contrast with the static procedures for the adolescents and adults. The complete, one-stage procedures are superior to a delayed or two-stage procedure. Experienced administration of pediatric anaesthesia and intensive care are mandatory.
Asunto(s)
Placas Óseas , Disostosis Craneofacial/cirugía , Cirugía Plástica/métodos , Acrocefalosindactilia/cirugía , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Masculino , Órbita/cirugía , Complicaciones Posoperatorias , Cráneo/cirugía , Cirugía Plástica/instrumentación , Factores de TiempoRESUMEN
Calcification of glutaraldehyde-preserved bioprosthetic cardiac valves represents a serious clinical problem. Previous work from this laboratory has established the presence in clinical bioprosthetic valve calcifications of vitamin K-dependent calcium-binding proteins, which contain the calcium-binding amino acid gamma-carboxyglutamic acid; no proteins containing gamma-carboxyglutamic acid are present in nonmineralized valves. The purpose of the present study was to examine a series of bovine circulatory bioprosthetic valve explants for calcification and proteins containing gamma-carboxyglutamic acid. Biochemical analyses of explanted bioprosthetic valves from calves demonstrated proteins with gamma-carboxyglutamic acid accumulating in calcified valves during both the onset and progression of valve calcification; calcium levels in the explanted calf bioprostheses were in the same range as those noted in clinical material. Accumulation of calcium and protein with gamma-carboxyglutamic acid occurred simultaneously and progressively, beginning 2 months after implantation. Small amounts of osteocalcin, the bone-derived protein containing gamma-carboxyglutamic acid, were present in both human and bovine bioprosthetic valve calcifications at comparable levels. No osteocalcin was detectable in non-mineralized valve tissue. Warfarin anticoagulant therapy did not prevent calcification or accumulation of protein with gamma-carboxyglutamic acid. It is concluded that proteins containing gamma-carboxyglutamic acid are involved in both the onset and progression of bioprosthetic valve calcification, and that conventional means of vitamin K antagonism do not alter this association or the course of bioprosthetic valve mineralization.
Asunto(s)
Válvula Aórtica/metabolismo , Bioprótesis , Calcinosis/metabolismo , Proteínas de Unión al Calcio/metabolismo , Prótesis Valvulares Cardíacas , Ácido 1-Carboxiglutámico/metabolismo , Adolescente , Animales , Válvula Aórtica/cirugía , Calcio/metabolismo , Bovinos , Niño , Preescolar , Humanos , Masculino , Osteocalcina , Tiempo de Protrombina , Warfarina/uso terapéuticoRESUMEN
The pathogenesis of valvar calcification, which complicates the course of cardiac valve disease and also affects tissue valve prostheses, is incompletely understood. The present work explores the possible role of the vitamin K-dependent, calcium-binding amino acid, gamma-carboxyglutamic acid (Gla) in valve mineralization. Gla is normally found in the vitamin K-dependent clotting factor proteins, and is also present in unique calcium binding proteins in bone, kidney, and lung. Unique Gla-containing proteins have also been isolated from pathologic calcifications including calcium containing renal stones and calcified atherosclerotic plaque. Calcified valves including specimens with calcific aortic stenosis, calcified porcine xenograft valves, and a calcified aortic homograft valve were analyzed for Gla content, complete amino acid analysis, and tissue calcium and phosphorus levels. Normal porcine valves contained protein-bound Gla (2.0-10.6 Gla/10(4) amino acids): no Gla was present in normal valve leaflets. Furthermore, Gla levels paralleled tissue calcium content in the calcified valves. In addition, complete amino acid analysis indicated a decline in valvar collagen content plus increased acidic proteins in conjunction with valvar calcification and the presence of Gla-containing proteins. These results suggest that calcific valvar disease may result in part from vitamin K-dependent processes.
Asunto(s)
Válvula Aórtica , Calcinosis/metabolismo , Proteínas de Unión al Calcio/metabolismo , Enfermedades de las Válvulas Cardíacas/metabolismo , Vitamina K/farmacología , Ácido 1-Carboxiglutámico/metabolismo , Animales , Válvula Aórtica/trasplante , Estenosis de la Válvula Aórtica/metabolismo , Bioprótesis , Humanos , Trasplante HomólogoRESUMEN
Changes of ICP and CVP during different elevated positionings of the upper part of the body, rotation of the head, and compression of the jugular veins were investigated in 21 patients. Upward positioning leads to ICP-decrease and slight increase of CVP, whereas head rotation and jugular vein compression lead to increased ICP, the CVP remaining almost constant. The pressure changes in the model are equivalent to those in the patients. Therefore it can be assumed that the ICP changes according to positioning are mainly physical phenomena. The conclusion in clinical use: Slight upward positioning with straight head position is optimal in head injured patients.