RESUMEN
Single-particle analysis by electron microscopy is a well established technique for analyzing the three-dimensional structures of biological macromolecules. Besides its ability to produce high-resolution structures, it also provides insights into the dynamic behavior of the structures by elucidating their conformational variability. Here, the different image-processing methods currently available to study continuous conformational changes are reviewed.
Asunto(s)
Electrones , Procesamiento de Imagen Asistido por Computador/estadística & datos numéricos , Imagenología Tridimensional/estadística & datos numéricos , Sustancias Macromoleculares/ultraestructura , Microscopía Electrónica/métodos , Proteínas/ultraestructura , Algoritmos , Humanos , Sustancias Macromoleculares/química , Microscopía Electrónica/instrumentación , Conformación Molecular , Simulación de Dinámica Molecular , Análisis de Componente Principal , Proteínas/química , TermodinámicaRESUMEN
BACKGROUND: Cutaneous calciphylaxis, seen most often in dialysis patients, is characterised by skin necrosis, and is a disabling and lifethreatening disease. Despite intensive topical treatment, recourse to parathyroidectomy is often necessary. We report the case of a female patient with skin necrosis due to calciphylaxis: pain and necrotic lesions were controlled by grafting of cultured autologous keratinocytes (Epibase). CASE REPORT: A 75-year-old woman with a 5-year history of dialysis-dependent chronic renal failure secondary to nephroangiosclerosis presented a very painful necrotic ulceration on her left leg. In spite of an autologous patch grafts, the lesions rapidly deteriorated. Laboratory data showed high levels of calcium, phosphate and parathyroid hormone and imaging suggested parathyroidal adenoma. Although cutaneous biopsy was not performed, the diagnosis of cutaneous necrosis due to calciphylaxis with tertiary hyperparathyroidism was established. Treatment consisted of a low-calcium and low-phosphorus diet with autologous keratinocytes grafts (Epibase). After the third application of keratinocytes, the pain disappeared, necrosis ceased and wound healing began. Subtotal parathyroidectomy was performed two months after the start of grafts. At three months, the patient was cured. DISCUSSION: . Calciphylaxis is an obstructive vascular disease secondary to calcification of the arterioles leading to ischemic tissue necrosis. Prompt diagnosis is essential since this disease is disabling and life-threatening due to sepsis and ischemic complications. In our case, autologous keratinocyte grafts allowed pain relief to be achieved within large expanses of cutaneous necrosis after correction of calcium and phosphorus levels, thereby allowing parathyroidectomy to be performed under optimal conditions.
Asunto(s)
Calcifilaxia/complicaciones , Calcifilaxia/cirugía , Queratinocitos/trasplante , Dermatosis de la Pierna/cirugía , Paratiroidectomía , Anciano , Procedimientos Quirúrgicos Dermatologicos , Femenino , Humanos , Fallo Renal Crónico/terapia , Dermatosis de la Pierna/etiología , Dermatosis de la Pierna/patología , Necrosis/etiología , Necrosis/cirugía , Diálisis Renal , Piel/patología , Trasplante AutólogoRESUMEN
Although rupture of a mitral papillary muscle during myocardial infarction is well known, and post-infarction transmural ruptures causing false aneurysms occasionally reported, the association of rupture of the anterior papillary muscle and a underlying transmural parietal rupture giving rise to a false aneurysm is quite exceptional, and, to the best of our knowledge, has not previously been reported. Despite the serious nature of the disease, surgical cure of the aneurysm with mitral valve replacement was successful, due to the limitation of the anatomical disruption by early pericardial symphysis.
Asunto(s)
Aneurisma/complicaciones , Insuficiencia de la Válvula Mitral/complicaciones , Músculos Papilares/lesiones , Aneurisma/cirugía , Prótesis Valvulares Cardíacas , Humanos , Masculino , Persona de Mediana Edad , Válvula MitralRESUMEN
A case is reported of dissection of the aorta in a lady of 35. The condition was complicated first by myocardial infarction and secondly by severe aortic incompetence which led, 20 years after the onset of the dissection, to the death of the patient from intractable heart failure. At post-mortem, an extensive dissection was found to involve the whole of the aorta and several of its branches, but did not involve the coronary arteries, which were normal except for the trunk of the left coronary; this was dilated. The natural history of dissections of the aorta is reviewed. The incidence, course and etiology of coronary aneurysms are also discussed.