Rafael I. González

Evaluación de una unidad de tratamiento del ataque cerebral en un hospital universitario

During 2003, 425 stroke patientswere admitted to our hospital and 105 (age range 30-89 years, 58% female) were hospitalizedat the Stroke Unit. Eighty three percent had ischemic and 16% had hemorrhagic stroke. Themost common etiologies were thrombosis in 41%, embolism in 36%, lacunar in 13%, arterialdissection in 5% and transient ischemic attack in 3%. Fifty eight percent of patients had partialanterior ischemic stroke (PACI), 73% had hypertension and 29.5% diabetes. Only 18% arrivedto the Stroke Unit with less of 6 hours of evolution, 7% of patients were admitted within the 3hours after the onset of symptoms and 18%, from 3 to 6 hours. The mean lenght of stay in theStroke Unit was 6.6 days and at the hospital 9.9 days (p <0.01). The mean costs per patient atthe Stroke Unit and at the hospital were US

Metal-nanotube composites as radiation resistant materials

5.550 and US

Anartria o apraxia del habla progresiva

4.815, respectively (p =ns).

Demencia semántica: Presentación de dos casos y revisión de la literatura

The improvement of radiation resistance in nanocomposite materials is investigated by means of classical reactive molecular dynamics simulations. In particular, we study the influence of carbon nanotubes (CNTs) in an Ni matrix on the trapping and possible outgassing of He. When CNTs are defect-free, He atoms diffuse alongside CNT walls and, although there is He accumulation at the metal-CNT interface, no He trespassing of the CNT wall is observed, which is consistent with the lack of permeability of a perfect graphene sheet. However, when vacancies are introduced to mimic radiation-induced defects, He atoms penetrate CNTs, which play the role of nano-chimneys, allowing He atoms to escape the damaged zone and reduce bubble formation in the matrix. Consequently, composites made of CNTs inside metals are likely to display improved radiation resistance, particularly when radiation damage is related to swelling and He-induced embrittlement.

Afasia progresiva fluente: ¿Una forma de presentación inicial de demencia semántica?

Se presentan dos casos de anartria progresiva, discutiendo la relacion o el diagnostico diferencial con la apraxia del habla progresiva. En ambos casos se trataba de mujeres mayores de 65 anos con un cuadro de perdida progresiva del lenguaje oral, con diparesia facial, lingual y velar, deterioro cognitivo de tipo frontal y discretos signos piramidales. Las imagenes cerebrales estructurales fueron normales. Uno de ellos pudo corresponder a una paralisis supranuclear progresiva, la otra a una degeneracion corticobasal. Se analiza la literatura, llegando a la conclusion de que existen una serie de cuadros que pueden presentarse con un sindrome pseudobulbar progresivo. El diagnostico definitivo debiera ser patologico.

Model for Self-Rolling of an Aluminosilicate Sheet into a Single-Walled Imogolite Nanotube

Frontotemporal dementia is a neurodegenerative condition that presents with a number of distinct behavioral phenotypes. One of them is semantic dementia (SD), where exists a profound impairment for semantic knowledge related to atrophy of temporal poles. Pathologically, in most cases positive intraneuronal ubiquitin and tau negative inclusions are observed. SD is characterized by fluent, effortless, grammatical speech which lacks informational content, with limited and repetitive content, as well as semantic paraphasias. Also, patients may present with associative visual agnosia, surface dyslexia or dysgraphia, behavioral alterations. Both episodic and autobiographical memory are close to normality. Two female patients with fluent progressive aphasia are reported; they failed in a simple test of semantic association (to point to one of four objects with lesser relation to others). Autobiographical memory was fair. SD can be wrongly diagnosed as left-sided variant of Alzheimer’s disease; absence of episodic amnesia and parietal defects may be useful for clinical diagnosis.

Dispersion of carbon nanotubes in aluminum improves radiation resistance

Se presenta el caso de un hombre de 57 anos que presenta un cuadro degenerativo con afasia fluente y moderadas alteraciones de conducta, sin defecto semantico significativo, agnosia visual ni agrafia lexical y su estudio imagenologico cerebral. Se discuten los conceptos de afasia progresiva fluente y demencia semantica, concluyendo que la primera puede evolucionar hacia esta ultima. Nuestro caso se encontraria en esta situacion. Se senala que la patologia de las afasias progresivas es variable, siendo lo mas frecuente una degeneracion frontotemporal (con o sin inclusiones de proteina tau); con menor frecuencia corresponde a una enfermedad de Alzheimer o una degeneracion corticobasal