Tufts University

About: Tufts University is a education organization based out in Medford, Massachusetts, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 32800 authors who have published 66881 publications receiving 3451152 citations. The organization is also known as: Tufts College & Universitatis Tuftensis.

'Malignant' Middle Cerebral Artery Territory Infarction: Clinical Course and Prognostic Signs

Abstract: Background: Although the clinical features of space-occupying ischemic stroke are well known, there are limited prospective data on the clinical course of complete middle cerebral artery territory infarction and on the predisposing factors leading to subsequent herniation and brain death. Methods: The clinical course of patients with complete middle cerebral artery territory infarction, defined by computed tomography and vascular imaging, was evaluated. Initial clinical presentation was assessed by the Scandinavian Stroke Scale and the Glasgow Coma Scale. Serial computed tomography with measurement of midline and septum pellucidum shift and data on the presence and location of vascular occlusion by angiography or Doppler ultrasound were obtained directly after admission. Time course and outcome were analyzed with regard to the clinical findings on admission and at follow-up. The functional status of surviving patients was assessed using the Barthel Index. Results: Fifty-five patients with complete middle cerebral artery territory infarction caused by occlusion of either the distal intracranial carotid artery or the proximal middle cerebral artery trunk were studied. In all patients, embolic infarction was presumed. The mean Scandinavian Stroke Scale score on admission was 20, and the time course of deterioration varied between 2 and 5 days. Forty-nine patients required ventilator assistance during the acute stage of disease. Only 12 patients (22%) survived the infarct. The cause of death was transtentorial herniation with subsequent brain death in 43 patients. Survivors had a mean Barthel Index score of 60 (range, 45 to 70). Conclusions: The prognosis of complete middle cerebral artery territory stroke is very poor and can be estimated by early clinical and neuroradiological data within the first few hours after the onset of symptoms. A space-occupying mass effect develops rapidly and predictably over the initial 5 days after presentation. Herniation occurred as an end point in 43 (78%) of these patients.

Mechanism of silk processing in insects and spiders

Abstract: Silk spinning by insects and spiders leads to the formation of fibres that exhibit high strength and toughness. The lack of understanding of the protein processing in silk glands has prevented the recapitulation of these properties in vitro from reconstituted or genetically engineered silks. Here we report the identification of emulsion formation and micellar structures from aqueous solutions of reconstituted silkworm silk fibroin as a first step in the process to control water and protein-protein interactions. The sizes (100-200 nm diameter) of these structures could be predicted from hydrophobicity plots of silk protein primary sequence. These micelles subsequently aggregated into larger 'globules' and gel-like states as the concentration of silk fibroin increased, while maintaining solubility owing to the hydrophilic regions of the protein interspersed among the larger hydrophobic regions. Upon physical shearing or stretching structural transitions, increased birefringence and morphological alignment were demonstrated, indicating that this process mimics the behaviour of similar native silk proteins in vivo. Final morphological features of these silk materials are similar to those observed in native silkworm fibres.