Stem cells and repair of lung injuries

Fueled by the promise of regenerative medicine, currently there is unprecedented interest in stem cells. Furthermore, there have been revolutionary, but somewhat controversial, advances in our understanding of stem cell biology. Stem cells likely play key roles in the repair of diverse lung injuries. However, due to very low rates of cellular proliferation in vivo in the normal steady state, cellular and architectural complexity of the respiratory tract, and the lack of an intensive research effort, lung stem cells remain poorly understood compared to those in other major organ systems. In the present review, we concisely explore the conceptual framework of stem cell biology and recent advances pertinent to the lungs. We illustrate lung diseases in which manipulation of stem cells may be physiologically significant and highlight the challenges facing stem cell-related therapy in the lung

Experimental concepts for toxicity prevention and tissue restoration after central nervous system irradiation

Several experimental strategies of radiation-induced central nervous system toxicity prevention have recently resulted in encouraging data. The present review summarizes the background for this research and the treatment results. It extends to the perspectives of tissue regeneration strategies, based for example on stem and progenitor cells. Preliminary data suggest a scenario with individually tailored strategies where patients with certain types of comorbidity, resulting in impaired regeneration reserve capacity, might be considered for toxicity prevention, while others might be "salvaged" by delayed interventions that circumvent the problem of normal tissue specificity. Given the complexity of radiation-induced changes, single target interventions might not suffice. Future interventions might vary with patient age, elapsed time from radiotherapy and toxicity type. Potential components include several drugs that interact with neurodegeneration, cell transplantation (into the CNS itself, the blood stream, or both) and creation of reparative signals and a permissive microenvironment, e.g., for cell homing. Without manipulation of the stem cell niche either by cell transfection or addition of appropriate chemokines and growth factors and by providing normal perfusion of the affected region, durable success of such cell-based approaches is hard to imagine

Collecting Psycholinguistic Response Time Data Using Amazon Mechanical Turk

Researchers in linguistics and related fields have recently begun exploiting online crowd-sourcing tools, like Amazon Mechanical Turk (AMT), to gather behavioral data. While this method has been successfully validated for various offline measures--grammaticality judgment or other forced-choice tasks--its use for mainstream psycholinguistic research remains limited. This is because psycholinguistic effects are often dependent on relatively small differences in response times, and there remains some doubt as to whether precise timing measurements can be gathered over the web. Here we show that three classic psycholinguistic effects can in fact be replicated using AMT in combination with open-source software for gathering response times client-side. Specifically, we find reliable effects of subject definiteness, filler-gap dependency processing, and agreement attraction in self-paced reading tasks using approximately the same numbers of participants and/or trials as similar laboratory studies. Our results suggest that psycholinguists can and should be taking advantage of AMT and similar online crowd-sourcing marketplaces as a fast, low-resource alternative to traditional laboratory research

An overview of tissue engineering approaches for management of spinal cord injuries

Severe spinal cord injury (SCI) leads to devastating neurological deficits and disabilities, which necessitates spending a great deal of health budget for psychological and healthcare problems of these patients and their relatives. This justifies the cost of research into the new modalities for treatment of spinal cord injuries, even in developing countries. Apart from surgical management and nerve grafting, several other approaches have been adopted for management of this condition including pharmacologic and gene therapy, cell therapy, and use of different cell-free or cell-seeded bioscaffolds. In current paper, the recent developments for therapeutic delivery of stem and non-stem cells to the site of injury, and application of cell-free and cell-seeded natural and synthetic scaffolds have been reviewed

Memory mechanisms for Wh-Dependency formation and their implications for Islandhood

The goal of this chapter is to provide a functionally specified model of how long-distance dependencies are understood in real time. In particular its emphasis will be how long-distance dependencies interact with working memory (WM) and how that interaction might inform our understanding of the form or origin of grammatical constraints. By long-distance dependencies, I refer primarily to unbounded displacement dependencies, such as those exhibited in wh-questions, relative clauses, topicalizations, comparative clauses, clefts, etc. The grammar appears to place no limit on the hierarchical distance that such dependencies can span. The head of the dependency – the displaced constituent itself – can occur many clauses away from the tail of the dependency: a gap or pronoun. The example in (1) illustrates this basic observation with relativization: the bold-face constituent, cookies, is only one clause distant from its gap in (1a). In (1b) and (1c), however, it is two and three clauses away, respectively. a. The cookies [S that Phil bakes ____] contain pistachios. b. The cookies [S that Billy bothers Phil to bake ____] contain pistachios. c. The cookies [S that everyone knows that Billy bothers Phil to bake ____] contain pistachios. There has long been a mutual influence between the study of long-distance dependencies and the study of WM constraints in language processing (Miller and Chomsky 1963). Between its head and tail, a large number of processing events could occur which are essentially irrelevant to the long-distance dependency itself. At the syntactic level, these include events like establishing other thematic dependencies, interpreting modifier relations, checking case and agreement, or resolving anaphora. The processing system must thus have a means of retaining information about the head of the long-distance dependencies until its “tail” can be constructed, at which point it must be able to effectively recover the head. And it must do so without suspending the intervening processing events that span the dependency. These requirements describe exactly the sort of cognitive juggling act that working memory systems are proposed to accomplish (e.g., Baddeley 1986, Miyake and Shah 1999)

Memory mechanisms for Wh-Dependency formation and their implications for Islandhood

The goal of this chapter is to provide a functionally specified model of how long-distance dependencies are understood in real time. In particular its emphasis will be how long-distance dependencies interact with working memory (WM) and how that interaction might inform our understanding of the form or origin of grammatical constraints. By long-distance dependencies, I refer primarily to unbounded displacement dependencies, such as those exhibited in wh-questions, relative clauses, topicalizations, comparative clauses, clefts, etc. The grammar appears to place no limit on the hierarchical distance that such dependencies can span. The head of the dependency – the displaced constituent itself – can occur many clauses away from the tail of the dependency: a gap or pronoun. The example in (1) illustrates this basic observation with relativization: the bold-face constituent, cookies, is only one clause distant from its gap in (1a). In (1b) and (1c), however, it is two and three clauses away, respectively. a. The cookies [S that Phil bakes ____] contain pistachios. b. The cookies [S that Billy bothers Phil to bake ____] contain pistachios. c. The cookies [S that everyone knows that Billy bothers Phil to bake ____] contain pistachios. There has long been a mutual influence between the study of long-distance dependencies and the study of WM constraints in language processing (Miller and Chomsky 1963). Between its head and tail, a large number of processing events could occur which are essentially irrelevant to the long-distance dependency itself. At the syntactic level, these include events like establishing other thematic dependencies, interpreting modifier relations, checking case and agreement, or resolving anaphora. The processing system must thus have a means of retaining information about the head of the long-distance dependencies until its “tail” can be constructed, at which point it must be able to effectively recover the head. And it must do so without suspending the intervening processing events that span the dependency. These requirements describe exactly the sort of cognitive juggling act that working memory systems are proposed to accomplish (e.g., Baddeley 1986, Miyake and Shah 1999)