Dubuque

A collection of poetry by Andrew Rich Stevens

Neurotrauma— From Injury to Repair:Clinical Perspectives, Cellular Mechanisms and Promoting Regeneration of the Injured Brain and Spinal Cord

Traumatic injury to the brain and spinal cord (neurotrauma) is a common event across populations and often causes profound and irreversible disability. Pathophysiological responses to trauma exacerbate the damage of an index injury, propagating the loss of function that the central nervous system (CNS) cannot repair after the initial event is resolved. The way in which function is lost after injury is the consequence of a complex array of mechanisms that continue in the chronic phase post-injury to prevent effective neural repair. This review summarises the events after traumatic brain injury (TBI) and spinal cord injury (SCI), comprising a description of current clinical management strategies, a summary of known cellular and molecular mechanisms of secondary damage and their role in the prevention of repair. A discussion of current and emerging approaches to promote neuroregeneration after CNS injury is presented. The barriers to promoting repair after neurotrauma are across pathways and cell types and occur on a molecular and system level. This presents a challenge to traditional molecular pharmacological approaches to targeting single molecular pathways. It is suggested that novel approaches targeting multiple mechanisms or using combinatorial therapies may yield the sought-after recovery for future patients

Suzbijanje geografskog širenja zaraze: kuga u Italiji od 1347.-1851.

After the establishment of the first quarantine station in the Republic of Ragusa (modern-day Dubrovnik) in 1377, the states and principalities of Italy developed a sophisticated system of defensive quarantine in an attempt to protect themselves from the ravages of plague. Using largely unknown and unseen historical maps, this paper reconstructs the extent and operation of the system used. It is shown that a cordon sanitaire existed around the coast of Italy for several centuries, consisting of three elements: (i) an outer defensive ring of armed sailing boats in the Mediterranean and the Adriatic, (ii) a middle coastal ring of forts and observation towers, and (iii) an inner defensive ring of land-based cavalry. The principles established, although not especially successful at the time against a disease of (then) unknown aetiology, are still used today in attempts to control the spread of infections of animal and human populations.Nakon uspostave prvoga lazareta u Dubrovačkoj Republici 1377., talijanske državice i kneževine razradile su sustav karantena kako bi se zaštitile od razarajućega djelovanja kuge. Oslanjajući se mahom na dosad nepoznate povijesne karte, u ovome se članku rekonstruira kako je i u kojem razmjeru djelovao sustav zaštite. Duž talijanske obale stoljećima je postojao sanitarni kordon, a sastojao se od tri dijela: (i) vanjski pojas sastavljen od naoružanih jedrenjaka na Sredozemnom i Jadranskome moru, (ii) srednji obrambeni pojas sastavljen od utvrda i promatračnica te (iii) unutarnji obrambeni pojas na kopnu sastavljen od konjice. Premda ovaj sustav svojevremeno i nije bio pretjerano uspješan u zaštiti od bolesti (tada) nepoznate etiologije, njegova se načela još uvijek rabe za sprječavanje širenja bolesti među ljudima i životinjama

XMM-Newton Reflection Grating Spectrometer Observations of the Prototypical Starburst Galaxy M82

We present results from XMM-Newton Reflection Grating Spectrometer observations of the prototypical starburst galaxy M82. These high resolution spectra represent the best X-ray spectra to date of a starburst galaxy. A complex array of lines from species over a wide range of temperatures is seen, the most prominent being due to Lyman-alpha emission from abundant low Z elements such as N, O, Ne, Mg and Si. Emission lines from Helium-like charge states of the same elements are also seen in emission, as are strong lines from the entire Fe-L series. Further, the OVII line complex is resolved and is seen to be consistent with gas in collisional ionization equilibrium. Spectral fitting indicates emission from a large mass of gas with a differential emission measure over a range of temperatures (from 0.2 keV to 1.6 keV, peaking at 0.7 keV), and evidence for super-solar abundances of several elements is indicated. Spatial analysis of the data indicates that low energy emission is more extended to the south and east of the nucleus than to the north and west. Higher energy emission is far more centrally concentrated.Comment: 5 pages, 4 figures, MNRAS accepte

The Dilemma of Using Sward Height as a Management Tool for Intensively Grazed Sheep Pasture in Spring

Sward height is often used as a tool for both animal and pasture management, especially when continuously grazing pasture. For example, sward height has been used to define the conditions for optimal feed intake of multiple-bearing ewes, both before and after lambing (Everett-Hincks et al.2005; Morris and Kenyon 2004). Sward height is easily applied by the grazier and so becomes an effective tool. However, changes in the leaf distribution and relative species makeup of the sward both seasonally (Thomson et al. 2001) and in response to grazing management (Webby and Pengelly 1986) mean that the amount of pasture per unit height will change. When these changes occur a dilemma is presented to the grazier. How do they manage the trade-off between a simple indicator for management decisions and the lost opportunity of harvesting pasture mass that may be accumulating below the assigned sward height? This paper presents data from an experiment that investigated the impacts of defoliation strategies on sward of differing starting masses, with defoliation management based on height rather than mass. The paper quantifies the accumulation of herbage below defoliation height and highlights the dilemma of using sward height as a management tool when aiming to maximise the utilisation of our pasture resource

Vascular endothelial growth factor-A165b restores normal glomerular water permeability in a diphtheria-toxin mouse model of glomerular injury

BACKGROUND/AIMS:Genetic cell ablation using the human diphtheria toxin receptor (hDTR) is a new strategy used for analysing cellular function. Diphtheria toxin (DT) is a cytotoxic protein that leaves mouse cells relatively unaffected, but upon binding to hDTR it ultimately leads to cell death. We used a podocyte-specific hDTR expressing (Pod-DTR) mouse to assess the anti-permeability and cyto-protective effects of the splice isoform vascular endothelial growth factor (VEGF-A165b). METHODS:The Pod-DTR mouse was crossed with a mouse that over-expressed VEGF-A165b specifically in the podocytes (Neph-VEGF-A165b). Wild type (WT), Pod-DTR, Neph-VEGF-A165b and Pod-DTR X Neph-VEGF-A165b mice were treated with several doses of DT (1, 5, 100, and 1,000 ng/g bodyweight). Urine was collected and the glomerular water permeability (LpA/Vi) was measured ex vivo after 14 days. Structural analysis and podocyte marker expression were also assessed. RESULTS: Pod-DTR mice developed an increased glomerular LpA/Vi 14 days after administration of DT (all doses), which was prevented when the mice over-expressed VEGF-A165b. No major structural abnormalities, podocyte ablation or albuminuria was observed in Pod-DTR mice, indicating this to be a mild model of podocyte disease. However, a change in expression and localisation of nephrin within the podocytes was observed, indicating disruption of the slit diaphragm in the Pod-DTR mice. This was prevented in the Pod-DTR X Neph-VEGF-A165b mice. CONCLUSION: Although only a mild model of podocyte injury, over-expression of the anti-permeability VEGF-A165b isoform in the podocytes of Pod-DTR mice had a protective effect. Therefore, this study further highlights the therapeutic potential of VEGF-A165b in glomerular disease

Can Inflation be Falsified?

Despite its central role in modern cosmology, doubts are often expressed as to whether cosmological inflation is really a falsifiable theory. We distinguish two facets of inflation, one as a theory of initial conditions for the hot big bang and the other as a model for the origin of structure in the Universe. We argue that the latter can readily be excluded by observations, and that there are also a number of ways in which the former can find itself in conflict with observational data. Both aspects of the theory are indeed falsifiable.Comment: 7 pages LaTeX file with two figures incorporated by epsf. Fifth Prize in Gravity Research Foundation Essay Competition. To appear, General Relativity and Gravitatio

Glucose Dynamics of Cortical Spreading Depolarization in Acute Brain Injury: A Systematic Review.

Cortical spreading depolarization (CSD) is an emerging mode of secondary neuronal damage in acute brain injury (ABI). Subsequent repolarisation is a metabolic process requiring glucose. Instances of CSD and glucose derangement are both linked to poor neurological outcome, but their causal inter-relationship is not fully defined. This systematic review seeks to evaluate the available human evidence studying CSD and glucose to further understand their dynamic relationship. We conducted a systematic review of studies examining CSD through electrocorticography and cerebral/systemic glucose concentrations in ABI, excluding animal studies. The search yielded 478 articles, of which 13 were eligible. Across 10 manuscripts, 125 patients received simultaneous monitoring, with 1987 CSD episodes observed. Eight of 10 studies observed correlation between CSD and glucose change. Seven of eight studies observed possible cumulative effect of recurrent CSD on glucose derangement and two identified correlation between glycopenia and incidence of CSD. These findings confirm a relationship between CSD and glucose, and suggest it may be cyclical, where CSD causes local glycopenia, which may potentiate further CSD. Positive observations were not common to all studies, likely due to differing methodology or heterogeneity in CSD propensity. Further study is required to delineate the utility of the clinical modulation of serum and cerebral glucose to alter the propensity for CSD following brain injury

Most soil trophic guilds increase plant growth: a meta-analytical review

Trophic cascades are important drivers of plant and animal abundances in aquatic and aboveground systems, but in soils trophic cascades have been thought to be of limited importance due to omnivory and other factors. Here we use a meta-analysis of 215 studies with 1526 experiments that measured plant growth responses to additions or removals of soil organisms to test how different soil trophic levels affect plant growth. Consistent with the trophic cascade hypothesis, we found that herbivores and plant pathogens (henceforth pests) decreased plant growth and that predators of pests increased plant growth. The magnitude of this trophic cascade was similar to that reported for aboveground systems. In contrast, we did not find evidence for trophic cascades in decomposer- and symbiont-based (henceforth mutualist) food chains. In these food chains, mutualists increased plant growth and predators of mutualists also increased plant growth, presumably by increasing nutrient cycling rates. Therefore, mutualists, predators of mutualists and predators of pests all increased plant growth. Further, experiments that added multiple organisms from different trophic levels also increased plant growth. As a result, across the dataset, soil organisms increased plant growth 29% and non-pest soil organisms increased plant growth 46%. Omnivory has traditionally been thought to confound soil trophic dynamics, but here we suggest that omnivory allows for a simplified perspective of soil food webs – one in which most soil organisms increase plant growth by preying on pests or increasing nutrient cycling rates. An implication of this perspective is that processes that decrease soil organism abundance (e.g. soil tillage) are likely to decrease aboveground productivity. Synthesis Soil foodwebs have resisted generalizations due to their diversity and interconnectedness. Here we use results from a meta-analysis to inform a simplified perspective of soil foodwebs: one in which most soil trophic guilds increase plant growth. Our review also includes the first widespread support for the presence of trophic cascades in soils