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Search Results: 1 - 10 of 1922 matches for " Bryan Cotton "
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All bleeding stops: how we can help...
William P Riordan, Bryan A Cotton
Critical Care , 2010, DOI: 10.1186/cc8969
Abstract: In an updated European guideline on management of bleeding following major trauma, Rossaint and colleagues [1] make evidence-based recommendations relevant to the care of these patients. This work represents an update to guidelines previously published by the group in 2007 [2].The challenge of providing comprehensive 'evidence-based' guidelines for the management of bleeding in trauma patients is readily apparent. The nature of the disease yields a broad range of patients - from the young and healthy to the elderly with multiple comorbidities. Moreover, the incredible variety of injury mechanisms in this diverse population guarantees that some studies will never be done. This is not discouraging, but rather an affirmation of the role of clinical judgment that is based on knowledge of published data, personal clinical experience, and the needs of each individual patient. As noted by Sackett and colleagues in their prescient commentary on evidence-based medicine [3]:'Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough. Without clinical expertise, practice risks becoming tyrannised by evidence, for even excellent external evidence may be inapplicable to or inappropriate for an individual patient. Without current best evidence, practice risks becoming rapidly out of date, to the detriment of patients.'An excellent example of the 'study that will never be done' is provided in the first recommendation: 'We recommend that the time elapsed between injury and operation be minimised for patients in need of urgent surgical bleeding control.' The implications of this are more complex when considered from the perspective of the individual patient, but can apply to anything that delays transfer to the operating room for control of bleeding. Unnecessary, and potentially dangerous, delays range from placement of the obligatory second 'large-bore IV' to imaging studies that may not change clinical management.The a
Cosyntropin as a diagnostic agent in the screening of patients for adrenocortical insufficiency
David D Hamilton, Bryan A Cotton
Clinical Pharmacology: Advances and Applications , 2010, DOI: http://dx.doi.org/10.2147/CPAA.S6475
Abstract: syntropin as a diagnostic agent in the screening of patients for adrenocortical insufficiency Review (4165) Total Article Views Authors: David D Hamilton, Bryan A Cotton Published Date April 2010 Volume 2010:2 Pages 77 - 82 DOI: http://dx.doi.org/10.2147/CPAA.S6475 David D Hamilton, Bryan A Cotton Department of Surgery, The University of Texas Health Science Center, Houston, TX, USA Abstract: Adrenocortical insufficiency occurs when there is inadequate release of cortisol from the adrenal cortex. Disturbances of the hypothalamic–pituitary–adrenal axis are common following trauma, surgical stress, and critical illness. While this is often a protective mechanism, these responses may become “uncoupled” or maladaptive resulting in an exacerbation of organ failure and higher mortality rates. In these clinical settings, the patient presents with a persistent systemic inflammation state, a hyperdynamic cardiovascular response, and vasopressor dependent shock. As such, the occurrence of adrenal insufficiency in the setting of critical illness is most appropriately termed critical illness-related corticosteroid insufficiency. In these settings, recent data suggests that these patients may benefit from a short course of low-dose steroid replacement therapy. Cosyntropin, a synthetic derivative of adrenocorticotropic hormone, is being used with increased frequency in the evaluation and diagnosis of adrenocortical insufficiency in this patient population. A random cortisol level is checked before a 250-μg injection of cosyntropin and then 30–60 minutes later. The cortisol levels and response to cosyntropin may be interpreted to identify an insufficient adrenal response. Of note, the setting of critical illness can greatly affect the cosyntropin test sensitivity on identifying adrenal insufficiency. Changes in the stress response during critical illness combined with the resuscitation and management of these patients greatly disturbs serum protein levels, especially those of albumin and transcortin. Common intensive care unit (ICU) diagnoses such as sepsis and malnutrition can increase baseline levels and blunt the cortisol response to cosyntropin stimulation, respectively. As well, numerous pharmacological agents routinely used in the ICU have been shown to interfere with cortisol levels and cosyntropin responsiveness. While steroids have a place in the ICU, specific dosing and length of administration remain inconsistent
FIBTEM provides early prediction of massive transfusion in trauma
Herbert Sch?chl, Bryan Cotton, Kenji Inaba, Ulrike Nienaber, Henrik Fischer, Wolfgang Voelckel, Cristina Solomon
Critical Care , 2011, DOI: 10.1186/cc10539
Abstract: This retrospective study included patients admitted to the AUVA Trauma Centre, Salzburg, Austria, with an injury severity score ≥16, from whom blood samples were taken immediately upon admission to the emergency room (ER). ROTEM? analyses (extrinsically-activated test with tissue factor (EXTEM), intrinsically-activated test using ellagic acid (INTEM) and fibrin-based extrinsically activated test with tissue factor and the platelet inhibitor cytochalasin D (FIBTEM) tests) were performed. We divided patients into two groups: massive transfusion (MT, those who received ≥10 units red blood cell concentrate within 24 hours of admission) and non-MT (those who received 0 to 9 units).Of 323 patients included in this study (78.9% male; median age 44 years), 78 were included in the MT group and 245 in the non-MT group. The median injury severity score upon admission to the ER was significantly higher in the MT group than in the non-MT group (42 vs 27, P < 0.0001). EXTEM and INTEM clotting time and clot formation time were significantly prolonged and maximum clot firmness (MCF) was significantly lower in the MT group versus the non-MT group (P < 0.0001 for all comparisons). Of patients admitted with FIBTEM MCF 0 to 3 mm, 85% received MT. The best predictive values for MT were provided by hemoglobin and Quick value (area under receiver operating curve: 0.87 for both parameters). Similarly high predictive values were observed for FIBTEM MCF (0.84) and FIBTEM A10 (clot amplitude at 10 minutes; 0.83).FIBTEM A10 and FIBTEM MCF provided similar predictive values for massive transfusion in trauma patients to the most predictive laboratory parameters. Prospective studies are needed to confirm these findings.Trauma-induced coagulopathy (TIC) affects 25 to 34% of all trauma patients upon emergency room (ER) admission and can be observed even before fluid resuscitation [1-3]. TIC increases the risk of massive transfusion (MT) which is associated with mortality rates up to 54% [1,4-6].MT
Treatments for reversing warfarin anticoagulation in patients with acute intracranial hemorrhage: a structured literature review
Brett F Bechtel, Timothy C Nunez, Jennifer A Lyon, Bryan A Cotton, Tyler W Barrett
International Journal of Emergency Medicine , 2011, DOI: 10.1186/1865-1380-4-40
Abstract: A structured literature search and review of articles relevant to intracranial hemorrhage and warfarin and treatment in the emergency department was performed. Databases for PubMed, CINAHL, and Cochrane EBM Reviews were electronically searched using keywords covering the concepts of anticoagulation drugs, intracranial hemorrhage (ICH), and treatment. The results generated by the search were limited to English- language articles and reviewed for relevance to our topic. The multiple database searches revealed 586 papers for review for possible inclusion. The final consensus of our comprehensive search strategy was a total of 23 original studies for inclusion in our review.Warfarin not only increases the risk of but also the severity of ICH by causing hematoma expansion. Prothrombin complex concentrate is statistically significantly faster at correcting the INR compared to fresh frozen plasma transfusions. Recombinant factor VIIa appears to rapidly reverse warfarin's effect on INR; however, this treatment is not FDA-approved and is associated with a 5% thromboembolic event rate. Slow intravenous dosing of vitamin K is recommended in patients with ICH. The 30-day risk for ischemic stroke after discontinuation of warfarin therapy was 3-5%. The risks of not reversing the anticoagulation in ICH generally outweigh the risk of thrombosis in the acute setting.Increasing numbers of patients are on anticoagulation including warfarin. There is no uniform standard for reversing warfarin in intracranial hemorrhage. Intravenous vitamin K in addition to fresh frozen plasma or prothrombin complex concentrate is recommended be used to reverse warfarin-associated intracranial hemorrhage. No mortality benefit for one treatment regimen over another has been shown. Emergency physicians should know their hospital's available warfarin reversal options and be comfortable administering these treatments to critically ill patients.Outpatient prescriptions for warfarin increased 45% to 31 millio
Emissions Mitigation Schemes in Australia—The Past, Present and Future  [PDF]
Deborah Cotton, Stefan Trück
Low Carbon Economy (LCE) , 2013, DOI: 10.4236/lce.2013.42009
Abstract:

Australia was one of the first countries in the world to adopt mandatory emissions trading schemes as part of its emissions mitigation program. To date there have been six states and one federal emissions mitigation schemes. Some state schemes operate in conjunction with other states or the federal scheme and some operate independently. This complex set of regulations and requirements for emitters has led to a deficiency in nationwide coverage with no firm target set for Australia. In July 2011 the Federal Labor Government released details of a carbon tax proposal which was passed by the two houses of Parliament by the end of 2011 and was introduced in July 2012. The Government states that an emissions trading scheme will be introduced in 2015 with a possible link to the European Emissions Trading Scheme (EU ETS). This paper provides a critical overview of Australian responses to climate change, with a particular emphasis on the numerous emissions mitigation schemes.

Homologous recombination in animal mitochondria
James Cotton
Genome Biology , 2001, DOI: 10.1186/gb-2001-2-10-reports0034
Abstract: This is rather surprising, as this paradigm is based on indirect evidence and is challenged by a growing body of data. The original observation that paternal mitochondria do not penetrate the egg is now known to be in error, with paternal organelles persisting for several hours after fertilization. It is also known that mammalian mitochondria contain the necessary enzymatic machinery for homologous recombination, and mitochondrial fusion is well known in Drosophila. Non-homologous recombination (unequal crossing-over) has been held responsible for variation in the number of tandem repeats in a number of animal mitochondrial genomes, and has been directly observed in a nematode. Two recent population studies have also suggested that recombination has occurred in human mtDNA.With all this evidence, it would seem likely that homologous recombination does occur in animal mitochondria, but the publication of human population studies last year provoked considerable debate, emphasizing that there is much interest in whether animal mtDNA does show homologous recombination, and considerable skepticism. Many authors will no doubt remain skeptical, despite the results of this paper, in which Ladoukakis and Zouros have exploited the unusual genetic system of the mussel to uncover direct evidence for homologous recombination within animal mitochondria.The unusual biparental inheritance of mitochondria in mussels of the families Unionidea and Mytilidaehas been known for about a decade, and is an interesting exception to the otherwise universal rule of maternal inheritance for animal mtDNA. Normally, female (F) and male (M) mitochondrial sequences differ by 20% - too great an amount to expect to observe homologous recombination. Luckily, a quirk of the Mytilus system allows a unique opportunity to observe mtDNA recombination in action. Occasionally, F genomes become 'masculinized', invading the M transmission route in sperm (see Figure 1). These MF genomes can now diverge from the
A new profusion of planktonic eukaryotes
James Cotton
Genome Biology , 2001, DOI: 10.1186/gb-2001-2-7-reports0016
Abstract: These methods have been very little used on eukaryotic microorganisms, however. Despite a growing sense of our ignorance of the extent of biodiversity, the feeling seems to have been that the largest branches of the tree of eukaryotic life are largely described. Recent culture-based studies have, however, identified two new groups of marine planktonic eukaryotes, raising expectations that tiny plankton may harbor more surprises. Moon-van der Staay and colleagues report one of the first large-scale molecular studies of marine picoplankton (microorganisms of < 3 μm diameter), revealing for the first time the true diversity of eukaryotes in this environment.Moon-van der Staay et al. used primers to regions of the 18S rRNA gene conserved across most, but not all, eukaryotes, to clone 103 and sequence 35 almost full-length 18S sequences derived from picoplankton of the equatorial Pacific. Only two of the sequences showed 99% identity to known organisms, but phylogenetic analysis revealed that most of the sequences are either from new members of known eukaryotic lineages or are related to known organisms. The results confirm the importance of autotrophic groups such as haptophytes and prasinophytes in this environment. Among the more arresting discoveries is a new lineage that appears to be very common among the picoplankton: 6 out of 35 sequenced clones belong to a lineage related to both the dinoflagellates and the parasitic Perkinsozoa. This clade could be related to the currently unsequenced heterotroph Oxyrrhis. Also well represented are acantharians, stramenopiles and dinoflagellates. In most cases, it is unclear whether the divergent environmental clones belong to auto- or heterotrophic clades within these groups, although the majority of dinoflagellate sequences seem, rather surprisingly, to form a lineage with a parasitic organism, Amoebophrya.The full text of Moon-van der Staay et al's article together with a similar article on Antarctic picoplankton by a differ
Oldest archaea?
James Cotton
Genome Biology , 2000, DOI: 10.1186/gb-2000-1-6-reports0076
Abstract: The existence of new uncultured types of archaea was first suggested in 1992, when two separate studies revealed archaea-like small-subunit (SSU) rRNA sequences in two different samples of seawater. These sequences were related to both the Crenarchaeota and Euryarchaeota, the two known lineages of archaea. Further work confirmed that these sequences represented organisms that were native to, and abundant in, cold seawater. Since this discovery, novel lineages of both archaean groups have been identified in a wide variety of marine, freshwater and terrestrial environments, confirming that the cultured archaea represent only a fraction of the group's diversity. Another surprise was to come, however, when Norman Pace and colleagues reported some particularly unusual archaeal sequences from a hot spring in Yellowstone National Park. These sequences were difficult to place phylogenetically, even when full-length SSU rRNA sequences became available, and are either very deeply branching crenarchaeotes, or an entirely new division of archaea (which they called 'korarchaeota'), or even a sister group to the Eukaryota. Using similar techniques, Kim et al. have now identified another branch of archaean diversity, even more ancient than the korarchaeote lineage.Kim et al. have twice previously reported unusual archaeal SSU rRNA sequences from diversity analyses of paddy-field soil archaeal communities. They have now designed PCR primers specific for these sequences, revealing the presence of similar molecules in paddy soils from around Japan. Using standard techniques, the researchers failed to produce amplification products using any primer pairs more than 700 base pairs apart, but succeeded in cloning 10 samples of around 645 nucleotides long. Phylogenies produced using a variety of different methods place these 10 sequences at the base of the Archaea (see Figure 1), below the Korarchaeota (which appear as basal crenarchaeotes in all of these analyses). The failure to detect
Evolution without sex
James Cotton
Genome Biology , 2000, DOI: 10.1186/gb-2000-1-3-reports0068
Abstract: The cycle of meiosis and syngamy observed in the vast majority of eukaryotes prevents alleles from accumulating any great number of mutations independent from one another, as mutations will become either fixed or extinct as a result of genetic drift. Welch and Meselson have realized that, in a completely asexual organism in which meiotic recombination has ceased, this relationship will break down, allowing formerly allelic sequences to diverge as they effectively become distinct, haploid loci. Very little recombination should be necessary to maintain an allelic relationship, so observing a greater degree of diversity between such loci in a single individual than between the same loci in two related species would be powerful evidence that the organisms have been evolving asexually since before the species' common ancestor. Welch and Meselson measured substitutional changes at selectively neutral sites in four genes from four species of bdelloids, and found exactly this pattern of extreme divergence between former alleles. They were especially careful to use multiple PCR reactions and to clone many molecules from each reaction, to ensure that all copies of these genes were sampled. This allowed them to show that, for two of the genes, existing copies form two distinct lineages in the asexual bdelloids, presumably descended from the alleles of a diploid sexual ancestor.A perspective article (Judson and Normark Science 2000, 288:1185-1186) commenting on Welch and Meselson's finding appeared in the same issue of Science and is available to subscribers.Bdelloid rotifers have uniquely strange genomes, differing completely from obligately or facultatively sexual rotifers. The lack of allele pairs on homologous chromosomes excludes the possibility that bdelloid rotifers are ordinary diploids engaging in very rare or cryptic sex. A few exotic possibilities remain that could produce this pattern in a sexual species - for example, an ancestral genome duplication in a lineage wi
Retroviruses from retrotransposons
James Cotton
Genome Biology , 2001, DOI: 10.1186/gb-2001-2-2-reports0006
Abstract: Much research has focused on the vertebrate retroviruses, where the Env proteins are important antigenic sites. Unfortunately, this involvement in mediating host immune responses produces strong selective pressure for polymorphism, producing rapid sequence divergence at this locus. It has therefore proved impossible to ascertain the origins of the env gene of these retroviruses. It is not even certain whether the vertebrate retroviruses acquired these genes in a single event or as multiple independent horizontal transfers. It has been established that the plant caulimoviruses, derived from a retrotransposon lineage, have cell-to-cell movement proteins related to those of a number of plant viruses. Now, Malik et al. present convincing evidence for the origins of the env genes of three distinct lineages of invertebrate retroviruses.Database searches with a conserved block of amino acids from the divergent Env proteins of insect errantiviruses identified similarity to ORFs from some baculoviruses (a group of double-stranded DNA insect viruses). The baculoviral ORFs have the transmembrane regions and signal peptides expected of viral envelope proteins, and tend to occur in viruses lacking the described baculoviral 'envelope analogous' gp64 gene, suggesting that the identified ORFs represent a second, unrelated envelope protein of baculoviruses. The fact that the errantiviruses are derived from a lineage of retrotransposons, whereas all known baculoviruses are infectious, strongly suggests that these genes originally evolved in a baculoviral genome and have subsequently been acquired by the errantiviruses. Cer elements from Caenorhabditis elegans are members of the BEL clade of LTR retrotransposons, and contain env genes showing strong similarity to phlebovirus G2 glycoproteins, whereas the closely related Tas element from Ascaris shows some limited similarity to herpesvirus gB glycoprotein, the herpesvirus protein primarily implicated in infection. The low similarity be
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