29 research outputs found
Edge effects at an induced forest-grassland boundary: forest birds in the Ongoye Forest Reserve, KwaZulu-Natal
Bird species diversity and guild composition between the edge (5-10 m from the margin) of primary forest abutting grassland and the deep interior (> 500 m from the margin) in the Dngoye Forest Reserve were compared. Edge and interior sites were chosen that were homogeneous with respect to habitat physiognomy i.e. influences of habitat structure and complexity were insignificant. There were no statistical differences in bird species diverstty between the forest edge and interior. However, there was significantly greater species turnover at the edge. The difference in bird species composition between the forest edge and interior was due to various edge-effects: removal of dead wood for firewood, soil compaction by cattle, and generally greater levels of disturbance. We question the wisdom of the generally applied edge-effect principle in the conservation of forest biodiversity. We suggest that the principle be applied only once there has been critical appraisal of the extent, nature, and effect of an edge and a clear conservation objective with regard to forest birds.S. Afr. J. Zool. 1997,32(3
Perceptions of vulture supplementary feeding site managers and potential hidden risks to avian scavengers
Under the current African vulture crisis, supplementary feeding sites (SFS), which provide carrion resources, have become a popular conservation tool to address vulture declines. In South Africa, this practice is unregulated and the context in which SFS operate and their adherence to best management practices is currently unknown. In this study, we conducted a survey with SFS managers regarding the management of their SFS to evaluate potential conservation implications of different practices. Half of the SFS surveyed were associated with livestock farming. Overall, most managers (84%) perceived some benefit from running an SFS, largely attributed to cleaning services provided by vultures. Over half of the managers perceived no disadvantages from running SFS. We found a positive correlation between numbers of vultures seen at SFS and the amount of food provided there. Despite unintentional and intentional poisoning being identified by experts as the most critical threats to vultures in Southern Africa, only 47 and 24% of managers, respectively, listed these as potential threats to vultures, highlighting limited understanding of current vulture conservation issues. Most managers (85%) vetted carcasses for provisioning suitability based on whether they had been treated with veterinary drugs, but relatively few managers (10%) did the same for lead (Pb) contamination. Only 30% of managers considered threats to vultures when they decided on a location for their SFS. Overall, this study unveils that at many SFS, safety conditions are not met and vultures may be exposed to risks, such as the ingestion of toxic substances (e.g., Pb) or electrocution by energy infrastructure. To minimize unintended negative consequences from SFS, it will be essential to increase the interaction between SFS managers and conservation practitioners, to increase the flow of information on best management practices and enforce stringent and clear guidelines that minimize any risks to vultures.Peer reviewe
Systemic ablation of MMP9 triggers invasive growth and metastasis of pancreatic cancer via deregulation of IL-6 expression in the bone marrow
Matrix metalloproteinase 9 (MMP9/Gelatinase B) is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and plays a central role in tumor cell invasion and metastasis. Here we complemented mechanistic insights in the cancer biology of MMP9 and investigated the effects of specific long-term loss-of-function, by genetic ablation, of MMP9 on PDAC initiation and progression in the well-established KPC mouse model of spontaneous PDAC. Tumor growth and progression were analyzed by histopathology and immunohistochemistry. Invasive growth of PDAC cells was analyzed by both in vitro (proliferation, survival, migration, invasion assays) and in vivo (experimental metastasis assays) methods. Retroviral shRNAi was used to knockdown target genes (MMP9, IL6R). Gene expression was analyzed by qRT-PCR, immunoblot, ELISA, in situ hybridization and zymography. PDAC tumors from MMP9-deficient mice were dramatically larger, more invasive and contained more stroma. Yet, ablation of MMP9 in PDAC cells did not directly promote invasive growth. Interestingly, systemic ablation of MMP9 led to increased IL-6 levels resulting from abrogation of MMP9-dependent SCF-signaling in the bone marrow (BM). IL-6 levels in MMP9-/- mice were sufficient to induce invasive growth and STAT3 activation in PDAC cells via IL-6 receptor (IL6R). Interference with IL6R blocked the increased invasion and metastasis of PDAC cells in MMP9-deficient hosts. In conclusion, ablation of systemic MMP9 initiated fatal communication between maintenance of physiological functions of MMP9 in the BM and invasive growth of PDAC via the IL-6/IL6R/STAT3 axis. Implications: Thus, the beneficial effects of host MMP9 on PDAC are an important caveat for the use of systemic MMP9 inhibitors in cancer
Macromolecular Fingerprinting of Sulfolobus Species in Biofilm: A Transcriptomic and Proteomic Approach Combined with Spectroscopic Analysis
Microorganisms in nature often live in surfaceassociated
sessile communities, encased in a self-produced
matrix, referred to as biofilms. Biofilms have been well studied in
bacteria but in a limited way for archaea. We have recently characterized
biofilm formation in three closely related hyperthermophilic
crenarchaeotes: Sulfolobus acidocaldarius, S. solfataricus, and
S. tokodaii. These strains form different communities ranging
from simple carpet structures in S. solfataricus to high density
tower-like structures in S. acidocaldarius under static condition.
Here, we combine spectroscopic, proteomic, and transcriptomic
analyses to describe physiological and regulatory features
associated with biofilms. Spectroscopic analysis reveals that in
comparison to planktonic life-style, biofilm life-style has distinctive
influence on the physiology of each Sulfolobus spp.
Proteomic and transcriptomic data show that biofilm-forming
life-style is strain specific (eg ca. 15% of the S. acidocaldarius
genes were differently expressed, S. solfataricus and S. tokodaii
had âŒ3.4 and âŒ1%, respectively). The -omic data showed that regulated ORFs were widely distributed in basic cellular functions,
including surface modifications. Several regulated genes are common to biofilm-forming cells in all three species. One of the most
striking common response genes include putative Lrs14-like transcriptional regulators, indicating their possible roles as a key
regulatory factor in biofilm development
Data-Dependent Middle-Down Nano-Liquid ChromatographyâElectron Capture Dissociation-Tandem Mass Spectrometry: An Application for the Analysis of Unfractionated Histones
Genome-Wide Meta-Analyses of Breast, Ovarian, and Prostate Cancer Association Studies Identify Multiple New Susceptibility Loci Shared by at Least Two Cancer Types.
UNLABELLED: Breast, ovarian, and prostate cancers are hormone-related and may have a shared genetic basis, but this has not been investigated systematically by genome-wide association (GWA) studies. Meta-analyses combining the largest GWA meta-analysis data sets for these cancers totaling 112,349 cases and 116,421 controls of European ancestry, all together and in pairs, identified at P < 10(-8) seven new cross-cancer loci: three associated with susceptibility to all three cancers (rs17041869/2q13/BCL2L11; rs7937840/11q12/INCENP; rs1469713/19p13/GATAD2A), two breast and ovarian cancer risk loci (rs200182588/9q31/SMC2; rs8037137/15q26/RCCD1), and two breast and prostate cancer risk loci (rs5013329/1p34/NSUN4; rs9375701/6q23/L3MBTL3). Index variants in five additional regions previously associated with only one cancer also showed clear association with a second cancer type. Cell-type-specific expression quantitative trait locus and enhancer-gene interaction annotations suggested target genes with potential cross-cancer roles at the new loci. Pathway analysis revealed significant enrichment of death receptor signaling genes near loci with P < 10(-5) in the three-cancer meta-analysis. SIGNIFICANCE: We demonstrate that combining large-scale GWA meta-analysis findings across cancer types can identify completely new risk loci common to breast, ovarian, and prostate cancers. We show that the identification of such cross-cancer risk loci has the potential to shed new light on the shared biology underlying these hormone-related cancers. Cancer Discov; 6(9); 1052-67. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 932.The Breast Cancer Association Consortium (BCAC), the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL), and the Ovarian Cancer Association Consortium (OCAC) that contributed breast, prostate, and ovarian cancer data analyzed in this study were in part funded by Cancer Research UK [C1287/A10118 and C1287/A12014 for BCAC; C5047/A7357, C1287/A10118, C5047/A3354, C5047/A10692, and C16913/A6135 for PRACTICAL; and C490/A6187, C490/A10119, C490/A10124, C536/A13086, and C536/A6689 for OCAC]. Funding for the Collaborative Oncological Gene-environment Study (COGS) infrastructure came from: the European Community's Seventh Framework Programme under grant agreement number 223175 (HEALTH-F2-2009-223175), Cancer Research UK (C1287/A10118, C1287/A 10710, C12292/A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692, and C8197/A16565), the US National Institutes of Health (CA128978) and the Post-Cancer GWAS Genetic Associations and Mechanisms in Oncology (GAME-ON) initiative (1U19 CA148537, 1U19 CA148065, and 1U19 CA148112), the US Department of Defence (W81XWH-10-1-0341), the Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer, Komen Foundation for the Cure, the Breast Cancer Research Foundation, and the Ovarian Cancer Research Fund [with donations by the family and friends of Kathryn Sladek Smith (PPD/RPCI.07)]. Additional financial support for contributing studies is documented under Supplementary Financial Support.This is the author accepted manuscript. The final version is available from the American Association for Cancer Research via http://dx.doi.org/10.1158/2159-8290.CD-15-122
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
An investigation into the decline of the bearded vulture : Gypaetus barbatus in southern Africa
Includes bibliographical references.The Bearded Vulture Gypaetus barbatus is a Critically Endangered species in southern Africa whose entire range in the Southern Hemisphere falls within the Maloti-Drakensberg mountains of South Africa and Lesotho, which forms the area of focus for this research. In this thesis I have attempted to synthesize 15 years of research on the Bearded Vulture population of southern Africa using various approaches to quantify the decline in the species, investigate the mechanisms of this decline and determine the most appropriate management actions necessary to attain the short-term speciesâ conservation target of a positive population growth rate. Firstly I assessed the territory occupancy, distribution and density of the population over two time periods to identify population trends. The number of occupied territories decreased by between 32%-51%, the breeding range decreased by 27% and breeding densities decreased by 20% over the past five decades. The birds occupy a breeding range of 28,125 km2 with higher densities recorded in the core of the range than in the peripheral areas. The population is estimated at between 368-408 individuals (109-221 breeding pairs). Three hypotheses were then examined in an attempt to explain which factors were associated with territories recorded as abandoned; those related to human impact, food availability and climate change. Of the seven covariates examined within the home range of an adult pair using a model selection process using Akaikeâs Information Criterion, the strongest support was for the human impact hypothesis, with abandonment more likely in territories with higher densities of power lines and human settlements. These findings were in accordance with the main causes of mortality. The movements of all age classes were investigated using data from satellite transmitters affixed to 18 birds to determine exposure to perceived benefits or anthropogenic risks. The overall foraging range of the population was estimated to be 51,767 km2 and non-adults were found to use 65% of this area whereas adults focussed their activities in an area of about 286 km2 around their nests. Non-adults increased the size of their range as they aged, with birds aged between 4-6 years facing the greatest exposure to risk factors. The genetic risk was examined by sampling two populations in sub-Saharan Africa to ascertain genetic variation, evolutionary placement and connectivity using Mitochondrial DNA fragment analyses. My results showed little to no differentiation between populations in southern Africa and Ethiopia suggesting that translocations of individuals from Ethiopia could be considered for introduction into the local population. The reduced haplotype diversity found in southern Africa suggests that translocations may be necessary to improve genetic diversity. Lastly I used population viability analysis models to determine the future population trend and identify the primary demographic and environmental constraints on the population. The models predicted a negative growth rate for the population over the next 50 years (Ă«=0.99) with a high probability (0.89) of extinction as a result of low survival estimates (particularly for adults; 86%) and reduced productivity (55%). Human activities (69%) and power line collisions (21%) were the primary reasons for the low survival rates with poisoning alone accounting for 90% of the deaths. To achieve a positive growth rate, mortality rates should be reduced by >50%, productivity increased by >25% and the population should be supplemented by at least six individuals annually for the next 20 years. Several recommendations are listed to address the primary threat of poisoning and continued monitoring of the population is essential to evaluate the success of the implementation of these recommendations. My research demonstrates the importance of focussing on small populations, declining populations and populations at the periphery of the speciesâ range and my results confirm that urgent intervention is required to improve the status of the population. My findings also contribute to achieving vulture conservation objectives regionally, continentally and internationally
The balancing of life roles as essential condition for personal leadership
M.Phil.The purpose of the study was to investigate the importance of balancing life roles as essential condition for personal leadership. The problem investigated in the study was that people experience unhappiness and unfulfilled lives due to imbalance between life roles. The problem arises because people do not identify and prioritise their life roles based on values, and they do not set goals to create balance between life roles. The general aim of the study was to investigate the nature of life roles, to explore the value of prioritised and balanced life roles, and to search for ways how balance between life roles can be created, all within the personal leadership framework. The research methodology used in the study included hermeneutic and descriptive strategies. The research methods that were used included a word and concept analysis in order to clarify concepts central to the title of the study. A literature study was conducted to clarify typical life roles as well as how people experience imbalance between these roles, and how prioritised and balanced life roles can be achieved, within the personal leadership framework. The following are the most important findings of the study: Roles refer to a place in society, together with a defined code of conduct, and attitudes that society deems appropriate for somebody occupying that specific role. It was also found that roles represent responsibilities, relationships and areas of contribution. The study found that certain concepts related to life roles can cause serious imbalance in a person's life. Life roles can be categorised into personal, family, work, recreational and community roles. The impact roles have on individuals were identified. Life dimensions (physical, mental, social and spiritual) and life roles are interrelated and can not be separated. By investigating the relationship between life roles and life dimensions it was found that each life role consists of a social, mental, physical and spiritual dimension, but also that these life dimensions consist out of life roles. * It was found that value clarification in order to identify life roles, and clear goal setting for each life role are important steps in achieving balance. * The study concluded by indicating that the balancing of life roles indeed form an important part of the personal leadership process
Obesity as an inflammatory condition
The prevalence of obesity has increased dramatically in the past decade.
Opsomming
Die voorkoms van obesiteit het oor die afgelope dekade dramaties gestyg en daarmee saam die voorspelling van ân toename in morbiditeit sowel as mortaliteit as gevolg van obesiteit-verwante siektetoestande
*Please note: This is a reduced version of the abstract. Please refer to PDF for full text