oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 14 )

2019 ( 145 )

2018 ( 189 )

2017 ( 210 )

Custom range...

Search Results: 1 - 10 of 144465 matches for " F. Reyers "
All listed articles are free for downloading (OA Articles)
Page 1 /144465
Display every page Item
Thrombocytopaenia in canine babesiosis and its clinical usefulness
F. Kettner,F. Reyers,D. Miller
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v74i3.512
Abstract: Canine babesiosis is a common cause of thrombocytopaenia but there are few formal studies that have investigated this haematological finding in dogs. Thrombocyte counts from full blood counts were retrospectively analysed for the years 1996-2002. Thrombocyte counts and mean platelet volumes of dogs with babesiosis were compared with those of dogs, seen over the same period of time, that did not have babesiosis. There were 1162 cases in the Babesiosis group and 10 808 in the Non-babesiosis group.Afrequency distribution of the thrombocyte counts showed a trimodal distribution in the Non-babesiosis group compared to a bimodal distribution in the Babesiosis group, with a strong positive skewness. The modes for the frequency distributions were 10, 40, 300 and 10, 35 — 109/l thrombocytes, respectively. The median thrombocyte count in the Babesiosis group was 14 — 109/l and 282 — 109/l in the Non-babesiosis group. There was a statistically significant difference in the median thrombocyte count between the Babesiosis group and the Non-babesiosis group. In the Babesiosis group, 99 %of the thrombocyte counts were below the lower reference range value (250 — 109/l ) and 62 % of thrombocyte counts were below 25 — 109/l . The mean platelet volume (11.1 fl) for the Babesiosis group was greater than the reference range (6-10 fl) and significantly larger than in the Non-babesiosis group (median 9.7 fl). Thrombocyte counts greater than 110 and 250 —109/l had a predictive value that the dog was not suffering from babesiosis of 99.3 % and 99.8 %, respectively. There was a statistically significant difference between the thrombocyte counts of dogs with babesiosis when grouped by parasitaemia scores. The mechanisms of the thrombocytopaenia are not fully understood, and multiple mechanisms, including concomitant thrombocytopaeniainducing diseases such as ehrlichiosis, probably result in this haematological finding. Babesiosis in the South African canine population is associated with thrombocytopaenia in nearly all patients and is severe in the majority of them. In the absence of thrombocytopaenia, babesiosis is an unlikely diagnosis.
Are urea and creatinine values reliable indicators of azotaemia in canine babesiosis?
M.P. De Scally,R.G. Lobetti,F. Reyers,D. Humphris
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v75i3.466
Abstract: Serum urea and creatinine are extensively used as parameters to screen for azotaemia. Their reciprocal plots roughly correlate with glomerular filtration rate (GFR). They are, however, subject to influence by non-renal factors and to increase their specificity they are often tested concurrently. In renal disease they are expected to behave similarly, with both parameters increasing as GFR decreases. Haemolysis, as it occurs in canine babesiosis, may cause non-renal elevations in serum urea, possibly due to ammonia loading. Furthermore, haemolysis with its related elevations in serum bilirubin and serum haemoglobin, may negatively bias the measurement of serum creatinine due to interference of these substances with the chemical analysis of serum creatinine. This negative bias occurs when the alkaline picrate method, or when direct enzymatic methods based on the measurement of hydrogen peroxide, are used. In order to investigate the significance of these perturbations in canine babesiosis, paired values of serum urea and serum creatinine from Babesia canis-negative, non-haemolysis dogs (Group 1), were used to establish a relationship between urea and creatinine over a range of azotaemia by linear regression analysis. This relationship was then used to predict serum creatinine values from actual serum urea values in B. canis-positive dogs (Group 2). The mean of the predicted serum creatinine values for Group 2 (237.03 mmol/ ) was then compared with the mean of the actual serum creatinine values for Group 2 (131.31 mmol/ ). For Group 2, themeanactual serumcreatinine demonstrated a significant negative bias relative to the mean predicted creatinine value. There was also a higher correlation between serum urea and serum creatinine in Group 1 than in Group 2. These findings may have been caused by either nonrenal elevations of serum urea values or by interference with the measurement of serum creatinine. Therefore, although it is possible that some Group 2 dogs with B. canis with high serum urea and normal, low, or zero values for serumcreatinine were not azotaemic, it is also possible that other Group 2 dogs with these biochemical findings did in fact have azotaemia. This study concluded that urea and creatinine do not behave in a similar and predictable manner over a range of azotaemia in canine babesiosis and are therefore not ideally suited for the detection of renal disease in this clinical setting.
The effect of diminazene aceturate on cholinesterase activity in dogs with canine babesiosis
R.J. Milner,F. Reyers,J.H. Taylor,J.S. Van den Berg
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v68i4.890
Abstract: A clinical trial was designed to evaluate the effects of diminazene aceturate and its stabiliser antipyrine on serum pseudocholinesterase (PChE) and red blood cell acetylcholinesterase (RBC AChE) in dogs with babesiosis. The trial was conducted on naturally occurring, uncomplicated cases of babesiosis (n = 20) that were randomly allocated to groups receiving a standard therapeutic dose of diminazene aceturate with antipyrine stabiliser (n = 10) or antipyrine alone (n = 10). Blood was drawn immediately before and every 15 minutes for 1 hour after treatment. Plasma PChE showed a 4 % decrease between 0 and 60 min within the treatment group (p < 0.05). No statistically significant differences were found between the treatment and control groups at any of the time intervals for PChE. There was an increase in RBC AChE activity at 15 min in the treatment group (p < 0.05). No significant differences were found between the treatment and control groups at any time interval for RBC AChE. In view of the difference in PChE, samples from additional, new cases (n = 10) of canine babesiosis were collected to identify the affect of the drug over 12 hours. No significant depression was identified over this time interval. The results suggests that the underlying mechanism in producing side-effects, when they do occur, is unlikely to be through cholinesterase depression.
Provisional clinical chemistry parameters in the African Sharptooth catfish (Clarias gariepinus)
J.G. Myburgh,C.J. Botha,D.G. Booyse,F. Reyers
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v79i4.265
Abstract: Pollution affects aquatic systems worldwide and there is an urgent need for efficient monitoring. Fish are generally sensitive to their environment and are thus considered to be valuable bioindicator species. The African Sharptooth catfish (Clarias gariepinus) is particularly important in this respect because of its very wide distribution. In order to use C. gariepinus as a bioindicator species its baseline clinical chemistry must be defined. Existing data are scarce, and the objective of this work was therefore to establish clinical chemistry parameters for C. gariepinus. Blood was collected from male and female catfish and a number of clinical chemistry parameters were determined. Plasma protein values, but particularly those of plasma albumin, were found to be very low, approximately half the value for dogs, but similar to the values in Channel catfish (Ictalurus punctatus). Plasma urea values in Sharptooth catfish were found to be much lower than in dogs, but only marginally lower than in Channel catfish. Plasma creatinine in Sharptooth catfish, however, was only a quarter of that of dogs and one third of that found in Channel catfish. These findings may have implications for using urea and / or creatinine as an index of renal glomerular filtration, as is done in mammals. Plasma enzyme activity ranges were much lower in Sharptooth catfish than in dogs, particularly for alkaline phosphatase (ALP) and alanine aminotransferase (ALT). By comparison, Channel catfish have an even lower ALT activity range but an ALP range that is very similar to dogs. The implications for using these enzymes as markers for liver disease are not clear from these data, as factors such as plasma half-life and tissue distribution remain to be determined. The very low plasma thyroxine (T4) levels have important implications for laboratory personnel, who will have to set up calibration and standardisation adaptations for the methods that are generally designed for human samples. Although the sample size was too small for reliable comparisons, it appeared that there was little difference in the parameters measured between male and female fish. The values obtained are a useful starting point for using C. gariepinus as a bioindicator species.
The effect of endotoxin and anti-endotoxin serum on synovial fluid parameters in the horse
R.D. Gottschalk,F. Reyers,S.S. Van den Berg
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v69i1.801
Abstract: The effects of a commercially available equine hyperimmune anti-endotoxin serum on synovial fluid parameters were evaluated in an induced synovitis model in normal horses. Four groups of 3 horses each received lipopolysaccharide (LPS) plus hyperimmune antiendotoxin (anti-LPS), LPS, anti-LPS, and Ringers lactate (control) respectively injected into the left intercarpal joint. Synovial fluid parameters were measured at 4, 8, 24 and 72 h. It was found that anti-LPS had no attenuating effect on the LPS and that it induced a synovitis almost equivalent to that induced by LPS alone. The introduction of sterile Ringers lactate solution into the carpal joint together with repeated aseptic arthrocentesis induces a mild inflammatory response.
Treatment of heartwater : potential adverse effects of furosemide administration on certain homeostatic parameters in normal sheep
A.S. Shakespeare,F. Reyers,S.R. Van Amstel,G.E. Swan
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v69i4.841
Abstract: Diuretics, in particular furosemide, are generally recommended as a supportive treatment in the advanced stages of heartwater in ruminants. However, after what appeared to be possible adverse effects accompanying its use in field cases of heartwater, the effects of this drug on certain blood and urine parameters were investigated in normal sheep at the same dose rates. Diuresis with concomitant natriuresis was significant after furosemide administration, as was the expected plasma volume decrease. Other significant changes included metabolic alkalosis, hypokalaemia and reduced blood ionised calcium. The difference in duration of the diuretic effect and the duration of the changes in blood parameters from c. 3 h and c. 6 h respectively make it difficult to determine a time interval between successive treatments with furosemide. It appears that the probable cause of death of sheep with heartwater is a drastic reduction in blood volume and decreased cardiac output that leads to general circulatory failure. A therapeutic approach that involves further loss of plasma volume due to diuresis appears contradictory. The added effects of potentiating respiratory alkalosis and the terminal drop in blood ionised calcium seen in heartwater-affected animals indicate that the use of furosemide in supportive treatment of this disease is not warranted.
A canine model of normovolaemic acute anaemia
T.C. Spotswood,R.M. Kirberger,L.M.P.K. Kirb,F. Reyers
Onderstepoort Journal of Veterinary Research , 2010, DOI: 10.4102/ojvr.v72i2.209
Abstract: The objective was to develop a non-terminal, acute normovolaemic anaemia model in dogs that has minimal effects on patient well-being. Eleven normal Beagle dogs were used. About 20 % of the circulating blood volume was removed from the jugular vein 1-3 times per day over a 3-4 day period until a haematocrit (Ht) of 13-17 % was obtained. Normovolaemia was maintained by replacing the volume deficit of the red blood cells with Ringer's lactate and re-infusing the plasma. Full blood count and Ht were monitored twice daily. The 13-17 % Ht was reached within 3-4 days with the number of phlebotomies ranging from four to seven. The model was primarily developed to determine echocardiographic values as well as Doppler abdominal splanchnic blood flow parameters in anaemic dogs as part of a study that will compare these results to similar studies in babesiosis-induced anaemia. The model may also be useful in the evaluation of the pathophysiology of anaemia in dogs or as a model for anaemia in humans.
Conserving Biodiversity Efficiently: What to Do, Where, and When
Kerrie A. Wilson,Emma C. Underwood,Scott A. Morrison,Kirk R. Klausmeyer,William W. Murdoch,Belinda Reyers,Grant Wardell-Johnson,Pablo A. Marquet,Phil W. Rundel,Marissa F. McBride,Robert L. Pressey,Michael Bode,Jon M. Hoekstra,Sandy Andelman,Michael Looker,Carlo Rondinini,Peter Kareiva,M. Rebecca Shaw,Hugh P. Possingham
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0050223
Abstract: Conservation priority-setting schemes have not yet combined geographic priorities with a framework that can guide the allocation of funds among alternate conservation actions that address specific threats. We develop such a framework, and apply it to 17 of the world's 39 Mediterranean ecoregions. This framework offers an improvement over approaches that only focus on land purchase or species richness and do not account for threats. We discover that one could protect many more plant and vertebrate species by investing in a sequence of conservation actions targeted towards specific threats, such as invasive species control, land acquisition, and off-reserve management, than by relying solely on acquiring land for protected areas. Applying this new framework will ensure investment in actions that provide the most cost-effective outcomes for biodiversity conservation. This will help to minimise the misallocation of scarce conservation resources.
Conserving Biodiversity Efficiently: What to Do, Where, and When
Kerrie A Wilson ,Emma C Underwood,Scott A Morrison,Kirk R Klausmeyer,William W Murdoch,Belinda Reyers,Grant Wardell-Johnson,Pablo A Marquet,Phil W Rundel,Marissa F McBride,Robert L Pressey,Michael Bode,Jon M Hoekstra,Sandy Andelman,Michael Looker,Carlo Rondinini,Peter Kareiva,M. Rebecca Shaw,Hugh P Possingham
PLOS Biology , 2007, DOI: 10.1371/journal.pbio.0050223
Abstract: Conservation priority-setting schemes have not yet combined geographic priorities with a framework that can guide the allocation of funds among alternate conservation actions that address specific threats. We develop such a framework, and apply it to 17 of the world's 39 Mediterranean ecoregions. This framework offers an improvement over approaches that only focus on land purchase or species richness and do not account for threats. We discover that one could protect many more plant and vertebrate species by investing in a sequence of conservation actions targeted towards specific threats, such as invasive species control, land acquisition, and off-reserve management, than by relying solely on acquiring land for protected areas. Applying this new framework will ensure investment in actions that provide the most cost-effective outcomes for biodiversity conservation. This will help to minimise the misallocation of scarce conservation resources.
Ecosystem Services, Land-Cover Change, and Stakeholders: Finding a Sustainable Foothold for a Semiarid Biodiversity Hotspot
Belinda Reyers,Patrick J. O'Farrell,Richard M. Cowling,Benis N. Egoh
Ecology and Society , 2009,
Abstract: Land-cover change has been identified as one of the most important drivers of change in ecosystems and their services. However, information on the consequences of land cover change for ecosystem services and human well-being at local scales is largely absent. Where information does exist, the traditional methods used to collate and communicate this information represent a significant obstacle to sustainable ecosystem management. Embedding science in a social process and solving problems together with stakeholders are necessary elements in ensuring that new knowledge results in desired actions, behavior changes, and decisions. We have attempted to address this identified information gap, as well as the way information is gathered, by quantifying the local-scale consequences of land-cover change for ecosystem services in the Little Karoo region, a semiarid biodiversity hotspot in South Africa. Our work is part of a stakeholder-engaged process that aims to answer questions inspired by the beneficiaries and managers of ecosystem services. We mapped and quantified the potential supply of, and changes in, five ecosystem services: production of forage, carbon storage, erosion control, water flow regulation, and tourism. Our results demonstrated substantial (20%–50%) declines across ecosystem services as a result of land-cover change in the Little Karoo. We linked these changes in land-cover to the political and land-use history of the region. We found that the natural features that deliver the Little Karoo’s ecosystem services, similar to other semiarid regions, are not being managed in a way that recognizes their constraints and vulnerabilities. There is a resulting decline in ecosystem services, leading to an increase in unemployment and vulnerability to shocks, and narrowing future options. We have proposed a way forward for the region that includes immediate action and restoration, mechanisms to fund this action, the development of future economic activity including tourism and carbon markets, and new ways that the science–stakeholder partnership can foster these changes. Although we acknowledge the radical shifts required, we have highlighted the opportunities provided by the resilience and adaptation potential of semiarid regions, their biodiversity, and their inhabitants.
Page 1 /144465
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.