Hypercoagulability in COVID-19

COVID-19 is associated with a hypercoagulable state that may present as pulmonary thrombosis, pulmonary embolism, and venous and arterial thrombosis.Suggested pathogenesis include direct infection of the endothelial cell with subsequent endothelial cell dysfunction, leading to increased procoagulant activity, decreased anticoagulant activity and decreased fibrinolysis. The severe immune inflammatory response in the lungs with cytokine release also plays a critical role (immunothrombosis). Hypoxia has a local and systemic effect on coagulation. Various markers of this state have been described, and especially the D-dimer level (and rapid changes in the D-dimer level) as a reliable prognostic marker. It is also used as indicator for initiation of anticoagulation by some experts. Due to the pleotrophic effects of heparin, it is the anticoagulant of choice for these patients (most often low molecular weight heparin, due to decreased risk of heparin induced thrombocytopenia, ease of use). No clinical trial data is available at the time of writing (28 May 2020), and suggested guidelines of experts in different countries are discussed

Venous thrombosis in the patient with cancer

The relationship between cancer and thrombosis has been known for many years. Thrombotic risk is increased in the patient with cancer, and the diagnosis of venous thromboembolism at the time that a malignancy presents influences patient outcome. Risk evaluation, prophylaxis and treatment of venous thromboembolism are practical issues that face doctors who are dealing with these patients.http://www.sajgo.co.za/index.php/sajg

The calibration of compound crump and sharp-crested gauging weirs in South Africa

Dissertation (PhD)--Stellenbosch University, 1996.One copy microfiche.Some digitised pages may appear illegible due to the condition of the original microfiche.ENGLISH ABSTRACT: The present network of now gauging stations in South Africa has grown from isolated observations on an ad extensive is to an extensive network of stations across the country. Standardised gauging stations to suit local conditions have been developed which include purposely desigll4:d compound weirs. Nearly all. compound gauging weirs In South Africa have. for practical reasons. been constructed without dividing walls. thus deviating lr',:.n the standards set by the British Standards Institution (1981). Uncertainty about the accuracy of calibration of such structures had to be darifi,ed and. where ~cessary. adjustments had to be made to existing calibration formulae in order to compensate for the de,,·iations. It was also necessary to determine whether the accuracies that could be attained were adequate in terms of the potential financial implications of inaccuracies. It has thus become necessary to re-evaluate the calibration of these structures which consist of mainly compound Crump .md sharp-crested weirs. Selected flow l"t'Cords were analysed and the data wa.\ used to determine the impact of errors on the required capacities of reservoirs. This wa., done in an anempt to provide guidelines for the accuracy required in flow records. An31ysing a single application of a flow record cannot provide guidelines for the required accuracy of a flow record and thus the gauging of flow. Although no general conclusions can be drawn. it appears thal the benefits arising from an improvement in the accuracy of a flow record are proportionally greater than the percentage improvement in accuracy. Three-dimensional flow conditions exist either upstream or downstream of the point of stage measurement depending on the presence or absence of diViding walls at a compound gauging weir. The existing calibro1tion theory does not account for the influences of three-dimensional flow conditions and a.-'isociatcd energy losses in the determination of the upstream total energy head. Hydraulic model tests were thus undenaken to detemline the magnitude of the resulting energy losses. New techniques were developed to compensate for these energy losses in the calibration theory of compound gauging weirs. Application of the new calculation techniques to rate compound weirs using a single point of stage measurement results in improvements in accuracy. It was found that compound weirs without dividing walls can be rated to greater levels of accuracy than weirs with dividing walls, where stage measurements are taken at a single pointAFRIKAANSE OPSOMMING: Die huidige nc!werk van vloclmectpumc III SUld-Afnka hel gegroei van gc'isoleerde waamemings op 'n ad hoc basis, tot 'n uitgebrcldc nctwerk. van meetpunte vcrsprei oor die hele land, Standaard mcetstruktuure aangepas vir plaaslike omstandighede is ontwikkei en sluit in doelgeboudc saamgestelde mcetstrukture. Byltans aile saamgestelde mcetstruklure in Suid-Afrika is weens praktisc oorwegings opgerig sonder verdeelmure, wal afwyk van die standaarde gestel deur die British Standards Institution (1981). Onsekerhede aangaande die akkuraathcid ,'an die kaJibrasie van sulke slrukture moes opgekJaar word en unpassjngs un die beSlaande leorie moes gedoen word om hier'OOf te kompenseer. iodien nodig. Oil was ook nodig om va~ Ie s,tel of akkuraathede Waf hulbaar is voldoende is, met inagneming Vlll poIensi~1c finamiitle implikasies van onakkuruthede. Oit hel dus nodig gcword om die bestaandc kaJibra.liic van saamgestelde meetstrukture. hoofsaakJik Crump en sterpkroin meetwaJle, Ie hcr·cval~r. Seleere vloei:rekords is ontl~ en die data is gcbruik om die impak van foule ~ bepaal op die berekende k.apasitei~ van opgaardamme. Oil IS gedoen in 'n poging om riglyne neer te Ie rakende die akkuraatheid verlang in 'n vloeirekord. Die ontleding van '0 enkele loepassing van 'n vloeirekord lewer nie genoegsame data om riglyne vas Ie stell. "ir die verlanp akkuraalheid van 'n vloeirekord of vloeimeling nie. AlhoeweJ geen duidelike riglyne hieruii vOilr1spruit nie. kom dit voor asof die voordele verkry uit '0 verbetering io die akkuraatheid van 'n vloeirekord in verhouding groter is as die vcrmiodering in die vloeimetingsfout. Drie-dimensionele II'loeitoeslande bestaan of stroomop of stroomaf van die punt van watervlakmeting, afl1iangende van die 'cenwoordigheid of afwesigheid van vcrdeelmure by 'n saamgestclde meetstlruktuur. Die beslaande kalibrasieleorie maak nie voorsiening vIr die invloed van drie-dimensionele vloeitoestande en die gepaardgaande energieverlicse op die bepahng van die totale stroomop energiehoogte nie. Hidrouliese mode1tor: sc is ondemeem om die omvang van die resulterende energieverliese vas te ste!. Nuwe tegnieke in die kaJibrasieteorie vir saamgestelde strukture is ontwikk.e1 0:t1 tc kompenseer vir hierdie energieverliese. 'n Verbc:tcde akkuraatheid word verkry wanneer die nuwe tegniek toegepas word op die kalibrasie van saamge~telde meetstrukture met 'n enkele punt van watervla.kmeting. Daar is gevind daR saamgestelde meetstrukture sonder verdeelmure illurater gekalibn:er lean word. as suuktt.Rmet vcrdeelmure waar walervlakke slegs by 'n enkclc punt gemeet word

Warfarin in non-valvular atrial fibrillation

The development of novel oral anticoagulants that are effective alternatives to warfarin in non-valvular atrial fibrillation (AF) is a welcome advance. However, a variety of unresolved problems with their use, and not least with their cost, make it important to re-evaluate the use of warfarin as it will likely remain the anticoagulant of choice in South African patients with non-valvular AF for the foreseeable future. In this article, we review the correct clinical use of warfarin. Guidance is provided on commencing warfarin treatment, maintenance dosing, the recommended steps when temporary withdrawal of treatment is necessary, the management of bleeding, and the use of warfarin in chronic kidney disease. Techniques for changing from warfarin to one of the new oral anticoagulants and vice versa are included

Anticoagulation therapy in diabetic patients

Diabetic patients have a high risk of developing arterial disease (coronary artery, cerebrovascular and peripheral arterial disease) and are therefore often given antiplatelet therapy. Although only retrospective studies suggest that diabetic patients are also prone to venous thrombo-embolism, many comorbid factors in the diabetic patient, such as heart failure, physical inactivity and atrial fibrillation increase the risk of venous thrombosis. A recent sub-analysis of the RECORD study examined the risk of hyperglycaemia during hip replacement, as a risk factor for postoperative venous thrombo-embolism. For these reasons, diabetic patients are also often given anticoagulant therapy.http://www.diabetesjournal.co.za

Hybrid expert ensembles for identifying unreliable data in citizen science

Citizen science utilises public resources for scientific research. BirdTrack is such a project established in 2004 by the British Trust for Ornithology (BTO) for the public to log their bird observations through its web or mobile applications. It has accumulated over 40 million observations. However, the veracity of these observations needs to be checked and the current process involves time-consuming interventions by human experts. This research therefore aims to develop a more efficient system to automatically identify unreliable observations from large volume of records. This paper presents a novel approach — a Hybrid Expert Ensemble System (HEES) that combines an Expert System (ES) and machine induced models to perform the intended task. The ES is built based on human expertise and used as a base member of the ensemble. Other members are decision trees induced from county-based data. The HEES uses accuracy and diversity as criteria to select its members with an aim of improving its accuracy and reliability. The experiments were carried out using the county-based data and the results indicate that (1) the performance of the expert system is reasonable for some counties but varied considerably on others. (2) An HEES is more accurate and reliable than the Expert System and also other individual models, with Sensitivity of 85% for correctly identifying unreliable observations and Specificity of 99% for reliable observations. These results demonstrated that the proposed approach has the ability to be an alternative or additional means to validate the observations in a timely and cost-effective manner and also has a potential to be applied in other citizen science projects where the huge amount of data needs to be checked effectively and efficiently

Cost-Effectiveness and Cost Utility of Treatment of Attention-Deficit/Hyperactivity Disorder:A Systematic Review

Objectives: This systematic review provides an overview of full economic evaluations of attention-deficit/hyperactivity disorder (ADHD) treatments, evaluates their outcomes, and highlights gaps in the literature. Data Sources: Electronic databases were searched for full economic evaluations of ADHD treatments for children, adolescents, or adults published in English or Dutch. Results: Twenty-nine studies met the inclusion criteria. Almost all studies that compared medication or psychosocial treatment to no treatment, placebo, or care as usual indicated that medication and psychosocial treatment were cost-effective compared to the control group. Stimulant treatment appeared to be cost-effective for the treatment of ADHD in children and adolescents. Only few studies focus on treatments in adults and psychosocial treatments and the number of studies with long time horizons and without industry funding is limited. Conclusions: Despite the rising interest in cost-effectiveness, this systematic review shows that more cost-effectiveness research of higher quality is warranted to aid in the optimal use of available treatments and resources for individuals with ADHD. Specifically, more studies should focus on treatments in adults and psychosocial treatments, and more studies with long time horizons and without industry funding are warranted. Nevertheless, we can conclude that treating ADHD is generally cost-effective compared to no treatment

Warfarin in non-valvular atrial fibrillation

The development of novel oral anticoagulants that are effective alternatives to warfarin in non-valvular atrial fibrillation (AF) is a welcome advance. However, a variety of unresolved problems with their use, and not least with their cost, make it important to re-evaluate the use of warfarin as it will likely remain the anticoagulant of choice in South African patients with non-valvular AF for the foreseeable future. In this article, we review the correct clinical use of warfarin. Guidance is provided on commencing warfarin treatment, maintenance dosing, the recommended steps when temporary withdrawal of treatment is necessary, the management of bleeding, and the use of warfarin in chronic kidney disease. Techniques for changing from warfarin to one of the new oral anticoagulants and vice versa are included.

Modelling of composite type variation of the Crump weir

The accurate measuring of flow in rivers is essential for optimal utilisation of the surface water resources in South Africa. Long-term hydrological records containing the characteristic parameters of change and variability are required for the effective management and conservation of scarce water resources. The runoff from catchments is measured by using gauging structures in rivers and at dams. In South African rivers, the use of compound gauging weirs is common due to the large variation in flows. This allows for accurate measuring of discharge in a river section at low and high flow rates (Wessels & Rooseboom 2009).http://www.civils.org.zaam201

COVID-19-associated coagulopathy and antithrombotic agents—lessons after 1 year

COVID-19 is associated with a high incidence of thrombotic complications, which can be explained by the complex and unique interplay between coronaviruses and endothelial cells, the local and systemic inflammatory response, and the coagulation system. Empirically, an intensified dose of thrombosis prophylaxis is being used in patients admitted to hospital with COVID-19 and several guidelines on this topic have been published, although the insufficiency of high quality and direct evidence has led to weak recommendations. In this Viewpoint we summarise the pathophysiology of COVID-19 coagulopathy in the context of patients who are ambulant, admitted to hospital, and critically ill or non-critically ill, and those post-discharge from hospital. We also review data from randomised controlled trials in the past year of antithrombotic therapy in patients who are critically ill. These data provide the first high-quality evidence on optimal use of antithrombotic therapy in patients with COVID-19. Pharmacological thromboprophylaxis is not routinely recommended for patients who are ambulant and post-discharge. A first ever trial in non-critically ill patients who were admitted to hospital has shown that a therapeutic dose of low-molecular-weight heparin might improve clinical outcomes in this population. In critically ill patients, this same treatment does not improve outcomes and prophylactic dose anticoagulant thromboprophylaxis is recommended. In the upcoming months we expect numerous data from the ongoing antithrombotic COVID-19 studies to guide clinicians at different stages of the disease.http://www.thelancet.com/haematologyam2022Medical Oncolog