To form or not to form a reaction complex: exploring ion-molecule reactions between C3H4 isomers and Xe+ and O2.

Ion-molecule reactions are an essential contributor to the chemistry of a diverse range of environments. While a great deal of work has been done to understand the fundamental mechanisms driving these reactions, there is still much more to discover. Here, we expand upon prior studies on ion-molecule reactions involving two isomers of C3H4, allene (H2C3H2) and propyne (H3C3H). Specifically, we probe the previously observed isomeric dependent reactivity of these molecules by reacting them with two ions with nearly identical ionization potentials, Xe+ and O2+. Our goal is to determine if the isomer-dependent reaction mechanisms previously observed are universal for C3H4 or if they depend on the ion character as well. Through the combination of experimental measurements and theoretical calculations, we found that both isomeric structure and identity of the ion contribute to the propensity of a reaction complex forming or for only long-range charge transfer to occur.

Snakebite in South Africa: A retrospective review May 2015-June 2020.

Snakebite envenoming in Sub-Saharan Africa present a significant public health problem. An investigation into how often species responsible for envenomation were correctly identified, as well as which venomous species caused the most frequent and problematic envenomation symptomatology were conducted to establish severity of this problem from a South African context. Descriptive statistics were used to quantitatively describe the variables in snakebite related Telelog call records reported to the Poison Information Helpline of the Western Cape (PIHWC) over a five-year period. A total of 1411 snakebite related calls were received. In 44% of all snakebite calls the bite was inflicted by an unidentified snake specie. The most snakebites occurred during the summer months from December-March. The most bites occurred in males (20-39 years). The incidence of snakebite in South Africa was 2.39 per 100 000 population, with the highest incidence of snakebite in North-West province of South Africa. In sub-Saharan Africa there is a major underestimation of the incidence of snakebite due to under reporting and absence of physical attendance to health care facilities. The PIHWC provides an invaluable service in assisting and in-forming medical personnel and the public on the management of snakebites. Data collected by centers provides a source of information on the prevalence of snakebites and medically important species that research should be aimed towards.

Ivermectin exposures reported to the Poisons Information Helpline in South Africa during the COVID-19 pandemic.

BACKGROUND: Ivermectin is an antiparasitic drug that has shown in vitro activity against COVID­19. Clinical studies supporting ivermectin for COVID­19 prevention and treatment are conflicting, with important limitations. Public support for ivermectin is significant, with extensive off-label use despite the conflicting views on its efficacy. Ivermectin tablets and injectable formulations are not registered in South Africa for human use by the South African Health Products Regulatory Authority. The National Department of Health does not currently recommend the use of ivermectin for COVID­19. OBJECTIVES: To describe cases of ivermectin exposure reported to the Poisons Information Helpline of the Western Cape (PIHWC) before and after publication of the drug's in vitro activity against SARS-CoV-2. METHODS: In a retrospective review, ivermectin-related calls reported to the PIHWC from 1 June 2015 to 30 June 2020 (period 1) were compared with calls received from 1 July 2020 to 31 July 2021 (period 2), dichotomised according to the first publication indicating ivermectin activity against SARS-CoV-2. RESULTS: Seventy-one cases were screened, and 65 were included for analysis; 19 cases were reported during period 1 and 46 during period 2. During period 2, 25 ivermectin cases (54.3%) were related to COVID­19 use. Of these, 24 cases (52.2%) involved veterinary preparations, 3 (6.5%) human preparations and 19 (41.3%) unknown preparations. Fourteen cases (73.7%) during period 1 and 30 (65.2%) during period 2 were reported to be symptomatic. The most common organ systems involved were the central nervous (n=26 cases; 40.0%), gastrointestinal (n=18; 27.7%), ocular (n=9; 13.8%) and dermatological (n=5; 7.7%) systems. CONCLUSION: Ivermectin-related exposure calls increased during study period 2, probably as a result of ivermectin being used as preventive and definitive therapy for COVID­19 in the absence of robust evidence on efficacy, dosing recommendations or appropriate formulations.

Marker-less online MR-guided stereotactic body radiotherapy of liver metastases at a 1.5 T MR-Linac - Feasibility, workflow data and patient acceptance.

INTRODUCTION: Stereotactic body radiotherapy (SBRT) is an established ablative treatment for liver tumors with excellent local control rates. Magnetic resonance imaging guided radiotherapy (MRgRT) provides superior soft tissue contrast and may therefore facilitate a marker-less liver SBRT workflow. The goal of the present study was to investigate feasibility, workflow parameters, toxicity and patient acceptance of MRgSBRT on a 1.5 T MR-Linac. METHODS: Ten consecutive patients with liver metastases treated on a 1.5 T MR-Linac were included in this prospective trial. Tumor delineation was performed on four-dimensional computed tomography scans and both exhale triggered and free-breathing T2 MRI scans from the MR-Linac. An internal target volume based approach was applied. Organ at risk constraints were based on the UKSABR guidelines (Version 6.1). Patient acceptance regarding device specific aspects was assessed and toxicity was scored according to the common toxicity criteria of adverse events, version 5. RESULTS: Nine of ten tumors were clearly visible on the 1.5 T MR-Linac. No patient had fiducial markers placed for treatment. All patients were treated with three or five fractions. Median dose to 98% of the gross tumor volume was 38.5 Gy. The median time from "patient identity check" until "beam-off" was 31 min. Median beam on time was 9.6 min. Online MRgRT was well accepted in general and no treatment had to be interrupted on patient request. No event of symptomatic radiation induced liver disease was observed after a median follow-up of ten month (range 3-17 months). CONCLUSION: Our early experience suggests that online 1.5 T MRgSBRT of liver metastases represents a promising new non-invasive marker-free treatment modality based on high image quality, clinically reasonable in-room times and high patient acceptance. Further studies are necessary to assess clinical outcome, to validate advanced motion management and to explore the benefit of online response adaptive liver SBRT.

Core competencies required by toxicology graduates in order to function effectively in a Poisons Information Centre: A Delphi study.

INTRODUCTION: The availability of trained Medical Toxicologists in developing countries is limited and education in Medical Toxicology remains inadequate. The lack of toxicology services contributes to a knowledge gap in the management of poisonings. A need existed to investigate the core competencies required by toxicology graduates to effectively operate in a Poisons Information Centre. The aim of this study was to obtain consensus from an expert group of health care workers on these core competencies. This was done by making use of the Delphi technique. METHODOLOGY: The Delphi survey started with a set of carefully selected questions drawn from various sources including a literature review and exploration of existing curricula. To capture the collective opinion of experts in South Africa, Africa and also globally, three different groups were invited to participate in the study. To build and manage the questionnaire, the secure Research Electronic Data Capture (REDCap) web platform was used. RESULTS: A total of 134 competencies were selected for the three rounds and in the end consensus was reached on 118 (88%) items. Panel members agreed that 113 (96%) of these items should be incorporated in a Medical Toxicology curriculum and five (4%) should be excluded. DISCUSSION: All participants agreed that effective communication is an essential skill for toxicology graduates. The curriculum can address this problem by including effective pedagogy to enhance oral and written communication skills.Feedback from panellists indicated that the questionnaires were country-specific and not necessarily representative of all geographical locations. This is an example of the 'battle of curriculum design' where the context in which the curriculum will be used, will determine the content. CONCLUSION: The Delphi method, based on three iterative rounds and feedback from experts, was effective in reaching consensus on the learning outcomes of a Medical Toxicology curriculum. The study results will ultimately improve education in Medical Toxicology.

Berg adder (Bitis atropos): An unusual case of acute poisoning.

A 5-year-old boy presented to hospital with mild local cytotoxic and severe neurotoxic symptoms. The neurotoxic symptoms included ptosis, fixed dilated pupils and flaccid paralysis with respiratory failure. Mild hyponatraemia was also a clinical feature. After various unsuccessful treatment options were followed, the Tygerberg Poison Information Centre was contacted and a diagnosis of berg adder bite was made. Berg adder bites are uncommon and therefore not usually considered in the differential diagnosis of a patient presenting with an unexplained clinical picture. A timeous poison information helpline consultation is recommended in this situation.

Antibody H3 Structure Prediction.

Antibodies are proteins of the immune system that are able to bind to a huge variety of different substances, making them attractive candidates for therapeutic applications. Antibody structures have the potential to be useful during drug development, allowing the implementation of rational design procedures. The most challenging part of the antibody structure to experimentally determine or model is the H3 loop, which in addition is often the most important region in an antibody's binding site. This review summarises the approaches used so far in the pursuit of accurate computational H3 structure prediction.