Pulmonary hypertension and the potential of 'drug' repurposing: A case for African medicinal plants.

Abstract: Pulmonary hypertension (PH) is a haemodynamic disorder in which elevated blood pressure in the pulmonary circulation is caused by abnormal vascular tone. Despite advances in treatment, PH mortality remains high, and drug repurposing has been proposed as a mitigating approach. This article reviews the studies that have investigated drug repurposing as a viable option for PH. We provide an overview of PH and highlight pharmaceutical drugs with repurposing potential, based on limited evidence of their mechanisms of action. Moreover, studies have demonstrated the benefits of medicinal plants in PH, most of which are of Indian or Asian origin. Africa is a rich source of many medicinal plants that have been scientifically proven to counteract myriad pathologies. When perusing these studies, one will notice that some African medicinal plants can counteract the molecular pathways (e.g. proliferation, vasoconstriction, inflammation, oxidative stress and mitochondrial dysfunction) that are also involved in the pathogenesis of PH. We review the actions of these plants with actions applicable to PH and highlight that they could be repurposed as adjunct PH therapies. However, these plants have either never been tested in PH, or there is little evidence of their actions against PH. We therefore encourage caution, as more research is needed to study these plants further in experimental models of PH while acknowledging that the outcomes of such proof of-concept studies may not always yield promising findings. Regardless, this article aims to stimulate future research that could make timely contributions to the field. Study synopsis: What the study adds. Pulmonary hypertension (PH) remains a fatal disease, and 80% of the patients live in developing countries where resources are scarce and specialised therapies are often unavailable. Drug repurposing is a viable option to try to improve treatment outcomes.Implications of the findings. We propose that another form of 'drug' repurposing is the use of medicinal plants, many of which have demonstrated benefits against pathological processes that are also key in PH, e.g. apoptosis, tumour-like growth of cells, proliferation, oxidative stress and mitochondrial dysfunction.

Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling.

There is a considerable interest to investigate surface crystallization in order to have a full mechanistic understanding of how layers of sparingly soluble salts (scale) build on component surfaces. Despite much recent attention, a suitable methodology to improve on the understanding of the precipitation/deposition systems to enable the construction of an accurate surface deposition kinetic model is still needed. In this work, an experimental flow rig and associated methodology to study mineral scale deposition is developed. The once-through flow rig allows us to follow mineral scale precipitation and surface deposition in situ and in real time. The rig enables us to assess the effects of various parameters such as brine chemistry and scaling indices, temperature, flow rates, and scale inhibitor concentrations on scaling kinetics. Calcium carbonate (CaCO3) scaling at different values of the saturation ratio (SR) is evaluated using image analysis procedures that enable the assessment of surface coverage, nucleation, and growth of the particles with time. The result for turbidity values measured in the flow cell is zero for all the SR considered. The residence time from the mixing point to the sample is shorter than the induction time for bulk precipitation; therefore, there are no crystals in the bulk solution as the flow passes through the sample. The study shows that surface scaling is not always a result of pre-precipitated crystals in the bulk solution. The technique enables both precipitation and surface deposition of scale to be decoupled and for the surface deposition process to be studied in real time and assessed under constant condition.

Self-reported occupational health hazards and measured exposures to airborne impurities and noise in shoe repair work.

The authors identified occupational risk factors of shoe repairers and measured their exposures to organic solvents, dust, chromium, degradation products of synthetic shoe materials, and noise. Exposures were measured in 11 shops selected from the workplaces of 82 repairers who responded to a questionnaire about their work environments. The questions dealt with, e.g., chemicals used, work related diseases, perceived hazards in the environment, ventilation, and use of personal protective equipment. Solvent vapor concentration averaged 1.95 (range 0.01-13.2) times the occupational limit (OL) of the mixture during gluing, with higher levels in facilities with no mechanical ventilation. TWA concentrations of organic solvents averaged 0.34 (range 0.01-1.23) times OLs in the breathing-zone samples. Of all shoe repair shops in Finland, 30% had no mechanical ventilation. Concentrations of airborne particles were 0.07-1.01 mg/m3, and those of insoluble and hexavalent chromium 0.10-0.32 and 0.01-0.08 microg/m3, respectively, near roughing, scoring and finishing machines. Several polymer degradation products were present in the air during machining of shoes. Ventilation exchange rates in shops with natural ventilation were less than once/hour. The repairers' average exposure to noise was below 85 dB. They reported many work-related diseases such as rhinitis (prevalence 21%), musculoskeletal disorders (16%), and dermatitis (9%). Measured dust concentrations were low, but the shoe repairers considered dust to be the most common hazard.