Pharmacological properties of members of the Sterculiaceae.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.There is a resurgence of interest in many countries in medicinal plants and their curative properties (HARBORNE & BAXTER, 1993). Little work has previously been conducted on the Sterculiaceae species, especially those located within South Africa. This was a perfect opportunity to broaden the available information on the medicinal properties and chemical constituents of this family, within KwaZulu-Natal. Of the 50 genera of the Sterculiaceae family, six are located in South Africa: Cola, Oombeya, Hermannia, Melhania, Sterculia and Waltheria . Seven Sterculiaceae species were chosen for investigation. They varied in growth type and use in traditional medicine. These species included: Oombeya rotundifolia, D. burgessiae, D. cymosa, Cola natalensis, C. greenwayi, Hermannia depressa and Sterculia murex. Plant material used in the study was collected from a variety of areas, all within KwaZulu-Natal or the Northern Province. There were two collection sites for D. rotundifolia, from differing habitats, and results were compared. The material was screened pharmacologically for anti-bacterial activity using the disc-diffusion assay and Minimal Inhibitory Assay (MIC), and for antiinflammatory activity using the COX-1 assay. Only D. rotundifolia and C. natalensis were tested for anti-bacterial activity using the disc-diffusion assay as the disc-diffusion asay was found to show inconsistencies in the results obtained. Bacteria used included: Escherichia coli and Klebsiella pneumoniae being Gram-negative, and Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis being Gram-positive. D. rotundifolia exhibited activity, both anti-bacterial and bacteriostatic, in the leaf, twig and bark extracts from both collection sites. Only the water extract obtained from the leaf material of C.natalensis exhibited slight anti-bacterial activity against S. epidermidis. Minimal inhibitory concentration (MIC) values were determined using a microdilution assay (25 mg ml-1 serially diluted 50 % to 0.195 mg ml-1). Bacteria used in the screening were: B. subtilis, E. coli, K. pneumoniae and S. aureus. None of the water extracts showed any antibacterial activity. Good MIC values were exhibited by D. cymosa ethanolic leaf extracts, C. greenwayi leaf ethyl acetate extracts especially against K. pneumoniae (0.78 mg ml-1) and S. aureus (0.39 mg rnl-1) and H. depressa ethanol and ethyl acetate leaf, stem and root extracts. D. burgessiae and S. murex showed low activity, with insignificant MIC values. D. rotundifolia plant material yielded the highest anti-inflammatory activity of all the plant species, with the extracts from the Umgeni Valley Nature Reserve(UVNR) showing the best results. The lowest activity was recorded in the aqueous bark extracts (5% inhibition)and the highest from the ethanolic leaf extract (97% inhibition). D. cymosa extracts showed high activity in ethanolic leaf and twig extracts with low activity in all the other extracts. D. burgessiae, C. greenwayi and S. murex extracts showed high activity in both ethanolic and dichloromethane extracts from leaf and twig material. Activity occurred in the dichloromethane extracts of H. depressa obtained from the stem (78%) and root (81%) extracts. C. natalensis extracts showed insignificant activity. Plant material was phytochemically screened for alkaloids, saponins, tannins, cardiac glycosides and cyanogenic glycosides. No alkaloids were detected using pH-partitioning and no cyanogenic glycosides were observed (TLC sandwich method) in any of the extracts of the seven species screened. Using the gelatin salt-block test, tannins were found to be present in the leaf and twig material of D. rotundifolia, the leaf material of C. greenwayi and the leaf, stem and root material of H depressa. The froth test indicated that saponins were present in the leaf and twig material of D. rotundifolia and leaf, root and stem material of H. depressa. The haemolysis test indicated the presence of saponins in the D. rotundifolia bark material. Screening for cardiac glycosides detected cardienolides in the leaf, twig and bark material of D. rotundifolia, and bufadienolides were detected in D. rotundifolia , D. cymosa, D. burgessiae and S. murex. Five species screened were selected for isolation of active anti-bacterial compounds: D. rotundifolia, D. burgessiae, D. cymosa, C. greenwayi and H. depressa. Material was extracted by Soxhlet and isolation techniques employed were VLC, TLC separation, Sephadex LH-20 column chromatography and HPLC techniques. The isolated compounds were analysed by NMR and GCMS. All isolated compounds were fatty acids: Palmitic acid, Myristic acid, Lauric acid, Stearic acid, Acetic acid as welll as stearyl alcohol, eicosane and octadecane. The aqueous eaf extract of H. Depressa exuded a thick mucilage. The production of this mucilage from the H. depressa aqueous extract may have medicinal or commercial value. A technique to separate the mucilaginous extract from the leaf material was devised. After extraction, the extract was screened to determine its sugar content through gas chromatography. It was screened for its pharmacological properties: antibacterial and anti-inflammatory activity. The hydrolysing effect of -amylase and HCI on the extract was determined to find its potential use as a bulking agent for use as an appetite suppressant, laxative or against the effects of diarrhoea. It was concluded that the extract is not likely to break down easily in the human digestive system and may be effective against the three listed ailments

Using quality assessment tools to critically appraise ageing research: a guide for clinicians

Evidence based medicine tells us that we should not accept published research at face value. Even research from established teams published in the highest impact journals can have methodological flaws, biases and limited generalisability. The critical appraisal of research studies can seem daunting, but tools are available to make the process easier for the non-specialist. Understanding the language and process of quality assessment is essential when considering or conducting research, and is also valuable for all clinicians who use published research to inform their clinical practice. We present a review written specifically for the practising geriatrician. This considers how quality is defined in relation to the methodological conduct and reporting of research. Having established why quality assessment is important, we present and critique tools which are available to standardise quality assessment. We consider five study designs: RCTs, nonrandomised studies, observational studies, systematic reviews and diagnostic test accuracy studies. Quality assessment for each of these study designs is illustrated with an example of published cognitive research. The practical applications of the tools are highlighted, with guidance on their strengths and limitations. We signpost educational resources and offer specific advice for use of these tools. We hope that all geriatricians become comfortable with critical appraisal of published research and that use of the tools described in this review – along with awareness of their strengths and limitations – become a part of teaching, journal clubs and practice

Differential Processing of Gaze Cueing from a Congruent and Incongruent Informant

Infants are known to be sensitive to, and be capable of, processing social information from birth. However, less is known about abilities related to actively choosing the information source on which to rely, over passively processing all available information. A recent study showed that 8-month-olds’ gaze following behaviour was influenced by the reliability of the informant (Tummeltshammer et al., 2014), suggesting that infants as young as 8 months of age might recognize whether the person in front of them is trustworthy. To better understand this discriminative ability of infants, the current study utilizes event-related potentials (ERPs), to investigate whether infants’ neural activity indicates the differentiation of a congruent informant (who always gives the correct gaze cue to the object location) from an incongruent informant (who only gives the correct gaze cue on 25% of trials). 9-month-old infants (N = 21) were presented with 32 static images in total which showed two female experimenters (16 images for each), one of whom looked at the object appearing on one of the corners 100% of the time (i.e. congruent informant) and the other only looked at the object 25 % of the time and looked away from the object 75% of the time (i.e. incongruent informant). A paired-sample t-test comparing between the congruent and incongruent informants showed that the amplitude of the negative deflection occurring at approximately 275ms post-stimuli over fronto-central regions was enhanced while infants were processing information given by a congruent informant (M= -15.05[µV], SD= 4.56), compared to when the information was given by an incongruent informant (M= -12.35[µV], SD= 3.79) (t= -2.49, p= .002). Previous studies have shown that a negative amplitude component occurring at around 400ms post-stimuli in 9-month infants (the negative component, or the Nc), has been associated with infants’ attentional allocation (e.g. Striano et al., 2006; Parise et al., 2008). While the negative peak observed in the present study is at an earlier latency than the Nc, this indicates a difference in neural processing of congruent and incongruent informants in 9-month-old infants. Furthermore, an enhanced positive slow wave (PSW) over fronto-temporal regions was observed for an incongruent informant (M= 9.27[µV], SD= 5.32) compared to a congruent informant (M= 6.12[µV], SD= 5.63) (t= -2.309, p=.003). As the PSW has been thought to reflect memory updating (Snyder, Webb & Nelson, 2002; Reid et al. 2004), this might reflect how infants alter their perception about the congruency of gaze cues during the short exposure to the information (16 per condition). In sum, the result demonstrates how quickly young infants can recognize the congruency of other people’s gaze cues. This study extends our understanding forward on how infants collect and process social information, as the current study offers evidence that infants as young as 9 months of age selectively process sources of information differentially in the social domain, which might enable them to learn efficiently at a social situation despite ample and complex information present

The dark art of interpretation in geomorphology

The process of interpretation, and the ways in which knowledge builds upon interpretations, has profound implications in scientific and managerial terms. Despite the significance of these issues, geomorphologists typically give scant regard to such deliberations. Geomorphology is not a linear, cause-and-effect science. Inherent complexities and uncertainties prompt perceptions of the process of interpretation in geomorphology as a frustrating form of witchcraft or wizardry – a dark art. Alternatively, acknowledging such challenges recognises the fun to be had in puzzle-solving encounters that apply abductive reasoning to make sense of physical landscapes, seeking to generate knowledge with a reliable evidence base. Carefully crafted approaches to interpretation relate generalised understandings derived from analysis of raw data with field observations/measurements and local knowledge to support appropriately contextualised place-based applications. In this paper we develop a cognitive approach (Describe-Explain-Predict) to interpret landscapes. Explanation builds upon meaningful description, thereby supporting reliable predictions, in a multiple lines of evidence approach. Interpretation transforms data into knowledge to provide evidence that supports a particular argument. Examples from fluvial geomorphology demonstrate the data-interpretation-knowledge sequence used to analyse river character, behaviour and evolution. Although Big Data and machine learning applications present enormous potential to transform geomorphology into a data-rich, increasingly predictive science, we outline inherent dangers in allowing prescriptive and synthetic tools to do the thinking, as interpreting local differences is an important element of geomorphic enquiry

Dissociating associative and motor aspects of action understanding:processing of dual-ended tools by 16-month-old infants.

When learning about the functions of novel tools, it is possible that infants may use associative and motoric processes. This study investigated the ability of 16-month-olds to associate the orientation in which an actor held a dual-function tool with the actor's prior demonstrated interest in one of two target objects, and their use of the tool on that target. The actors' hand posture did not differ between conditions. The infants were shown stimuli in which two actors acted upon novel objects with a novel tool, each actor employing a different function of the tool. Using an eye-tracker, infants' looking time at images depicting the actors holding the tool in an orientation congruent or incongruent with the actor's goal was measured. Infants preferred to look at the specific part of the tool that was incongruent with the actor's goal. Results show that the association formed involves the specific part of the tool, the actor, and the object the actor acted upon, but not the orientation of the tool. The capacity to form such associations is demonstrated in this study in the absence of motor information that would allow 16-month-olds to generate a specific representation of how the tool should be held for each action via mirroring processes

Can neural activities during the traditional Piagetian AB search task explain infants’ perseverative search error? : Preliminary results

Since the infant perseverative error (AB error) was first reported by Piaget in 1954, these findings have been well replicated. Yet there is no general agreement on why the error occurs and what aspect of infants’ cognition AB error reflects. Since looking and reaching measures have yielded mixed evidence of infant ability, neurological measures indexing online cognitive processes may shed light on the mechanisms underlying the error, clarifying how different experimental manipulations may highlight different aspects of infants’ cognition involved in the error. In this pilot study, we monitored neural activities while infants engaged in the task in a live setting. We tested 50 9-month-old infants and the final sample consisted of the data from 36 infants. EEG data collected during a 5-second delay period between infants’ observing the toy being hidden and their being allowed to search were grouped into 4 conditions according to the phase (A- or B-trial) and their performance (accurate or inaccurate). The result indicated that theta-band oscillatory activities might perhaps predict infants’ search performance. However, due to the small number of data and large individual differences, none of the statistical comparisons found a significant difference across conditions. Nevertheless, a methodological procedure and analysis pipeline for future EEG research using a live AB task has been established. This pilot study has positioned us ready to untangle a complex cognitive process involved in a behavioural task such as this AB search task utilising a neurological measure

Aerosol emission from the respiratory tract:an analysis of aerosol generation from oxygen delivery systems

INTRODUCTION: continuous positive airway pressure (CPAP) and high-flow nasal oxygen (HFNO) provide enhanced oxygen delivery and respiratory support for patients with severe COVID-19. CPAP and HFNO are currently designated as aerosol-generating procedures despite limited high-quality experimental data. We aimed to characterise aerosol emission from HFNO and CPAP and compare with breathing, speaking and coughing. MATERIALS AND METHODS: Healthy volunteers were recruited to breathe, speak and cough in ultra-clean, laminar flow theatres followed by using CPAP and HFNO. Aerosol emission was measured using two discrete methodologies, simultaneously. Hospitalised patients with COVID-19 had cough recorded using the same methodology on the infectious diseases ward. RESULTS: In healthy volunteers (n=25 subjects; 531 measures), CPAP (with exhalation port filter) produced less aerosol than breathing, speaking and coughing (even with large >50 L/min face mask leaks). Coughing was associated with the highest aerosol emissions of any recorded activity. HFNO was associated with aerosol emission, however, this was from the machine. Generated particles were small (<1 µm), passing from the machine through the patient and to the detector without coalescence with respiratory aerosol, thereby unlikely to carry viral particles. More aerosol was generated in cough from patients with COVID-19 (n=8) than volunteers. CONCLUSIONS: In healthy volunteers, standard non-humidified CPAP is associated with less aerosol emission than breathing, speaking or coughing. Aerosol emission from the respiratory tract does not appear to be increased by HFNO. Although direct comparisons are complex, cough appears to be the main aerosol-generating risk out of all measured activities

The key challenges of discussing end-of life stroke care with patients and families: a mixed-methods electronic survey of hospital and community healthcare professionals

Background: Communication between professionals, patients and families about palliative and end-of-life care after stroke is complex and there is a need for educational resources in this area. Methods: To explore the key learning needs of healthcare professionals, a multidisciplinary, expert group developed a short electronic survey with open and closed questions, and then distributed it to six UK multiprofessional networks and two groups of local clinicians. Results: A total of 599 healthcare professionals responded. Educational topics that were either definitely or probably needed were: ensuring consistent messages to families and patients (88%); resolving conflicts among family members (83%); handling unrealistic expectations (88%); involving families in discussions without them feeling responsible for decisions (82%); discussion of prognostic uncertainties (79%); likely mode of death (72%); and oral feeding for 'comfort' in patients at risk of aspiration (71%). The free-text responses (n = 489) and 82 'memorable' cases identified similar themes. Conclusion: Key topics of unmet need for education in end-of-life care in stroke have been identified and these have influenced the content of an open access, web-based educational resource