Mechanisms of systemic resistance to pathogen infection in plants and their potential application in forestry.

BACKGROUND: The complex systemic responses of tree species to fight pathogen infection necessitate attention due to the potential for yield protection in forestry. RESULTS: In this paper, both the localized and systemic responses of model plants, such as Arabidopsis and tobacco, are reviewed. These responses were compared to information available that investigates similar responses in woody plant species and their key differences were highlighted. In addition, tree-specific responses that have been documented were summarised, with the critical responses still relying on certain systemic acquired resistance pathways. Importantly, coniferous species have been shown to utilise phenolic compounds in their immune responses. Here we also highlight the lack of focus on systemic induced susceptibility in trees, which can be important to forest health. CONCLUSIONS: This review highlights the possible mechanisms of systemic response to infection in woody plant species, their potential applications, and where research may be best focused in future.

The unbearable loneliness of COVID-19: COVID-19-related correlates of loneliness in South Africa in young adults.

This is the first study to examine the association between COVID-19 related variables and loneliness among young adults in South Africa during COVID-19. Participants (N=337) were university students who completed the UCLA Loneliness Scale and five selected subscales of the WHO COVID-19 Behavioural Insights Tool. The mean loneliness scores were significantly higher than previous studies in other contexts as well as studies conducted in the time of COVID-19. Correlational analysis found that greater perceived risk of infection, limited perceived knowledge of COVID-19 and lower appraisals of resilience were associated with increased loneliness. In a regression analysis, when all COVID-19 variables were considered simultaneously, only resilience, self-rated knowledge, and risk perception emerged as significant correlates of loneliness. These findings suggest that loneliness is a significant public health concern in South Africa in the time of COVID-19. It also suggests that self-efficacy and resilience can potentially be reinforced by public health campaigns that focus on enhancing COVID-19-related knowledge and preparedness.

A multicentre cross-sectional descriptive study evaluating the cardiovascular risk profile of preoperatively identified patients with hypertension.

BACKGROUND: The prevalence of hypertension in adults in South Africa (SA) is 35%. Hypertension is the most important modifiable risk factor for cardiovascular (CV) and chronic kidney disease (CKD) in sub-Saharan Africa. However, 49% of people are unaware of their blood pressure status. Screening for hypertension prior to surgery provides a unique opportunity to diagnose and treat affected individuals. Furthermore, assessing overall CV risk identifies patients at highest risk for complications, and improves the utilisation of scarce resources. OBJECTIVES: To evaluate the CV risk profile of hypertensive patients in the adult population of the Western Cape Province presenting for elective non-cardiac, non-obstetric surgery. METHODS: This report documents the CV risk profile of patients recruited to the HASS-2 study (Hypertension and Surgery Study 2), which was undertaken in seven Western Cape hospitals. Patients were screened for hypertension and pharmacological treatment was initiated or adjusted in patients with stages 1 and 2 disease. Stage 3 patients were referred to a physician. In the present substudy, patients with stages 1 and 2 hypertension were assessed for associated CV risk factors, the presence of target organ damage, and documented CV or kidney disease; they received an overall risk stratification according to the 2018 European Society of Cardiology and the European Society of Hypertension Guidelines. RESULTS: Sixty-one patients with stage 1 and 12 with stage 2 hypertension were analysed. Established CV disease was present in 13.7% of the study population, and CKD (eGFR <60 mL/min) in 10.8%. Seventy-one percent of the study group had a raised body mass index, and 55.9% underlying metabolic syndrome. Prediabetes and diabetes were present in 16.1% and 14.5%, respectively. According to the 2018 European guidelines, 34.7% were at moderate, 33.3% at high and 16.7% at very high risk for a CV event in the following 10 years. CONCLUSIONS: The perioperative period is a critical time during which surgeons, nurses and anaesthetists can influence patients' CV risk of adverse events. This involves appropriate screening, education and treatment. In this study population, nearly 9 out of 10 elective surgical patients with stage 1 or 2 hypertension had CV risk factors placing them at moderate to very high risk. The simultaneous assessment of these additional CV risk parameters, in addition to diagnosis and management of hypertension, may further decrease the health and financial burden in resource-limited facilities in SA, and improve CV outcomes.

A multicentre prospective observational study of the prevalence of preoperative anaemia and iron deficiency in adult elective surgical patients in hospitals in Western Cape Province, South Africa.

BACKGROUND: Preoperative anaemia has been shown to be an independent risk factor for postoperative morbidity and mortality. Iron deficiency is the leading cause of anaemia globally. There are limited data describing the burden of perioperative anaemia and the relative contribution of iron deficiency in South Africa (SA). OBJECTIVES: To determine the prevalence and severity of preoperative anaemia in adults presenting for elective surgery in Western Cape Province, SA, and to investigate the contribution of iron deficiency as a cause of the anaemia. For this purpose, an investigative protocol from a recent consensus statement on the management of perioperative anaemia was applied. METHODS: We performed a prospective, observational study in adult patients presenting for elective non-cardiac, non-obstetric surgery over a 5-day period at six Western Cape government-funded hospitals. The World Health Organization patient classification was applied, and patients with anaemia were investigated for iron deficiency. RESULTS: The prevalence of preoperative anaemia was 28% (105/375; 95% confidence interval (CI) 23.5 - 32.5); 55/105 patients (52%) had moderate and 11/105 (11%) severe anaemia. Iron deficiency was the cause of anaemia in 37% (32/87; 95% CI 26.6 - 46.9), but only 9% of iron-deficient patients received iron supplementation prior to surgery. CONCLUSIONS: Preoperative anaemia was common in this study, and more than half of the affected patients had moderate to severe anaemia. Iron deficiency was responsible for almost 40% of cases. Iron supplementation was under-utilised in the preoperative period as a means of increasing haemoglobin. The introduction of system-wide policies would empower perioperative physicians to mitigate the risk associated with preoperative anaemia in the Western Cape.

A multicentre prospective observational study of the prevalence and glycaemic control of diabetes mellitus in adult non-cardiac elective surgical patients in hospitals in Western Cape Province, South Africa.

BACKGROUND: Diabetes mellitus (DM) is a common condition. The high burden of undiagnosed DM and a lack of large population studies make accurate prevalence estimations difficult, especially in the surgical environment. Furthermore, poorly controlled DM is associated with an increased risk of perioperative complications and mortality. OBJECTIVES: The primary objective was to establish the prevalence of DM in elective adult non-cardiac, non-obstetric surgical patients in hospitals in Western Cape Province, South Africa. The secondary objectives were to assess the glycaemic control and compliance with treatment of known diabetics. METHODS: A 5-day multicentre, prospective observational study was performed at six government-funded hospitals in the Western Cape. Screening for DM was done using finger-prick capillary blood glucose (CBG) testing. Patients found to have a CBG ≥6.5 mmol/L had their glycated haemoglobin (HbA1c) level measured. DM was diagnosed based on the Society for Endocrinology, Metabolism and Diabetes of South Africa (SEMDSA) diagnostic criteria. Patients known to have DM had their HbA1cmeasured and completed a Morisky Medication Adherence Scale (MMAS-4) questionnaire to assess glycaemic control and compliance with treatment. RESULTS: Of the 379 participants, 61 were known diabetics (16.2%; 95% confidence interval (CI) 12.4 - 19.8). After exclusion of 8 patients with incomplete results, a new diagnosis of DM was made in 5/310 patients (1.6%; 95% CI 0.2 - 3.0). The overall prevalence of DM was 17.8% (66/371; 95% CI 13.9 - 21.7). HbA1c results were available for 57 (93.4%) of the 61 known diabetics. Of these, 27 (47.4%; 95% CI 34.4 - 60.3) had an HbA1c level ≥8.5% and 14 (24.6%; 95% CI 13.4 - 35.8) had a level ≤7%. Based on positive responses to two or more questions on the MMAS-4 questionnaire, 12/60 participants (20.0%) were deemed non-compliant. CONCLUSIONS: There is a low rate of undiagnosed DM in our elective surgical population, but in a high proportion of patients with DM the condition is poorly controlled. Poorly controlled DM is known to increase postoperative complications and is likely to increase the burden of perioperative care. Resources should be focused on improvement of long-term glycaemic control in patients presenting for elective surgery.

A multicentre, cross-sectional study investigating the prevalence of hypertensive disease in patients presenting for elective surgery in the Western Cape Province, South Africa.

BACKGROUND: Hypertension is common, affecting over one billion people worldwide. In sub-Saharan Africa, hypertensive disease not only affects the older population but is becoming increasingly prevalent in younger individuals. In South Africa (SA), >30% of the adult population has hypertension, making it the single most common cardiovascular risk factor and the predominant contributor to cardiovascular disease and mortality. Elevated blood pressure is the most common perioperative comorbidity encountered in non-cardiac surgical patients, with an overall prevalence of 20 - 25%, and it remains poorly controlled in low- and middle-income countries. Hypertension in the perioperative setting may adversely affect patient outcome. It therefore not only flags possible perioperative challenges to anaesthesiologists, but also identifies patients at risk of long-term morbidity and mortality. OBJECTIVES: To determine the prevalence and severity of hypertension in elective adult surgical patients in the Western Cape Province, SA. RESULTS: The study population included all elective surgical patients from seven hospitals in the Western Cape during a 1-week period. Hypertension, defined as having had a previous diagnosis of hypertension or meeting the blood pressure criteria of >140/90 mmHg, was identified in 51.8% of patients during preoperative assessment. Significantly, newly diagnosed hypertension was present in 9.9% of all patients presenting for elective surgery. Although 98.1% of the known hypertensive patients were on antihypertensive therapy, 36.9% were inadequately controlled. There are numerous reasons for this, but notably 32.1% of patients admitted to forgetting to take their medication, making patient factors the most common reason for treatment non-compliance. CONCLUSIONS: The perioperative period may be an important opportunity to identify undiagnosed hypertensive patients. The perioperative encounter may have a significant public health implication in facilitating appropriate referral and treatment of patients with hypertension to decrease long-term cardiovascular complications in SA.

Optimising perioperative care for hip and knee arthroplasty in South Africa: a Delphi consensus study.

BACKGROUND: A structured approach to perioperative patient management based on an enhanced recovery pathway protocol facilitates early recovery and reduces morbidity in high income countries. However, in low- and middle-income countries (LMICs), the feasibility of implementing enhanced recovery pathways and its influence on patient outcomes is scarcely investigated. To inform similar practice in LMICs for total hip and knee arthroplasty, it is necessary to identify potential factors for inclusion in such a programme, appropriate for LMICs. METHODS: Applying a Delphi method, 33 stakeholders (13 arthroplasty surgeons, 12 anaesthetists and 8 physiotherapists) from 10 state hospitals representing 4 South African provinces identified and prioritised i) risk factors associated with poor outcomes, ii) perioperative interventions to improve outcomes and iii) patient and clinical outcomes necessary to benchmark practice for patients scheduled for primary elective unilateral total hip and knee arthroplasty. RESULTS: Thirty of the thirty-three stakeholders completed the 3 months Delphi study. The first round yielded i) 36 suggestions to preoperative risk factors, ii) 14 (preoperative), 18 (intraoperative) and 23 (postoperative) suggestions to best practices for perioperative interventions to improve outcomes and iii) 25 suggestions to important postsurgical outcomes. These items were prioritised by the group in the consecutive rounds and consensus was reached for the top ten priorities for each category. CONCLUSION: The consensus derived risk factors, perioperative interventions and important outcomes will inform the development of a structured, perioperative multidisciplinary enhanced patient care protocol for total hip and knee arthroplasty. It is anticipated that this study will provide the construct necessary for developing pragmatic enhanced care pathways aimed at improving patient outcomes after arthroplasty in LMICs.

The relationship between pre-operative hypertension and intra-operative haemodynamic changes known to be associated with postoperative morbidity.

Hypertension is not consistently associated with postoperative cardiovascular morbidity and is therefore not considered a major peri-operative risk factor. However, hypertension may predispose to peri-operative haemodynamic changes known to be associated with peri-operative morbidity and mortality, such as intra-operative hypotension and tachycardia. The objective of this study was to determine whether pre-operative hypertension was independently associated with haemodynamic changes known to be associated with adverse peri-operative outcomes. We performed a five-day multicentre, prospective, observational cohort study which included all adult inpatients undergoing elective, non-cardiac, non-obstetric surgery. We recruited 343 patients of whom 164 (47.8%) were hypertensive. An intra-operative mean arterial pressure of < 55 mmHg occurred in 59 (18.2%) patients, of which 25 (42.4%) were hypertensive. Intra-operative tachycardia (heart rate> 100 beats.min-1 ) occurred in 126 (38.9%) patients, of whom 61 (48.4%) were hypertensive. Multivariable logistic regression did not show an independent association between the stage of hypertension and either clinically significant hypotension or tachycardia, when controlled for ASA physical status, functional status, major surgery, duration of surgery or blood transfusion. There was no association between pre-operative hypertension and peri-operative haemodynamic changes known to be associated with major morbidity and mortality. These data, therefore, support the recommendation of the Joint Guidelines of the Association of Anaesthetists of Great Britain and Ireland (AAGBI) and the British Hypertension Society to proceed with elective surgery if a patient's blood pressure is < 180/110 mmHg.

The influence of fluid management on outcomes in preeclampsia: a systematic review and meta-analysis.

BACKGROUND: The optimal fluid management strategy to ensure best outcomes in preeclamptic patients remains a controversial issue, with little evidence to support any one approach. OBJECTIVE: The aim of this systematic review was to investigate the effect of various fluid management strategies on clinical outcomes, haemodynamic indices and biochemical markers in preeclamptic women and their babies. Primary outcome measures were the occurrence of pulmonary oedema and/or the development of renal impairment. METHODS: A systematic review of randomised fluid management strategies was conducted. Five electronic databases were searched using the expanded search terms: 'intravenous fluid', 'plasma substitutes', 'intravenous fluid management', 'intravenous fluid therapy', plasma volume expansion', 'fluid restriction', 'oncotic therapy', 'crystalloids', 'colloids', 'preeclampsia', 'toxemia of pregnancy', 'pregnancy-induced hypertension', 'eclampsia' and 'gestational proteinuric hypertension'. RESULTS: Six randomised controlled trials (RCTs), from nine publications, were included in the final analysis. There were no differences between groups with respect to the incidence of pulmonary oedema, perinatal mortality, preterm delivery and caesarean section. Colloid volume expansion was associated with a significantly lower systolic and diastolic blood pressure, but had no effect on heart rate or cardiac index. Data on systemic vascular resistance (SVR), serum atrial natriuretic peptide (ANP) and urine volume could not be aggregated. CONCLUSION: Data on the ideal fluid strategy in women with preeclampsia is limited, and insufficient to make any strong recommendations. Further randomised controlled studies are needed to provide more evidence for which fluid management strategies are best suited to this heterogeneous patient group.

Measuring life events in a sample of South African students: comparison of the Life Experiences Survey and the Schedule of Recent Experiences.

This study compared the Life Experiences Survey and the Schedule of Recent Experiences for a sample of 213 students. Scores on the Life Experiences Survey-Negative discriminated between rural and urban students and between African language speakers and Afrikaans/English speakers. A small but significant correlation between Life Experiences Survey-Negative and scores on the Center for Epidemiological Studies-Depression scale was found, while there was no correlation between scores on the Schedule of Recent Experiences with depression. The Life Experiences Survey-Negative was the only significant predictor of Depression scores. The Life Experiences Survey-Negative interacted significantly with all the measures of social support (Friends, Family, Satisfaction, and Number of Supports) in predicting depression, while the Schedule of Recent Experiences only interacted significantly with support from Family and Number of Supports. The study also provides support for clearly distinguishing between desirable and undesirable events, since positive events moderated the correlation of negative events with depression. The Life Experiences Survey is a more promising measure of life events than the Schedule of Recent Experiences in the South African context.

Using the Maslach Burnout Inventory to assess educators' burnout at a university in South Africa.

Use of the Maslach Burnout Inventory with 94 faculty members at the University of the Western Cape, South Africa is described. Analysis indicated that the inventory can be considered a reliable measure of burnout in this educational setting. Confirmatory factor analysis indicated that the factorial structure of the scale was similar to those previously reported for educational groups in North America. Multiple regression analysis also indicated the significant predictors of the components of burnout in the present study (role conflict, role ambiguity, participation in decision-making, and number of students) are similar to those previously identified.

Problem-solving appraisal in the association of life stress and depression: a South African study.

This study focuses on the role that appraisal of problem-solving skills plays in the relationship of stress to distress. 450 black South African university students completed the Life Experiences Survey, the Problem Solving Inventory, and the Centre for Epidemiological Studies Depression Scale. Multiple regression analysis indicated a direct effect for problem-solving appraisal on depression, but no support could be found for the stress-buffering effects of problem-solving appraisal.

Cross-cultural application of the Center for Epidemiological Studies Depression Scale: a study of black South African students.

This article reports normative and psychometric data for the Center for Epidemiological Studies Depression Scale when used with black South African students. Subjects were 450 undergraduate students in psychology. The reliability, validity, and factor structure of the scale were consistent with previously reported findings. The correlations of CES-Depression Scale scores with certain demographic variables are also reported.

Instantaneous transmitral flow using Doppler and M-mode echocardiography: comparison with radionuclide ventriculography.

To improve the accuracy of Doppler echocardiographic indices of left ventricular filling, we derived two indices of instantaneous transmitral flow with the use of Doppler velocities and M-mode echocardiography. These indices were calculated from the product of pulsed Doppler mitral velocities and either the excursion of the anterior mitral leaflet or the separation of both mitral leaflets as measures of the changing mitral orifice area. The derived flow indices and the mitral velocities alone were compared to left ventricular filling as determined by radionuclide ventriculography in 24 patients. When compared as areas under the matched decile divisions of the derived filling sequences by linear regression analysis, the relationship for combined Doppler and M-mode versus radionuclide left ventricular filling was closer to the line of identity (slope = 0.98 and 0.94 using the anterior mitral leaflet and both mitral leaflets, respectively, both p = NS versus the line of identity) than was the relationship for mitral velocities alone versus radionuclide left ventricular filling (slope = 0.74, p less than 0.05 versus the line of identity). The instantaneous mitral volume flow indices more closely resemble the time course and shape of radionuclide left ventricular filling curves than do mitral velocities alone, and the application of these indices should assist the quantitative description by Doppler echocardiography of left ventricular filling.