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.

Population-level impact of beliefs and attitudes on vaccine decision-making in South Africa: results from the COVID-19 Vaccine Survey (2021/2022).

OBJECTIVES: In addition to being home to more than seven million HIV-infected individuals, South Africa also has a high burden of COVID-19 and related comorbidities worldwide. We aimed to identify the most influential "beliefs" and "attitudes" on vaccine decision-making behavior. STUDY DESIGN: This study used panel data from cross-sectional surveys. METHODS: We used the data from Black South Africans who participated in the "COVID-19 Vaccine Surveys" (November 2021 and February/March 2022) in South Africa. Besides standard risk factor analysis, such as multivariable logistic regression models, we also used the modified version of population attributable risk percent and estimated the population-level impacts of beliefs and attitudes on vaccine decision-making behavior using the methodology in multifactorial setting. RESULTS: A total of 1399 people (57% men and 43% women) who participated in both surveys were analyzed. Of these, 336 (24%) reported being vaccinated in survey 2. Overall low perceived risk, concerns around efficacy, and safety were identified as the most influential factors and associated with 52%-72% (<40 years) and 34%-55% (40+ years) of the unvaccinated individuals. CONCLUSION: Our findings highlighted the most influential beliefs and attitudes on vaccine decision-making and their population-level impacts, which are likely to have significant public health implications exclusively for this population.

Artificial intelligence in healthcare: Proposals for policy development in South Africa.

Despite the tremendous promise offered by artificial intelligence (AI) for healthcare in South Africa, existing policy frameworks are inadequate for encouraging innovation in this field. Practical, concrete and solution-driven policy recommendations are needed to encourage the creation and use of AI systems. This article considers five distinct problematic issues which call for policy development: (i) outdated legislation; (ii) data and algorithmic bias; (iii) the impact on the healthcare workforce; (iv) the imposition of liability dilemma; and (v) a lack of innovation and development of AI systems for healthcare in South Africa. The adoption of a national policy framework that addresses these issues directly is imperative to ensure the uptake of AI development and deployment for healthcare in a safe, responsible and regulated manner.

Outcomes of paediatric patients ventilated in a high-care area outside an intensive care unit.

BACKGROUND: Limited availability of paediatric intensive care beds in the public sector is a major challenge in South Africa. It often results in patients being ventilated in a high-care area (HCA) outside an intensive care setting. The outcomes of paediatric patients ventilated outside a paediatric intensive care unit (ICU) are not well documented. OBJECTIVES: To describe characteristics and outcomes of patients ventilated in a paediatric HCA. METHODS: A retrospective chart review of children (0 - 16 years) requiring mechanical ventilation in the HCA at Chris Hani Baragwanath Academic Hospital, Johannesburg, between 1 February and 31 October 2015 was performed. RESULTS: A total of 214 patients required mechanical ventilation during the study period. Fifty-four percent were male and 91.1% were HIV-negative. The most common diagnoses were acute lower respiratory tract infections (59.3% of the post-neonatal group, 28.8% of the neonatal group) and sepsis (6.8% of the post-neonatal group, 28.8% of the neonatal group). The ultimate rate of acceptance to an ICU was 69.0%. Only 41.6% of cases referred to an ICU were initially accepted, with limited bed availability being the main reason for refusal. Patients with respiratory illnesses were more likely and those with neurological illness less likely to be accepted to an ICU. Patients with low-risk diagnoses were more likely to be accepted than those with very high-risk diagnoses. The overall mortality rate was 32.2%, with 52.2% of these deaths occurring in the HCA. Patients aged 1 - 5 years had the highest mortality rate (48.0%). Lower respiratory tract infections (36.8%) and sepsis (20.6%) were the main causes of death. The mortality rate of suitable ICU candidates in the HCA was higher than that in an ICU (33.3% v. 24.3%). The standardised mortality ratio (SMR), as predicted by the Paediatric Index of Mortality 3 score, for all patients who died in the HCA was 3.3, while the SMR for patients who died in an ICU was 1.3. The odds ratio for mortality of suitable candidates ventilated in the HCA v. patients who were ventilated in an ICU was 1.80 (95% confidence interval 1.39 - 6.03). CONCLUSIONS: Although a reasonable number of paediatric patients ventilated in an HCA survive, survival is lower than in those ventilated in an ICU. However, offering life-supporting therapies in an HCA may offer benefit where ICU care is unavailable. Emphasis needs to be placed on improving access to ICU care as well as optimising the use of available resources.

Bat thermoregulation in the heat: Limits to evaporative cooling capacity in three southern African bats.

High environmental temperatures pose significant physiological challenges related to energy and water balance for small endotherms. Although there is a growing literature on the effect of high temperatures on birds, comparable data are scarcer for bats. Those data that do exist suggest that roost microsite may predict tolerance of high air temperatures. To examine this possibility further, we quantified the upper limits to heat tolerance and evaporative cooling capacity in three southern African bat species inhabiting the same hot environment but using different roost types (crevice, foliage or cave). We used flow-through respirometry and compared heat tolerance limits (highest air temperature (Ta) tolerated before the onset of severe hyperthermia), body temperature (Tb), evaporative water loss, metabolic rate, and maximum cooling capacity (i.e., evaporative heat loss/metabolic heat production). Heat tolerance limits for the two bats roosting in more exposed sites, Taphozous mauritianus (foliage-roosting) and Eptesicus hottentotus (crevice-roosting), were Ta = ~44 °C and those individuals defended maximum Tb between 41 °C and 43 °C. The heat tolerance limit for the bat roosting in a more buffered site, Rousettus aegyptiacus (cave-roosting), was Ta = ~38 °C with a corresponding Tb of ~38 °C. These interspecific differences, together with a similar trend for higher evaporative cooling efficiency in species occupying warmer roost microsites, add further support to the notion that ecological factors like roost choice may have profound influences on physiological traits related to thermoregulation.

Chronic lung disease and a history of tuberculosis (post-tuberculosis lung disease): Clinical features and in-hospital outcomes in a resource-limited setting with a high HIV burden.

BACKGROUND: Many patients with previous pulmonary tuberculosis (PTB) continue to experience respiratory symptoms long after completion of tuberculosis (TB) therapy, often resulting in numerous hospital visits and admissions. OBJECTIVES: To describe the profile of patients with chronic lung disease (CLD) with or without a history of PTB, and their in-hospital outcomes. METHODS: We conducted a retrospective review of patients with CLD admitted with respiratory symptoms to Dora Nginza Hospital, Port Elizabeth, South Africa, from 1 April 2016 to 31 October 2016. These patients were divided into two groups: CLD with a history of PTB (CLD-TB) and CLD without a history of PTB. Patients with current culture-positive TB were excluded. Baseline characteristics and clinical outcomes (duration of hospitalisation and in-hospital mortality) were compared between the two groups. RESULTS: During the study period, a total of 4 884 patients were admitted and 242 patients received a diagnosis of CLD. In the CLD patient group, 173 had CLD-TB and 69 had no history of PTB. Patients with CLD-TB presented with respiratory symptoms a median of 41 months (interquartile range (IQR) 101) after completion of TB therapy. CLD-TB patients were predominantly male (59.5%), and compared with patients with no history of PTB were more likely to be HIV-positive (49.7% v. 8.7%; p=0.001) and had had more frequent hospital admissions before the current admission (median 2.0 (IQR 2.0) v. 0; p=0.001) and longer hospital stays (median 5 days (IQR 7) v. 2 (4); p=0.002). However, there was no statistically significant difference in in-hospital mortality between the two groups (17.3% v. 10.1%; p=0.165). CONCLUSIONS: In patients with CLD, a history of PTB is associated with numerous hospital admissions and longer hospital stays but not with increased in-hospital mortality. TB therefore continues to be a public health burden long after cure of active disease.

Philtrum reconstruction in unilateral cleft lip repair.

The philtrum is an important aesthetic structure in the midface. A number of philtrum reconstruction techniques have been advocated for secondary cleft lip revision procedures. Conventional surgical management involves end-to-end orbicularis oris muscle approximation during primary cleft lip repair, often resulting in a flat lip appearance that requires secondary revision surgery at a later stage. A novel modification of the approximation of the orbicularis oris muscle is described that may be implemented with any cleft lip technique in order to create an accentuated philtrum column for a natural looking philtrum. The muscle roll technique results in eversion of the orbicularis oris muscle, successfully recapturing the philtrum column topography. This is achieved by utilizing two inverted horizontal sutures, with an additional philtrum takedown suture placed in the region of the dimple to accentuate the philtrum anatomy and three-dimensional profile. This novel technique in unilateral cleft lip repair addresses philtrum architecture during primary surgery, which may reduce the requirement for secondary surgical intervention. Its application may be particularly suitable in outreach programmes where postoperative follow-up may be compromised.

Chronic lung disease and a history of tuberculosis (post-tuberculosis lung disease): Clinical features and in-hospital outcomes in a resource-limited setting with a high HIV burden

Background. Many patients with previous pulmonary tuberculosis (PTB) continue to experience respiratory symptoms long after completion of tuberculosis (TB) therapy, often resulting in numerous hospital visits and admissions.Objectives. To describe the profile of patients with chronic lung disease (CLD) with or without a history of PTB, and their in-hospital outcomes. Methods. We conducted a retrospective review of patients with CLD admitted with respiratory symptoms to Dora Nginza Hospital, Port Elizabeth, South Africa, from 1 April 2016 to 31 October 2016. These patients were divided into two groups: CLD with a history of PTB (CLD-TB) and CLD without a history of PTB. Patients with current culture-positive TB were excluded. Baseline characteristics and clinical outcomes (duration of hospitalisation and in-hospital mortality) were compared between the two groups.Results. During the study period, a total of 4 884 patients were admitted and 242 patients received a diagnosis of CLD. In the CLD patient group, 173 had CLD-TB and 69 had no history of PTB. Patients with CLD-TB presented with respiratory symptoms a median of 41 months (interquartile range (IQR) 101) after completion of TB therapy. CLD-TB patients were predominantly male (59.5%), and compared with patients with no history of PTB were more likely to be HIV-positive (49.7% v. 8.7%; p=0.001) and had had more frequent hospital admissions before the current admission (median 2.0 (IQR 2.0) v. 0; p=0.001) and longer hospital stays (median 5 days (IQR 7) v. 2 (4); p=0.002). However, there was no statistically significant difference in in-hospital mortality between the two groups (17.3% v. 10.1%; p=0.165).Conclusions. In patients with CLD, a history of PTB is associated with numerous hospital admissions and longer hospital stays but not with increased in-hospital mortality. TB therefore continues to be a public health burden long after cure of active disease

Evaluation of locally manufactured patient-specific custom made implants for cranial defects using a silicone mould.

BACKGROUND: Cranial vault defects can pose a significant problem for neurosurgeons where autologous bone is no longer available for cranioplasty. Numerous materials exist to create implants which include polymethyl methacrylate (PMMA) and titanium. A technique using 3-dimensional CT scan reconstruction of a cranial defect and creating a silicon mould which can be autoclaved in theatre to create a PMMA implant was developed. OBJECTIVE: The aim of this study is to evaluate the efficacy, cosmetic result, safety and cost-effectiveness of this procedure and compare this to existing techniques. METHOD: An ambispective study was performed in patients requiring cranioplasty with a custom made implant. Patients were assessed for risk factors and cosmetic outcome, surgical technique was described and complications and cost compared to existing literature between 2010 and 2016. RESULTS: Thirty retrospective and 30 consecutive prospective patients were recruited into the study. Overall sepsis rate was 8.3%. All septic cases had superficial sepsis of which 2 grafts were removed due to cerebrospinal fluid leakage resulting in wound breakdown. A 100% accurate implant to defect ratio was achieved leading to a high satisfaction rate. Average cost was 5 times cheaper than the closest market related product. CONCLUSION: Patient specific moulds using PMMA to create custom implants are safe, have excellent cosmetic results and are a very cost-effective option to manage cranial defects. Accurate planning strategies for large craniotomies, where bone will potentially be discarded, add to surgical effectiveness and cost-saving to the patient.

Tympanoplasty surgery: a retrospective audit of surgical outcomes at a regional hospital.

BACKGROUND: Chronic Suppurative Otitis Media (CSOM) is a common condition in our setting, resulting in tympanoplasty surgery being one of the common surgical procedures performed. Little is published regarding outcomes of tympanoplasty surgery in patients living with Human Immunodeficiency Virus (HIV), which has a high prevalence in South Africa. METHODS: A retrospective review of all tympanoplasty surgeries performed at our institute. Outcomes of surgery according to patient demographics, documented HIV status, seniority of surgeon, type and techniques of graft placement and hearing outcomes were reviewed. RESULTS: Successful closure of perforations was 84.4%. Closure rates in the 10 patients known to be HIV positive were 100%. The number of patients meeting the criteria for The Belfast Rule of Thumb (BROT) increased from 26.3% (n = 20) preoperatively to 68.4% (n = 52) postoperatively. CONCLUSION: The results are comparable to both the results obtained at a tertiary hospital and those published internationally. Successful outcomes are obtainable in patients infected with HIV; however, as to the optimal timing of this surgery, this would require further investigation.

Release of syngnathia by anticlockwise rotation and mandibular advancement using bilateral alloplastic temporomandibular joint prostheses: a new approach.

We describe a new approach to the planning of treatment and subsequent operation on a patient with syngnathia and severe mandibular retrognathism. To facilitate a large mandibular advancement we applied alloplastic temporomandibular joint (TMJ) prostheses to the coronoid processes after anticlockwise rotation of the mandible. To the best of our knowledge this is the first documented case of its kind.

Fluoride content of toothpastes available in South Africa.

A high dental caries burden coupled with a lack of water or salt fluoridation make it imperative that toothpastes available to the South African consumer demonstrate adequate potential for caries control and contain between 1000ppm and 1500ppm total fluoride (TF), with at least 1000ppm F in free available/soluble form. METHODS: The objective was to determine TF, total soluble fluoride (TSF) and insoluble fluoride (IF) concentrations in 22 fluoride toothpastes commercially available in South Africa. Samples were purchased from a major pharmaceutical and food retailer located in the two metropolitan areas in South Africa. TF and TSF concentrations were determined potentiometrically, in quadruplicate, following acid hydrolysis of the samples using a calibrated Combination Fluoride Ion Selective Electrode. IF was calculated by subtracting TSF from TF. RESULTS: Although TF content was found to be statistically significantly lower than manufacturer declaration (3.2x10-7; p≤0.05), 77.3% of the samples still contained adequate free, available/soluble F levels. Relative mean TSF content for toothpastes formulated with a calcium-based abrasive was 85% (sd ±14.5; n=6) as opposed to 98.6% (sd ±2.6; n=16) for those containing silica. CONCLUSIONS: The total fluoride concentration of all the toothpastes was lower than that declared by the manufacturers, with one in four having TSF concentrations of less than 1000ppm F. The relative TSF concentrations for the calcium-containing toothpastes were lower than for the silica-based products, reducing their preventive and protective potential. The results call for strengthened regulation and quality control of fluoride toothpastes in South Africa, as well as international efforts to improve related norms.

Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond.

In the past decades, many efforts have been devoted to characterizing {001} platelet defects in type Ia diamond. It is known that N is concentrated at the defect core. However, an accurate description of the atomic structure of the defect and the role that N plays in it is still unknown. Here, by using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy we have determined the atomic arrangement within platelet defects in a natural type Ia diamond and matched it to a prevalent theoretical model. The platelet has an anisotropic atomic structure with a zigzag ordering of defect pairs along the defect line. The electron energy-loss near-edge fine structure of both carbon K- and nitrogen K-edges obtained from the platelet core is consistent with a trigonal bonding arrangement at interstitial sites. The experimental observations support an interstitial aggregate mode of formation for platelet defects in natural diamond.

'Pain and stress are part of my profession': Using dental practitioners' views of occupation-related factors to inform dental training

Background. Stress is prevalent among dental workers and students. A possible means to address this would be to include stress management programmes in undergraduate dental programmes. The purpose of this study was to establish how the current cohort of dental practitioners incorporate occupational health and self-care principles into professional practice, and their potential relevance to future curriculum design.Objectives. To gain input from participants regarding stress and burnout ­ their causes, implications and prevention ­ as linked to their practice in dentistry.Methods. A qualitative research design was used, with a purposive sampling technique. The study population consisted of dentists, dental therapists, hygienists and specialists. A total of 36 participants participated in four focus-group discussions to explore dental education, occupational health, stress and self-care. The data were thematically analysed.Results. Dental training in the South African context, occupational health experiences, self-care, coping strategies and education were the main themes that emerged. Dental services in the public sector were reported to be overwhelmed by high patient volumes and shortages of staff and resources, which added to these stressors. The coping strategies adopted were exercise, stretching, reducing workload and encouraging teamwork. The participants believed that the causes of musculoskeletal disorders, and their impact, should be taught in dental training, as students do not perceive this as a potential problem. A multidisciplinary approach and teamwork training are the recommendations for curricula.Conclusion. Stress management techniques and workplace posture assessment should be taught in preclinical training to make students aware of managing stress and correct working postures. A multidisciplinary approach should be used. Dental curricula should include occupational health safety principles

Evaluation of locally manufactured patient-specific custom made implants for cranial defects using a silicone mould

Background: Cranial vault defects can pose a significant problem for neurosurgeons where autologous bone is no longer available for cranioplasty. Numerous materials exist to create implants which include polymethyl methacrylate (PMMA) and titanium. A technique using 3-dimensional CT scan reconstruction of a cranial defect and creating a silicon mould which can be autoclaved in theatre to create a PMMA implant was developed. Objectives: The aim of this study is to evaluate the efficacy, cosmetic result, safety and cost-effectiveness of this procedure and compare this to existing techniques.Methods: An ambispective study was performed in patients requiring cranioplasty with a custom made implant. Patients were assessed for risk factors and cosmetic outcome, surgical technique was described and complications and cost compared to existing literature between 2010 and 2016.Results: Thirty retrospective and 30 consecutive prospective patients were recruited into the study. Overall sepsis rate was 8.3%. All septic cases had superficial sepsis of which 2 grafts were removed due to cerebrospinal fluid leakage resulting in wound breakdown. A 100% accurate implant to defect ratio was achieved leading to a high satisfaction rate. Average cost was 5 times cheaper than the closest market related product.Conclusion: Patient specific moulds using PMMA to create custom implants are safe, have excellent cosmetic results and are a very cost-effective option to manage cranial defects. Accurate planning strategies for large craniotomies, where bone will potentially be discarded, add to surgical effectiveness and cost-saving to the patient

Tympanoplasty surgery: a retrospective audit of surgical outcomes at a regional hospital

Background: Chronic Suppurative Otitis Media (CSOM) is a common condition in our setting, resulting in tympanoplasty surgery being one of the common surgical procedures performed. Little is published regarding outcomes of tympanoplasty surgery in patients living with Human Immunodeficiency Virus (HIV), which has a high prevalence in South Africa.Aims:To audit the outcomes of tympanoplasty surgeries performed, including outcomes in patients with HIV.Methods:A retrospective review of all tympanoplasty surgeries performed at our institute. Outcomes of surgery according to patient demographics, documented HIV status, seniority of surgeon, type and techniques of graft placement and hearing outcomes were reviewed.Results:Successful closure of perforations was 84.4%. Closure rates in the 10 patients known to be HIV positive were 100%. The number of patients meeting the criteria for The Belfast Rule of Thumb (BROT) increased from 26.3% (n = 20) preoperatively to 68.4% (n = 52) postoperatively.Conclusions:The results are comparable to both the results obtained at a tertiary hospital and those published internationally. Successful outcomes are obtainable in patients infected with HIV; however, as to the optimal timing of this surgery, this would require further investigation

Lead poisoning in shooting-range workers in Gauteng Province, South Africa: Two case studies.

BACKGROUND: Lead exposure constitutes a major public health concern globally. Relative to developed nations, lead exposure is understudied and poorly addressed in Africa, and there is a dearth of information available to inform lead poisoning prevention strategies, even in high-risk groups such as workers in shooting ranges who are potentially exposed to lead daily. METHODS: Two workers at a private shooting range in Gauteng, South Africa (SA), had blood lead levels and exposure histories taken. RESULTS: Workers had highly elevated blood lead levels and clinical symptoms associated with elevated blood lead levels. CONCLUSION: Workers in private SA shooting ranges are vulnerable to lead exposure and poisoning, and scaled-up action is required to protect them and their families, as well as shooting-range users, from lead and the related health risks.

Preoperative evaluation of micro-organisms in non-operated cleft in soft palate: impact on use of antibiotics.

To identify the pathogenic micro-organisms that had colonised preoperatively in clefts in the soft palate and oro-nasopharynx, we retrospectively studied the preoperative microbiological profiles of 200 infants who had had primary repair of all types of cleft in the soft palate. Data from a private practice that specialises in the repair of facial clefts were extracted randomly from patients' files. We analysed the results of the culture of preoperative swabs taken from clefts in the soft palate and oro-nasopharynx, and the resistance profile of organisms towards various antibiotics. A total of 23 different pathogenic micro-organisms were isolated from 115 (57%) of the sample. Klebsiella pneumoniae most commonly colonised clefts in the lip, alveolus, and palate. This was considerably higher than in other groups. The second most common micro-organism was Staphylococcus aureus, which was found most often in patients with isolated clefts in the hard palate. Those with complete cleft lip and palate presented with more pathogenic micro-organisms in preoperative cultures than those with other types of cleft. We need to find a way to control pathogenic micro-organisms in the oral and oro-nasopharyngeal region preoperatively to limit postoperative complications.