Rational design of a survey protocol for avocado sunblotch viroid in commercial orchards to demonstrate pest freedom.

Avocado sunblotch viroid (ASBVd) is a subcellular pathogen of avocado that reduces yield from a tree, diminishes the appearance of the fruit by causing unsightly scarring and impedes trade because of quarantine conditions that are imposed to prevent spread of the pathogen via seed-borne inoculum. For countries where ASBVd is officially reported, permission to export fruit to another country may only be granted if an orchard can be demonstrated to be a pest free production site. The survey requirements to demonstrate pest freedom are usually defined in export protocols that have been mutually agreed upon by the trading partners. In this paper, we introduce a flexible statistical protocol for use in optimizing sampling strategies to establish pest free status from ASBVd in avocado orchards. The protocol, which is supported by an interactive app, integrates statistical considerations of multistage sampling of trees in orchards with a RT-qPCR assay allowing for detection of infection in pooled samples of leaves taken from multiple trees. While this study was motivated by a need to design a survey protocol for ASBVd, the theoretical framework and the accompanying app have broader applicability to a range of plant pathogens in which hierarchical sampling of a target population is coupled with pooling of material prior to diagnosis.

Tyramine-induced gastrointestinal dysregulation is attenuated via estradiol associated mechanisms in a zebrafish larval model.

Development of targeted therapeutics to alleviate gastrointestinal (GI) inflammation and its debilitating consequences are required. In this context, the trace aminergic system may link together sex, diet and inflammation. Utilising a zebrafish larval model of GI inflammation, the current study aimed to investigate mechanisms by which excess amounts of trace amines (TAs) may influence GI health. In addition, we probed the potential role of 17ß-estradiol (E2) and its receptors, given the known female-predominance of many GI disorders. To assess GI functionality and integrity, live imaging techniques (neutral red staining) and post-mortem immunofluorescent staining of tight junction proteins (occludin and ZO-1) were analyzed respectively. In addition, behavioural assays, as an indication of overall wellbeing, as well as whole body H2O2 and prostaglandin E2 assays were performed to inform on oxidative and inflammatory status. Excess ß-phenethylamine (PEA), tryptamine (TRP) and ρ-tyramine (TYR) resulted in adverse GI and systemic effects. In this regard, clear beneficial effects of E2 to modulate the effects of PEA, TRP and TYR was evident. Moreover, agmatine displayed potential protective effects on GI epithelium and whole body oxidative status, however, potential to induce systemic inflammation suggests the importance of dosage and administration optimisation. Taken together, TYR seems like the most prominent TA to have damaging GI effects, feasibly exacerbating GI inflammation. In this context, the relative lack of E2 may provide mechanistic insights into the reported female-predominance of GI disorders. Moreover, an effective therapeutic in this context may be required to maintain GI TA load despite fluctuating E2 levels.

Aspalathus linearis (Rooibos) and Agmatine May Act Synergistically to Beneficially Modulate Intestinal Tight Junction Integrity and Inflammatory Profile.

In order to promote gastrointestinal health, significant increases in the prevalence of gastrointestinal disorders should be paralleled by similar surges in therapeutics research. Nutraceutical interventions may play a significant role in patient management. The current study aimed to determine the potential of Aspalathus linearis (rooibos) to prevent gastrointestinal dysregulation resulting from high-dose trace-amine (TA) exposure. Considering the substantial female bias in functional gastrointestinal disorders, and the suggested phytoestrogenicity of rooibos, the study design allowed for a comparison between the effects of an ethanol extract of green rooibos and 17ß-estradiol (E2). High levels of ρ-tyramine (TYR) and agmatine (AGM), but not ß-phenethylamine (PEA) or tryptamine (TRP), resulted in prostaglandin E2 (PGE2) hypersecretion, increased tight-junction protein (TJP; occludin and ZO-1) secretion and (dissimilarly) disrupted the TJP cellular distribution profile. Modulating benefits of rooibos and E2 were TA-specific. Rooibos pre-treatment generally reduced IL-8 secretion across all TA conditions and prevented PGE2 hypersecretion after exposure to both TYR and AGM, but was only able to normalise TJP levels and the distribution profile in AGM-exposed cells. In contrast, E2 pre-treatment prevented only TYR-associated PGE2 hypersecretion and TJP dysregulation. Together, the data suggest that the antioxidant and anti-inflammatory effects of rooibos, rather than phytoestrogenicity, affect benefits illustrated for rooibos.

Rooibos (Aspalathus linearis) alters secretome trace amine profile of probiotic and commensal microbes in vitro.

ETHNOPHARMACOLOGY RELEVANCE: Aspalathus linearis (Burm.f.) R. Dahlgren (rooibos) tea is anecdotally renowned for its calming effect in the context of gastrointestinal discomfort, but little scientific support is available to elucidate potential mechanisms of action. Enhancement of dietary polyphenol content to improve gut health via prebiotic-like modulation of the gut microbiota has gained significant research interest. Given the known high polyphenol content of rooibos, rooibos tea may potentially exert a prebiotic effect in the gut to facilitate an improvement in chronic inflammatory gastrointestinal conditions. AIM OF THE STUDY: This study aimed to determine the prebiotic or health-modulating potential of rooibos tea in terms of its effect on gut microbial growth and secretome trace amine composition, as well as to determine how differential rooibos processing alters this activity. METHODS: Three rooibos preparations (green and fermented leave aqueous extracts, as well as a green leaf ethanol extract) were compared in terms of their phenolic composition (qTOF-LC/MS). Moreover, the effect of rooibos exposure on growth and secretome trace amine levels of probiotic and commensal microbes were assessed (LC/MS). In addition, given the known female bias prevalent for many gastrointestinal disorders, experiments were conducted in the absence and presence of estradiol. RESULTS: Polyphenolic composition of rooibos was drastically reduced by fermentation. Aqueous extracts of both green and fermented rooibos improved microbial growth, although fermented rooibos had the most pronounced effect (p < 0.01). In terms of secretome trace amine profile, both aqueous extracts of rooibos seemed to facilitate increased putrescine secretion (p < 0.0001) and decreased tryptamine production (p < 0.0001). Estradiol seemed to suppress trace amine secretion by bacteria (Lactobacillus plantarum, Lactobacillus reuteri and Enterococcus mundtii) but increased it in yeast (Saccharomyces boulardii). CONCLUSION: Rooibos altered gut probiotic and commensal microbial growth and secretome trace amine profiles in vitro, suggesting it has potential to modulate gut microbial composition and functionality as a prebiotic. Current data suggest that these effects are highly dependent on raw material processing. Finally, rooibos may be able to prevent estradiol-associated alterations in trace amine profile, which may have important implications for patient management in female-predominant gastrointestinal disorders.

Investigating the ultrastructural and viscoelastic characteristics of whole blood after exposure to the heavy metals cadmium, lead and chromium, alone and in combination.

In recent years, heavy metal exposure has become a serious health concern as more humans are being exposed to heavy metals on a daily basis. Most of the environmental contamination and human exposure result from anthropogenic activities such as mining and smelting. The industrial and agricultural sectors also play a big role. Cigarette smoke in particular contains trace amounts of heavy metals that put chronic smokers at serious risk. Previous studies have determined that there is a strong correlation between heavy metal exposure and adverse effects on the coagulation system. The aim of this study was to investigate the effect of cadmium, lead and chromium alone and in combination on erythrocytes and fibrin networks that form part of the coagulation system as well as the viscoelastic properties of thrombus formation by using thromboelastography®. The choice of metals for this study was based on a previous study that compared the levels of metals between smokers and nonsmokers and found significantly higher levels of cadmium, lead and chromium in the platelet-rich fibrin of smoking individuals. Scanning electron microscopy analysis revealed that the cadmium and chromium combination groups caused the highest degree of echinocyte formation and fibrin network alterations. These findings were supported by the thromboelastography® analysis that indicated a significant decrease in reaction-time and split point values for the chromium-containing group, suggesting a shorter initiation time for clot formation. The findings of this study support the hypothesis that the coagulation pathway is a potential target for heavy metal toxicity.

Stakeholders' Perceptions of the Delivery and Quality of Sexually Transmitted Infection Treatment by Private Practitioners in Windhoek; Namibia

The primary objective of this study was to explore the perceptions of the community and other stakeholders regarding the delivery and quality of sexually transmitted infection (STI) treatment and care provided by private general practitioners (PGPs) in Windhoek; Namibia. The study provided a situational and contextual analysis employing qualitative methodologies using different methods of data collection. The methodology used included (1) a review of available country policy documents on STI management and surveillance; as well as the policy with regard to private primary care providers; (2) eight in-depth interviews conducted with key informants and (3) three focus-group discussions held with community members attending PGP practices in Windhoek. The perceptions of the care received from PGPs differed from one person to the next. It emerged that some participants had good experiences and some had negative experiences of the care given. The participants believed that going to a PGP for treatment is a matter of affordability that goes hand in hand with the expectations of receiving care; whilst maintaining confidentiality. The study established that there is no real difference between the care provided to patients with medical aid or those without medical aid. It is recommended that interactions between the public and private sector at various levels be initiated to ensure that curable STIs are appropriately managed and that national guidelines for STI management are adhered to. Health workers should also be sensitised about their approach towards patients. It is further recommended that awareness creation amongst PGPs with regard to the public health importance of STIs needs to be raised to encourage them to participate in the STI-control programme

Foreign Nursing Students: Their Profile and Perceptions Ofnursing Care in Namibia

A survey was conducted using open and close-ended questions to determine how visiting nursing students in Namibia could be assisted during their visits (cultural encounters). Many students decide to complete their clinical exposure in a foreign country; either for personal reasons or in order to meet the course requirements for transcultural nursing. Since 1998; Namibia has received a number of these students. In discussion and from passing remarks from the students themselves; the question has arisen as to how an optimum placement for each student might be achieved. Aspects of the Campina-Bacote model and The Process of Cultural Competence in the Delivery of Health Care Services were used to answer this question. It was decided to gather both biographical (profile) information and information on perceptions of nursing care in Namibia from such foreign nursing students. The biographical (profile) information collected indicates a prevalence of certain shared biographical characteristics among international students. Such students tend to be adventurous; caring and sensitive to human rights issues. This finding correlates with the constructs of cultural desire and cultural awareness as described in the model of Campina-Bacote. Based on this finding; specific recommendations were made for clinical allocations. From the data gathered from the open-ended questions; three themes emerged: firstly; nursing in Namibia has identifiable characteristics; secondly; there is a paternalistic and one-sided communication style among nursing caregivers in Namibia; and finally; nursing care delivery in this country is often characterised by a detached attitude. It was concluded that these themes correlated with a cultural awareness and cultural knowledge among the nursing students. The discovery of these themes was useful for making recommendations for clinical guidelines to help these students adapt; as well as for providing a foundation and substantiation for clinical placement

Free field frequency discrimination abilities of cochlear implant users.

Poor music perception abilities of cochlear implant users may be attributed to limited pitch resolution afforded by the implant system. We investigated (i) what the typical frequency discrimination thresholds of cochlear implant users would be in free field listening conditions and (ii) whether frequency discrimination behaviour would be influenced by the position of the reference frequency relative to the frequency response of filters selected from the user's map. Frequency discrimination thresholds were determined according to an adaptive two-alternative forced choice (2AFC) method, using pure tones delivered in free field conditions. Results showed that finer frequency resolution than previously thought could be available to cochlear implant users. Results are interpreted in terms of intermediate pitch percepts possibly created by near-simultaneous activation of adjacent electrodes, resulting in overlapping neural populations to be stimulated. The findings may contribute to strategies aiming to improve music perception abilities of cochlear implant users.

Trans-Cultural Nursing : Exploring the Experiences of International Students Visiting Namibia

"In a rapidly changing world; where people from diverse cultures move about more readily; nurses may find themselves faced with patients and clients with a totally different world perspective and health belief system. Because this aspect has long been recognised by nurse educators; many educational institutions; in a proactive fashion; have incorporated trans-cultural nursing content in their nursing curricula. As possible options for students to gain clinical exposure in caring for a culturally diverse population; educational visits by student nurses to foreign countries have been increasingly accepted and credited. Namibia is amongst the countries that are visited by foreign nursing students; who are usually well-prepared with regard to what is required during their clinical exposure; as their educational institutions provide them with instructions and objectives. However; they are not as well-prepared in respect of ""acclimatising"" to the country per se and the world view of Namibians. In fact; it appears that there is a huge gap between their expectations and reality. Consequently; it becomes necessary to provide them with basic guidelines to bridge this discrepancy and to make their visit more meaningful. A qualitative; explorative; descriptive and contextual study was conducted to determine the nature of their experiences. Data were collected over a period of four years by means of narratives that were written by students who had spent at least 12 weeks within the Namibian health care services as visiting nurses. Three themes emerged; namely (1) experiences relating to recognition of differences in care delivery; (2) experiences relating to feelings of culture shock; and (3) appreciation for experiencing a cultural encounter. Based on these themes; guidelines were constructed. These guidelines addressed aspects such as the health structure of the country; health belief systems; legal aspects; and the philosophy of nursing care in Namibia."

Ethambutol resistance testing by mutation detection.

OBJECTIVE: To identify chromosomal mutations that confer resistance to ethambutol (EMB) in Mycobacterium tuberculosis. DESIGN: Drug-resistant (n = 235) and drug-susceptible (n = 117) M. tuberculosis isolates collected from the Western Cape in South Africa were subjected to embB gene analysis and the results were compared to phenotypic EMB testing. RESULTS: Genotypic analysis identified mutations at codon 306 of the embB gene in 20% (47/235) of the resistant isolates in comparison to only 1.7% (4/235) of those that were phenotypically resistant to EMB by the agar diffusion method. No gene mutations were detected in susceptible isolates. Phenotypic retesting in BACTEC demonstrated that the 47 genotypically resistant isolates were phenotypically resistant to EMB. This implies that 91.4% (43/47) of EMB resistance had been phenotypically missed by routine laboratory procedures. EMB resistance was closely linked to multidrug resistance (MDR); 87.2% (41/47) of the EMB-resistant isolates were resistant to both isoniazid and rifampicin. A newly developed one-step amplification refractory mutation system polymerase chain reaction (ARMS-PCR) method correctly detected the EMB-resistant genotype. CONCLUSION: Implementation of more accurate diagnosis of EMB resistance may enhance patient management in South Africa, as standardised treatment of MDR-TB with second-line drugs is currently dependent on the outcome of the EMB resistance test.

The Contribution of the Clinical Nurse Instructor to the Development of Critical Thinking Skills of the Student Nurse in Namibia

A quantitative; non-experimental and exploratory study was undertaken to determine the contribution by the clinical nurse instructor to develop critical thinking skills of student nurses in Namibia. The study was conducted at the training hospitals of Namibia; namely Windhoek; Oshakati and Onandjokwe State hospitals. Clinical nurse instructors from all disciplines were included in the study; as well as student nurses in their second; third and fourth year of undergraduate nursing study. The findings of the study revealed that; although the clinical instructors in the training hospitals of Namibia are aware of their responsibility; they do not focus on the development of critical thinking of student nurses in Namibia. A need for in-service programmes to emphasise the development of critical thinking skills of both clinical nurse instructors and student nurses was identified

Numerical simulation of pulsating flow in the aortic arch.

In order to investigate the flow profiles in the aorta a numerical three-dimensional model of the aortic arch was created. The velocity fields were simulated by applying an inlet velocity corresponding to the physiological velocity of the pressure wave at the aortic valve. The velocity field distribution was found to be uniform throughout the model during the time of increasing inlet velocities. With decreasing inlet velocities a region of low flow developed in the descending portion of the model leading to recirculating flow at the inner wall. At this region of low flow the variation in velocity with time at the inner wall was approximately twice the variation at the outer wall. As a result of the recirculating flow, the wall shear stresses at the inner wall are low and oscillating, predisposing to the development of atherosclerosis. This model shows that transient fluid flow in the aortic arch can be simulated. Biological studies are needed to prove that this model can be used to predict sites of pathology.

Dorsal ganglion of the wrist--pathogenesis and biomechanics. Operative v. conservative treatment.

It is shown that the dorsal ganglion arises as a herniation from the dorsal scapholunate ligament. This herniation increases in size (according to La Place's law) owing to the unidirectional pinchcock effect of the mucosal folds of the duct and the pressure of the overlying extensor retinaculum until the distending pressure inside the ganglion equals the overlying tissue pressure. Wrist gangliography, retrograde wrist arthrography, histology and nuclear magnetic resonance were used to prove this conclusively. Bearing the pathogenesis in mind, the best clinical results were obtained by excision of the ganglion with 0.5 cm2 of dorsal scapholunate ligament and closure of the dorsal capsule with a 3/0 Vicryl purse-string suture. Non-surgical sclerotherapy led to severe inflammation and sepsis and a recurrence rate of 45%. Conservative therapy is illogical since the communicating duct remains and synovial fluid from the scapholunate joint will cause a reherniation and recurrence of the ganglion.

Effects of clobazam and clonazepam on saccadic eye movements and other parameters of psychomotor performance.

The effects of two benzodiazepine anticonvulsants clobazam (20 mg) and clonazepam (2 mg) in a variety of psychomotor performance tests were compared in a placebo controlled double-blind acute oral dose study in ten healthy volunteers. Assessments included critical flicker fusion (CFF) threshold, the Sternberg memory scanning and choice reaction time (CRT), peak saccadic velocity (PSV) and visual analogue scales, all previously shown to be sensitive to the effects of benzodiazepines. Clobazam did not significantly impair saccadic eye movements, CFF threshold, Sternberg memory scanning and CRT compared to placebo. Clonazepam significantly lowered PSV, reduced the CFF threshold, slowed the Sternberg CRT and decreased an alertness factor in the visual analogue scales compared to placebo. Clonazepam significantly increased memory scanning time compared to clobazam. Clobazam was remarkably free of cognitive and psychomotor side-effects.

Fluorescent labelling of histone H3: effect on histone-histone interaction and core particle assembly.

Substitution of Cys 110 of chicken histone H3 with N-iodoacetyl-N1-(5-sulpho-1-naphthyl)ethylenediamine or iodoacetamide prevents octamer formation in 2 M NaCl but does not prevent polyglutamic acid-mediated core particle assembly.

Splenectomy in onyalai. A report on 5 cases.

Onyalai is an acquired immune thrombocytopenia with 10% mortality. Conservative measures such as traditional medicines, corticosteroids and blood transfusion have not always controlled severe bleeding or prevented death. Five patients (2 male, 3 female) with onyalai who had uncontrollable haemorrhage, thrombocytopenia and documented previous attacks of severe bleeding, underwent splenectomy. The patients were screened for malaria, sickle-cell anaemia and bilharzia. Vitamin K and epsilon-aminocaproic acid were administered pre-operatively, and fresh blood was given during surgery. The duration of follow-up varied between 280 and 544 days. There were no operative complications. Bleeding stopped in all patients and the platelet counts increased within 24 hours. All achieved normal platelet counts, but these were not always sustained. Three patients remained free of disease with normal platelet counts up to days 539, 539 and 544 of follow-up. Two patients had a recurrence of bleeding and died from cerebral haemorrhage and haemorrhagic shock.

Macrodactyly. A review with a case report.

Macrodactyly is an unsightly congenital abnormality of a digit (of the hand or foot) usually requiring multiple surgical procedures. A poor cosmetic result (usually more acceptable than the original finger, but still aesthetically unsatisfactory) is often the outcome. The surgical procedures which may be utilized for this problem are numerous, ranging from ablation of the digit as a primary surgical procedure to numerous defatting procedures combined with other techniques.

Octamer reconstitution from acid-extracted chicken erythrocyte histones.

Histone octamers have been reconstituted from acid-extracted chicken erythrocyte histones. By the criteria of molecular size on exclusion chromatography as well as sedimentation velocity and conformational properties established by circular dichroism, fluorescence spectroscopy and imido-ester cross-linking, the reconstituted octamers have a structure identical to that of salt-extracted octamers.