Photo-assisted bio-fabrication of silver nanoparticles using Annona muricata leaf extract: exploring the antioxidant, anti-diabetic, antimicrobial, and cytotoxic activities

Green synthesis of metal nanoparticles is reputed to have a robust range of biomedical applications. Silver nanoparticles (AgNPs) bio-fabricated using aqueous leaf extract of Annona muricata were characterized and evaluated for in-vitro antioxidant, lipid peroxidation inhibition, anti-diabetic and antimicrobial activities as well as cytotoxicity in human keratinocyte cells (HaCaT). The extract induced colour change of silver salt solution which absorbed at 420 nm and confirmed the formation of AgNPs. FTIR showed that free amide and hydroxyl groups were responsible for the synthesized nanoparticles. Both XRD and SAED confirmed the crystalline nature of the particles with face centered cubic (FCC) phase. The zeta potential revealed -27.2 mV potential and average distribution size of 35 nm. DLS indicated that the majority of the particles were 86.78 nm size and with a polydispersity index (PDI) of 0.329. AgNPs displayed strong activities against DPPH (IC₅₀ = 51.80 μg/ml), ABTS (IC₅₀ = 30.78 μg/ml), α-amylase (IC₅₀ = 0.90 μg/ml) and α-glucosidase (IC₅₀ = 3.32 μg/ml). The particles exhibited a dose-dependent inhibition of Fe²⁺-induced lipid peroxidation with effective antimicrobial activity against a battery of bacterial strains and cytotoxicity in HaCaT cell line. These findings revealed the potential biomedical applications of the particles and further work will be required to establish its molecular mechanism of action.

SAT0595 INTERSTITIAL LUNG DISEASE IN SOUTH AFRICAN ADULTS PATIENTS WITH AUTOIMMUNE RHEUMATIC DISEASES

Background:

Interstitial lung disease (ILD) is prevalent in patients with autoimmune rheumatic diseases (ARD), leads to significant morbidity and mortality, and is poorly characterized in South Africa.

Objectives:

To describe the clinical, serological and radiological features of ILD associated with ARD in a tertiary referral hospital.

Methods:

A cross-sectional study of outpatients attending the rheumatology and respiratory clinics of Groote Schuur Hospital between October 2018 and September 2019. Clinical, serological and radiological features were documented. We compared features of 3 groups of patients: rheumatoid arthritis (RA), systemic sclerosis (SSc) and “Other” autoimmune rheumatic diseases (OARD) which included Idiopathic Inflammatory Myopathies, Mixed Connective Tissue Disease, Systemic Lupus Erythematous, ANCA-associated vasculitis, Sjogren’s Syndrome and overlap syndromes. Factors associated with Usual Interstitial Pneumonia (UIP) were sought by univariate and multivariate analysis. P-values ≤ 0.05 were considered statistically significant. Analyses was performed with STATA 14.0 (Stata Corp LP, USA).

Results:

Of 124 patients, 29.8 % had RA, 25,8 % SSc and 44.4 % OARD. Most patients were female (86.3%), of mixed racial ancestry (75.0%), and the median (IQR) age was 55 (46-66). Over one-third were smokers, 22.6% had emphysema, and one third had previous pulmonary tuberculosis (PTB) infection. Smoking, emphysema, and previous PTB were higher in RA group but the difference was not statistically significant. All SSc patients and more than two-thirds of RA and OARD patients had gastroesophageal reflux disease (GORD).

Similar to reports elsewhere, Nonspecific interstitial pneumonia (NSIP) was the commonest ILD (63.7 %), followed by UIP (26.6%) and other patterns (9.7%). Contrary to other reports, we found similar frequencies of NSIP and UIP patterns in patients with RA. RA patients were significantly older (median (IQR)) age at ILD onset 62 (55-68) years, compared to SSc (49 (38-56) and OARD (42 (33-56) (p < 0.001). The percentage of predicted Forced Vital Capacity (FVC) were significantly worse in SSc and OARD groups and DLCO in OARD. RA diagnosis (OR 3.8, 95% CI 1.5-9.5), older age (0R 1.1, 95% CI 1.0-1.1), COPD (OR 3.2, 95% CI 1.4-8.0), longer ARD-ILD interval, higher FVC (OR 1.0, 95% CI 1.0-1.1) and previous Methotrexate (MTX) use (OR 2.6, 95% CI 1.1-6.0) were significantly associated with UIP. Multivariable analysis showed that only COPD and previous MTX use was associated with UIP (OR 2.8 (95% CI 1.0 – 8.0) and 1.0 (95% CI 1.0 – 1.0) respectively).

Regarding MTX exposure, 37.1% of patients were prescribed MTX before ILD diagnosis, and 33.9% continued, started or restarted after ILD diagnosis. No case of acute pneumonitis was documented.

Conclusion:

ILD was most commonly diagnosed in RA and SSc, with NSIP seen most frequently overall. RA patients presented better Pulmonary function tests despite higher frequency of UIP. The use of MTX seems to not be associated with the development of acute pneumonitis in patients with ILD

References:

[1]Wallace, B., D. Vummidi, and D. Khanna,Management of connective tissue diseases associated interstitial lung disease: a review of the published literature.Current Opinion in Rheumatology, 2016.28(3): p. 236-245.

[2]Dellaripa, P.F.,Interstitial lung disease in the connective tissue diseases; a paradigm shift in diagnosis and treatment.Clinical Immunology, 2018.186: p. 71-73.

Disclosure of Interests:

None declared

De novo protein structure determination by heavy-atom soaking in lipidic cubic phase and SIRAS phasing using serial synchrotron crystallography

During the past few years, serial crystallography methods have undergone continuous development and serial data collection has become well established at high-intensity synchrotron-radiation beamlines and XFEL radiation sources. However, the application of experimental phasing to serial crystallography data has remained a challenging task owing to the inherent inaccuracy of the diffraction data. Here, a particularly gentle method for incorporating heavy atoms into micrometre-sized crystals utilizing lipidic cubic phase (LCP) as a carrier medium is reported. Soaking in LCP prior to data collection offers a new, efficient and gentle approach for preparing heavy-atom-derivative crystals directly before diffraction data collection using serial crystallography methods. This approach supports effective phasing by utilizing a reasonably low number of diffraction patterns. Using synchrotron radiation and exploiting the anomalous scattering signal of mercury for single isomorphous replacement with anomalous scattering (SIRAS) phasing resulted in high-quality electron-density maps that were sufficient for building a complete structural model of proteinase K at 1.9 Å resolution using automatic model-building tools.

Unsuccessful TB treatment outcomes with a focus on HIV co-infected cases: a cross-sectional retrospective record review in a high-burdened province of South Africa

BACKGROUND

South Africa did not meet the MDG targets to reduce TB prevalence and mortality by 50% by 2015, and the TB cure rate remains below the WHO target of 85%. TB incidence in the country is largely fuelled by the HIV epidemic, and co-infected patients are more likely to have unsuccessful TB treatment outcomes. This paper analyses the demographic and clinical characteristics of new TB patients with unsuccessful treatment outcomes, as well as factors associated with unsuccessful treatment outcomes for HIV co-infected patients.

METHODS

A cross-sectional retrospective record review of routinely collected data for new TB cases registered in the Free State provincial electronic TB database between 2009 and 2012. The outcome variable, unsuccessful treatment, was defined as cases ≥15 years that 'died', 'failed' or 'defaulted' as the recorded treatment outcome. The data were subjected to descriptive and logistic regression analyses.

RESULTS

From 2009 to 2012 there were 66,940 new TB cases among persons ≥15 years (with a recorded TB treatment outcome), of these 61% were co-infected with HIV. Unsuccessful TB treatment outcomes were recorded for 24.5% of co-infected cases and 15.3% of HIV-negative cases. In 2009, co-infected cases were 2.35 times more at risk for an unsuccessful TB treatment outcome (OR: 2.35; CI: 2.06-2.69); this figure decreased to 1.8 times by 2012 (OR: 1.80; CI: 1.63-1.99). Among the co-infected cases, main risk factors for unsuccessful treatment outcomes were: ≥ 65 years (AOR: 1.71; CI: 1.25-2.35); receiving treatment in healthcare facilities in District D (AOR: 1.15; CI 1.05-1.28); and taking CPT (and not ART) (AOR: 1.28; CI: 1.05-1.57). Females (AOR: 0.93; CI: 0.88-0.99) and cases with a CD4 count >350 (AOR: 0.40; CI: 0.36-0.44) were less likely to have an unsuccessful treatment outcome.

CONCLUSIONS

The importance of TB-HIV/AIDS treatment integration is evident as co-infected patients on both ART and CPT, and those who have a higher CD4 count are less likely to have an unsuccessful TB treatment outcome. Furthermore, co-infected patients who require more programmatic attention are older people and males.

Recent advances in understanding hypertension development in sub-Saharan Africa

Consistent reports indicate that hypertension is a particularly common finding in black populations. Hypertension occurs at younger ages and is often more severe in terms of blood pressure levels and organ damage than in whites, resulting in a higher incidence of cardiovascular disease and mortality. This review provides an outline of recent advances in the pathophysiological understanding of blood pressure elevation and the consequences thereof in black populations in Africa. This is set against the backdrop of populations undergoing demanding and rapid demographic transition, where infection with the human immunodeficiency virus predominates, and where under and over-nutrition coexist. Collectively, recent findings from Africa illustrate an increased lifetime risk to hypertension from foetal life onwards. From young ages black populations display early endothelial dysfunction, increased vascular tone and reactivity, microvascular structural adaptions as well as increased aortic stiffness resulting in elevated central and brachial blood pressures during the day and night, when compared to whites. Together with knowledge on the contributions of sympathetic activation and abnormal renal sodium handling, these pathophysiological adaptations result in subclinical and clinical organ damage at younger ages. This overall enhanced understanding on the determinants of blood pressure elevation in blacks encourages (a) novel approaches to assess and manage hypertension in Africa better, (b) further scientific discovery to develop more effective prevention and treatment strategies and

Factors influencing treatment default among tuberculosis patients in a high burden province of South Africa

OBJECTIVE

To determine and describe the factors influencing treatment default of tuberculosis (TB) patients in the Free State Province of South Africa.

METHODS

A retrospective records review of pulmonary TB cases captured in the ETR.Net electronic TB register between 2003 and 2012 was performed. Subjects were >15 years of age and had a recorded pre-treatment smear result. The demographic and clinical characteristics of defaulters were described. Multivariate logistic regression analysis was used to determine factors associated with treatment default. The odds ratios (OR) together with their corresponding 95% confidence intervals (CI) were estimated. Statistical significance was considered at 0.05.

RESULTS

A total of 7980 out of 110 349 (7.2%) cases defaulted treatment. Significantly higher proportions of cases were male (8.3% vs. female: 5.8%; p<0.001), <25 years old (9.1% vs. 25-34 years: 8.7%; 35-44 years: 7.0%; 45-54 years: 5.2%; 55-64 years: 4.4%; >64 years: 3.9%; p<0.001), undergoing TB retreatment (11.0% vs. new cases: 6.3%; p<0.001), had a negative pre-treatment sputum smear result (7.8% vs. positive smear results: 7.1%; p<0.001), were in the first 2 months of treatment (95.5% vs. >2 months: 4.8%; p<0.001), and had unknown HIV status (7.8% vs. HIV-positive: 7.0% and HIV-negative: 5.7%; p<0.001). After controlling for potential confounders, multivariate analysis revealed a two-fold increased risk of defaulting treatment when being retreated compared to being treated for the first time for TB (adjusted OR (AOR) 2.0, 95% CI 1.85-2.25). Female cases were 40% less likely to default treatment compared to their male counterparts (AOR 0.6, 95% CI 0.51-0.71). Treatment default was less likely among cases >24 years old compared to younger cases (25-34 years: AOR 0.8, 95% CI 0.77-0.87; 35-44 years: AOR 0.6, 95% CI 0.50-0.64; 45-54 years: AOR 0.4, 95% CI 0.32-0.49; 55-64 years: AOR 0.3, 95% CI 0.21-0.43; >64 years: AOR 0.3, 95% CI 0.19-0.35). Co-infected cases receiving antiretroviral therapy (ART) were 40% less likely to default TB treatment relative to those whose ART status was unknown (AOR 0.6, 95% CI 0.46-0.57).

CONCLUSIONS

Salient factors influence TB patient treatment default in the Free State Province. Therefore, the strengthening of clinical and programmatic interventions for patients at high risk of treatment default is recommended. In particular, ART provision to co-infected cases facilitates TB treatment adherence and outcomes.

Quantification of systemic renin-angiotensin system peptides of hypertensive black and white African men established from the RAS-Fingerprint®

Objective:

The objective of this study was to make use of a quantitative and qualitative approach comparing the systemic renin-angiotensin system (RAS) of hypertensive black and white African men by using RAS equilibrium analysis.

Materials and methods:

This sub-study involved 23 black (n = 15) and white (n = 8) hypertensive men aged 39.5–41 years, living in the North West Province of South Africa. The RAS-Fingerprinting was determined with LC-MS/MS quantification of angiotensin peptides. Blood pressure and other variables were determined with known methods.

Results:

The main finding of this study was the significant lower Ang I (<5.0 and 45.1 pg/ml; p = 0.005) and Ang II (15.6 and 123.9 pg/ml; p ⩽ 0.001) encountered in the hypertensive black African men compared to their white counterparts. Levels of Ang 1-5 (downstream metabolite of Ang 1-7) (1.8 and 3.0 pg/ml), were detected in black and white hypertensive men, respectively.

Conclusions:

The observed differences between circulating RAS components, which are reflected via equilibrium angiotensin levels, point to a distinctive molecular regulation of the RAAS in the two study cohorts. The increased peripheral resistance observed in hypertensive black individuals might take over a dominant role in control of blood pressure in this study population. A novel highly sensitive LC-MS/MS method resolved the issue of peptide recovery variations during sample preparation by using internal standards for each individual angiotensin metabolite.

Standing sedation with medetomidine and butorphanol in captive African elephants (Loxodonta africana)

Doses for standing sedation allowing for various procedures in otherwise inaccessible, untrained captive African elephant bulls are presented. Thirty-three standing sedations were performed in 12 males aged 8-30 years (one to four sedations per animal). Each bull received a combination of 0.009 ± 0.002 mg/kg medetomidine and 0.03 ± 0.007 mg/kg butorphanol. Full sedation was reached on average 25.5 min after injection. The addition of hyaluronidase (1000-2000 IU) significantly reduced time to full sedation to 16.5 min (paired t test, P = 0.024). Reversal was induced with intramuscular atipamezole 0.008 (±0.002) and naltrexone 0.035 (±0.015) mg/kg. Recovery took on average 7 min (3-18 min). The medetomidine/butorphanol combination provided safe standing sedation for smaller procedures.

Demonstration of simultaneous experiments using thin crystal multiplexing at the Linac Coherent Light Source

Multiplexing of the Linac Coherent Light Source beam was demonstrated for hard X-rays by spectral division using a near-perfect diamond thin-crystal monochromator operating in the Bragg geometry. The wavefront and coherence properties of both the reflected and transmitted beams were well preserved, thus allowing simultaneous measurements at two separate instruments. In this report, the structure determination of a prototypical protein was performed using serial femtosecond crystallography simultaneously with a femtosecond time-resolved XANES studies of photoexcited spin transition dynamics in an iron spin-crossover system. The results of both experiments using the multiplexed beams are similar to those obtained separately, using a dedicated beam, with no significant differences in quality.

A novel skin penetration enhancer: evaluation by membrane diffusion and confocal microscopy

PURPOSE

The aim of this study was to determine the in vitro transdermal efficacy of a Meyer Zall Laboratories (MZL) oil/water emulsion in two separate preparations containing the actives, coal tar and the non-steroidal anti-inflammatory drug, diclofenac sodium.

METHOD

The release rate of the two active ingredients from MZL dermatological preparations, Exorex and Athru-Derm and four comparator products was determined using an enhancer cell system, whilst specific penetration characteristics of the MZL formulation were elucidated using confocal and electron microscopy. The latter properties were explored at both the organ level, using human skin, as well as at a cellular level using a melanoma cell line.

RESULTS

While the in vitro release rates for all formulations was high, coal tar and diclofenac release from Exorex and Athru-Derm respectively was, at nearly all time intervals, significantly higher than from comparator products. Microscopy revealed the presence of spherical liposomal type structures in both the MZL lotion and a comparator gel. In the MZL lotion, the majority of these structures, referred to here as emzaloid particles, were in the order of magnitude of about 50 nm to 1 microm in diameter with a small minority exceeding these dimensions. After application of Athru-Derm to human skin, intact emzaloid particles of submicron dimensions were detected in the epidermis in association with the cell membranes. The affinity of the MZL lotion for cell membranes was further demonstrated with melanoma cells; in addition, the formulation was seen to penetrate even to the nucleus of viable cells.

CONCLUSION

Overall the data suggest that the oil/water base in MZL formulations is a highly efficient transdermal vehicle able to transport a wide range of indication- specific actives to their site of action.

A pharmacochemic investigation of Gomphrena celosioides (Amaranthaceae)

A chemical and biological screen was performed on Gomphrena celosioides (Amaranthaceae) known as prostrate globe amaranth. Chemical tests showed the presence of saponins, steroids, phenolic substances, flavonoids, amino acids, sugars and betacyanins in the plant. The roots exhibited a weak antibacterial activity against three Gram positive bacteria. An action on the autonomic nervous system of rats was shown by all the plant parts, when tested by the method of Malone and Robichaud. Sympathetic and parasympathetic symptoms were observed.