14 results on '"Ian L. Ross"'
Search Results
2. Characteristics and Challenges of Primary Adrenal Insufficiency in Africa: A Review of the Literature
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Thabiso R. P. Mofokeng, Salem A. Beshyah, and Ian L. Ross
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Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Backgrounds. Africa comprises 54 countries with varying degrees of economic development. As with other healthcare systems, rare diseases such as adrenal insufficiency are neglected and poorly documented. Objectives. We wished to explore primary adrenal insufficiency (PAI) in Africa, its prevalence, aetiology, genetics, presentation, diagnosis, and treatment and to determine the unmet needs in clinical care, education, and research. Materials and Methods. A narrative nonsystematic review of the literature was undertaken. We searched two online databases (PubMed and Google scholar) using the search terms “Addison’s disease/PAI, primary adrenal insufficiency coupled with “Africa,” “country names,” and “genetic disorders.” A total of 184 PAI records were reviewed. The exclusion of abstracts, conference proceedings, single case reports, and duplicate studies covering the same subject matter yielded 124 articles, of which 97 informed the final manuscript. Results. A wide range of aetiology of PAI was encountered, but their true prevalence is unknown. Aetiology varied with region and age of presentation as reflected by predominantly TB, HIV, and infective causes occurring in sub-Saharan Africa and more congenital forms described in North Africa associated with consanguinity. In Africa, the diagnostic criteria for PAI do not universally accord with conventional criteria, and there is a heavy reliance on clinical suspicion and biochemistry, including random cortisol of
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- 2022
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3. Effect of prednisolone on inflammatory markers in pericardial tuberculosis: A pilot study
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Justin Shenje, Rachel P. Lai, Ian L. Ross, Bongani M. Mayosi, Robert J. Wilkinson, Mpiko Ntsekhe, and Katalin A. Wilkinson
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background: Pericardial disorders are a common cause of heart disease, and the most common cause of pericarditis in developing countries is tuberculous (TB) pericarditis. It has been shown that prednisolone added to standard anti-TB therapy leads to a lower rate of constrictive pericarditis. We conducted a pilot study to evaluate the effect of adjunctive prednisolone treatment on the concentration of inflammatory markers in pericardial tuberculosis, in order to inform immunological mechanisms at the disease site. Methods: Pericardial fluid, plasma and saliva samples were collected from fourteen patients with pericardial tuberculosis, at multiple time points. Inflammatory markers were measured using multiplex luminex analysis and ELISA. Results: In samples from 14 patients we confirmed a strongly compartmentalized immune response at the disease site and found that prednisolone significantly reduced IL-6 concentrations in plasma by 8 hours of treatment, IL-1beta concentrations in saliva, as well as IL-8 concentrations in both pericardial fluid and saliva by 24 hours. Conclusion: Monitoring the early effect of adjunctive immunotherapy in plasma or saliva is a possibility in pericarditis. Keywords: Tuberculosis, HIV, Pericarditis, Steroids, Treatment monitoring
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- 2018
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4. SCIMP is a transmembrane non-TIR TLR adaptor that promotes proinflammatory cytokine production from macrophages
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Lin Luo, Nilesh J. Bokil, Adam A. Wall, Ronan Kapetanovic, Natalie M. Lansdaal, Faustine Marceline, Belinda J. Burgess, Samuel J. Tong, Zhong Guo, Kirill Alexandrov, Ian L. Ross, Margaret L. Hibbs, Jennifer L. Stow, and Matthew J. Sweet
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Science - Abstract
Toll-like receptors engage TIR domain-containing adaptors to control proinflammatory gene expression in response to pathogens and tissue damage. Here the authors show that the non-TIR domain-containing transmembrane protein SCIMP is a previously unrecognized TLR adaptor expressed by macrophages.
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- 2017
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5. Poor Penetration of Antibiotics Into Pericardium in Pericardial Tuberculosis
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Justin Shenje, F. Ifeoma Adimora-Nweke, Ian L. Ross, Mpiko Ntsekhe, Lubbe Wiesner, Armin Deffur, Helen M. McIlleron, Jotam Pasipanodya, Tawanda Gumbo, and Bongani M. Mayosi
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Rifampicin ,Ethambutol ,Pyrazinamide ,Drug penetration ,Pericardium ,Protein binding ,Medicine ,Medicine (General) ,R5-920 - Abstract
Pericardial tuberculosis (TB) is associated with high therapy failure and high mortality rates. Antibiotics have to penetrate to site of infection at sufficient non-protein bound concentrations, and then enter bacteria to inhibit intracellular biochemical processes. The antibiotic concentrations achieved in pericardial fluid in TB pericarditis have never been measured before. We recruited two cohorts of patients with TB pericarditis, and left a pigtail catheter in-situ for serial drug concentration measurements over 24 h. Altogether, 704 drug concentrations were comodeled for pharmacokinetic analyses. The drug concentrations achieved in pericardial fluid were compared to the minimum inhibitory concentrations (MICs) of clinical Mycobacterium tuberculosis isolates. The total rifampicin concentration pericardial-to-serum ratios in 16 paired samples were 0.19 ± 0.33. The protein concentrations of the pericardial fluid in TB pericarditis were observed to be as high as in plasma. The non-protein bound rifampicin concentrations in pericardial fluid were 4-fold lower than rifampicin MICs in the pilot study, and the peak concentration was 0.125 versus 0.208 mg/L in the second (p = 0.001). The rifampicin clearance from pericardial fluid was 9.45 L/h versus 7.82 L/h in plasma (p = 0.002). Ethambutol peak concentrations had a pericardial-to-plasma ratio of 0.55 ± 0.22; free ethambutol peak concentrations were 2.30-lower than MICs (p
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- 2015
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6. Sleep and cognition in South African patients with non-functioning pituitary adenomas.
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Olivia de Villiers, Claudia Elliot-Wilson, Kevin G F Thomas, Patrick L Semple, Thurandrie Naiker, Michelle Henry, and Ian L Ross
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Medicine ,Science - Abstract
Strong lines of evidence in the neuroscience literature indicate that (a) healthy sleep facilitates cognitive processing, and (b) sleep disruption is associated with cognitive dysfunction. Despite the fact that patients with pituitary disease often display both disrupted sleep and cognitive dysfunction, few previous studies investigate whether these clinical characteristics in these patients might be related. Hence, we explored whether sleep disruption in patients with pituitary disease mediates their cognitive dysfunction. We recruited 18 patients with non-functioning pituitary adenomas (NFPA) and 19 sociodemographically matched healthy controls. They completed the Global Sleep Assessment Questionnaire (thus providing self-report data regarding sleep disruption) and were administered the Brief Test of Adult Cognition by Telephone, which assesses cognitive functioning in the domains of processing speed, working memory, episodic memory, inhibition, and reasoning. We found no significant differences in cognition between patients and controls. Furthermore, spectra of sleep disturbance did not differ significantly between patients and controls. Our data suggest that NFPA patients' cognition and sleep quality is relatively intact, and that sleep disruption does not mediate cognitive dysfunction. Larger studies should characterize sleep and cognition in patients with NFPA (and other pituitary diseases) to confirm whether disruption of the former mediates impairment in the latter.
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- 2024
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7. Outcome of COVID-19 infections in patients with adrenal insufficiency and excess
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Hanna F Nowotny, Jillian Bryce, Salma R Ali, Roberta Giordano, Federico Baronio, Irina Chifu, Lea Tschaidse, Martine Cools, Erica LT van den Akker, Henrik Falhammar, Natasha M Appelman-Dijkstra, Luca Persani, Guglielmo Beccuti, Ian L Ross, Simona Grozinsky-Glasberg, Alberto M Pereira, Eystein S Husebye, Stefanie Hahner, S Faisal Ahmed, and Nicole Reisch
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adrenal insufficiency ,cushing’s syndrome ,glucocorticoids ,sars-cov-2 ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Background: Information on clinical outcomes of coronavirus disease 19 (COVID-19) infection in patients with adrenal disorders is scarce. Methods: A collaboration between the European Society of Endocrinology (ESE) Rare Disease Committee and European Reference Network on Rare Endocrine Conditions via the European Registries for Rare Endocrine Conditions allowed the collection of data on 64 cases (57 adrenal insufficiency (AI), 7 Cushing’s syndrome) th at had been reported by 12 centres in 8 European countries between January 2020 and Dec ember 2021. Results: Of all 64 patients, 23 were males and 41 females (13 of those children) with a median age of 37 and 51 years. In 45/57 (95%) AI cases, COVID -19 infection was confirmed by testing. Primary insufficiency was present in 45/57 p atients; 19 were affected by Addison’s disease, 19 by congenital adrenal hyperpla sia and 7 by primary AI (PAI) due to other causes. The most relevant comorbidities w ere hypertension (12%), obesity (n = 14%) and diabetes mellitus (9%). An increase by a median of 2. 0 (IQR 1.4) times the daily replacement dose was reported in 42 (74%) patie nts. Two patients were administered i.m. injection of 100 mg hydrocortisone, and 11/64 were admitted to the hospital. Two patients had to be transferred to the intensive care unit, one with a fatal outcome. Four patients reported persistent SARS-CoV-2 inf ection, all others complete remission. Conclusion: This European multicentre questionnaire is the first to collect data on the outcome of COVID-19 infection in patients with adrenal gland disorders. It suggests good clinical outcomes in case of duly dose adjustments and emphasiz es the importance of patient education on sick day rules.
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- 2023
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8. Significant barriers to diagnosis and management of adrenal insufficiency in Africa
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Thabiso R P Mofokeng, Salem A Beshyah, Fazleh Mahomed, Kwazi C Z Ndlovu, and Ian L Ross
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adrenal insufficiency ,hypoadrenalism ,sub-saharan africa ,middle east and north africa ,s-cortisol serum cortisol ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Background: The burden and management of primary adrenal insufficiency (PAI) in Africa have not been well documented. We aimed to identify specific dis ease characteristics, patient demographics, and patterns of clinical management in es tablished PAI in Africa. Methods: An online survey of physicians’ experience relating to PAI. Results: There were 1334 responses received, 589 were complete, and 332 respondents reported managing patients with hypoadrenalism. The described responses were related to a calculated pool of 5787 patients with hypoadrenalism (2746 females, 3041 males), of whom 2302 had PAI. The likely causes of PAI in Sub-Saharan Africa (SSA) vs the Middle East and North Africa (MENA) regions included aut oimmune disease (20% vs 60.3%; P < 0.001), tuberculosis (34% vs 4.1%; P < 0.001), AIDS (29.8% vs 1%; P < 0.001), malignancy, and genetic conditions. Sixteen percent of AD patie nts (376/2302) presented in an adrenal crisis. Medical emergency identification was not u sed by 1233 (83.6%) SSA vs 330 (40.4%) MENA patients (P < 0.001), respectively. Relative non-availability of diagnostic tests across both regions included adrenal antibo dies 63% vs 69.6% (P = 0.328), s-cortisol 49.4 % vs 26.7% (P = 0.004), s-ACTH 55.7% vs 53.3% (P = 0.217), and adrenal CT scans 52.4% vs 31.8% (P = 0.017) in the SSA and MENA region, respectively. Across the entire cohort, the overall hydrocortisone use and extrapolated proportion of synacthen use were 59.4% and 50.7%, respectively. Conclusions: Through the perception and practice of healthcare professional s, we identified significant challenges in the diagnosis and management of PAI wh ich may herald high mortality. Differences between regions may reflect the allocation of healthcare resources.
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- 2020
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9. Tiered healthcare in South Africa exposes deficiencies in management and more patients with infectious etiology of primary adrenal insufficiency.
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Thabiso Rafaki Petrus Mofokeng, Kwazi Celani Zwakele Ndlovu, Salem A Beshyah, and Ian L Ross
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Medicine ,Science - Abstract
ObjectiveWe wished to determine the prevalence, etiology, presentation, and available management strategies for primary adrenal insufficiency (PAI) in South Africa (SA), hypothesizing a prevalence greater than the described 3.1 per million. There is great inequity in healthcare allocation, as two parallel healthcare systems exist, potentially modifying PAI patients' clinical profiles, private being better resourced than public healthcare.MethodsAn online survey of physicians' experience relating to PAI.ResultsThe physicians were managing 811 patients, equal to a prevalence of 14.2 per million. Likely causes of PAI in public/ academic vs private settings included: AIDS-related [304 (44.8%) vs 5 (3.8%); pConclusionA survey of South African physicians suggests a higher prevalence than previously reported. Patients presented with typical symptoms, and 15.5% presented in adrenal crisis. Significant disparities in the availability of physicians' expertise, diagnostic resources, and management options were noted in the public versus private settings. Greater awareness among health practitioners to timeously diagnose PAI is required to prevent a life-threatening outcome.
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- 2020
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10. Anti-Retroviral Therapy Increases the Prevalence of Dyslipidemia in South African HIV-Infected Patients.
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Joel A Dave, Naomi S Levitt, Ian L Ross, Miguel Lacerda, Gary Maartens, and Dirk Blom
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Medicine ,Science - Abstract
Data on the prevalence of dyslipidaemia and associated risk factors in HIV-infected patients from sub-Saharan Africa is sparse. We performed a cross-sectional analysis in a cohort of HIV-infected South African adults.We studied HIV-infected patients who were either antiretroviral therapy (ART)-naive or receiving non-nucleoside reverse transcriptase inhibitor (NNRTI)-based or protease inhibitor (PI)-based ART. Evaluation included fasting lipograms, oral glucose tolerance tests and clinical anthropometry. Dyslipidemia was defined using the NCEP ATPIII guidelines.The median age of the participants was 34 years (range 19-68 years) and 78% were women. The prevalence of dyslipidemia in 406 ART-naive and 551 participants on ART was 90.0% and 85%, respectively. Low HDL-cholesterol (HDLC) was the most common abnormality [290/406 (71%) ART-naïve and 237/551 (43%) ART- participants]. Participants on ART had higher triglycerides (TG), total cholesterol (TC), LDL-cholesterol (LDLC) and HDLC than the ART-naïve group. Severe dyslipidaemia, (LDLC> 4.9 mmol/L or TG >5.0 mmol/L) was present in
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- 2016
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11. Gateway-assisted vector construction to facilitate expression of foreign proteins in the chloroplast of single celled algae.
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Melanie Oey, Ian L Ross, and Ben Hankamer
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Medicine ,Science - Abstract
With a rising world population, demand will increase for food, energy and high value products. Renewable production systems, including photosynthetic microalgal biotechnologies, can produce biomass for foods, fuels and chemical feedstocks and in parallel allow the production of high value protein products, including recombinant proteins. Such high value recombinant proteins offer important economic benefits during startup of industrial scale algal biomass and biofuel production systems, but the limited markets for individual recombinant proteins will require a high throughput pipeline for cloning and expression in microalgae, which is currently lacking, since genetic engineering of microalgae is currently complex and laborious. We have introduced the recombination based Gateway® system into the construction process of chloroplast transformation vectors for microalgae. This simplifies the vector construction and allows easy, fast and flexible vector design for the high efficiency protein production in microalgae, a key step in developing such expression pipelines.
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- 2014
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12. Flow cytometry pulse width data enables rapid and sensitive estimation of biomass dry weight in the microalgae Chlamydomonas reinhardtii and Chlorella vulgaris.
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Maurizio Chioccioli, Ben Hankamer, and Ian L Ross
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Medicine ,Science - Abstract
Dry weight biomass is an important parameter in algaculture. Direct measurement requires weighing milligram quantities of dried biomass, which is problematic for small volume systems containing few cells, such as laboratory studies and high throughput assays in microwell plates. In these cases indirect methods must be used, inducing measurement artefacts which vary in severity with the cell type and conditions employed. Here, we utilise flow cytometry pulse width data for the estimation of cell density and biomass, using Chlorella vulgaris and Chlamydomonas reinhardtii as model algae and compare it to optical density methods. Measurement of cell concentration by flow cytometry was shown to be more sensitive than optical density at 750 nm (OD750) for monitoring culture growth. However, neither cell concentration nor optical density correlates well to biomass when growth conditions vary. Compared to the growth of C. vulgaris in TAP (tris-acetate-phosphate) medium, cells grown in TAP + glucose displayed a slowed cell division rate and a 2-fold increased dry biomass accumulation compared to growth without glucose. This was accompanied by increased cellular volume. Laser scattering characteristics during flow cytometry were used to estimate cell diameters and it was shown that an empirical but nonlinear relationship could be shown between flow cytometric pulse width and dry weight biomass per cell. This relationship could be linearised by the use of hypertonic conditions (1 M NaCl) to dehydrate the cells, as shown by density gradient centrifugation. Flow cytometry for biomass estimation is easy to perform, sensitive and offers more comprehensive information than optical density measurements. In addition, periodic flow cytometry measurements can be used to calibrate OD750 measurements for both convenience and accuracy. This approach is particularly useful for small samples and where cellular characteristics, especially cell size, are expected to vary during growth.
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- 2014
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13. Impact of procedural steps and cryopreservation agents in the cryopreservation of chlorophyte microalgae.
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Tony V L Bui, Ian L Ross, Gisela Jakob, and Ben Hankamer
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Medicine ,Science - Abstract
The maintenance of traditional microalgae collections based on liquid and solid media is labour intensive, costly and subject to contamination and genetic drift. Cryopreservation is therefore the method of choice for the maintenance of microalgae culture collections, but success is limited for many species. Although the mechanisms underlying cryopreservation are understood in general, many technical variations are present in the literature and the impact of these are not always elaborated. This study describes two-step cryopreservation processes in which 3 microalgae strains representing different cell sizes were subjected to various experimental approaches to cryopreservation, the aim being to investigate mechanistic factors affecting cell viability. Sucrose and dimethyl sulfoxide (DMSO) were used as cryoprotectants. They were found to have a synergistic effect in the recovery of cryopreserved samples of many algal strains, with 6.5% being the optimum DMSO concentration. The effect of sucrose was shown to be due to improved cell survival and recovery after thawing by comparing the effect of sucrose on cell viability before or after cryopreservation. Additional factors with a beneficial effect on recovery were the elimination of centrifugation steps (minimizing cell damage), the reduction of cell concentration (which is proposed to reduce the generation of toxic cell wall components) and the use of low light levels during the recovery phase (proposed to reduce photooxidative damage). The use of the best conditions for each of these variables yielded an improved protocol which allowed the recovery and subsequent improved culture viability of a further 16 randomly chosen microalgae strains. These isolates included species from Chlorellaceae, Palmellaceae, Tetrasporaceae, Palmellopsis, Scenedesmaceae and Chlamydomonadaceae that differed greatly in cell diameter (3-50 µm), a variable that can affect cryopreservation success. The collective improvement of each of these parameters yielded a cryopreservation protocol that can be applied to a broad range of microalgae.
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- 2013
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14. RNAi knock-down of LHCBM1, 2 and 3 increases photosynthetic H2 production efficiency of the green alga Chlamydomonas reinhardtii.
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Melanie Oey, Ian L Ross, Evan Stephens, Janina Steinbeck, Juliane Wolf, Khairul Adzfa Radzun, Johannes Kügler, Andrew K Ringsmuth, Olaf Kruse, and Ben Hankamer
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Medicine ,Science - Abstract
Single cell green algae (microalgae) are rapidly emerging as a platform for the production of sustainable fuels. Solar-driven H2 production from H2O theoretically provides the highest-efficiency route to fuel production in microalgae. This is because the H2-producing hydrogenase (HYDA) is directly coupled to the photosynthetic electron transport chain, thereby eliminating downstream energetic losses associated with the synthesis of carbohydrate and oils (feedstocks for methane, ethanol and oil-based fuels). Here we report the simultaneous knock-down of three light-harvesting complex proteins (LHCMB1, 2 and 3) in the high H2-producing Chlamydomonas reinhardtii mutant Stm6Glc4 using an RNAi triple knock-down strategy. The resultant Stm6Glc4L01 mutant exhibited a light green phenotype, reduced expression of LHCBM1 (20.6% ±0.27%), LHCBM2 (81.2% ±0.037%) and LHCBM3 (41.4% ±0.05%) compared to 100% control levels, and improved light to H2 (180%) and biomass (165%) conversion efficiencies. The improved H2 production efficiency was achieved at increased solar flux densities (450 instead of ∼100 µE m(-2) s(-1)) and high cell densities which are best suited for microalgae production as light is ideally the limiting factor. Our data suggests that the overall improved photon-to-H2 conversion efficiency is due to: 1) reduced loss of absorbed energy by non-photochemical quenching (fluorescence and heat losses) near the photobioreactor surface; 2) improved light distribution in the reactor; 3) reduced photoinhibition; 4) early onset of HYDA expression and 5) reduction of O2-induced inhibition of HYDA. The Stm6Glc4L01 phenotype therefore provides important insights for the development of high-efficiency photobiological H2 production systems.
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- 2013
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