Transsulfuration and folate pathways in rheumatoid arthritis: A systematic review and meta-analysis.

BACKGROUND: Metabolomic assessment of the transsulfuration and folic acid biochemical pathways could lead to the identification of promising biomarkers of nitric oxide dysregulation and oxidative stress in rheumatoid arthritis (RA). METHODS: We conducted a systematic review and meta-analysis of transsulfuration (methionine, homocysteine, and cysteine) and folic acid (folic acid, vitamin B6 , and vitamin B12 ) metabolites in RA patients in remission and healthy controls. Electronic databases were searched from inception to 15 July 2023 for relevant articles. We assessed the risk of bias using the JBI checklist and the certainty of evidence using GRADE. RESULTS: In 28 eligible studies, compared to controls, RA patients had significantly higher concentrations of homocysteine (standardized mean difference, SMD = 0.74, 95% CI 0.54-0.93, p < 0.001; low certainty of evidence) and methionine (SMD = 1.00, 95% CI 0.57-1.44, p < 0.001; low certainty) and lower concentrations of vitamin B6 (SMD = -6.62, 95% CI -9.65 to -3.60, p < 0.001; low certainty). By contrast, there were non-significant between-group differences in vitamin B12 and folic acid. In meta-regression and subgroup analysis, there were no associations between the effect size and several study and patient characteristics except for homocysteine (year of publication, C-reactive protein, triglycerides, and analytical method) and folic acid (biological matrix). CONCLUSIONS: The results of our study suggest that homocysteine, methionine, and vitamin B6 are promising biomarkers to assess nitric oxide dysregulation and oxidative stress in RA. (PROSPERO registration number: CRD42023461081).

The association between bilirubin concentrations and inflammatory bowel disease: Insights from a systematic review and meta-analysis.

BACKGROUND: Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), poses a significant challenge to health care systems because of its chronic nature and increasing global prevalence. Effective management of IBD requires accurate diagnostic tools and biomarkers. This systematic review and meta-analysis aimed to evaluate the relationship between bilirubin concentrations and IBD activity and outcomes. METHODS: A comprehensive search of electronic databases identified 11 studies that included 2606 subjects with IBD and 3607 healthy controls. RESULTS: Bilirubin concentrations were significantly lower in subjects with IBD when compared to controls (SMD = -0.96, 95% CI -1.21 to -0.70; p < .001). Although substantial heterogeneity was observed, sensitivity analysis confirmed the robustness of the results. Publication bias was detected, but subgroup analyses did not significantly alter the results. Meta-regression showed that age was a significant factor influencing the association between bilirubin concentrations and IBD. Subgroup analyses showed a more pronounced reduction in bilirubin concentrations in subjects with CD than those with UC. CONCLUSION: This study supports the potential utility of bilirubin as a biomarker in IBD, emphasizing the need for further research to validate its clinical significance.

Association between blood Pentraxin-3 concentrations and rheumatic diseases: A systematic review and meta-analysis.

BACKGROUND: Among the Pentraxins, the long Pentraxin-3 (PTX-3) is associated with several processes, particularly in the earliest phases of the innate humoral response. Increased blood PTX-3 concentrations have been observed in a wide range of conditions, from infectious to cardiovascular disorders. Since its increase is more rapid than C-reactive protein (CRP), PTX-3 can be useful to detect and monitor early inflammation. To dissect its pathophysiological role in rheumatic diseases (RD), we conducted a systematic review and meta-analysis comparing blood PTX-3 concentrations in RD patients and healthy individuals and investigating possible associations with clinical, demographic, and study characteristics. METHODS: We performed a search of published evidence until April 2024 in PubMed, Web of Science and Scopus, which led to the selection of 60 relevant manuscripts from a total of 1072 records. RESULTS: Our synthesis revealed a statistically significant difference in PTX-3 concentrations between RD patients and controls (standard mean difference, SMD = 1.02, 95% CI 0.77-1.26, p < .001), that correlated with CRP concentrations. The effect size was associated with geographical region of study conduction, RD type, with a reduction of the observed heterogeneity in patients with low LDL-cholesterol and triglycerides concentrations. CONCLUSIONS: Our study has shown a significant increase in blood PTX-3 concentrations in RD patients, which was associated with specific patient characteristics. Nevertheless, additional studies are needed to better define the utility of measuring PTX-3 in the early phase of RD. Our study was conducted in compliance with the PRISMA 2020 statement (study protocol available at PROSPERO CRD42024516600).

A systematic review and meta-analysis of circulating adhesion molecules in rheumatoid arthritis.

BACKGROUND: The availability of robust biomarkers of endothelial activation might enhance the identification of subclinical atherosclerosis in rheumatoid arthritis (RA). We investigated this issue by conducting a systematic review and meta-analysis of cell adhesion molecules in RA patients. METHODS: We searched electronic databases from inception to 31 July 2023 for case-control studies assessing the circulating concentrations of immunoglobulin-like adhesion molecules (vascular cell, VCAM-1, intercellular, ICAM-1, and platelet endothelial cell, PECAM-1, adhesion molecule-1) and selectins (E, L, and P selectin) in RA patients and healthy controls. Risk of bias and certainty of evidence were assessed using the JBI checklist and GRADE, respectively. RESULTS: In 39 studies, compared to controls, RA patients had significantly higher concentrations of ICAM-1 (standard mean difference, SMD = 0.81, 95% CI 0.62-1.00, p < 0.001; I2 = 83.0%, p < 0.001), VCAM-1 (SMD = 1.17, 95% CI 0.73-1.61, p < 0.001; I2 = 95.8%, p < 0.001), PECAM-1 (SMD = 0.82, 95% CI 0.57-1.08, p < 0.001; I2 = 0.0%, p = 0.90), E-selectin (SMD = 0.64, 95% CI 0.42-0.86, p < 0.001; I2 = 75.0%, p < 0.001), and P-selectin (SMD = 1.06, 95% CI 0.50-1.60, p < 0.001; I2 = 84.8%, p < 0.001), but not L-selectin. In meta-regression and subgroup analysis, significant associations were observed between the effect size and use of glucocorticoids (ICAM-1), erythrocyte sedimentation rate (VCAM-1), study continent (VCAM-1, E-selectin, and P-selectin), and matrix assessed (P-selectin). CONCLUSIONS: The results of our study support a significant role of cell adhesion molecules in mediating the interplay between RA and atherosclerosis. Further studies are warranted to determine whether the routine use of these biomarkers can facilitate the detection and management of early atherosclerosis in this patient group. PROSPERO Registration Number: CRD42023466662.

Recent temporal trends, characteristics and outcomes of patients with non-COVID-19 community-acquired pneumonia at two tertiary hospitals in Australia: an observational study.

BACKGROUND: Community-acquired pneumonia (CAP) leads to considerable morbidity and mortality globally. However, data on CAP burden in Australia, especially during the coronavirus disease 2019 (COVID-19) pandemic, are limited. AIMS: We characterised and assessed clinical outcomes of non-COVID-19 CAP hospitalisations over a 6-year period at two major hospitals in South Australia. METHODS: All non-COVID-19 CAP hospitalisations were identified using the International Statistical Classification of Diseases and Related Health Problems, Tenth revision, Australian modification (ICD-10-AM) codes, between 1 January 2018 and 31 December 2023, at two tertiary hospitals in Adelaide. Clinical outcomes included in-hospital and 30-day mortality, length of stay (LOS) in, intensive care unit (ICU) admission and 30-day readmissions. Multilevel regression models were utilised to identify predictors of clinical outcomes. RESULTS: Over the 6-year period, there were 7853 non-COVID-19 CAP hospitalisations, with a temporal increase from 100 per 100 000 population in 2018 to 208 per 100 000 population in 2023 (P < 0.001). The mean (SD) age was 75.1 (17.6) years, and 54.6% were males. The mean age declined over time (P < 0.05), while other characteristics remained stable. Streptococcus pneumoniae was the most commonly identified bacterium (21.8% of cases). In-hospital mortality occurred in 7.8% of patients, with 30-day mortality and readmission rates of 14.3% and 16.9% respectively. LOS declined significantly during the pandemic years; however, mortality remained stable over time. Frailty status, malnutrition and number of comorbidities significantly predicted 30-day mortality and LOS, in addition to pneumonia severity and ICU admission. CONCLUSIONS: There has been an increasing trend of hospitalisations for non-COVID-19 CAP during the COVID-19 pandemic, with a concomitant trend towards shorter LOS and no significant shift in other clinical outcomes.

Prescribing of antivirals for COVID-19 in a South Australian local health network according to statewide guidelines.

Antiviral drugs were rapidly implemented into clinical practice for the treatment of high-risk patients with COVID-19, prompting the development of statewide guidelines. This South-Australian study reviewed guideline adherence, assessed prescribing patterns and highlighted the inappropriate management of relative drug-drug interactions and dosing for renal function. Additionally, it evaluated the impact of inappropriate antiviral drug use and suggested methods to improve quality use of medicines.

Nano-targeting vascular remodeling in cancer: Recent developments and future directions.

Tumor growth and progression are strictly dependent on the adequate blood supply of oxygen and nutrients. The formation of new blood vessels and vascular networks is essential to ensure this demand. Blood vessels also facilitate the invasion of cancer cells into nearby tissues and their subsequent metastasis. Tumor cells represent the main driver of the neovascularization process through the direct or indirect, by neighboring non-cancer cells, release of pro-angiogenic molecules. The mediators (e.g., growth factors and extracellular matrix components), signaling pathways, cellular components, and processes (e.g., endothelial cell proliferation and migration) activated in tumor angiogenesis are similar to those involved in normal vascular development, except they lack efficient control mechanisms. Consequently, newly formed tumor vessels are typically fragile and hyperpermeable with a reduced and erratic blood flow. Targeting the tumor vasculature has been the focus of intense research over the last 20 years. However, despite the initial interest and expectations, the systemic use of anti-angiogenic drugs has not always led to therapeutic breakthroughs and, in some cases, has been associated with the development of tumor adaptive resistance resulting in a more aggressive phenotype. Therefore, new therapeutic approaches have focused on combining anti-angiogenic agents with chemotherapy or immunotherapy and/or optimizing (normalizing) the structure and function of tumor blood vessels to ensure a more efficient drug delivery. In this context, nanomedicine offers the significant advantage of targeting and releasing anti-angiogenic drugs at specific sites, minimizing toxicity in healthy tissues. Several nanoparticles possess intrinsic modulatory effects on angiogenesis, while others have been developed to facilitate drug delivery in association with chemotherapy, thermotherapy, radiotherapy or in response to specific stimuli within the tumor environment (e.g., enzymes, ions, redox potential) or exogenous stimuli (e.g., temperature, electricity, magnetic fields, and ultrasound). Other nanoparticles can modify, under specific conditions, their physical properties (e.g., dimensions, structure, and interactions) to increase penetration in tumor cells. This review provides a comprehensive appraisal of the critical modulators of tumor vascular biology, the most promising nano-strategies that specifically target such modulators, and the directions for future research and clinical applications.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratio and disease activity in rheumatoid arthritis: A systematic review and meta-analysis.

BACKGROUND: Inflammatory indexes derived from routine haematological parameters, particularly the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR), have been shown to discriminate between patients with and without rheumatoid arthritis (RA). However, their capacity to discriminate between RA patients with and without active disease has not been systematically appraised. METHODS: We searched PubMed, Web of Science, Scopus and Google Scholar, from inception to June 2022, for studies comparing NLR and/or PLR values between RA patients with and without active disease. Risk of bias and certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and GRADE, respectively. RESULTS: In 18 studies (2122 RA patients with active disease, mean age 50 years, 20% males; 1071 RA patients with nonactive disease, mean age 50 years, 25% males), active disease was associated with significantly higher NLR (standard mean difference, SMD = 0.37, 95% CI 0.19 to 0.55, p < .001; low certainty of evidence) and PLR values (SMD = 0.48, 95% CI 0.32 to 0.64, p < .001; low certainty of evidence). In sensitivity analysis, the SMD values were not substantially influenced by sequentially removing individual studies. There was no publication bias. In meta-regression, the effect size was not associated with other study and patient characteristics, including sex, Disease Activity Score-28, C-reactive protein and erythrocyte sedimentation rate. CONCLUSIONS: NLR and PLR can significantly discriminate between RA patients with and without active disease. Further studies are required to determine their diagnostic performance, singly or in combination with other parameters, in routine practice.

Prevalence and clinical significance of electrocardiographic signs of atrial myopathy in rheumatoid arthritis: results from the EDRA study.

OBJECTIVES: We sought to determine whether the increased risk of atrial fibrillation and stroke in rheumatoid arthritis (RA) can be accounted for by an increased prevalence of electrocardiographic markers of atrial myopathy. METHODS: We retrospectively evaluated clinical and electrocardiographic data of 218 RA patients prospectively enrolled in the Endothelial Dysfunction Evaluation for Coronary Heart Disease Risk Estimation in Rheumatoid Arthritis study (EDRA study ClinicalTrials.gov: NCT02341066) and 109 controls matched by age and gender. The prevalence of interatrial blocks (IAB, partial - pIAB or advanced - aIAB), abnormal P-wave terminal force in lead V1 (aPtfV1) and atrial myopathy (electrocardiographically defined as the presence of 1) aIAB, or 2) pIAB plus abnormal aPtfV1) was assessed in each group. RA patients were followed-up for 5 years for incident atrial fibrillation and cardiovascular events. RESULTS: Barring the prevalence of hyperlipidaemia and obesity, the demographic characteristics and cardiovascular risk profile of RA patients and controls were comparable. All subjects enrolled in the study were free from previous cardiovascular disease and atrial fibrillation. Compared to controls, RA patients had longer P-wave duration (118±12 vs. 112±10 ms, p<0.001) and higher prevalence of pIAB (43% vs. 21%, p<0.001) and abnormal PtfV1 (27% vs. 10%, p<0.001). Accordingly, atrial myopathy was significantly more prevalent (15% vs 4%, p=0.003) in RA patients. In multiple regression, male gender (OR [95% CI] = 3.09 [1.48-6.47], p=0.003) and RA (OR [95% CI] = 4.83 [1.58-14.73], p=0.006) were independently associated with atrial myopathy. Atrial myopathy was not significantly associated with incident atrial fibrillation or cardiovascular events in RA patients after 5 years of follow-up. CONCLUSIONS: Electrocardiographic markers of atrial myopathy are independently associated with RA. Further studies with larger sample size and longer follow-up are needed to determine whether the increased prevalence of atrial myopathy contributes to the increased risk of atrial fibrillation and stroke in this group.

Comorbidities and their management in women with breast cancer-an Australian survey of breast cancer survivors.

PURPOSE: Breast cancer survivors experience significant burden from comorbid chronic conditions, but little is known about how well these conditions are managed. We conducted a national survey of Australian breast cancer survivors to examine the burden of chronic conditions, their impact and care alignment with the principles of chronic condition management. METHODS: A study-specific survey incorporated questions about chronic conditions using the Charlson Comorbidity Index (CCI), functional status using the Vulnerable Elders Survey (VES) and perceived quality of care for cancer and non-cancer conditions using the Patient Assessment of Care for Chronic Conditions Survey (PACIC). Members of Breast Cancer Network Australia (BCNA) were invited via email to complete the survey either online or through direct mail. RESULTS: The survey was sent to 2198 BCNA members and 177 responses were received (8.1%). Respondents were women aged 32-88 years (median 60.1 years). The majority were married (116; 67.7%) and had private insurance (137; 80.0%) and reported good to excellent health (119; 73.5%). Other health conditions were reported by 157 (88.7%), the most common being chronic pain (27.1%) and fatigue (22.0%). When asked about management of comorbidities or cancer, less than 20% were routinely asked about management goals, helped to set goals or asked about health habits. CONCLUSIONS: In this population of survivors with good health status and high rates of private insurance, comorbidities were common and their management, as well as management of breast cancer, was poorly aligned with chronic condition management principles.

New horizons in managing older cancer survivors: complexities and opportunities.

Older adults represent a growing population amongst cancer survivors who require specific consideration given the complex and largely unknown interactions between cancer-related concerns and age-related conditions. The increasing use of geriatric assessment (GA) has enabled oncologists to appropriately assess older patients' overall health status, personalise anti-cancer treatment and improve survival. However, whilst current research and practice focus on improving the management of older adults with cancer in the acute setting, the progress in the field of survivorship research in geriatric oncology is lagging. As cancer survivorship is a continuum, planning for a healthy survivorship should start at the time of cancer diagnosis. GA can play an important role in identifying potential survivorship issues and optimising delivery of survivorship care. A goal-directed, patient-focused geriatric survivorship care plan that involves a multidisciplinary team provides a framework for a personalised delivery of survivorship care in this patient group and there is a need for tailored interventions that support self-management and care integration. Research on the impact of cancer and its treatment on geriatric-specific outcomes needs to be prioritised through global initiatives to encompass a diverse and heterogenous population of adult cancer survivors.

A comprehensive review of machine learning algorithms and their application in geriatric medicine: present and future.

The increasing access to health data worldwide is driving a resurgence in machine learning research, including data-hungry deep learning algorithms. More computationally efficient algorithms now offer unique opportunities to enhance diagnosis, risk stratification, and individualised approaches to patient management. Such opportunities are particularly relevant for the management of older patients, a group that is characterised by complex multimorbidity patterns and significant interindividual variability in homeostatic capacity, organ function, and response to treatment. Clinical tools that utilise machine learning algorithms to determine the optimal choice of treatment are slowly gaining the necessary approval from governing bodies and being implemented into healthcare, with significant implications for virtually all medical disciplines during the next phase of digital medicine. Beyond obtaining regulatory approval, a crucial element in implementing these tools is the trust and support of the people that use them. In this context, an increased understanding by clinicians of artificial intelligence and machine learning algorithms provides an appreciation of the possible benefits, risks, and uncertainties, and improves the chances for successful adoption. This review provides a broad taxonomy of machine learning algorithms, followed by a more detailed description of each algorithm class, their purpose and capabilities, and examples of their applications, particularly in geriatric medicine. Additional focus is given on the clinical implications and challenges involved in relying on devices with reduced interpretability and the progress made in counteracting the latter via the development of explainable machine learning.

Development of a HPLC-MS/MS Method to Assess the Pharmacokinetics and Tumour Distribution of the Dimethylarginine Dimethylaminohydrolase 1 Inhibitors ZST316 and L-257 in a Xenograft Model of Triple-Negative Breast Cancer in Mice.

We describe the development and validation of an HPLC-MS/MS method to assess the pharmacokinetics and tumour distribution of ZST316, an arginine analogue with inhibitory activity towards dimethylarginine dimethylaminohydrolase 1 (DDAH1) and vasculogenic mimicry, and its active metabolite L-257 in a xenograft model of triple-negative breast cancer (TNBC). The method proved to be reproducible, precise, and highly accurate for the measurement of both compounds in plasma and tumour tissue following acute and chronic (five days) intraperitoneal administration of ZST316 (30 mg/Kg daily) in six-week-old severe combined immunodeficiency disease (SCID) mice inoculated with MDA-MB-231 TNBC cells. ZST316 was detected in tumour tissue and plasma after 1 h (6.47 and 9.01 µM, respectively) and 24 h (0.13 and 0.16 µM, respectively) following acute administration, without accumulation during chronic treatment. Similarly, the metabolite L-257 was found in tumour tissue and plasma after 1 h (15.06 and 8.72 µM, respectively) and 24 h (0.17 and 0.17 µM, respectively) following acute administration of ZST316, without accumulation during chronic treatment. The half-life after acute and chronic treatment ranged between 4.4-7.1 h (plasma) and 4.5-5.0 h (tumour) for ZST316, and 4.2-5.3 h (plasma) and 3.6-4.9 h (tumour) for L-257. The results of our study demonstrate the (a) capacity to accurately measure ZST316 and L-257 concentrations in plasma and tumour tissue in mice using the newly developed HPLC-MS/MS method, (b) rapid conversion of ZST316 into L-257, (c) good intra-tumour penetration of both compounds, and (d) lack of accumulation of both ZST316 and L-257 in plasma and tumour tissue during chronic administration. Compared to a previous method developed by our group to investigate ZST316 in plasma, the main advantages of the new method include a wider range of linearity which reduces the need for dilutions and the combined assessment of ZST316 and L-257 in plasma and tumour tissue which limits the required amount of matrix. The new HPLC-MS/MS method is useful to investigate the in vivo effects of ZST316 and L-257 on vasculogenic mimicry, tumour mass, and metastatic burden in xenograft models of TNBC.

Divergent Dimethylarginine Dimethylaminohydrolase Isoenzyme Expression in the Central Nervous System.

The endogenous methylated derivative of ʟ-arginine, Nω,Nω'-dimethyl-ʟ-arginine (asymmetric dimethylarginine, ADMA), an independent risk factor in many diseases, inhibits the activity of nitric oxide synthases and, consequently, modulates the availability of nitric oxide. While most studies on the biological role of ADMA have focused on endothelial and inducible nitric oxide synthases modulation and its contribution to cardiovascular, metabolic, and renal diseases, a role in regulating neuronal nitric oxide synthases and pathologies of the central nervous system is less understood. The two isoforms of dimethylarginine dimethylaminohydrolase (DDAH), DDAH1 and DDAH2, are thought to be the main enzymes responsible for ADMA catabolism. A current impediment is limited knowledge on specific tissue and cellular distribution of DDAH enzymes within the brain. In this study, we provide a detailed characterization of the regional and cellular distribution of DDAH1 and DDAH2 proteins in the adult murine and human brain. Immunohistochemical analysis showed a wide distribution of DDAH1, mapping to multiple cell types, while DDAH2 was detected in a limited number of brain regions and exclusively in neurons. Our results provide key information for the investigation of the pathophysiological roles of the ADMA/DDAH system in neuropsychiatric diseases and pave the way for the development of novel selective therapeutic approaches.

An updated systematic review and meta-analysis of the effect of statins on asymmetric dimethylarginine.

OBJECTIVES: We conducted an updated systematic review and meta-analysis of the effect of statins on serum or plasma concentrations of the endogenous inhibitor of endothelial nitric oxide synthase, asymmetric NG,NG-dimethyl-l-arginine (ADMA). METHODS: A systematic literature search was conducted in the electronic databases PubMed, Web of Science, and Scopus, from inception to July 2021. Risk of bias and certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist for analytical studies and GRADE, respectively. RESULTS: In 23 studies, reporting 25 treatment arms in 845 participants (mean age 53 years, 57% males, treatment duration 4-48 weeks), statins significantly reduced ADMA concentrations (SMD = -0.39, 95% CI -0.62 to -0.16, p = 0.001; moderate certainty of evidence). The extreme heterogeneity observed was substantially reduced in study subgroups of specific class and individual statins, regional areas, and analytical methods for ADMA concentrations. There was no publication bias. In sensitivity analysis, the corresponding SMD values were not substantially modified when individual studies were sequentially removed. Significant associations were observed, in meta-regression, between the SMD and publication year (t = -3.25, p = 0.003), but not baseline cholesterol concentrations. CONCLUSION: Statin treatment significantly lowers ADMA concentrations. This effect is independent of baseline cholesterol. Prospective studies are required to determine whether ADMA-lowering mediates, at least partly, the protective effects of statins against atherosclerotic cardiovascular disease. (PROSPERO registration number: CRD42021275123).

ADMA and homoarginine independently predict mortality in critically ill patients.

BACKGROUND: Arginine metabolites are associated with cardiovascular and all-cause mortality in several patient groups. We investigated whether arginine metabolites are associated with mortality in patients with critical illness and whether associations are independent of other factors affecting prognosis in an Intensive Care Unit (ICU). METHODS: 1155 acutely unwell adult patients admitted to a mixed medical-surgical ICU were studied. Arginine, asymmetric dimethyl-l-arginine (ADMA), monomethyl-l-arginine (MMA), symmetric dimethyl-l-arginine (SDMA) and l-homoarginine were measured in a plasma sample collected at admission to ICU by liquid chromatography tandem mass spectrometry. Risk of death score was calculated using data submitted to the Australia and New Zealand Intensive Care Society. RESULTS: In this cohort, 163 patients (14.1%) died. ADMA (odds ratio = 1.159 (1.033-1.300) per 0.1 µmol/L increment, p = 0.012), homoarginine (odds ratio = 0.963 (0.934-0.992), p = 0.013) and risk of death score (odds ratio = 1.045 (1.037-1.053) per 1% increment, p < 0.001) were independently associated with mortality in ICU patients. The area under the receiver operator characteristic curve for risk of death score, ADMA and homoarginine combined for mortality was greater than for risk of death score alone (0.815 (95% CI 0.790-0.837) vs 0.796 (95% CI 0.781-0.820), p = 0.019). Other arginine metabolites were not independently associated with mortality. CONCLUSIONS: ADMA is positively and homoarginine negatively associated with mortality in ICU patients, independent of other clinical factors. Measuring ADMA and homoarginine may refine models to predict ICU mortality. Reducing ADMA and increasing homoarginine are potential therapeutic targets to reduce mortality in critically ill patients.

Chemical similarities and differences among inhibitors of nitric oxide synthase, arginase and dimethylarginine dimethylaminohydrolase-1: Implications for the design of novel enzyme inhibitors modulating the nitric oxide pathway.

Nitric oxide (NO) is a signalling molecule that controls a multitude of regulatory functions including neurotransmission, vascular tone, immune response, and angiogenesis. Regulating NO concentrations in cells using small molecules is an active area of research in the treatment of several pathologies such as cardiovascular disease, cancer, and inflammatory conditions. Small molecule-inhibition of critical NO regulatory enzymes, NO synthase (NOS), arginase, and dimethylarginine dimethyaminohydrolase-1 (DDAH1), has shown therapeutic benefits as well as limitations and is a focus of current research.In recent years, DDAH1 has been explored as a potential target to indirectly regulate NO in diseases characterized by excessive NO production. This review discusses the biological and pathophysiological role of the NO pathway, the existing inhibitors of NOS, arginase and DDAH1, and the conventional and structure-guided structure-activity relationship studies involved in their discovery. The key structural elements of amino acid-derived inhibitors responsible for selective inhibition of each enzyme, and the chemical features responsible for dual enzyme inhibition are also discussed. Finally, a synthetic scheme for developing both selective and dual inhibitors using common starting materials is provided, offering unique insights in the quest for the rational design of novel NO pathway inhibitors.

Geospatial analysis of Helicobacter pylori infection in South Australia: Should location influence eradication therapy?

BACKGROUND AND AIM: Rates of antimicrobial-resistant Helicobacter pylori infection are rising globally; however, geospatial location and its interaction with risk factors for infection have not been closely examined. METHODS: Gastric biopsy specimens were collected to detect H. pylori infection at multiple centers in Adelaide, South Australia, between 1998 and 2017. The geospatial distribution of antibiotic-resistant H. pylori in the Greater Adelaide region was plotted using choropleth maps. Moran's I was used to assess geospatial correlation, and multivariate linear regression (MLR) was used to examine associations between migration status, socioeconomic status, age, gender, and rates of H. pylori positivity and antibiotic resistance. Geographically weighted regression (GWR) was used to determine the extent to which the associations varied according to geospatial location. RESULTS: Of 20 108 biopsies across 136 postcodes within the Greater Adelaide region, 1901 (9.45%) were H. pylori positive. Of these, 797 (41.9%) displayed clarithromycin, tetracycline, metronidazole, or amoxicillin resistance. In MLR, migration status was associated with the rate of H. pylori positivity (ß = 3.85% per 10% increase in a postcode's migrant population; P < 0.001). H. pylori positivity and resistance to any antibiotic were geospatially clustered (Moran's I = 0.571 and 0.280, respectively; P < 0.001 for both). In GWR, there was significant geospatial variation in the strength of the migrant association for both H. pylori positivity and antibiotic resistance. CONCLUSION: Our study demonstrates the heterogeneous geospatial distribution of H. pylori positivity and antibiotic resistance, as well as its interaction with migrant status. Geographic location and migrant status are important factors to consider for H. pylori eradication therapy.

Increasing Helicobacter pylori clarithromycin resistance in Australia over 20 years.

BACKGROUND: Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide, and eradication rates are falling in many countries, primarily due to clarithromycin and metronidazole resistance. AIMS: There is a paucity of contemporary Australian data, which we sought to address by evaluating local rates of resistance of H. pylori to amoxicillin, clarithromycin, metronidazole and tetracycline over the past 20 years. METHODS: All gastric biopsy specimens collected at endoscopy to detect H. pylori infection at a single centre underwent routine culture and antibiotic susceptibility testing between 1998 and 2017. Specimens from 12 842 patients were cultured for H. pylori, of which 1473 positive cultures were tested for antibiotic susceptibility. RESULTS: Antibiotic resistance to clarithromycin increased by 3.7% per year (incidence rate ratio [IRR] 1.037; P = 0.014) over 20 years, with a corresponding 5.0% annual increase in minimum inhibitory concentration (MIC) (odds ratio 1.050; P < 0.001). Since 2010, average clarithromycin resistance has exceeded 20%, with >25% of isolates resistant in the past 2 years of data capture. In contrast, rates of resistance to metronidazole (35.3%), amoxicillin (0.14%) and tetracycline (0.34%) and their MIC have remained stable. Review of a representative sample (n = 120; 8%) of these patients revealed that only 5% had documented prior H. pylori eradication therapy. CONCLUSIONS: Over the past 20 years there has been a substantial rise in clarithromycin resistance, with stable metronidazole resistance and low rates of resistance to amoxicillin and tetracycline. Current first-line H. pylori eradication therapy may fail to achieve adequate eradication rates, and optimal first-line therapy in Australia should be revisited.

A Capillary Electrophoresis-Based Method for the Measurement of Hydroxychloroquine and Its Active Metabolite Desethyl Hydroxychloroquine in Whole Blood in Patients with Rheumatoid Arthritis.

A capillary electrophoresis method was developed to detect and measure hydroxychloroquine (HCQ) and its active metabolite desethyl hydroxychloroquine (DHCQ) in whole blood in patients with rheumatoid arthritis. The best separation in terms of peak area reproducibility, migration time, peak shape, and resolution of adjacent peaks was obtained in a 60 cm, 75 µm i.d. uncoated fused-silica capillary using a background electrolyte mixture of an aqueous 55 mmol/L TRIS solution brought to pH 2.6 with phosphoric acid and methanol (85:15) and a voltage and a temperature of separation of 20 kV and 30 °C, respectively. Analytes were separated in less than 12 min, with excellent linearity (R2 ≥ 0.999) in the concentration range of 0.5-8 µmol/L. The recovery of analytes spiked in whole blood was 99-101% for HCQ and 98-99% for DHCQ. Analysis of five samples from patients with rheumatoid arthritis receiving HCQ 400 mg daily yielded mean steady-state concentrations of 2.27 ± 1.61 and 1.54 ± 0.55 µmol/L for HCQ and DHCQ, respectively, with a HCQ to DHCQ ratio of 1.40 ± 0.77.