Genomic insights into the c-di-GMP signaling and biofilm development in the saprophytic spirochete Leptospira biflexa

C-di-GMP is a bacterial second messenger with central role in biofilm formation. Spirochete bacteria from Leptospira genus present a wide diversity, with species of medical importance and environmental species, named as saprophytic. Leptospira form biofilms in the rat's reservoir kidneys and in the environment. Here, we performed genomic analyses to identify enzymatic and effector c-di-GMP proteins in the saprophytic biofilm-forming species Leptospira biflexa serovar Patoc. We identified 40 proteins through local alignments. Amongst them, 16 proteins are potentially functional diguanylate cyclases, phosphodiesterases, or hybrid proteins. We also identified nine effectors, including PilZ proteins. Enrichment analyses suggested that c-di-GMP interacts with cAMP signaling system, CsrA system, and flagella assembly regulation during biofilm development of L. biflexa. Finally, we identified eight proteins in the pathogen Leptospira interrogans serovar Copenhageni that share high similarity with L. biflexa c-di-GMP-related proteins. This work revealed proteins related to c-di-GMP turnover and cellular response in Leptospira and their potential roles during biofilm development.

Primary results from IMpassion131, a double-blind, placebo-controlled, randomised phase III trial of first-line paclitaxel with or without atezolizumab for unresectable locally advanced/metastatic triple-negative breast cancer

BACKGROUND

In the phase III IMpassion130 trial, combining atezolizumab with first-line nanoparticle albumin-bound-paclitaxel for advanced triple-negative breast cancer (aTNBC) showed a statistically significant progression-free survival (PFS) benefit in the intention-to-treat (ITT) and programmed death-ligand 1 (PD-L1)-positive populations, and a clinically meaningful overall survival (OS) effect in PD-L1-positive aTNBC. The phase III KEYNOTE-355 trial adding pembrolizumab to chemotherapy for aTNBC showed similar PFS effects. IMpassion131 evaluated first-line atezolizumab-paclitaxel in aTNBC.

PATIENTS AND METHODS

Eligible patients [no prior systemic therapy or ≥12 months since (neo)adjuvant chemotherapy] were randomised 2:1 to atezolizumab 840 mg or placebo (days 1, 15), both with paclitaxel 90 mg/m² (days 1, 8, 15), every 28 days until disease progression or unacceptable toxicity. Stratification factors were tumour PD-L1 status, prior taxane, liver metastases and geographical region. The primary endpoint was investigator-assessed PFS, tested hierarchically first in the PD-L1-positive [immune cell expression ≥1%, VENTANA PD-L1 (SP142) assay] population, and then in the ITT population. OS was a secondary endpoint.

RESULTS

Of 651 randomised patients, 45% had PD-L1-positive aTNBC. At the primary PFS analysis, adding atezolizumab to paclitaxel did not improve investigator-assessed PFS in the PD-L1-positive population [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.60-1.12; P = 0.20; median PFS 6.0 months with atezolizumab-paclitaxel versus 5.7 months with placebo-paclitaxel]. In the PD-L1-positive population, atezolizumab-paclitaxel was associated with more favourable unconfirmed best overall response rate (63% versus 55% with placebo-paclitaxel) and median duration of response (7.2 versus 5.5 months, respectively). Final OS results showed no difference between arms (HR 1.11, 95% CI 0.76-1.64; median 22.1 months with atezolizumab-paclitaxel versus 28.3 months with placebo-paclitaxel in the PD-L1-positive population). Results in the ITT population were consistent with the PD-L1-positive population. The safety profile was consistent with known effects of each study drug.

CONCLUSION

Combining atezolizumab with paclitaxel did not improve PFS or OS versus paclitaxel alone. CLINICALTRIALS.GOV: NCT03125902.

POS1242 FACTORS ASSOCIATED WITH MORTALITY IN PATIENTS WITH RHEUMATIC DISEASES AND COVID-19 IN MEXICO

Background:

As of the 25th of January 2021, more than 150 thousand deaths as consequence of COVID-19 have been reported in Mexico [1]. Advanced age, male gender and comorbidities have been described as risk factors for severe disease and mortality in general population [2]. COVID-19 mortality in Mexican patients with rheumatic and musculoskeletal diseases (RMDs) is unknown.

Objectives:

To describe characteristics of Mexican patients with RMDs and COVID-19, and to analyse factors associated with mortality.

Methods:

The Global Rheumatology Alliance COVID-19 (GRA) physician reported registry, is an international effort to collect information on COVID19 in adult patients with RMDs. GRA is an observational registry. The first patient from Mexico was registered on April 17, 2020. All Mexican patients registered in GRA until October 30, 2020 were included in this analysis. The association of mortality with demographic and clinical variables was estimated using logistic regression analysis.

Results:

A total of 323 patients were registered, with a median age of 52 (IQR 41-61) years old, 166 (51.4%) patients lived in Mexico City. The most frequent RMDs were rheumatoid arthritis, 149 (46.1%) and systemic lupus erythematosus, 24 (19.8%). Over a third of patients with RMDs and COVID-19 (119 (36.8%)) were hospitalized, and 43 (13.3%) died. Table 1 shows clinical and demographic characteristics. In the univariable analysis, the absence of comorbidities was a protective factor, OR 0.3 (95% CI 0.1-0.6). Factors associated with mortality at COVID-19 diagnosis were age over 65 years old, having type 2 diabetes, chronic renal insufficiency, treatment at COVID-19 diagnosis with corticosteroids or with CD20 inhibitors. In the multivariable adjusted analysis, these factors remained independently associated with mortality. No associations with other treatments or comorbidities at COVID-19 diagnosis were found.

Conclusion:

Mexican patients with RMDs and COVID-19 in the GRA physician reported registry had a mortality of 13.3%. Factors associated with mortality were those described in the general population, such as older age and being on corticosteroids and CD20 inhibitors treatment at COVID-19 diagnosis.

References:

[1]WHO. Coronavirus disease (COVID-19) pandemic. https://www.who.int/emergencies/diseases/novel-coronavirus-2019. (accessed 26 January, 2021).

[2]Zhou F, et al. Lancet 2020;395(10229):1054-62.

Table 1.

Clinical and demographic characteristics of patients with rheumatic diseases and COVID-19 in Mexico and mortality.

Characteristics at COVID-19 diagnosisTotalN=323Death43 (13.3)Survivors280 (86.7)UnivariableOR (95% CI)MultivariableOR (95% CI)Women, n(%)268 (82.9)33 (76.7)235 (83.9)0.6 (0.3-1.4)0.5 (0.2-1.3)Age >65 years old, n(%)62 (19.2)18 (41.9)44 (15.7)3.9 (1.9-7.7)3.9 (1.9-8.3)RMDs* n(%)-Rheumatoid arthritis149 (46.1)23 (53.5)126 (45.0)1.6 (0.7-3.7)-Systemic Lupus Erythemathosus64 (19.8)10 (23.3)54 (19.3)1.6 (0.6-4.3)-Spondyloarthritis (axial and others)33 (10.2)2 (4.7)31 (11.1)0.1 (0.1-2.8)-Others77 (23.8)8 (18.6)69 (24.6)1-Moderate/High disease activity1, n(%)57 (18.6)7 (17.9)50 (18.7)1.0 (0.4-2.5)-None comorbidities, n(%)136 (42.1)8 (18.6)128 (45.7)0.3 (0.1-0.6)-Hypertension*, n(%)88 (27.2)12 (27.9)76 (27.1)1.0 (0.5-2.1)-Type 2 Diabetes*, n(%)49 (15.2)13 (30.2)36 (12.9)2.9 (1.4-6.1)2.4 (1.1-5.4)Obesity*, n(%)21 (6.5)3 (6.9)18 (6.4)1.1 (0.3-3.9)-Chronic obstructive pulmonary disease*, n(%)15 (4.6)1 (2.3)14 (5.0)0.5 (0.1-3.5)-Chronic renal insufficiency*, n(%)17 (5.2)6 (13.9)11 (3.9)3.9 (1.4-11.4)3.4 (1.1-10.4)Cardiovascular diseases*, n(%)14 (4.3)2 (4.7)12 (4.3)1.1 (0.2-5.0)-Corticosteroids*, n(%)171 (52.9)30 (69.7)141 (50.3)2.3 (1.1-4.5)3.0 (1.4-6.5)CsDMARD*, n(%)247 (76.5)33 (16.3)214 (76.4)1.0 (0.5- 2.2)-CD20 inhibitor*, n(%)21 (6.5)7 (16.3)14 (5.0)3.7 (1.4-9.9)4.9 (1.7-14.5)

*Overlapped, 1 307 patients.

Disclosure of Interests:

None declared

Cryptosporidium spp. in groundwater supplies intended for human consumption - A descriptive review of global prevalence, risk factors and knowledge gaps

Cryptosporidiosis is one of the leading causes of diarrhoeal illness and mortality induced by protozoan pathogens worldwide. As a largely waterborne disease, emphasis has been given to the study of Cryptosporidium spp. in surface waters, readily susceptible to pathogenic contamination. Conversely, the status of Cryptosporidium in potable groundwater sources, generally regarded as a pristine and "safe" drinking-water supply owing to (sub)-soil protection, remains largely unknown. As such, this investigation presents the first literature review aimed to ascertain the global prevalence of Cryptosporidium in groundwater supply sources intended for human consumption. Thirty-seven peer-reviewed studies were identified and included in the review. Groundwater sample and supply detection rates (estimated 10-20%) indicate Cryptosporidium is frequently present in domestic groundwater sources, representing a latent health concern for groundwater consumers. Specifically, sample (10.4%) and source (19.1%) detection rates deriving from comprehensive "temporal" investigations are put forward as representative of a contamination 'baseline' for Cryptosporidium in 'domestic' groundwater supplies. Proposed 'baseline' prevalence figures are largely applicable in preventive risk-based catchment and groundwater quality management including the formulation of Quantitative Microbial Risk Assessment (QMRA). Notwithstanding, a large geographical disparity in available investigations and lack of standardized reporting restrict the transferability of research findings. Overall, the mechanisms responsible for Cryptosporidium transport and ingress into groundwater supplies remain ambiguous, representing a critical knowledge gap, and denoting a distinctive lack of integration between groundwater and public-health sub-disciplines among investigations. Key recommendations and guidelines are provided for prospective studies directed at more integrative and multi-disciplinary research.

Assessment of two behavioural models (HBM and RANAS) for predicting health behaviours in response to environmental threats: Surface water flooding as a source of groundwater contamination and subsequent waterborne infection in the Republic of Ireland

Extreme weather events (EWEs) are increasing in frequency, posing a greater risk of adverse human health effects. As such, developing sociological and psychological based interventions is paramount to empowering individuals and communities to actively protect their own health. Accordingly, this study compared the efficacy of two established social-cognitive models, namely the Health Beliefs Model (HBM) and Risks-Attitudes-Norms-Abilities-Self-regulation (RANAS) framework, in predicting health behaviours following EWEs. Surface water flooding was used as the exemplar EWE in the current study, due to the increasing incidence of these events in the Republic of Ireland over the past decade. Levels of prior experience with flooding were considered for analyses and comparative tools included a number of variables predicting health behaviours and intervention potential scores (i.e. measure of impact of targeting each model element). Results suggest that the RANAS model provides a robust foundation for designing interventions for any level of experience with an extreme weather event, however, use of the simpler HBM may be more cost-effective among participants unacquainted with an EWE and in relatively infrequent health threat scenarios. Results provide an evidence base for researchers and policymakers to appropriately engage with populations about such threats and successfully promote spatiotemporally appropriate health behaviours in a changing climate.

Twelve-month mental health service use in six countries of the Americas: A regional report from the World Mental Health Surveys

AIMS

To provide cross-national data for selected countries of the Americas on service utilization for psychiatric and substance use disorders, the distribution of these services among treatment sectors, treatment adequacy and factors associated with mental health treatment and adequacy of treatment.

METHODS

Data come from data collected from 6710 adults with 12 month mental disorder surveys across seven surveys in six countries in North (USA), Central (Mexico) and South (Argentina, Brazil, Colombia, Peru) America who were interviewed 2001-2015 as part of the World Health Organization (WHO) World Mental Health (WMH) Surveys. DSM-IV diagnoses were made with the WHO Composite International Diagnostic Interview (CIDI). Interviews also assessed service utilization by the treatment sector, adequacy of treatment received and socio-demographic correlates of treatment.

RESULTS

Little over one in four of respondents with any 12 month DSM-IV/CIDI disorder received any treatment. Although the vast majority (87.1%) of this treatment was minimally adequate, only 35.3% of cases received treatment that met acceptable quality guidelines. Indicators of social-advantage (high education and income) were associated with higher rates of service use and adequacy, but a number of other correlates varied across survey sites.

CONCLUSIONS

These results shed light on an enormous public health problem involving under-treatment of common mental disorders, although the problem is most extreme among people with social disadvantage. Promoting services that are more accessible, especially for those with few resources, is urgently needed.

Reduction of Breast Cancer Treatment Delay as a Result of Efforts Carried Out by Two Brazilian NGOs

Background: Brazilian breast cancer patients present disease often at advanced stages (III, IV). Previous studies indicated that system delay is a causal factor of bad prognosis and increased mortality rate. In the state of Paraíba, northeast of Brazil, two non-governmental organizations (NGOs) Américas Amigas and Mulheres de Peito de Campina Grande (MLDP), promote faster access to treatment by donating diagnostic mammography and biopsies as well as anatomo-histopathological and immunohistochemical analysis. Aim: The current study aimed at evaluating the effectiveness of the assistance provided by both NGOs and comparing patient flow between HNL and FAP, two reference cancer centers in João Pessoa and Campina Grande, respectively. Methods: Time-to-treatment was analyzed for different time intervals between first medical consultation and initiation of treatment. Comparison was performed between three groups of patients: 40 patients from Hospital Napoleão Laureano (HNL) in João Pessoa; 80 patients from Fundação Assistencial da Paraíba (FAP) in Campina Grande and 15 patients from FAP, who received support from the NGOs. Kaplan-Meier analysis was performed to compare time-intervals among the groups. To estimate the impact of socioeconomic variables Cox regression analysis was performed. Results: Mean time-interval between first medical consultation and hospital admission was 135 (SD=21.0), 370 (SD=73.7) and 515 (SD=36.6) days, for patients of HNL, MLDP and FAP, respectively ( P = 0.0021). Time intervals analyzed for patients within the FAP hospital, between first medical consultation and hospital admission, tended to be shorter for patients who were assisted by the NGOs, compared with those who did not receive any assistance from the NGOs. Patients who had consulted specialized oncological health services beforehand had an increased chance (HZ=2.32; 95% CI: 1.17-4.60; P = 0.016) of being admitted at the reference hospital within 90 days after the first medical consultation, compared with those who had not consulted such specialized services. There were no significant differences between HNL and FAP, regarding the time interval between hospital admission and treatment initiation ( P = 0.21). Conclusion: The assistance to patients provided by the two NGOs, aimed at speeding up the diagnosis process, accelerated patient flow between first medical consultation and admission at the hospitals. Regarding HNL, patients from the inland had been sent by primary health units in their municipalities, directly to the cancer reference hospital in João Pessoa, without being referred to an in-between health service. Such procedure explains the variation of time intervals when admissions at FAP and HNL are compared. The results of the current study indicate that by providing faster breast cancer diagnosis, the NGOs’ mediation can significantly improve patient flow.

Surface water flooding, groundwater contamination, and enteric disease in developed countries: A scoping review of connections and consequences

Significant volumes of research over the past four decades has sought to elucidate the social, infrastructural, economic, and human health effects of climate change induced surface flooding. To date, epidemiological and public health studies of flooding events have focused on mental health effects, vector-borne diseases, and infectious enteric disease due to floodwater contact (i.e. typically low consumption rates). The inherent nature of groundwater (i.e. out of sight, out of mind) and the widely held belief that aquifers represent a pristine source of drinking water due to natural attenuation may represent the "perfect storm" causing direct consumption of relatively large volumes of surface flood-contaminated groundwater. Accordingly, the current study sought to systematically identify and synthesize all available peer-reviewed literature pertaining to the nexus between surface flooding, groundwater contamination and human gastroenteric outcomes. Just 14 relevant studies were found to have been published during the period 1980-2017, thus highlighting the fact that this potentially significant source of climate-related exposure to environmental infection has remained understudied to date. Studies differed significantly in terms of type and data reporting procedures, making it difficult to discern clear trends and patterns. Approximately 945 confirmed cases of flood-related enteric disease were examined across studies; these concurred with almost 10,000 suspected cases, equating to approximately 20 suspected cases per confirmed case. As such, no regional, national or global estimates are available for the human gastrointestinal health burden of flood-related groundwater contamination. In light of the demonstrable public health significance of the concurrent impacts of groundwater susceptibility and climate change exacerbation, strategies to increase awareness about potential sources of contamination and motivate precautionary behaviour (e.g. drinking water testing and treatment, supply interruptions) are necessary. Mainstreaming climate adaptation concerns into planning policies will also be necessary to reduce human exposure to waterborne sources of enteric infection.

Modeling the Growth Kinetics of Anodic TiO2 Nanotubes

The fundamental understanding of the barrier layer (δ(b)) growth in TiO2 nanotubes (NTs) is here established and compared with the classical metal oxidation theory from Mott and Cabrera. The role of δ(b) in the anodization of TiO2 NTs under different applied potentials and times was analyzed using scanning transmission electron microscopy (STEM). Contrary to the well-known case of anodic aluminum oxide, we found that δ(b) of TiO2 NTs progressively grows over time due to the nonsteady anodization regime. We then establish a relation between the phenomenological growth of the barrier layer with time and applied voltage, δ(b)(V,t) using the high-field Mott and Cabrera conduction theory. The developed model was found to be in excellent agreement with the experimental data from both STEM and anodization curves. On the basis of these results, the relationship between δ(b) and the anodization time and potential can now be quantitatively understood.

Polyacrylic acid coated and non-coated iron oxide nanoparticles are not genotoxic to human T lymphocytes

The use of iron oxide nanoparticles (ION) for diagnostic and therapeutic purposes requires a clear favorable risk-benefit ratio. This work was performed with the aim of studying the ability of polyacrylic acid (PAA)-coated and non-coated ION to induce genotoxicity in human T lymphocytes. For that purpose, their influence on cell cycle progression and on the induction of chromosome aberrations was evaluated. Blood samples collected from healthy human donors were exposed to PAA-coated and non-coated ION, at different concentrations, for 48h. The obtained results showed that, for all culture conditions, the tested ION are not genotoxic and do not influence the cell cycle arrest. Their possible cumulative effect with the iron-dependent genotoxic agent BLM was also evaluated. Blood samples collected from healthy human donors were exposed to ION, at different concentrations, for 48h, in the presence of a pre-determined toxic concentration of BLM. The obtained results showed that, for all culture conditions, the tested ION do not potentiate the clastogenic effects of BLM.

Role of temperature in the recombination reaction on dye-sensitized solar cells

The DSC recombination kinetics was studied up to 100 °C without electrolyte leakage or external contamination using a unique laser assisted glass sealing process. In addition to temperature having a strong influence on the recombination reaction rate, the energy of the exited electrons was found to be critical for determining the recombination activation energy.

Tailoring the Ti surface via electropolishing nanopatterning as a route to obtain highly ordered TiO2 nanotubes

Highly ordered TiO2 nanotubes (NTs) were synthesized by the electrochemical anodization of Ti foils subjected to electropolishing (EP) pre-treatment. We found that the Ti surface roughness plays an important role in the onset of pore nucleation in enhancing the local focusing effect of the electrical field. Additionally, EP induces the formation of dimple structures on the metal surface, which can work as a pre-pattern prior to anodization. These shallow ripples lead to a preferentially ordered pore nucleation, offering an organizational improvement of the anodic oxide NTs. We found that, depending on the EP applied potential, the roughness and the spatial period of the ripple-like structures varies from 8-2 nm and from 122-30 nm, respectively. Such tuning allowed us to focus on the influence of the initial Ti pre-surface topography features on the NTs' length, organization, and hexagonal arrangement quality, as well as diameter and density. Our results show that an EP under 10 V is the most suitable to obtain a small Ti surface roughness, the largest NT length (40% enhancement), and the effective improvement of the ordered hexagonal NTs' arrays over larger areas. Furthermore, the NTs' dimensions (pore diameters and density) were also found to depend on the initial Ti surface topography. The use of optimized EP allows us to obtain highly hexagonal self-ordered samples at a reduced time and cost.

Hypomagnesemia is a risk factor for nonrecovery of renal function and mortality in AIDS patients with acute kidney injury

The objective of the present study was to determine the prevalence of electrolyte disturbances in AIDS patients developing acute kidney injury in the hospital setting, as well as to determine whether such disturbances constitute a risk factor for nephrotoxic and ischemic injury. A prospective, observational cohort study was carried out. Hospitalized AIDS patients were evaluated for age; gender; coinfection with hepatitis; diabetes mellitus; hypertension; time since HIV seroconversion; CD4 count; HIV viral load; proteinuria; serum levels of creatinine, urea, sodium, potassium and magnesium; antiretroviral use; nephrotoxic drug use; sepsis; intensive care unit (ICU) admission, and the need for dialysis. Each of these characteristics was correlated with the development of acute kidney injury, with recovery of renal function and with survival. Fifty-four patients developed acute kidney injury: 72% were males, 59% had been HIV-infected for >5 years, 72% had CD4 counts <200 cells/mm(3), 87% developed electrolyte disturbances, 33% recovered renal function, and 56% survived. ICU admission, dialysis, sepsis and hypomagnesemia were all significantly associated with nonrecovery of renal function and with mortality. Nonrecovery of renal function was significantly associated with hypomagnesemia, as was mortality in the multivariate analysis. The risks for nonrecovery of renal function and for death were 6.94 and 6.92 times greater, respectively, for patients with hypomagnesemia. In hospitalized AIDS patients, hypomagnesemia is a risk factor for nonrecovery of renal function and for in-hospital mortality. To determine whether hypomagnesemia is a determinant or simply a marker of critical illness, further studies involving magnesium supplementation in AIDS patients are warranted.