The impact of stable 27Al in 26Al/10Be meteoric ratio in PM2.5 from an urban area

Meteoric ¹⁰Be and ²⁶Al radionuclides are produced in the atmosphere, and the relationship between them has potential applications in atmospheric and climate research. In particular, the meteoric ²⁶Al/¹⁰Be ratio has potential applications such as a chronometer for old ice, a tracer for the air exchange between the lower stratosphere and upper troposphere, production and distribution in the atmosphere of both radionuclides, and the study on solar activity. In this work, their concentrations in the fine fraction of airborne particulate matter from an urban area have been precisely determined using Accelerator Mass Spectrometry (AMS). To obtain new data about the ²⁶Al/¹⁰Be ratio and its subsequent applications, PM_2.5 in aerosol samples has been analyzed. The average ratio in samples from Mexico City was significantly higher than those previously reported by other authors. The high enrichment factors for stable Aluminum indicate that both resuspended and anthropogenic ²⁷Al content in PM_2.5 contributes significantly to the high values of ²⁶Al in the ²⁶Al/¹⁰Be ratio. An adjustment of ²⁷Al concentrations from external contributions was carried out, and the corrected ²⁶Al/¹⁰Be ratios were similar to those previously reported. In this study, a precise assessment of the possible contribution of other Aluminum sources to the aerosol samples has been carried out. Finally, the obtained ratios indicate the possibility of its future use in applications such as the dating of glaciers.

Impact of an enhanced screening program on the detection of non-AIDS neoplasias in patients with human immunodeficiency virus infection

BACKGROUND

The incidence of non-AIDS defining cancer (NADC) is higher in people living with HIV (PLWH) than in the general population, and it is already one of the leading causes of death in the HIV-infected population. It is estimated that the situation will be aggravated by the progressive aging of PLWH. Early diagnosis through intensive cancer screening may improve the ability for therapeutic interventions and could be critical in reducing mortality, but it might also increase expenditure and harms associated with adverse events. The aim of this study is to evaluate an enhanced screening program for early diagnosis of cancer in PLWH compared to standard practice. The specific objectives are (1) to compare the frequency of cancer diagnosed at an early stage, (2) to analyze safety of the enhanced program: adverse events and unnecessary interventions, (3) to analyze the cost-utility of the program, and (4) to estimate the overall and site-specific incidence of NADC in PLWH.

METHODS

We will conduct a multicenter, non-blinded, randomized, controlled trial, comparing two parallel arms: conventional vs enhanced screening. Data will be recorded in an electronic data collection notebook. Conventional intervention group will follow the standard of care screening in the participating centers, according to the European AIDS Clinical Society recommendations, and the enhanced intervention group will follow an expanded screening aimed to early detection of lung, liver, anal, cervical, breast, prostate, colorectal, and skin cancer. The trial will be conducted within the framework of the Spanish AIDS Research Network Cohort (CoRIS).

DISCUSSION

The trial will evaluate the efficacy, safety, and efficiency of an enhanced screening program for the early diagnosis of cancer in HIV patients compared to standard of care practice. The information provided will be relevant since there are currently no studies on expanded cancer screening strategies in patients with HIV, and available data estimating cost effectiveness or cost-utility of such as programs are scarce. An enhanced program for NADC screening in patients with HIV could lead to early diagnosis and improve the prognosis of these patients, with an acceptable rate of unnecessary interventions, but it is critical to demonstrate that the benefits clearly outweigh the harms, before the strategy could be implemented.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04735445. Registered on 25 June 2019.

Zebrafish irritant responses to wildland fire-related biomass smoke are influenced by fuel type, combustion phase, and byproduct chemistry

Human exposure to wildfire-derived particulate matter (PM) is linked to adverse health outcomes; however, little is known regarding the influence of biomass fuel type and burn conditions on toxicity. The aim of this study was to assess the irritant potential of extractable organic material (EOM) of biomass smoke condensates from five fuels (eucalyptus, pine, pine needle, peat, or red oak), representing various fire-prone regions of the USA, burned at two temperatures each [flaming (approximately 640°C) or (smoldering approximately 500°C)] using a locomotor assay in zebrafish (Danio rerio) larvae. It was postulated that locomotor responses, as measures of irritant effects, might be dependent upon fuel type and burn conditions and that these differences relate to combustion byproduct chemistry. To test this, locomotor activity was tracked for 60 min in 6-day-old zebrafish larvae (25-32/group) immediately after exposure to 0.4% dimethyl sulfoxide (DMSO) vehicle or EOM from the biomass smoke condensates (0.3-30 µg EOM/ml; half-log intervals). All EOM samples produced concentration-dependent irritant responses. Linear regression analysis to derive rank-order potency indicated that on a µg PM basis, flaming pine and eucalyptus were the most irritating. In contrast, on an emission-factor basis, which normalizes responses to the amount of PM produced/kg of fuel burned, smoldering smoke condensates induced greater irritant responses (>100-fold) than flaming smoke condensates, with smoldering pine being the most potent. Importantly, irritant responses significantly correlated with polycyclic aromatic hydrocarbon (PAH) content, but not with organic carbon or methoxyphenols. Data indicate that fuel type and burn condition influence the quantity and chemical composition of PM as well as toxicity.

Meteoric 10Be in aerosol filters in the city of Seville

Cosmogenic radionuclides in the one-million-year half-life range, like ¹⁰Be, find application fields in several Sciences. They are powerful tools in Geology and Geochronology, as they are very important tracers on the Earth, being utilized as chronometer. Meteoric ¹⁰Be (T_1/2 = 1.39 × 10⁶ y) associated to aerosols can be used as a tracer of atmospheric processes and specifically as indicators of the cosmogenic interactions in lower Stratosphere, upper Troposphere, the air exchange between both and deposition processes on the Earth surface. The applications of ¹⁰Be are even more relevant when combined with other radionuclides such as ²⁶Al. In order to provide new data about concentration ¹⁰Be in this type of samples, the first atmospheric air filters in Spain have been analysed. Values around 10⁴ at/m³ (atoms per cubic meter of air) for ¹⁰Be have been obtained. Due to the location and the features of the sampling site (urban area, at sea level and mid latitude), a new radiochemical procedure was designed and developed in our laboratory for the Accelerator Mass Spectrometry (AMS) measurement of ¹⁰Be in this kind of samples. The samples were measured in SARA, the 1 MV AMS system at Centro Nacional de Aceleradores (CNA).

Determination of denudation rates by the measurement of meteoric 10Be in Guadiana river sediment samples (Spain) by low-energy AMS

The concentration of meteoric ¹⁰Be in estuarine sediment samples has been measured by Spanish Accelerator for Radionuclides Analysis (SARA) at CNA and subsequently used to assess the denudation rate in Guadiana river basin together with the sediment budget method, on both sides of the frontier between Spain and Portugal. The two methods yielded coincident results. The estimation by the ¹⁰Be method gave the denudation rate of (0.76 ± 0.10) × 10^-2 cm/y. After correcting for an approximate 80% attenuation of the sediment discharge into the ocean, caused by the river dams, the sediment budget method yielded the rate of (0.77 ± 0.17) × 10^-2 cm/y.

Decreasing rates of acute myocardial infarction in people living with HIV: a nationwide cohort study in Spain, 2004-2015

OBJECTIVES

Contemporary data from country-wide cohorts are needed to reveal trends in the occurrence of acute myocardial infarction (AMI) in people living with HIV (PLWH). We analysed time trends in the standardized incidence rate (sIR) of AMI in PLWH in Spain from 2004 to 2015, and compared them with trends in the general population.

METHODS

A longitudinal study in a nationwide contemporary multicentre HIV-infected cohort was carried out. Data on all incident AMI events were collected, and age- and sex-standardized IRs calculated. To analyse the IR of AMI in the general population, the national rates of hospital discharges for AMI per 100 000 inhabitants stratified for age and sex from 2004 to 2015 were obtained using the morbidity report data from the National Statistics Institute. A Poisson regression model was fitted to assess the effect of covariates of interest on AMI occurrence.

RESULTS

The sIRs of AMI in 2004-2015 were 237.92 [95% confidence interval (CI) 225.95-249.90] and 66.75 (95% CI: 23.49-110.01) per 100 000 patient-years in male and female PLWH, respectively. There was a decrease in the sIR of AMI in male PLWH from 279.02 (95% CI: 265.46-292.59) per 100 000 person-years in 2004-2009 to 222.13 (95% CI: 210.83-233.42) per 100 000 person-years in 2010-2015. Compared with the general population, the sIR ratio was 1.41 (95% CI: 1.26-1.55) in 2004-2009, and 1.28 (95% CI: 1.15-1.43) in 2010-2014. AMI occurrence was associated with older age (P < 0.066 for each 10-year age stratum ≥ 35-years compared with the 25-34 year stratum), higher plasma HIV RNA (P < 0.001), lower CD4 count (P < 0.04 for CD4 strata > 350 cells/μL compared with the 0-100 cells/μL stratum), and the period 2004-2009 (P < 0.001).

CONCLUSIONS

There has been a decreasing incidence of AMI in PLWH in Spain, associated with improving immune and virological status, but the incidence of AMI has remained higher than in the general population.

Risk of clinically significant depression in HIV-infected patients: effect of antiretroviral drugs

OBJECTIVES

We aimed to characterize depression in newly diagnosed HIV-infected patients, to determine the effect of antiretroviral therapy (ART) on its incidence, and to investigate whether efavirenz use was associated with a higher risk, compared with non-efavirenz-containing regimens, in the Spanish CoRIS cohort.

METHODS

CoRIS is a contemporary, multicentre cohort of HIV-infected patients, antiretroviral-naïve at entry, launched in 2004. Poisson regression models were used to investigate demographic, clinical and treatment-related factors associated with a higher incidence of clinically significant depression to October 2010.

RESULTS

In total, 5185 patients (13 089 person-years) participated in the study, of whom 3379 (65.2%) started ART during follow-up. The incidence rates of depression before and after starting ART were 11.68 [95% confidence interval (CI) 9.01-15.15] and 7.06 (95% CI 5.45-9.13) cases per 1000 person-years, respectively. After adjustment, there was an inverse association between the occurrence of depression and the initiation of ART [incidence rate ratio (IRR) 0.53; 95% CI 0.28-0.99], while the likelihood of depression increased in patients of age > 50 years (IRR 1.94; 95% CI 1.21-3.12). Longer exposure to ART was associated with a decreased IRR of depression in unadjusted and adjusted analyses. The IRR for patients receiving < 2, 2-4 and > 4 years of ART was 0.72 (95% CI 0.36-1.44), 0.10 (95% CI 0.04-0.25) and 0.05 (95% CI 0.01-0.17), respectively, compared with ART-naïve patients. This protective effect was also observed when durations of exposure to nonnucleoside reverse transcriptase inhibitor-based regimens and efavirenz-containing regimens were analysed separately.

CONCLUSIONS

The incidence of clinically significant depression was lower among HIV-infected patients on ART. The protective effect of ART was also observed with efavirenz-containing regimens.

Nephrotic syndrome and AA amyloidosis revealing adult-onset cryopyrin-associated periodic syndrome

Cryopyrin-associated periodic syndrome (CAPS) is due to gain-of-function mutations in the cryopyrin gene, which determines an overactive inflammatory response. AA amyloidosis is a complication of this syndrome. A 53-year-old man was referred to us because of lower limb edema. Past history: at the age of 20, he complained of arthralgia/arthritis and bilateral hypoacusis. At the age of 35, he presented posterior uveitis, several episodes of conjunctivitis, and progressive loss of visual acuity. Laboratory tests disclosed nephrotic syndrome, and renal biopsy showed AA amyloidosis. He was given anakinra with improvement of arthritis. A genetic study revealed the p.D303N mutation in the cryopyrin gene, and he was diagnosed as having AA amyloidosis due to CAPS. Twenty-one months after starting anakinra, the arthritis has disappeared, although nephrotic-range proteinuria persisted. It is important to be aware of cryopyrin-associated periodic syndrome because it can cause irreversible complications, and there is effective therapy.

Acute administration of dopaminergic drugs has differential effects on locomotion in larval zebrafish

Altered dopaminergic signaling causes behavioral changes in mammals. In general, dopaminergic receptor agonists increase locomotor activity, while antagonists decrease locomotor activity. In order to determine if zebrafish (a model organism becoming popular in pharmacology and toxicology) respond similarly, the acute effects of drugs known to target dopaminergic receptors in mammals were assessed in zebrafish larvae. Larvae were maintained in 96-well microtiter plates (1 larva/well). Non-lethal concentrations (0.2-50 μM) of dopaminergic agonists (apomorphine, SKF-38393, and quinpirole) and antagonists (butaclamol, SCH-23390, and haloperidol) were administered at 6 days post-fertilization (dpf). An initial experiment identified the time of peak effect of each drug (20-260 min post-dosing, depending on the drug). Locomotor activity was then assessed for 70 min in alternating light and dark at the time of peak effect for each drug to delineate dose-dependent effects. All drugs altered larval locomotion in a dose-dependent manner. Both the D1- and D2-like selective agonists (SKF-38393 and quinpirole, respectively) increased activity, while the selective antagonists (SCH-23390 and haloperidol, respectively) decreased activity. Both selective antagonists also blunted the response of the larvae to changes in lighting conditions at higher doses. The nonselective drugs had biphasic effects on locomotor activity: apomorphine increased activity at the low dose and at high doses, while butaclamol increased activity at low to intermediate doses, and decreased activity at high doses. This study demonstrates that (1) larval zebrafish locomotion can be altered by dopamine receptor agonists and antagonists, (2) receptor agonists and antagonists generally have opposite effects, and (3) drugs that target dopaminergic receptors in mammals appear, in general, to elicit similar locomotor responses in zebrafish larvae.

Zebrafish developmental screening of the ToxCast™ Phase I chemical library

Zebrafish (Danio rerio) is an emerging toxicity screening model for both human health and ecology. As part of the Computational Toxicology Research Program of the U.S. EPA, the toxicity of the 309 ToxCast™ Phase I chemicals was assessed using a zebrafish screen for developmental toxicity. All exposures were by immersion from 6-8 h post fertilization (hpf) to 5 days post fertilization (dpf); nominal concentration range of 1 nM-80 μM. On 6 dpf larvae were assessed for death and overt structural defects. Results revealed that the majority (62%) of chemicals were toxic to the developing zebrafish; both toxicity incidence and potency was correlated with chemical class and hydrophobicity (logP); and inter-and intra-plate replicates showed good agreement. The zebrafish embryo screen, by providing an integrated model of the developing vertebrate, compliments the ToxCast assay portfolio and has the potential to provide information relative to overt and organismal toxicity.

Assessing locomotor activity in larval zebrafish: Influence of extrinsic and intrinsic variables

The U.S. Environmental Protection Agency is evaluating methods to screen and prioritize large numbers of chemicals for developmental toxicity. We are exploring methods to detect developmentally neurotoxic chemicals using zebrafish behavior at 6 days of age. The behavioral paradigm simultaneously tests individual larval zebrafish under both light and dark conditions in a 96-well plate using a video tracking system. We have found that many variables affect the level or pattern of locomotor activity, including age of the larvae, size of the well, and the presence of malformations. Some other variables, however, do not appear to affect larval behavior including type of rearing solution (10% Hank's vs. 1:3 Danieau vs 60 mg/kg Instant Ocean vs 1× and 1:10× EPA Moderately Hard Water). Zebrafish larval behavior using a microtiter plate format may be an ideal endpoint for screening developmentally neurotoxic chemicals, but it is imperative that many test variables be carefully specified and controlled.

Rearing conditions differentially affect the locomotor behavior of larval zebrafish, but not their response to valproate-induced developmental neurotoxicity

Zebrafish (Danio rerio) are widely used in developmental research, but still not much is known about the role of the environment in their development. Zebrafish are a highly social organism; thus exposure to, or isolation from, social environments may have profound developmental effects. Details of rearing conditions are often sparse in the zebrafish literature. This study compared (1) the activity of larval zebrafish that were raised individually vs in groups, and (2) the effect of the developmental neurotoxicant valproate. We randomly assigned embryos to single- or group-reared social environments from 0 to 5days post fertilization (dpf), while treating them with or without valproate (final concentration 48μM) from 0 to 2dpf, resulting in a total of four groups (group control, group treated, single control, single treated). At 5dpf all embryos were transferred to singly-housed environments where they remained for locomotor activity testing (alternating periods of light and dark) conducted on day 6. Larvae that had been reared in groups had higher levels of activity in the dark period compared to larvae that had been raised individually. Valproate increased activity in both the singly-reared and group-reared larvae during periods of darkness but not light. Further analyses of dark activity indicated that rearing condition did not differentially affect larval responses to valproate. These results indicate that rearing conditions affected the locomotion of zebrafish larvae, but did not alter the effect of the developmental neurotoxicant valproate.

Imipenem-induced Clostridium difficile diarrhea in a patient with chronic renal failure

An 80-year-old man was diagnosed to have pneumonia and advanced chronic kidney disease. He presented with anuria and hemodialysis, by temporary femoral catheter, was initiated. He was empirically treated with imipenem/cilastatin 500 mg/24 h after hemodialysis. After 10 days of antibiotic intake, he developed severe diarrhea. Diagnosis of Clostridium difficile (CD)-associated diarrhea was confirmed by detection of the toxins A and B in his stool. Imipenem therapy was discontinued; Vancomycin 500 mg orally every 6 h and 1000 mg per rectum every day was added. After two weeks of this treatment, the patient reported complete resolution of the diarrhea and stool samples were negative for Clostridium toxin. In this case, the most possible cause of CD colitis was considered to be imipenem because of the temporal relationship between exposure to the drug and onset of symptoms.

Esterase metabolism of cholinesterase inhibitors using rat liver in vitro

A variety of chemicals, such as organophosphate (OP) and carbamate pesticides, nerve agents, and industrial chemicals, inhibit acetylcholinesterase (AChE) leading to overstimulation of the cholinergic nervous system. The resultant neurotoxicity is similar across mammalian species; however, the relative potencies of the chemicals across and within species depend in part on chemical-specific metabolic and detoxification processes. Carboxylesterases and A-esterases (paraoxonases, PON) are two enzymatic detoxification pathways that have been widely studied. We used an in vitro system to measure esterase-dependent detoxification of 15 AChE inhibitors. The target enzyme AChE served as a bioassay of inhibitor concentration following incubation with detoxifying tissue. Concentration-inhibition curves were determined for the inhibitor in the presence of buffer (no liver), rat liver plus calcium (to stimulate PONs and thereby measure both PON and carboxylesterase), and rat liver plus EGTA (to inhibit calcium-dependent PONs, measuring carboxylesterase activity). Point estimates (concentrations calculated to produce 20, 50, and 80% inhibition) were compared across conditions and served as a measure of esterase-mediated detoxification. Results with well-known inhibitors (chlorpyrifos oxon, paraoxon, methyl paraoxon, malaoxon) were in agreement with the literature, serving to support the use of this assay. Only a few other inhibitors showed slight or a trend towards detoxification via carboxylesterases or PONs (mevinphos, aldicarb, oxamyl). There was no apparent PON- or carboxylesterase-mediated detoxification of the remaining inhibitors (carbofuran, chlorfenvinphos, dicrotophos, fenamiphos, methamidophos, methomyl, monocrotophos, phosphamidon), suggesting that the influence of esterases on these chemicals is minimal. Thus, generalizations regarding these metabolic pathways may not be appropriate. As with other aspects of AChE inhibitors, their metabolic patterns appear to be chemical-specific.

The dynamics of successive induction in larval zebrafish

Charles Sherrington identified the properties of the synapse by purely behavioral means-the study of reflexes-more than 100 years ago. They were subsequently confirmed neurophysiologically. Studying reflex interaction, he also showed that activating one reflex often facilitates another, antagonistic one: successive induction, which has since been demonstrated in a wide range of species, from aphids to locusts to dogs and humans. We show a particularly orderly example in zebrafish (Danio rerio) larvae; the behavior (locomotion) of larvae is low in dark and intermediate in light, but low in light and substantially higher in dark when dark followed light. A quantitative model of a simple dynamic process is described that readily captures the behavior pattern and the effects of a number of manipulations of lighting conditions.

Acute neuroactive drug exposures alter locomotor activity in larval zebrafish

As part of the development of a rapid in vivo screen for prioritization of toxic chemicals, we have begun to characterize the locomotor activity of zebrafish (Danio rerio) larvae by assessing the acute effects of prototypic drugs that act on the central nervous system. Initially, we chose ethanol, d-amphetamine, and cocaine, which are known, in mammals, to increase locomotion at low doses and decrease locomotion at higher doses. Wild-type larvae were individually maintained in 96-well microtiter plates at 26 degrees C, under a 14:10 h light:dark cycle, with lights on at 0830 h. At 6 days post-fertilization, ethanol (1-4% v/v), d-amphetamine sulfate (0.1-20.0 microM) or cocaine hydrochloride (0.2-50.0 microM) were administered to the larvae by immersion. Beginning 20 min into the exposure, locomotion was assessed for each animal for 70 min using 10-minute, alternating light (visible light) and dark (infrared light) periods. Low concentrations of ethanol and d-amphetamine increased activity, while higher concentrations of all three drugs decreased activity. Because ethanol effects occurred predominately during the light periods, whereas the d-amphetamine and cocaine effects occurred during the dark periods, alternating lighting conditions proved to be advantageous. These results indicate that zebrafish larvae are sensitive to neuroactive drugs, and their locomotor response is similar to that of mammals.

A bibliometric overview of infectious diseases research in European countries (2002-2007)

This study analyses the distribution of papers published by authors from the European Union (EU) in 47 international infectious diseases journals from 2002 to 2007. The Web of Science of the Institute for Scientific Information was used to collect medical articles. From 46,149 papers recovered, 24,064 (52.1%) were from the EU. The EU15 countries published 23,239 papers (96.7%). The ten countries that joined the EU in 2004 published only 767 (3.2%) and the two countries that last joined the EU in 2007 contributed only 0.1% of the papers. The United States contributed 41.2% of the documents. The leading EU27 countries in number of publications were the United Kingdom, France, and Germany. After taking the population into account, Denmark, Sweden, and The Netherlands headed the list, and after correcting for gross domestic product the greatest producers were Malta, Estonia, and Sweden. In conclusion, the production of scientific papers on infectious diseases during the last six years was greater in the EU than in the United States. The contribution to the infectious diseases research of the 12 countries that joined the EU in the last few years has yet been limited.

Hydroxylation of demethoxy-Q6 constitutes a control point in yeast coenzyme Q6 biosynthesis

Coenzyme Q is a lipid molecule required for respiration and antioxidant protection. Q biosynthesis in Saccharomyces cerevisiae requires nine proteins (Coq1p-Coq9p). We demonstrate in this study that Q levels are modulated during growth by its conversion from demethoxy-Q (DMQ), a late intermediate. Similar conversion was produced when cells were subjected to oxidative stress conditions. Changes in Q(6)/DMQ(6) ratio were accompanied by changes in COQ7 gene mRNA levels encoding the protein responsible for the DMQ hydroxylation, the penultimate step in Q biosynthesis pathway. Yeast coq null mutant failed to accumulate any Q late biosynthetic intermediate. However, in coq7 mutants the addition of exogenous Q produces the DMQ synthesis. Similar effect was produced by over-expressing ABC1/COQ8. These results support the existence of a biosynthetic complex that allows the DMQ(6) accumulation and suggest that Coq7p is a control point for the Q biosynthesis regulation in yeast.