Remediation of Thirdhand Tobacco Smoke with Ozone: Probing Deep Reservoirs in Carpets

We assessed the efficacy of ozonation as an indoor remediation strategy by evaluating how a carpet serves as a sink and long-term source of thirdhand tobacco smoke (THS) while protecting contaminants absorbed in deep reservoirs by scavenging ozone. Specimens from unused carpet that was exposed to smoke in the lab ("fresh THS") and contaminated carpets retrieved from smokers' homes ("aged THS") were treated with 1000 ppb ozone in bench-scale tests. Nicotine was partially removed from fresh THS specimens by volatilization and oxidation, but it was not significantly eliminated from aged THS samples. By contrast, most of the 24 polycyclic aromatic hydrocarbons detected in both samples were partially removed by ozone. One of the home-aged carpets was installed in an 18 m³ room-sized chamber, where its nicotine emission rate was 950 ng day^-1 m^-2. In a typical home, such daily emissions could amount to a non-negligible fraction of the nicotine released by smoking one cigarette. The operation of a commercial ozone generator for a total duration of 156 min, reaching concentrations up to 10,000 ppb, did not significantly reduce the carpet nicotine loading (26-122 mg m^-2). Ozone reacted primarily with carpet fibers, rather than with THS, leading to short-term emissions of aldehydes and aerosol particles. Hence, by being absorbed deeply into carpet fibers, THS constituents can be partially shielded from ozonation.

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.

Altered microbiomes in thirdhand smoke-exposed children and their home environments

INTRODUCTION

Tobacco smoke contains numerous toxic chemicals that accumulate in indoor environments creating thirdhand smoke (THS). We investigated if THS-polluted homes differed in children's human and built-environment microbiomes as compared to THS-free homes.

METHODS

Participants were n = 19 THS-exposed children and n = 10 unexposed children (≤5 years) and their caregivers. Environmental and biological samples were analyzed for THS pollutants and exposure. Swab samples were collected from the built-environment (floor, table, armrest, bed frame) and child (finger, nose, mouth, and ear canal), and 16S ribosomal RNA genes were analyzed for bacterial taxa using high-throughput DNA sequencing.

RESULTS

Phylogenetic α-diversity was significantly higher for the built-environment microbiomes in THS-polluted homes compared to THS-free homes (p < 0.014). Log2-fold comparison found differences between THS-polluted and THS-free homes for specific genera in samples from the built-environment (e.g., Acinetobacter, Bradyrhizobium, Corynebacterium, Gemella, Neisseria, Staphylococcus, Streptococcus, and Veillonella) and in samples from children (esp. Corynebacterium, Gemella, Lautropia, Neisseria, Rothia, Staphylococcus, and Veillonella).

CONCLUSION

When exposed to THS, indoor and children microbiomes are altered in an environment-specific manner. Changes are similar to those reported in previous studies for smokers and secondhand smoke-exposed persons. THS-induced changes in child and built-environmental microbiomes may play a role in clinical outcomes in children.

IMPACT

Despite smoking bans, children can be exposed to tobacco smoke residue (i.e., thirdhand smoke) that lingers on surfaces and in settled house dust. Thirdhand smoke exposure is associated with changes in the microbiomes of the home environment and of the children living in these homes. Thirdhand smoke is associated with increased phylogenetic diversity of the home environment and changes in the abundances of several genera of the child microbiome known to be affected by active smoking and secondhand smoke (e.g., Corynebacterium, Staphylococcus, Streptococcus). Thirdhand smoke exposure by itself may induce alterations in the microbiome that play a role in childhood pathologies.

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.

Nicotine, Cotinine, and Tobacco-Specific Nitrosamines Measured in Children's Silicone Wristbands in Relation to Secondhand Smoke and E-cigarette Vapor Exposure

INTRODUCTION

Simple silicone wristbands (WB) hold promise for exposure assessment in children. We previously reported strong correlations between nicotine in WB worn by children and urinary cotinine (UC). Here, we investigated differences in WB chemical concentrations among children exposed to secondhand smoke from conventional cigarettes (CC) or secondhand vapor from electronic cigarettes (EC), and children living with nonusers of either product (NS).

METHODS

Children (n = 53) wore three WB and a passive nicotine air sampler for 7 days and one WB for 2 days, and gave a urine sample on day 7. Caregivers reported daily exposures during the 7-day period. We determined nicotine, cotinine, and tobacco-specific nitrosamines (TSNAs) concentrations in WB, nicotine in air samplers, and UC through isotope-dilution liquid chromatography with triple-quadrupole mass spectrometry.

RESULTS

Nicotine and cotinine levels in WB in children differentiated between groups of children recruited into NS, EC exposed, and CC exposed groups in a similar manner to UC. WB levels were significantly higher in the CC group (WB nicotine median 233.8 ng/g silicone, UC median 3.6 ng/mL, n = 15) than the EC group (WB nicotine median: 28.9 ng/g, UC 0.5 ng/mL, n = 19), and both CC and EC group levels were higher than the NS group (WB nicotine median: 3.7 ng/g, UC 0.1 ng/mL, n = 19). TSNAs, including the known carcinogen NNK, were detected in 39% of WB.

CONCLUSIONS

Silicone WB show promise for sensitive detection of exposure to tobacco-related contaminants from traditional and electronic cigarettes and have potential for tobacco control efforts.

IMPLICATIONS

Silicone WB worn by children can absorb nicotine, cotinine, and tobacco-specific nitrosamines, and amounts of these compounds are closely related to the child's urinary cotinine. Levels of tobacco-specific compounds in the silicone WB can distinguish patterns of children's exposure to secondhand smoke and e-cigarette vapor. Silicone WB are simple to use and acceptable to children and, therefore, may be useful for tobacco control activities such as parental awareness and behavior change, and effects of smoke-free policy implementation.

Remediating Thirdhand Smoke Pollution in Multiunit Housing: Temporary Reductions and the Challenges of Persistent Reservoirs

INTRODUCTION

Toxic tobacco smoke residue, also known as thirdhand smoke (THS), can persist in indoor environments long after tobacco has been smoked. This study examined the effects of different cleaning methods on nicotine in dust and on surfaces.

AIMS AND METHODS

Participants had strict indoor home smoking bans and were randomly assigned to: dry/damp cleaning followed by wet cleaning 1 month later (N = 10), wet cleaning followed by dry/damp cleaning (N = 10) 1 month later, and dry/damp and wet cleaning applied the same day (N = 28). Nicotine on surfaces and in dust served as markers of THS and were measured before, immediately after, and 3 months after the cleaning, using liquid chromatography with triple quadrupole mass spectrometry (LC-MS/MS).

RESULTS

Over a 4-month period prior to cleaning, surface nicotine levels remained unchanged (GeoMean change: -11% to +8%; repeated measures r = .94; p < .001). Used separately, dry/damp and wet cleaning methods showed limited benefits. When applied in combination, however, we observed significantly reduced nicotine on surfaces and in dust. Compared with baseline, GeoMean surface nicotine was 43% lower immediately after (z = -3.73, p < .001) and 53% lower 3 months later (z = -3.96, p < .001). GeoMean dust nicotine loading declined by 60% immediately after (z = -3.55, p < .001) and then increased 3 months later to precleaning levels (z = -1.18, p = .237).

CONCLUSIONS

Cleaning interventions reduced but did not permanently remove nicotine in dust and on surfaces. Cleaning efforts for THS need to address persistent pollutant reservoirs and replenishment of reservoirs from new tobacco smoke intrusion. THS contamination in low-income homes may contribute to health disparities, particularly in children.

IMPLICATIONS

Administered sequentially or simultaneously, the tested cleaning protocols reduced nicotine on surfaces by ~50% immediately after and 3 months after the cleaning. Nicotine dust loading was reduced by ~60% immediately after cleaning, but it then rebounded to precleaning levels 3 months later. Cleaning protocols were unable to completely remove THS, and pollutants in dust were replenished from remaining pollutant reservoirs or new secondhand smoke intrusion. To achieve better outcomes, cleaning protocols should be systematically repeated to remove newly accumulated pollutants. New secondhand smoke intrusions need to be prevented, and remaining THS reservoirs should be identified, cleaned, or removed to prevent pollutants from these reservoirs to accumulate in dust and on surfaces.

Tobacco smoke is a likely source of lead and cadmium in settled house dust

INTRODUCTION

Environmental exposure to lead (Pb) and cadmium (Cd) are risk factors for adverse health outcomes in children and adults. This study examined whether thirdhand smoke residue contributes to Pb and Cd in settled house dust.

METHODS

Participants were 60 multiunit housing residents in San Diego, California. All had indoor smoking bans during the study period, and 55 were nonsmokers. Wipe samples from different surfaces and vacuum floor dust samples were analyzed for nicotine, a marker of thirdhand smoke, and for Pb and Cd using liquid chromatography-triple quadrupole mass spectrometry and inductively coupled plasma-mass spectrometry, respectively.

RESULTS

Examined in each sample type separately, Pb and Cd loadings were significantly correlated (r = 0.73, vacuum floor dust; 0.52, floor wipes; 0.72, window sill/trough wipes; all p < 0.0025). Pb and Cd loadings from different sample types were not correlated (all p > 0.30). Nicotine loading in dust was significantly correlated with Pb and Cd loading in dust (r = 0.49 for Pb; r = 0.39 for Cd, all p < 0.0025). Pb and Cd loadings on floor or window surfaces, showed no association with nicotine loading in dust, on floors, or on furniture (all p < 0.30).

CONCLUSIONS

Tobacco smoke is a likely source of Pb and Cd that accumulates in settled house dust in multiunit housing, suggesting that Pb and Cd are constituents of thirdhand smoke that lingers long after smoking has ended.

Persistent tobacco smoke residue in multiunit housing: Legacy of permissive indoor smoking policies and challenges in the implementation of smoking bans

Secondhand smoke (SHS) is a common indoor pollutant in multiunit housing (MUH). It is also the precursor of thirdhand smoke (THS), the toxic mixture of tobacco smoke residue that accumulates in indoor environments where tobacco has been used. This study examined the levels, distribution, and factors associated with THS pollution in low-income MUH. Interviews were conducted 2016-2018 in a cross-sectional study of N = 220 MUH homes in San Diego, California. Two surface wipe samples were collected per home and analyzed for nicotine, a THS marker, using liquid chromatography-triple quadrupole mass spectrometry. Nicotine was detected in all homes of nonsmokers with indoor smoking bans (Geo Mean = 1.67 µg/m²; 95% CI = [1.23;2.30]) and smokers regardless of an indoor ban (Geo Mean = 4.80 µg/m²; 95% CI = [1.89;12.19]). Approximately 10% of nonsmokers' homes with smoking bans showed nicotine levels higher than the average level in homes of smokers without smoking bans from previous studies (≥30 µg/m²). Housing for seniors, smoking bans on balconies, indoor tobacco use, difficult to reach surfaces, and self-reported African-American race/ethnicity were independently associated with higher THS levels. Individual cases demonstrated that high levels of surface nicotine may persist in nonsmoker homes for years after tobacco use even in the presence of indoor smoking bans. To achieve MUH free of tobacco smoke pollutants, attention must be given to identifying and remediating highly polluted units and to implementing smoking policies that prevent new accumulation of THS. As THS is a form of toxic tobacco product waste, responsibility for preventing and mitigating harmful impacts should include manufacturers, suppliers, and retailers.

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.

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.

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.

A bibliometric analysis of tuberculosis research indexed in PubMed, 1997-2006

OBJECTIVE

To describe a bibliometric review of the literature on tuberculosis (TB) research indexed in PubMed over a 10-year period.

METHODS

Medline was used via the PubMed online service of the US National Library of Medicine from 1997 to 2006. The search strategy was: [(tuberculosis) OR (tuberculous) in all fields].

RESULTS

A total of 35 735 references were located. The average annual growth rate was +4.7%. The articles were published in 2874 scientific journals. Sixteen journals contained 25% of the TB journal literature. The main journal was the International Journal of Tuberculosis and Lung Disease. Western Europe was the most productive region, with 31.1% of the articles. The USA ranked second (21%) and Asia third (19.9%). The USA is the predominant country, followed by India, Japan and the United Kingdom. When normalised by population, the order of prominence is Switzerland, New Zealand and Denmark. Normalised by GDP, Gambia, Malawi and Guinea-Bissau were the most productive countries. Normalised by estimated number of TB cases, Iceland, Switzerland and Norway were in leading positions.

CONCLUSIONS

There was increasing research activity in the field of TB during the period 1997-2006. The countries with more estimated cases of TB produced less research in TB than industrialised countries.

Bioactive glass as precursor of designed-architecture scaffolds for tissue engineering

In this work, the conditions to obtain concentrated and fluid suspensions from a bioactive glass (55-SiO(2); 41-CaO; 4-P(2)O(5); mol %) were investigated. The influence of the heat treatment of the glass on the specific surface area, solubility, bioactivity, and finally on their dispersion characteristics was studied. Zeta potential and viscosity measurements were carried out, and based on the obtained results, the best dispersant was selected. The optimum concentration of dispersant, maximum content of solid and time of mixing were also investigated. Slurries containing 50 vol % could be obtained calcining the glass at 1100 degrees C and using Darvan 811 (sodium polyacrylate) as dispersant. Scaffolds with designed architecture were prepared from these suspensions combining the gelcasting method and the stereolithography technique. A polymeric negative (replica of the desired structure) was previously obtained by stereolithography. The slurry was cast into the molds and then polymerized (gelcasting method). The negative was eliminated by heat treatment. After sintering at 1300 degrees C, scaffolds with interconnected porosity and three-dimensional channels of 400-470 microm and macropores of 1.4 microm were obtained.

Clinical characterisation of pneumonia caused by atypical pathogens combining classic and novel predictors

The aim of this study was to characterise community-acquired pneumonia (CAP) caused by atypical pathogens by combining distinctive clinical and epidemiological features and novel biological markers. A population-based prospective study of consecutive patients with CAP included investigation of biomarkers of bacterial infection, e.g., procalcitonin, C-reactive protein and lipopolysaccharide-binding protein (LBP) levels. Clinical, radiological and laboratory data for patients with CAP caused by atypical pathogens were compared by univariate and multivariate analysis with data for patients with typical pathogens and patients from whom no organisms were identified. Two predictive scoring models were developed with the most discriminatory variables from multivariate analysis. Of 493 patients, 94 had CAP caused by atypical pathogens. According to multivariate analysis, patients with atypical pneumonia were more likely to have normal white blood cell counts, have repetitive air-conditioning exposure, be aged <65 years, have elevated aspartate aminotransferase levels, have been exposed to birds, and have lower serum levels of LBP. Two different scoring systems were developed that predicted atypical pathogens with sensitivities of 35.2% and 48.8%, and specificities of 93% and 91%, respectively. The combination of selected patient characteristics and laboratory data identified up to half of the cases of atypical pneumonia with high specificity, which should help clinicians to optimise initial empirical therapy for CAP.

Hydroxyapatite/SiO(2)-CaO-P(2)O(5) glass materials: in vitro bioactivity and biocompatibility

Materials obtained by the heat treatment of mixtures of hydroxyapatite (HA) and a silicate-based glass of the system SiO(2)-CaO-P(2)O(5) have been investigated. The influence of the glass content on the porosity, microstructure and on the constituent phases of the final materials was studied. The influence of these factors on the in vitro bioactive behaviour of the obtained materials was also investigated. In addition, an in vitro biocompatibility assay with osteoblastic-like cells was carried out. The addition of the glass to HA induced different solid-state reactions that yield the transformation of HA into alpha- and beta-tricalcium phosphate as well as the formation of silicon-containing phases (silicocarnotite or pseudowollastonite). In these mixtures an enhancement in the porosity, pore size and a heterogeneous microstructure was observed, compared with the precursors. As the sol gel glass content increased, the previous effects were higher. The materials showed the formation of an apatite-like layer on their surface when soaked in simulated body fluid, being faster in the sample with a higher content of glass. The formation of the new layer began in preferential zones in both samples, depending on the different reactivity of the crystalline phases formed. A synergistic effect between HA and glass was observed, showing in the mixtures a faster bioactive behaviour than in HA and glass themselves. The obtained materials allow a good attachment, spread and proliferation of the osteoblastic-like cells and no cytotoxic effect was observed.

Regression of papilloma high-grade lesions (CIN 2 and CIN 3) is stimulated by therapeutic vaccination with MVA E2 recombinant vaccine

Human papillomavirus (HPV) is the etiologic agent for cervical cancer. In Mexico, a women dies every 2 h, and since 1990 the statistics have shown that the numbers of deaths are increasing. We conducted a phase II clinical trial to evaluate the potential use of the MVA E2 recombinant vaccinia virus in treating high-grade lesions (CIN 2 and CIN 3) associated with oncogenic papillomavirus. Fifty-four female patients with high degree lesions were treated either with an MVA E2 therapeutic vaccine or with conization. Thirty-four women received the therapeutic vaccine, at a total of 10(7) virus particles per dose injected directly into the uterus once every week over a 6-week period. Twenty control patients were treated with conization. By colposcopy, 19 patients out of 34 showed no lesion, in three patients the lesions were reduced by 85-90%, in eight other lesions had reduced by 60%, and in four more patients, they were reduced by 25%. Histological analysis showed total elimination of high-grade lesions in 20 out of 34 patients after treatment with MVA E2. Eleven patients had a 50% reduction in lesion size. In two other patients, the lesion was reduced to CIN 2 and in one more patient the lesion was reduced to low grade (CIN 1). All patients developed antibodies against the MVA E2 vaccine, and generated a specific cytotoxic response against papilloma-transformed cells. DNA viral load was significantly reduced in MVA E2-treated patients. Conization eliminated the lesions in 80% of the patients, but patients did not develop cytotoxic activity specific against cancer cells and did not eliminate the papillomavirus. In addition, three patients treated with conization had recurrence of lesions 1 year later. These results show that therapeutic vaccination with MVA E2 proved to be very effective in stimulating the immune system against papillomavirus, and in generating regression of high-grade lesion.

Epidemiology of community-acquired pneumonia in adult patients at the dawn of the 21st century: a prospective study on the Mediterranean coast of Spain

This study presents data from a prospective study of adult patients with community‐acquired pneumonia (CAP). Of 493 patients included in the study, 223 (45.2%) were aged ≥ 65 years, and 265 (53.7%) had one or more underlying diseases, mostly chronic obstructive pulmonary disease, diabetes mellitus or dementia. In total, 281 microorganisms were identified in 250 (50.7%) patients, with two or more pathogens detected in 28 (5.7%) cases. Microbial diagnosis varied according to age, severity, co‐morbidity and site‐of‐care, but there was much overlap among groups. Streptococcus pneumoniae was the single most prevalent organism in outpatients, patients admitted to hospital, and patients who died, either as a single pathogen or combined with another organism. Infections caused by ‘atypical’ pathogens were seen across all groups, including the elderly and patients with co‐morbidities. Mortality varied according to the pneumonia severity index (PSI) of the pneumonia patient outcomes research team. Shock (OR 34.48), an age of > 65 years (OR 25) and altered mental status (OR 9.92) were factors associated independently with 30‐day mortality. Key findings from this study were the advanced age of the population with CAP, and the high prevalence of dementia as an underlying disease. The study also revealed that microbiological diagnosis of CAP remains problematic. Although certain epidemiological features may help to predict the microbial aetiology, the overlap among groups reduces the usefulness of this information in guiding therapeutic decisions. Greater effort should be made to improve identification methods for microbial pathogens causing CAP.

Severe toxicity associated with the combination of tenofovir and didanosine: case report and review

The combination of tenofovir and didanosine results in an increase in the didanosine plasma exposure and might augment the risk for didanosine toxicity. Although pharmacokinetic studies support a didanosine dose reduction to 250 mg when used concurrently with tenofovir in patients weighing at least 60 kg, no data are available in lower-weight patients. We describe a case of lactic acidosis and acute liver failure in a low-weight patient receiving tenofovir and a reduced dose of didanosine (200 mg/day). To our knowledge, this is the first case of severe toxicity associated with a reduced dose schedule of didanosine. Previous cases of severe toxicity associated with the combination of tenofovir and didanosine are reviewed.

Community-acquired pneumonia of mixed etiology: prevalence, clinical characteristics, and outcome

Community-acquired pneumonia (CAP) of mixed etiology has increasingly been appreciated in the literature, but its clinical significance remains unknown. The aim of this analysis was to describe the prevalence, clinical characteristics, and outcome of CAP of mixed etiology. Data were obtained from a 2-year prospective study of consecutive patients with CAP in whom an extensive microbiological workup was performed. Predefined strict criteria were used to establish the etiology. A total of 493 patients were included. A single pathogen was detected in 222 (45%) cases and two or more pathogens in 28 (5.7%) cases. Mixed infections were seen across all age groups and in patients treated both in hospital and as outpatients. The most frequent combinations of pathogens were those of a bacterium plus an "atypical" organism (28.6%) and of two bacterial organisms (28.6%). Compared with patients with monomicrobial pneumonia, patients with mixed pneumonia were more likely to have underlying conditions (64% vs. 45%, p=0.04) and dementia (25% vs. 10%, p=0.02). The incidence of a defined series of complications was higher in patients with mixed pneumonia (39.3% vs. 18.6%; OR=2.84; p=0.02). Community-acquired pneumonia of mixed etiology is uncommon. Patients with mixed pneumonia are more likely to have underlying medical conditions, and they may have a more severe course of disease.

The influence of the phosphorus content on the bioactivity of sol–gel glass ceramics

The aim of this work was to study the influence of the phosphorus on the crystallization and bioactivity of glass-ceramics obtained from sol-gel glasses. For this purpose two sol-gel glasses with a similar composition but one of them containing P2O5 (70% SiO2; 30% CaO and 70% SiO2; 26% CaO; 4% P2O5, mol%) were prepared. Pieces of these glasses were treated at temperatures ranging between 700 degrees C and 1400 degrees C for 3 h. The obtained materials were characterized by XRD, FTIR, SEM-EDS and the biaxial flexural strength was determined in samples heated at 1100 degrees C. In addition, an in vitro bioactivity study in simulated body fluid (SBF) was carried out. The results showed that phosphorus plays an important role in the crystallization of the glasses: it induced the crystallization of calcium phosphate phases, the stabilization of the wollastonite phase at high temperature as well as the crystallization of SiO2 phases at low temperatures. Moreover, the presence of phosphorus produced a heterogeneous distribution of defects in the pieces and, therefore, the flexural strength of samples containing this element decreased. Finally, glass-ceramics obtained from glasses containing phosphorus showed the fastest formation rate of the apatite layer when soaked in SBF.

Bioactive and biocompatible pieces of HA/sol-gel glass mixtures obtained by the gel-casting method

Hydroxyapatite (HA)/glass mixtures have shown a faster bioactive behaviour than HA itself. On the other hand, the gel-casting method is a simple and reproducible colloidal method to produce ceramic pieces with complex shapes. In this work, pieces of HA/glass mixtures were prepared by the gel-casting method. A study for obtaining concentrated slurries of these mixtures is reported; the bioactivity and biocompatibility of the obtained pieces have been studied also. The influence of pH, dispersant concentration, the content and milling of glass, and the way to prepare the suspensions were investigated. The lowest viscosity and better rheological properties were achieved with the lowest glass content, when the glass was added after the dispersion of the HA powder and when the glass was not milled after calcination. Fluid suspensions with a high solid content (50 vol.%) could be prepared and well-shaped pieces were obtained from these slurries. These pieces showed in vitro bioactive behavior in simulated body fluid; additionally, the proliferation and spreading assays with osteoblastic cells (HOS) showed that the pieces are biocompatible. The results obtained indicate that the gel-casting of HA/glass mixtures produces bioactive and biocompatible pieces with the required shapes. Therefore, these materials could be good candidates for clinical applications and scaffolds for tissue engineering.

Epidemiological and clinical characteristics of occult bacteremia in an adult emergency department in Spain: influence of blood culture results on changes in initial diagnosis and empiric antibiotic treatment

A prospective study was carried out to analyze the usefulness of blood culture results for adult patients who were discharged from the emergency department with bacteremia. Over a 29-month period, 110 patients with significant bacteremia who were seen in the emergency department and discharged home were studied. The mean age of the patients was 61.8 years. The most frequent initial major diagnosis was urinary tract infection (UTI) (n=63; 57.3%). Gram-negative organisms were isolated in 79 (71.8%) cases. A change in diagnosis (44.5% cases) was more common when the initial diagnosis was something other than UTI or when empiric antimicrobial therapy was ineffective or was not given (P<0.001). The significant predictors of modification of the initial empiric antibiotic therapy were ineffective empiric antimicrobial therapy and transfer of the patient from the emergency department to an infectious diseases outpatient clinic (P=0.01). Blood culture results may be useful for achieving the correct diagnosis in adult patients with bacteremia and for guiding treatment in the subsequent management of outpatients.

Altered neurometabolite development in HIV-infected children: correlation with neuropsychological tests

BACKGROUND

HIV-infected children have abnormal cerebral metabolites, measured by proton MR spectroscopy ((1)H-MRS), but how these abnormalities relate to brain function is unclear.

METHODS

Metabolite concentrations in five brain regions of 20 HIV-infected and 13 control children were measured, and these findings were correlated with age, log(10) plasma viral load, CD4 count, and neuropsychological scores.

RESULTS

Compared with control subjects, HIV patients had decreased choline concentration [Cho] in left frontal white matter (LFW) (-12%; p = 0.04); those with high viral load (>5,000 HIV RNA copies/mL) had decreased right basal ganglia (RBG) [Cho] (-15%; p = 0.005), and [Cr] (-13%; p = 0.02). Patients with high viral load also had higher [Cho] in the midfrontal gray matter (MFG) (+25%; p = 0.002) and lower myo-inositol [Ins] in the RBG (-18%; p = 0.04) than patients with low HIV viral load. N-Acetyl aspartate concentration ([NAA]) correlated with age in right frontal white matter (RFW) (r = 0.59, p = 0.04), LFW (r = 0.66, p = 0.02), and right hippocampus (RHIP) (r = 0.69, p = 0.02) only in control subjects. In contrast, [Ins] correlated with age in both RFW and LFW (r = 0.71, p = 0.0006; r = 0.65, p = 0.006) only in the HIV patients. Log(10) plasma viral load correlated positively with [Ins] in RFW (r = 0.54, p = 0.02) and [Cho] in MFG (r = 0.49, p = 0.04). Compared with control subjects, HIV patients had poorer spatial memory (p = 0.045) and delayed spatial memory correlated with [Cho] in RHIP (r = 0.68, p = 0.02).

CONCLUSIONS

These data suggest that normal brain development may be affected in children infected with HIV at birth, particularly evidenced by the lack of age-related increases in the neuronal marker [NAA]. Early, aggressive treatment of infants with HIV before development of encephalopathy is warranted.

Further assessment of an in vitro screen that may help identify organophosphorus pesticides that are more acutely toxic to the young

Some, but not all, organophosphorus pesticides are more acutely toxic to the young as compared to adults. We have developed an in vitro assay that measures the detoxification potential (via carboxylesterase and A-esterases) of tissues. Previous results using this in vitro screen correlated with the marked in vivo sensitivity of the young to chlorpyrifos and also correlated with the equal sensitivity of the young and adult to methamidophos (Padilla et al., 2000). We have now extended these observations to two other pesticides that have already been shown in the literature to be more toxic to the young: parathion (paraoxon) and malathion (malaoxon). In our in vitro assay, liver or plasma from 7-d-old rats were much less efficacious than adult tissues at detoxification of the active metabolites of these two pesticides. Using our in vitro assay we also tested the active metabolite of diazinon, diazoxon, and again found that young liver or plasma possessed much less detoxification capability than adult tissues. From these results, we predicted that young animals would be more sensitive to diazinon, which, in fact, was the case: When postnatal day (PND) 17 or adult rats were given a dosage of 75 mg/kg diazinon, adult brain cholinesterase (ChE) was only inhibited 38%, while the brain ChE in the PND 17 animals showed much more inhibition (75%). We conclude that our in vitro screen may prove to be a useful, quick, convenient test for identifying which organophosphorus pesticides may be more acutely toxic to the young as compared to adults.

Physiological variables to use in the gender comparison in highly trained runners

AIM

The aims of this investigation were to compare physiological characteristics between highly trained middle-distance and marathon male (n=17) and female (n=11) runners; to determine the most suitable variables to use in the gender comparison in these subjects, considering physical difference between genders; and to indicate some of the best predictors of performance in running events in which oxidative metabolism prevails.

METHODS

Subjects performed a progressive maximal exercise on the treadmill to determine maximal oxygen uptake (VO(2max)) and velocities corresponding to a blood lactate concentration of 4 mmol x L(-1) (upsilon(OBLA)) and to the lactate threshold (upsilon(LT)). Cost of running (Cr) and maximal aerobic velocity (upsilon(a max)) were calculated from VO(2) measurements.

RESULTS

Males presented higher VO(2max), upsilon(a max), upsilon(OBLA), upsilon(LT), and VO(2) @ upsilon(OBLA) and upsilon(LT) (p<0.001), but females had higher upsilon(OBLA) and upsilon(LT) (p<0.01) expressed as %VO(2max). upsilon(a max) correlated with performance time relative to the world record in both, females (r=-0.77, p<0.01) and males (r=-0.58, p<0.05); and upsilon(LT) with performance only in males (r=-0.59, p<0.05).

CONCLUSION

In conclusion, female athletes seemed to compensate partly their aerobic profile with higher %VO(2max) @ u(OBLA) and u(LT), suggesting that both maximal and submaximal physiological variables should be considered when evaluating and comparing highly trained athletes of both genders. upsilon(a max) is one of the best predictors of performance in running events in which oxidative metabolism prevails.