Evaluating smartphone-based optical readouts for immunoassays in human and veterinary healthcare: A comparative study

Recent advances have significantly enhanced the use of smartphone devices for medical diagnostics. This study uses high-resolution cameras in mobile devices to capture and process bioassay images, enabling the quantification of diverse biomarkers across a range of diagnostic tests conducted on 96-well microplates. The study evaluates the effectiveness of this technology through protein quantification techniques and immunoassays that generate colorimetric responses at specific wavelengths. It includes the assessment of bicinchoninic acid and Bradford protein quantification methods, alongside a conventional immunoassay for detecting mare antibodies in colostrum to monitor foal immunodeficiencies. Further application involves the readout of magneto-actuated immunoassays aimed at quantifying bacteria. The results obtained from benchtop spectrophotometry at 595, 562, and 450 nm are compared with those acquired using a smartphone, which identified color intensities in shades of blue, purple, and yellow. This comparison yields promising correlations for the samples tested, suggesting a high degree of accuracy in the smartphone capability to analyze bioassay outcomes. The analysis via smartphone is facilitated by a specific app, which processes the images captured by the phone camera to quantify color intensities corresponding to different biomarker concentrations. Detection limits of 12.3 and 22.8 μg mL-1 for the bicinchoninic acid assay and 36.7 and 45.4 μg mL-1 for the Bradford are obtained for protein quantification using the spectrophotometer and the smartphone app, respectively. For mare's antibodies in colostrum, the values are 1.14 and 1.72 ng mL-1, while the detection of E. coli is performed at 2.0 x 104 and 2.9 × 104 CFU mL-1, respectively. This approach offers further advantages, including wide availability, cost-effectiveness, portability, compared to traditional and expensive benchtop instruments.

Improved biosensing of Legionella by integrating filtration and immunomagnetic separation of the bacteria retained in filters

A novel approach is presented that combines filtration and the direct immunomagnetic separation of the retained bacteria Legionella in filters, for further electrochemical immunosensing. This strategy allows for the separation and preconcentration of the water-borne pathogen from high-volume samples, up to 1000 mL. The limit of detection of the electrochemical immunosensor resulted in 100 CFU mL-1 and improved up to 0.1 CFU mL-1 when the preconcentration strategy was applied in 1 L of sample (103-fold improvement). Remarkably, the immunosensor achieves the limit of detection in less than 2.5 h and simplified the analytical procedure. This represents the lowest concentration reported to date for electrochemical immunosensing of Legionella cells without the need for pre-enrichment or DNA amplification. Furthermore, the study successfully demonstrates the extraction of bacteria retained on different filtering materials using immunomagnetic separation, highlighting the high efficiency of the magnetic particles to pull out the bacteria directly from solid materials. This promising feature expands the applicability of the method beyond water systems for detecting bacteria retained in air filters of air conditioning units by directly performing the immunomagnetic separation in the filters.

Composites of ZnO nanoparticles and biomass based activated carbon: adsorption, photocatalytic and antibacterial capacities

Composite material (AC-ZnO) was prepared by growing ZnO nanoparticles during the production of biomass based-activated carbon (AC) via the incorporation of zinc acetate in the process. Comprehensive analyses confirmed the presence of ZnO nanoparticles over the AC surface and described the particular nature of the composite adsorbent. Methylene blue (MB) equilibrium data fitted the Dubinin-Radushkevich model. The MB adsorption capacity was higher for the bare activated carbons (197.9-188.7 mg/g) than the activated carbons with ZnO nanoparticles (137.6-149.7 mg/g). The adsorption of the MB on the adsorbents is physical because the mean adsorption energy (E) is between 1.76 and 2.00 kJ/mol. Experiments that combine adsorption and photocatalysis were carried out with different loads of adsorbents and with and without UV-light exposure. Photocatalytic activity was identified mostly at the first stage of the adsorption process and, in the case of experiments with less load of the composite AC-ZnO, because the light obstruction effect of the activated carbon is more for higher loads. The ZnO grown over AC improves the adsorption of cations such as Pb, Al and Fe in aqueous phase (polluted river water) and provides antibacterial capacity against Escherichia coli and Salmonella typhimurium.

Diagnostic concordance of DSM-IV and DSM-5 Posttraumatic Stress Disorder (PTSD) in a clinical sample

BACKGROUND

The present study aims to analyze diagnostic concordance between the DSM-IV and the DSM-5 for posttraumatic stress disorder (PTSD) diagnostic criteria and their different groups of symptoms. Furthermore, analyses are conducted to establish the features of participants with no concordant diagnoses.

METHOD

The study assessed 166 people over 18 who had experienced at least one traumatic event. PTSD diagnosis was established using the Global Scale for Posttraumatic Stress (EGEP), a self-report measure to assess PTSD.

RESULTS

The presence of cognitive avoidance was a determinant in the PTSD DSM-5 diagnosis (86% positive predictive value). The analysis of the non-concordant individuals revealed that individuals who were diagnosed according to the DSM-IV criteria but not the DSM-5 criteria were primarily indirect victims. Conversely, individuals who were diagnosed with the DSM-5 criteria and not with the DSM-IV criteria presented cognitive avoidance and alterations in cognition not included in the DSM-IV criteria.

CONCLUSIONS

A within-subjects concordance analysis showed high agreement for PTSD diagnosis between the two classifications. Differences between the diagnoses are due to the new definition of C (avoidance) and D (negative alterations in cognitions and mood) in the DSM-5.

Environmental Assessment of Classical Human Astrovirus in Uruguay

The aim of this study was to determine the molecular epidemiology of classical human astrovirus (HAstV) strains in sewage samples from four Uruguayan cities: Bella Unión, Salto, Paysandú, and Fray Bentos, located in the Northwestern region of the country. Overall, 96 sewage samples were collected biweekly between March 2011 and February 2012 and were subject to ultracentrifugation methodology in order to concentrate the viruses. RT-PCR directed to the ORF2 genome region was performed followed by sequencing and phylogenetic analysis. Forty-three (45 %) out of 96 analyzed samples were positive for HAstV (Mamastrovirus 1) and 31 of them were successfully sequenced being 21 (49 %) of them classified as HAstV-1 genotype (1a lineage) and 10 (23 %) as HAstV-2 genotype (eight strains belonging to the 2d lineage and two strains to the 2c lineage). The 1a lineage circulated throughout the year, while the 2d lineage only in the coldest months (June to October). Strikingly, the 2c lineage was detected only in Salto city during March 2011. In this city it was observed the highest frequency of HAstV and the greatest genetic diversity, probably due to its role as high touristic spot with an important influx of visitants from others regions of Uruguay and also from other countries. This study constitutes the first report in Uruguay that describes the phylogenetic diversity and genotype distribution of HAstV strains circulating in the Northwestern region evidencing a high frequency and also the presence of several different lineages.

An approach to the arsenic status in cardiovascular tissues of patients with coronary heart disease

Among non-cancer effects of arsenic, cardiovascular diseases have been well documented; however, few are known about the arsenic fate in cardiovascular tissues. We studied the analytic bioinorganic arsenic behaviour in cardiovascular tissues from an arsenic exposure coronary heart disease patient group from Antofagasta-Chile against a small unexposed arsenic coronary heart patient group. Total arsenic concentrations were measured in pieces of cardiovascular tissues of the arsenic-exposed and unexposed coronary heart patient groups by hydride generation atomic absorption spectrometry (HG-AAS); speciation analysis was made by high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). Pieces of auricle (AU), mammary artery (MAM), saphenous vein (SAP) and fat residuals (FAT) were considered in this study. The arsenic concentrations in AU and MAM tissues were significantly different between both groups of patients. Also, it was demonstrated that the AU is an 'As(3+) target tissue.' Otherwise, linking of the total concentrations of arsenic with conditional variables and variables related to medical geology factors allowed us to infer that the latter are more important for the cardiovascular risk of arsenic exposure in the Antofagasta region. Knowledge of total arsenic and the prevalence of the trivalent ion (As(3+)) in the AU of patients could contribute to understanding the effect of arsenic on cardiovascular diseases.

Distribution and biotransformation of arsenic species in chicken cardiac and muscle tissues

This study evaluated the bioaccumulation and biotransformation of arsenic species in chicken heart and meat tissues. The experimental study was carried out using two sets of samples. In the first one, 10-d-old chickens were exposed to sodium arsenate, using spiked drinking water. These chickens grew normally and were killed after 50 d of arsenic exposure. The second set were edible chickens used as blanks for a parallel study. The total arsenic and arsenic species content in the exposed samples were at least twice those in the normal edible chicken. It has been demonstrated that sodium arsenate is biotransformed to arsenite and an unknown species and its distribution varies among the different cardiac and meat tissues. One important aspect is the capability of the auricle to preconcentrate the most toxic species, arsenite, in the exposed chicken. A nonidentified arsenic species from the edible chicken was detected. Arsenobetaine was also detected in several tissues. This article shows that chicken can be used as a representative animal when considering inorganic arsenic exposure in humans.

Environmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine catalytic converters

A comparison of platinum-group element (PGE) emission between gasoline and diesel engine catalytic converters is reported within this work. Whole raw exhaust fumes from four catalysts of three different types were examined during their useful lifetime, from fresh to 80,000 km. Two were gasoline engine catalysts (Pt-Pd-Rh and Pd-Rh), while the other two were diesel engine catalysts (Pt). Samples were collected following the 91441 EUDC driving cycle for light-duty vehicle testing, and the sample collection device used allowed differentiation between the particulate and soluble fractions, the latter being the most relevant from an environmental point of view. Analyses were performed by inductively coupled plasma-mass spectrometry (ICP-MS) (quadrupole and high resolution), and special attention was paid to the control of spectral interference, especially in the case of Pd and Rh. The results obtained show that, for fresh catalysts, the release of particulate PGE through car exhaust fumes does not follow any particular trend, with a wide range (one-two orders of magnitude) for the content of noble metals emitted. The samples collected from 30,000-80,000 km present a more homogeneous PGE release for all catalysts studied. A decrease of approximately one order of magnitude is observed with respect to the release from fresh catalysts, except in the case of the diesel engine catalyst, for which PGE emission continued to be higher than in the case of gasoline engines. The fraction of soluble PGE was found to represent less than 10% of the total amount released from fresh catalysts. For aged catalysts, the figures are significantly higher, especially for Pd and Rh. Particulate PGE can be considered as virtually biologically inert, while soluble PGE forms can represent an environmental risk due to their bioavailability, which leads them to accumulate in the environment.

Platinum-group elements: quantification in collected exhaust fumes and studies of catalyst surfaces

Automotive catalytic converters, in which Pt, Pd and Rh (platinum-group elements; PGEs) are the active components for eliminating several noxious components from exhaust fumes, have become the main source of environmental urban pollution by PGEs. This work reports on the catalyst morphology through changes in catalyst surface by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and laser-induced breakdown spectrometry (LIBS) from fresh to aged catalytic converters. The distribution of these elements in the fresh catalysts analysed (Pt-Pd-Rh gasoline catalyst) is not uniform and occurs mainly in a longitudinal direction. This heterogeneity seems to be greater for Pt and Pd. PGEs released by the catalysts, fresh and aged 30,000 km, were studied in parallel. Whole raw exhaust fumes from four catalysts of three different types were also examined. Two of these were gasoline catalysts (Pt-Pd Rh and Pd-Rh) and the other two were diesel catalysts (Pt). Samples were collected following the 91,441 EUDC driving cycle for light-duty vehicle testing. The results show that at 0 km the samples collected first have the highest content of particulate PGEs and although the general tendency is for the release to decrease with increasing number of samples taken, exceptions are frequent. At 30,000 km the released PGEs in gasoline and diesel catalysts decreased significantly. For fresh gasoline catalysts the mean of the total amount released was approximately 100, 250 and 50 ng km(-1) for Pt, Pd and Rh, respectively. In diesel catalysts the Pt release varied in the range 400-800 ng km-1. After ageing the catalysts up to 30,000 km, the gasoline catalysts released amounts of Pt between 6 and 8 ng km(-1), Pd between 12 and 16 ng km(-1) and Rh between 3 and 12 ng km(-1). In diesel catalysts the Pt release varied in the range 108-150 ng km(-1). The soluble portion of PGEs in the HNO3 collector solution represented less than 5% of the total amount for fresh catalysts. For 30,000 km the total amount of soluble PGEs released was similar or slightly higher than for 0 km.

Hepatic and erythrocytic glutathione peroxidase activity in liver diseases

Hepatic and erythrocytic glutathione peroxidase activity, together with malondialdehyde levels, were determined as indicators of peroxidation in 83 patients from whom liver biopsies had been taken for diagnostic purposes. On histological study, the patients were classified into groups as minimal changes (including normal liver), steatosis, alcoholic hepatitis, hepatic cirrhosis, light to moderately active chronic hepatitis, and severe chronic active hepatitis. The glutathione peroxidase activity in erythrocytes showed no significant changes in any liver disease group. In the hepatic study, an increased activity was observed in steatosis with respect to the minimal changes group, this increased activity induced by the toxic agent in the initial stages of the alcoholic hepatic disease declining as the hepatic damage progressed. There was a negative correlation between the levels of hepatic malondialdehyde and hepatic glutathione peroxidase in subjects with minimal changes. This suggested the existence of an oxidative equilibrium in this group. This equilibrium is broken in the liver disease groups as was manifest in a positive correlation between malondialdehyde and glutathione peroxidase activity.

Trace enrichment and measurement of platinum by flow injection inductively coupled plasma mass spectrometry

A flow injection system incorporating an alumina microcolumn has been coupled to inductively coupled plasma mass spectrometry (ICP-MS) for on-line preconcentration and determination of platinum (IV) in natural waters. Depending on the nature of the sample, a nominal preconcentration factor of up to 600 can be achieved by eluting with 50microl of 2 mol/l NH(4)OH. The limit of detection after a 5 min preconcentration time was 4 ngl(-1), with a relative standard deviation of 4% (100 ngl(-1) working solution). The proposed method was assessed for the determination of platinum (IV) in natural waters, motor car exhaust and some common analytical reagents.

Resistance of Neosartorya fischeri to wet and dry heat

Dry heat resistance parameters for Neosartorya fischeri ascospores were obtained at 90 degrees C and 95 degrees C under 30%, 40%, 50%, 60%, and 75% relative humidity (RH) conditions. The dry heat treated spores were exposed to saturated water vapor (for 20-24 h at 4 degrees C) prior to recovery in buffer held at two temperatures (0 degrees C and 80 degrees C). Approximately the same level of recovery was obtained at the two buffer temperatures except at the shortest heating times for the heat treatment carried at 30% and 40% RH, where the number of survivors was significantly higher for spores placed in the buffer held at 80 degrees C. The effect of this high temperature was attributed to heat activation of the ascospores that remained dormant during the dry heat treatment conditions mentioned above. The wet heat resistance of N. fischeri ascospores was also determined at temperatures ranging from 82.5 degrees C to 95 degrees C. The results indicate that as the RH decreased, the heat resistance of the ascospores increased. There were about four orders of magnitude difference in the heat resistance between wet heat (100% RH) and the lowest dry heat treatment condition (30% RH).

Factors affecting recovery of Neosartorya fischeri ascospores after exposure to dry heat

Recovery of Neosartorya fischeri ascospores subjected to a dry heat treatment (DHT) at 95 degrees C, 50% relative humidity (RH) for 60 minutes increased exponentially as the initial temperature of the recovery buffer increased. Different diluents were evaluated and the same recovery pattern was obtained when water or dilute buffers were used to recover the DHT spores. However, when glycerol was added to the buffer, the number of spores recovered in solutions held in ice water increased with increasing glycerol concentration. When the DHT spores were exposed to an atmosphere saturated with water vapor (100% RH) before being placed in the buffer, the recovery was independent of the initial temperature of the buffer. This occurred even if the spores were subsequently dried before being introduced into the buffer. It is hypothesized that the temperature-dependent recovery was due to injury of the DHT spores during the sudden rehydration in dilute solutions at low temperatures.

4-Alkyl-1,4-dihydropyridines derivatives as specific PAF-acether antagonists

A new series of 4-alkyl-1,4-dihydropyridines (1,4-DHP) were synthesized and evaluated for their ability to inhibit washed rabbit platelet aggregation induced by PAF-acether (1-O-hexadecyl/octadecyl-2-O-acetyl-sn-glycero-3-phosphorylcholine) and to reverse PAF-induced hypotension in anesthetized rats. Additionally, compounds were evaluated for their ability to inhibit the binding of radiolabeled PAF to its receptor on rabbit platelets. Among these compounds, 6I and 6L were the most potent and specific antagonists. At concentrations up to 100 microM, neither compound 6I nor compound 6L caused platelet aggregation nor did they inhibit platelet aggregation induced by collagen or adenosine diphosphate. Compound 6L did not show in vitro calcium channel blocker activity measured on vascular smooth muscle preparations of rabbit aorta and on [3H]nitrendipine binding assays. The compound did not show any cardiovascular effects in anesthetized rat at iv doses up to 1000 micrograms/kg, and the Ki value was 568.62 nmol. These results indicate that compound 6L is a potent and specific PAF antagonist with 1,4-dihydropyridine structure but devoid of a significant cardiovascular activity related to calcium-antagonist properties.

Infection of pregnant guinea pigs with attenuated Junin virus strains

The effect of the attenuated XJC13 and XJ0 strains of Junin virus (JV) was studied in guinea pigs infected before and during pregnancy. The 58% mortality rate in animals infected during gestation and the 16.7% mortality rate in chronically infected animals were attributed to a viral effect. An abortion rate of 33% occurred in animals infected before the 7th week of gestation. Regardless of the time of infection, JV was isolated from central nervous system tissue, placentas, and fetuses of animals killed just before parturition, even when circulating neutralizing antibodies were present. Results confirmed that transplacental infection is a regular event and showed that guinea pigs are more susceptible to attenuated JV strains during pregnancy, most probably due to immunosuppression, hormonal changes, or both.

Congenital guinea pig infection with attenuated Junin virus strains

Guinea pigs born from mothers infected before or during pregnancy with 10(3) PFU of the attenuated XJC13 or XJ0 strains of Junin virus (JV) by the intramuscular route showed 31.5% mortality that was not attributable to the mothers' clinical condition or to lack of care. There was a slight drop in mortality rate when the mothers were infected at the beginning or end of their gestation period. JV isolation from the 9 offspring killed from 1 to 125 days of age proved that virus transmitted transplacentally or soon after birth was able to persist, although titers were not higher than 10(2.7) PFU/g of tissue in various organs, including brain. Cell-associated viremia could thus account for viral spread after birth. Since an active humoral response was detected in the same animals, although Nt antibody titers were below 1:16, a state of tolerance did not exist in these congenitally infected animals. The carrier state appeared to modify guinea pig susceptibility to JV; after challenge with the pathogenic XJ strain of JV, 2 animals survived and developed normal humoral responses, while half of the remaining animals did not show typical signs of Argentine hemorrhagic fever. Although JV persistence appeared to cause no deleterious effects in surviving guinea pigs, its long-term risk remains to be determined.

Transplacental infection in guinea pigs inoculated with an attenuated strain of Junin virus

Transplacental infection by the attenuated XJC13 strain of Junin virus (JV) in the guinea pig model was evaluated. 5 pregnant guinea pigs were infected intramuscularly at 45 +/- 3 days of pregnancy. 4 animals were killed at 14 days postinfection (p.i.), and 1 was sacrificed at 137 days p.i. at the end of its second pregnancy. Evidence of JV was obtained by Vero cell cocultivation in all 14 fetuses harvested (brain and/or spleen) and in 10 of 11 placentas. The results strongly suggest that the attenuated JV strain infected the fetus by the transplacental route, as previously demonstrated for the pathogenic XJ strain. Despite limited sampling, the acute as well as the chronic stage proved viable.